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G Wassmer

Publications and source records attributed to G Wassmer.

At least 19 recordsLinked to original sources
PubMed2006

What is the value of available risk-scores in predicting postoperative complications after aorto-iliac surgery? A prospective non randomized study.

AIM: With an aging population, atherosclerotic manifestations are steadily increasing. Beside the anatomical and pathophysiological preoperative risk-factors accompanying perioperative risk-factors like patient's age, length of operation, blood loss and skill of the surgeon, all need to be accounted for when assessing the risk of morbidity and mortality after vascular surgery. The demand for cost effectiveness may make a risk-score system useful. The aim of the present study was, therefore, to prospectively apply various scoring systems in order to estimate outcome in patients undergoing aortobifemoral surgery due to arterial occlusive disease at the aorto-iliac level. METHODS: A prospective non randomized study was carried out. The SPSS 9.0 statistical package for Windows and, for nominal data, chi-squared-tests were used to compare rates between groups. For continuous data analysis of variance (ANOVA) was performed. When appropriate, a multivariate analysis with binary-regression by Wald was used. Sensitivity and specificity was done using ROC-curves. P < 0.05 was considered significant. From May 1996 to June 2000, 107 patients were included in the study. Besides basic data, all postoperative complications were noted according to a specific definition. Four different risk-scoring systems were used: ASA-classification; the acute physiology and chronic health evaluation (APACHE-II) system; the physiological and operative severity score for enumeration of mortality and morbidity (POSSUM) classification and, finally, the simplified acute physiology score (SAPS) classification. RESULTS: We found no significant correlation between risk-scores and outcome. None of the scoring systems used was able to predict mortality. The independent factors that influenced the postoperative complication rate were operating time, blood loss, intraoperative assisted ventilation time and age. The endpoint using the relative operating characteristic (ROC) curves analysis was either mortality or morbidity. CONCLUSIONS: It can be concluded that none of the systems analyzed separately was useful for determining morbidity and mortality. We still lack a system, that can be used preoperatively in an individual case and the vascular surgeon still has to build up his own clinical judgement or to transfer a clinical judgement.

Adult↗
PubMed2004

Endotension is influenced by wall compliance in a latex aneurysm model.

OBJECTIVES: Even though endovascular aneurysm repair (EVAR) creates a closed chamber except for patent branches, the intra-sac pressure is never zero. This study was designed to investigate whether, and to what extent, aneurysm wall compliance influences intra-sac pressure. DESIGN: In vitro experimental study. METHODS: Aneurysm models with six and 12 latex layers were produced, resulting in elastic and stiff circumferential compliance (3.5 +/- 0.5 and 0.9 +/- 0.3%/100 mmHg, respectively). The models with an 18 mm internal neck and maximum aneurysm diameter of 60 mm were inserted into an in vitro circulation system. The systemic mean pressure (SPmean) was varied from 50 to 120 mmHg. After the aneurysm was excluded with a knitted polyethylene graft, aneurysm sac mean pressure (ASPmean) and aneurysm sac pulse pressure (ASPpulse) were measured. Data are presented as mean +/- SD. Statistics were performed using repeated measurements of variance; p<0.05 was considered significant. RESULTS: In the model EVAR created a closed chamber without endoleak, but with an aneurysm sac pressure related to wall compliance. In the elastic aneurysm model with six latex coats the aneurysm sac mean pressure (ASPmean) and the aneurysm sac pulse pressure (ASPpulse) at all systemic pressures were significantly lower than they were in the stiffer model with 12 latex coats (p<0.05). At a SPmean of 90 mmHg, the ASPmean was 21.0 +/- 0.9 mmHg (six latex coats) and 26.0 +/- 0.2 mmHg (12 latex coats) (p<0.05), the ASPpulse was 5.7 +/- 0.2 mmHg (six latex coats) and 8.8 +/- 0.3 mmHg (12 latex coats) (p<0.05). CONCLUSIONS: This in vitro model demonstrated that the aneurysm sac mean pressure (ASPmean) and the aneurysm sac pulse pressure (ASPpulse) were significantly influenced by the compliance of the aneurysm wall. These data highlight the need for further studies regarding endotension.

Aortic Aneurysm, Abdominal↗
PubMed2003

Recombinant human erythropoietin, epoetin beta, in patients with relapsed lymphoma treated with aggressive sequential salvage chemotherapy--results of a randomized trial.

The aim of the study was to investigate the effects of erythropoietin (epoetin beta) on red blood cell (RBC) transfusions, hemoglobin (Hb) levels, and quality of life (QOL) in patients with relapsed lymphoma treated with an aggressive sequential salvage chemotherapy (SSCT) regimen. Sixty patients with early or late relapsed Hodgkin's disease ( n=39) or first relapse of aggressive non-Hodgkin's lymphoma ( n=21) were randomized to receive epoetin beta 10,000 IE subcutaneously three times a week or no epoetin during salvage chemotherapy. Patients in both study arms received two cycles of DHAP (dexamethasone, high-dose cytarabine, cisplatin); patients in partial remission (PR) or complete remission (CR) then received cyclophosphamide, followed by peripheral blood stem cell (PBSC) harvest, methotrexate plus vincristine, and etoposide. The final myeloablative course was BEAM (carmustine, etoposide, cytarabine, and melphalan) followed by autologous stem cell support. The primary endpoint of the study was the number of RBC units needed during SSCT. In addition, Hb levels and QOL were measured. The mean number of RBC units given in the epoetin beta arm was 4.5 compared to 8.3 in the control arm ( P=0.0134). The mean Hb levels during therapy were 10.4 g/dl in the epoetin beta arm and 9.7 g/dl in the control ( P=0.018). From baseline until BEAM therapy QOL (EORTC QLQ C30) and fatigue (MFI) assessment showed little QOL worsening or stable levels in both arms with a steeper increase of fatigue levels in the control group. Patients with relapsed lymphoma undergoing aggressive chemotherapy and stem cell support benefited from epoetin beta therapy, with a decrease of RBC transfusion requirements and lower rise of fatigue levels.

Adult↗
PubMed2003

Endotension as a result of pressure transmission through the graft following endovascular aneurysm repair--an in vitro study.

BACKGROUND: endovascular aneurysm repair (EVAR) significantly reduces, but does not abolish aneurysm sac pressure, possibly because of trans-fabric transmission. OBJECTIVE: to investigate how blood pressure is transmitted through different types of grafts into the aneurysm sac. DESIGN: experimental study, in vitro. METHODS: a latex aneurysm was inserted into an in vitro circulation model. The systemic mean pressure (SPmean) was varied from 50 to 120 mmHg. The grafts used for aneurysm exclusion were: thin wall polyethylene (PE), thick wall polyethylene (PE) and thin wall ePTFE. Mean aneurysm sac pressure (ASPmean) was measured, as was pulse pressure (ASPpulse). RESULTS: at an SPmean of 70 mmHg, the ASPmean was 34 +/- 0.8 mmHg (polyethylene knitted, thick wall), 30 +/- 1.0 mmHg (polyethylene woven, thin wall), and 17 +/- 0.6 mmHg (thin wall ePTFE). The ASPmean increased with SPmean, the relationship depending on the graft material. Stiffer grafts were associated with lower ASPmean and ASPpulse (p<0.001). CONCLUSIONS: the relationship between aneurysm sac mean pressure and systemic pressure (SP) depends on the graft material. These data highlights the need for further studies regarding endotension.

Aortic Aneurysm, Abdominal↗
PubMed2002

Epidemiology of Peyronie's disease.

Francois Gigot de la Peyronie, surgeon to Louis XV of France, has become synonymous with the rather enigmatic though not uncommon condition of Peyronie's disease (PD), a localized connective tissue disorder of the penile tunica albuginea. The true prevalence of Peyronie's disease is unknown. Therefore, we decided to perform an evaluation of existing epidemiological data. A prevalence rate of 3.2% was determined in male inhabitants of the greater Cologne area. This is much higher than revealed by the data reported up to now, thus rendering the accepted prevalence rates of 0.3% to 1% untenable. The actual prevalence of Peyronie's disease may be even higher, considering many patients' reluctance to report this embarrassing condition to their physicians. Along these lines, most clinicians note that the number of Peyronie's patients has increased since the advent of oral sildenafil. Comparably high prevalences are known for diabetes and urolithiasis, suggesting a greater frequency of this rare disease than formerly believed.

Age Distribution↗
PubMed2001

Image quality of digital chest X-rays: wet versus dry laser printers.

The aim of this study was to compare the image quality of digital chest x-rays (Thoravision) obtained with 2 "wet" laser imagers of different matrix sizes and a "dry" system. Fifty chest x-rays in 2 planes were printed out in normal (100%) and reduced (61%) format using 3 different systems: 2 "wet" laser imagers (Agfa Matrix LR 3300, 4256 x 5174 pixels, 315 dpi; Agfa Scopix LR 5200, 8512 x 10348 pixels, 630 dpi), and one "dry" system (Agfa Drystar 3000,4352 x 5295 pixels, 330 dpi). All tests yielded normal findings. Anonymous images were evaluated by 4 independent reviewers on record forms rating the detectability of predefined anatomic structures. When the image quality of diagnosis-relevant, anatomic structures was evaluated on digital chest x-rays reproduced in normal and reduced format, the wet laser imagers did not show significant advantages over the dry system, Agfa Drystar 3000. The Agfa Drystar 3000 system is a feasible alternative for reproducing digital images, particularly for decentralized archives.

Adult↗
PubMed2001

ACE and angiotensinogen gene genotypes and left ventricular mass in athletes.

BACKGROUND: Genetic factors may be important in modifying heart size due to long-term athletic training. The significance of polymorphisms of genes of the renin-angiotensin system in myocardial mass in a population of athletes participating in different disciplines is not known. METHODS: The angiotensin I-converting enzyme gene insertion/deletion (I/D) polymorphism, angiotensinogen gene M235T polymorphism and angiotensin II type 1 receptor gene A1166C polymorphism were determined in 83 male Caucasian endurance athletes and associated with left ventricular mass. RESULTS: No association with left ventricular mass was found for the polymorphisms of angiotensin I-converting enzyme gene I/D, angiotensinogen gene M235T and angiotensin II type 1 gene A1166C when studied separately. However, combined analysis of the angiotensin I-converting enzyme gene I/D polymorphism and angiotensinogen gene M235T polymorphism genotypes suggested an association with left ventricular mass (g m(-2)) (P = 0.023). Athletes with the angiotensin I-converting enzyme gene DD/angiotensinogen gene TT genotype combination had greater left ventricular mass compared with all other genotype combinations (179.8 +/- 26.1 g m(-2) vs. 145.2 +/- 27.3 g m(-2), P = 0.003). CONCLUSIONS: These results suggest an association of combined angiotensin I-converting enzyme gene I/D polymorphism genotypes, and angiotensinogen gene M235T polymorphism genotypes with left ventricular hypertrophy due to long-term athletic training. A synergistic effect of angiotensin I-converting enzyme gene DD genotype and angiotensinogen gene TT genotype on left ventricular mass in endurance athletes appears to occur.

Adolescent↗
PubMed2001

Hypertension guidelines and their limitations--the impact of physicians' compliance as evaluated by guideline awareness.

OBJECTIVE: The initial step of an optimal therapeutic strategy for patients with arterial hypertension is the recognition and acceptance of new recommendations by the physicians themselves. This guideline awareness of the physicians has never been evaluated in detail. DESIGN: The awareness of content of current recommendations in hypertension diagnosis, treatment and treatment control was therefore assessed in primary care physicians using a questionnaire. The guidelines of the German Hypertension Society were used as the reference standard. PARTICIPANTS: A total of 24 899 German physicians, including all internists, all cardiologists and 22% of general practitioners were contacted in a nationwide survey. MAIN OUTCOME MEASURES: The number of answers in agreement with the guideline was used as a measure of guideline awareness. Adequate awareness of content of guideline recommendations was defined as the correct answer to five out of eight questions; the correct answers had to include the appropriate definition of hypertension. RESULTS: The analysis was based on 11 547 returned questionnaires (47.1%). An adequate guideline awareness was found in 23.7% of the total study population, especially in 37.1% of cardiologists, in 25.6% of internists and in 18.8% of general practitioners. While the guideline awareness was significantly influenced by the duration of private practice, regional and municipal factors had only minor influence on the results. CONCLUSION: The impact of hypertension guidelines on actual medical knowledge is modest. Thus, the information strategies about current treatment guidelines must be improved and tailored to the needs of physicians in clinical practice to ultimately improve patient care.

Awareness↗
PubMed2001

A new and accurate prediction model for growth response to growth hormone treatment in children with growth hormone deficiency.

OBJECTIVE: To identify parameters which predict individual growth response to recombinant human GH (rhGH) therapy and to combine these parameters in a prediction model. DESIGN: Fifty-eight prepubertal patients with GH deficiency (17 females) participated in this prospective multicenter trial with 1 year of follow-up. METHODS: Auxological measurements, parameters of GH status and markers of bone metabolism were measured at baseline and at 1, 3 and 6 months after the start of rhGH treatment. Correlations with height velocity during the first 12 months of treatment (HV+12) were calculated. Prediction models were derived by multiple regression analysis. RESULTS: The model which best predicted HV+12 combined the following parameters: pretreatment bone age retardation as a fraction of chronological age, pretreatment serum levels of IGF-I, urinary levels of deoxypyridinoline (a marker of bone resorption) after 1 month of treatment and height velocity after 3 months of treatment. This model explained 89% of the variation in HV+12 with a standard deviation of the residuals of 0.93 cm/year. Defining successful rhGH therapy as a doubling of pretreatment height velocity, the model had a specificity of 90% and a sensitivity of 100% in predicting therapeutic success. CONCLUSIONS: This model is an accurate and practicable tool to predict growth response in GH-deficient children. It may help to optimize rhGH therapy by individual dose adjustment and contribute to improved overall outcomes.

Adolescent↗
PubMed2001

Detection of porcine bone lesions and fissures: comparing digital selenium, digital luminescence, and analog film-screen radiography.

OBJECTIVE: The purpose of our study was to compare the diagnostic performance of a digital selenium detector (Thoravision) with that of analog film-screen systems and digital luminescence radiography in skeletal radiography for the detection of fissures and lesions in porcine bones. MATERIALS AND METHODS: One hundred bones taken from domestic pigs (50 ribs and 50 femurs) were divided into two equal groups. Fissures and bone lesions were created in 50 bones and 50 served as controls. The bones were examined using film-screen systems, digital luminescence radiography, and digital selenium radiography at various doses. Digital selenium radiography exposure values were adapted to the image geometry differing from the reference methods with a detector focus distance of 2.15 m. Four radiologists independently evaluated image quality and detectability of fissures and lesions on a five-point scale of confidence. Statistical evaluation was based on receiver operating characteristic curve analysis. RESULTS: Fissures and bone lesions were detected most reliably using the mammography film-screen system, but the difference in the results of the analog and digital reference images did not achieve statistical significance. CONCLUSION: Compared with analog film-screen systems, the lower spatial resolution of the digital selenium and digital luminescence radiography systems does not affect detectability of fissures and bone lesions in porcine bone. Selenium is effective in skeletal radiography for detecting fissures and bone lesions. With digital selenium and digital luminescence radiography, the surface dose can be cut to half that required for 200-speed film-screen systems without losing any diagnostically relevant information.

Animals↗
PubMed2000

Perioperative treatment with filgrastim stimulates granulocyte function and reduces infectious complications after esophagectomy.

We investigated the effects of recombinant G-CSF (Filgrastim) on the function of neutrophils and the rate of infectious complications in an open-label, nonrandomized study of patients with esophageal cancer undergoing esophagectomy. In this single-center phase-II trial 20 sequential patients (19 evaluable) received Filgrastim at standard doses (300 microg or 480 microg) subcutaneously for 2 days prior to and up to 7 days after surgery. The phagocytotic activity of neutrophils and the oxidative burst in the study group and in an experimental control group (n=27) were measured on days -2, 2, and 10. Neutrophil function was enhanced in the Filgrastim-treated group by factor 1.2 for phagocytosis (p=0.016) and 1.4 for oxidative burst (p)=0.154). Leukocyte counts increased from 7.6 x 10(9)/l (day -2) to a maximum of 45 x 10(9)/l on day 6. No infection was reported in the study group (mean age 59.7 years; 13 men, seven women) up to 10 days after surgery. In contrast, 23 patients (29.9%) in a historical control group (mean age 56 years; 67 men, ten women) treated at the same center developed infections within the first 10 days (p = 0.008). In addition, no postoperative deaths occurred in the study group, compared with 9.1% in the group of historical controls. Thus, in this study, administration of Filgrastim stimulated neutrophil function in patients undergoing esophagectomy, and it might be effective in reducing infectious complications related to the surgical procedure.

Adult↗
PubMed2000

Epidemiology of erectile dysfunction: results of the 'Cologne Male Survey'.

The last few decades have seen a marked increase in mean life expectancy in Central Europe. This has made elderly people and their quality of life a matter of ever-increasing medical concern. Available data from the United States and Scandinavia relating to erectile dysfunction (ED) do not enable us to draw valid conclusions about the current situation in Germany. The aim of the present study was to evaluate the epidemiology of male sexuality in Germany, and the proportion of men who need medical treatment because of increased suffering from this.A newly developed and validated questionnaire on male erectile dysfunction was mailed to a representative population sample of 8000 men, 30-80 y of age in the Cologne urban district. The response included 4489 evaluable replies (56.1%). The response rates in different age groups ranged from 49.2% to 68.4%. Regular sexual activity was reported by 96.0% (youngest age group) to 71.3% (oldest group). There were 31.5%-44% of responders who were dissatisfied with their current sex life. The prevalence of ED was 19.2%, with a steep age-related increase (2.3-53.4%) and a high co-morbidity of ED with hypertension, diabetes, pelvic surgery and 'lower urinary tract symptoms'. When treatment need was defined by co-occurrence of ED and dissatisfaction with sex life, 6.9% men required treatment for ED. Oral treatment of ED was preferred by 73.8% of respondents. There were 46.2% respondents who were willing to contribute more than DM 50 (25 Euro) per month for ED treatment. We conclude that regular sexual activity is a normal finding in advanced age. ED is a frequent disorder, contributing to dissatisfaction with sex life in a considerable proportion of men. The high burden of ED is reflected in willingness to pay for treatment. ED is frequently associated with chronic diseases. Therefore adequate diagnostic workup is essential, to offer patients individually adapted treatment. General non-reimbursability of treatment for ED appears to be unacceptable.

Adult↗
PubMed2000

Influence of puberty on muscle area and cortical bone area of the forearm in boys and girls.

The aim of the current study is to analyze the interaction of the muscle and bone system (muscle-bone unit) during puberty in males and females by computed tomography of the nondominant forearm. The data presented here are the first results from 318 healthy children (159 boys and 159 girls), aged 6-22 yr, and 336 adults (parents) participating in the DONALD Study (Dortmund Nutritional and Anthropometric Longitudinally Designed Study). Cortical area (CA) of the radius representing bone strength and muscle area (MA) representing muscle strength were measured with peripheral quantitative computed tomography (XCT 2000; Stratec, Pforzheim, Germany). A single slice measurement at a site corresponding to 65% of the ulnar length proximal to the radial endplate was used. MA and CA of the radius have been determined by a built-in software algorithm using density differences. There was a strong correlation between MA (x) and CA (y) in all children, adolescents, and adults (y = 0.019x + 10.93; r2 = 0.77). Before puberty, boys and girls displayed a similar relation between MA and CA. CA in relation to MA was greater in girls than in boys during puberty. Analysis of covariance was performed investigating the dependency of CA on MA, five pubertal stages, sex, and interaction of sex and pubertal stages. MA representing muscle strength was the strongest predictor of CA (P < 0.001) representing bone mass. Pubertal stage (P < 0.001) and interaction of pubertal stage*sex (P = 0.002) also had a significant influence on CA. r2 of the model was 0.85. These data suggest that in pubertal girls and women rather than in pubertal boys and men an additional factor shifts the relationship between MA and CA to higher values of cortical area. The present data confirm previous studies of the influence of puberty and estrogens or related factors on the muscle-bone interaction.

Adolescent↗
PubMed1999

Resampling-based methods for the analysis of multiple endpoints in clinical trials.

We consider multivariate tests for comparing two treatments with multiple endpoints. The test decision is drawn from the simultaneous consideration of the univariate tests for the single endpoints. A general class of these tests, called cut-off tests, can be given, which, however, can lead to highly conservative procedures because the dependencies among the endpoints are not taken into account. In applying resampling-based methods considerable improvements for these tests can be achieved. Resampling-based cut-off tests are proposed which are sensitive against a treatment difference in a single endpoint, in a subgroup of endpoints, or in all endpoints. The results of Monte Carlo simulations demonstrate that a remarkable gain in statistical power as compared to the crude simultaneous consideration can be reached. In particular, for the multivariate one-sided test situation the proposed tests can be recommended. As an example the application of the tests is demonstrated by data from a clinical trial.

Clinical Trials as Topic↗
PubMed1999

Adaptive sample size calculations in group sequential trials.

A method for group sequential trials that is based on the inverse normal method for combining the results of the separate stages is proposed. Without exaggerating the Type I error rate, this method enables data-driven sample size reassessments during the course of the study. It uses the stopping boundaries of the classical group sequential tests. Furthermore, exact test procedures may be derived for a wide range of applications. The procedure is compared with the classical designs in terms of power and expected sample size.

Acne Vulgaris↗
PubMed1998

[Digital selenium radiography: a comparison of the picture quality of thoracic images in normal and reduced image formats based on the structural anatomical details].

PURPOSE: Is there a loss of information when using selenium radiographic images displayed with reduced image format compared to full format? METHOD: Digital selenium radiographic chest images in two planes were obtained in 35 patients for medical reasons. The digital data sets of each patient were separately displayed in full format on two different films and were printed in reduced format on one film. The format was reduced to 61% of the full format using an acquisition matrix of 2166 x 2488 pixels, an image display matrix of 4000 x 5000 pixels and a film format of 43 x 49 cm. All images were anonymously evaluated by four independent readers using a questionnaire concerning anatomic structures. RESULTS: Format reduction did not result in a loss of information in diagnostically relevant anatomic details. CONCLUSIONS: Displaying digital selenium radiographic data sets of thoracic view in two planes on one film presumably does not lead to a loss of diagnostic information. This procedure may help to reduce film costs.

Adult↗
PubMed1998

Age-dependent differences in the prevalence of allergic rhinitis and atopic sensitization between an eastern and a western German city.

Recent studies have found a higher prevalence of allergic rhinitis and atopic sensitization among adults living in eastern than those living in western Germany. We hypothesize that prevalence rates were similar before Germany was divided and diverged after the division. Because there are no historical data comparing atopic status between the two parts of Germany, we tested this hypothesis by comparing the prevalence of atopy among persons who were born during different decades. As part of the EC Respiratory Health Survey, a respiratory health questionnaire was mailed to a population-based sample of 8363 subjects aged 20-44 years from a city in the former West Germany (Hamburg) and a city in the former East Germany (Erfurt). Of the target population, 6428 (77%) subjects responded. Subsamples of 731 subjects from Erfurt and 1159 subjects from Hamburg participated in medical examinations, including skin prick tests and specific IgE measurements. Prevalence rates of allergic sensitization were similar in Hamburg and Erfurt for those born in the periods 1946-51 and 1952-61, respectively, but differed between Hamburg and Erfurt subjects born in the period 1962-71. After adjustment for several potential predictors, the younger subjects from Hamburg had a higher odds ratio (OR) of sensitization than those Hamburg subjects born before 1952 (skin prick test reactivity: OR 2.06, any specific IgE > 0.35 kU/l: OR 1.61). The younger subjects from Erfurt were not more frequently sensitized than the older subjects (skin prick test reactivity: OR 1.05, any specific IgE > 0.35 kU/l: OR 0.79). No single allergen could be identified as responsible for the observed difference. We conclude that factors related to a "Western lifestyle", which were prevalent in the West German city during the 1960s and 1970s, may be responsible for the higher prevalence of allergic sensitization observed in Hamburg.

Adult↗