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Biomedical subjects

A Neumann

Publications and source records attributed to A Neumann.

At least 19 recordsLinked to original sources
PubMed2007

[Management of iatrogenic esophageal perforations].

BACKGROUND: Iatrogenic esophageal perforations are still a life-threatening clinical entity. PATIENTS AND RESULTS: We present the case reports of six patients to demonstrate different treatment options and we focus on new therapeutic strategies which have evolved in the interdisciplinary management of iatrogenic esophageal perforations. Two patients with perforations in the cervical esophagus were operated and in another patient the perforation was closed with fibrin glue. Three patients with perforations in the thoracic esophagus were treated with self-expandable plastic stents. CONCLUSION: The surgical therapy of esophageal perforations still is regarded to be the gold standard and nonadherence should only be considered based on interdisciplinary decisions in individual cases. However, positive results are increasingly being reported for conservative endoscopic treatment, particularly for thoracic perforations.

Adult↗
PubMed2006

[Osteosynthesis in facial bones: silicon nitride ceramic as material].

BACKGROUND: The favorable properties of silicon nitride (Si3N4) ceramic, such as high stability and biocompatibility suggest its biomedical use as an implant material. The aim of this study was to test its suitability for osteosynthesis. MATERIALS AND METHODS: A Si3N4 prototype minifixation system was manufactured and implanted for osteosynthesis of artificial frontal bone defects in three minipigs. After 3 months, histological sections, CT and MRI scans were obtained. Finite element modeling (FEM) was used to simulate stresses and strains on Si3N4 miniplates and screws to calculate survival probabilities. RESULTS: Si3N4 miniplates and screws showed satisfactory intraoperative workability. There was no implant loss, displacement or fracture. Bone healing was complete in all animals and formation of new bone was observed in direct contact to the implants. CONCLUSIONS: Si3N4 ceramic showed a good biocompatibility outcome both in vitro and in vivo. This ceramic may serve as biomaterial for osteosynthesis, e.g. of the midface including reconstruction of the floor of the orbit and the skull base. Advantages compared to titanium are no risk of implantation to bone with mucosal attachment, no need for explantation, no interference with radiological imaging.

Animals↗
PubMed2006

[Evolution of functional autonomy in geriatric medium-term care units: a reliable performance indicator?].

The objective of this study was to compare the evolution of the level of functional dependence of patients between the time of their hospital admission and release following treatment received in the geriatric medium-term care units, in order to propose this variable as a clinical performance indicator for this type of service. The differential score of physical dependence observed was determined for each hospital stay, and the adjusted significant functional improvement rate (SFI) was calculated for every unit. This adjusted SFI rate was then compared to the overall rate of all of the units combined. The overall SFI rates were 23% in 2004. Seven of the 49 units studied present an adjusted rate significantly inferior to the average rate of the total number of units combined. This study constitutes one of the first performance analyses in the medium-term sector, and the adjusted SFI rate seems to be a pertinent and reliable indicator within this framework.

Activities of Daily Living↗
PubMed2006

Radiation treatment for ductal carcinoma in situ (DCIS): is a boost to the tumor bed necessary?

The aim of the presented study was to evaluate the long-term outcome of breast-conserving surgery and radiation for the treatment of ductal carcinoma in situ (DCIS) and the role of the radiation boost to the tumor bed. The files of 75 women with DCIS treated by breast-conserving surgery followed by definitive radiation from 1988 to 1997 were reviewed for demographic data, prognostic variables, radiation dose, radiation boost, recurrence, and outcome. Total radiation dose was 5000 cGy delivered in 25 fractions. Twenty patients (26.7%) received an additional boost to the tumor bed of 1000 cGy in 5 fractions. Median follow-up time was 81.5 months (range, 22-145). Pearson correlation coefficient and its significance was calculated between the variables. Log rank test was used to analyze differences in local recurrence rates between patients who did or did not receive a boost, and a Cox regression model was fitted to the data to predict recurrence. Ten patients (13%) had local recurrence; one patient showed lymphatic spread. Histopathologic examination revealed DCIS in 6 cases (60%) and invasive duct carcinoma in 4 (40%)(one minimally invasive). The recurrence group included 3 of the 20 patients who received a radiation boost (15%) and 7 of the 55 who did not (12.7%) (p=0.7). Correlation analysis of patient characteristics, prognostic factors, and treatment was significant only between mastitis as the presenting symptom (n=4) and longer time to recurrence (p=0.02). The recurrence rate in the present study was similar to other series of conservative treatment for DCIS of the breast. No additional value was found for the radiation boost. Larger controlled randomized studies are needed to confirm these findings.

Adult↗
PubMed2005

Effects of the antioxidative vitamins A, C and E on liver metastasis and intrametastatic lipid peroxidation in BOP-induced pancreatic cancer in Syrian hamsters.

BACKGROUND/AIMS: Antioxidative vitamins are known to inhibit metastasis. Therefore we evaluated the impact of vitamins A (retinol), C (ascorbic acid) and E (alpha-tocopherol) on liver metastasis in a model of ductal pancreatic adenocarcinoma in hamster. METHODS: One hundred and twenty male Syrian hamsters were randomized into 8 groups (Gr.) (n = 15). Gr. 1-4 were given 0.5 ml normal saline subcutaneously (s.c.) weekly, whereas Gr. 5-8 received 10 mg N-nitrosobis(2-oxopropyl)amine (BOP)/kg body weight s.c. for 3 months for tumor induction. In the 13th week Gr. 2 and 6 were administered retinol, Gr. 3 and 7 received ascorbic acid and Gr. 4 and 8 were given alpha-tocopherol orally. No treatment was performed in Gr. 1 and 5. After 24 weeks animals were sacrificed, pancreas and liver were histologically determined. Activities of glutathione-peroxidase (GSH-Px), superoxide dismutase (SOD) and concentration of thiobarbituric-acid-reactive substances (TBARS) were analyzed in hepatic tissue. RESULTS: Retinol and alpha-tocopherol decreased the incidence of liver metastases (44.4 vs. 86.7%, p < 0.05). The number and size of liver metastases were significantly reduced by retinol. Activities of GSH-Px and SOD were increased and concentration of TBARS was decreased in NML and LiMe by all vitamins. CONCLUSION: Obviously, antioxidative vitamins prevent oxidative stress in hepatocytes. This may be one mechanism decreasing liver metastasis in pancreatic cancer in the present trial.

Administration, Oral↗
PubMed2005

[Frequency specific auditory evoked responses. Experiments on stimulus polarity, sweep frequency, stimulus duration, notched-noise masking level, and threshold estimation in volunteers with normal hearing].

Auditory evoked responses to tone-pips in notched-noise provide frequency specific estimations of thresholds. Most often, test frequencies are 0.5-4 kHz. Thresholds are expected to match with a high degree to behavioral thresholds. However, only few studies are available containing data on stimulus and averaging parameters, especially at a test frequency of 0.25 kHz. In order to find "optimal" parameters for a widely used device (Nicolet Spirit Version 1.6), we designed five experiments on stimulus polarity (Exp.I), sweep frequency (Exp.II), stimulus duration (Exp.III), notched noise level (Exp.IV), and threshold estimation (Exp.V). The experiments also included a low test frequency of 0.25 kHz. These experiments were applied to 29 healthy volunteers (n=29, aged 20-41 years with normal hearing and no history of illness of the ear). We found that alternating stimulus polarity and a sweep frequency of 43.5/s evoked responses that were highest with respect to amplitudes (0.2-0.4 mV) and correlations (0.49-0.91). A novel finding of the study was that the highest amplitudes and correlations could be achieved if stimulus durations and notched-noise-levels were specifically adjusted to the test frequencies (stimulus durations 0.25 kHz: 4 ms, 0.5 Hz: 2 ms, 1-4 kHz: 1 ms, notched-noise-levels 0.25-0.5 Hz: +10 dB, 1-4 kHz: +/-0 dB). Deviations from behavioral thresholds did not exceed +/-5 dB in 93% of the measures. The results indicate that frequency specific auditory evoked responses provide reliable threshold estimations. Future experiments are required to confirm the threshold deviations for hard of hearing individuals.

Acoustic Stimulation↗
PubMed2005

[Reconstruction of the tympanic membrane applying cartilage: indications, techniques and results].

Autogenous cartilage-perichondrium-composite-grafts have become essential and well established transplant materials in reconstructive middle ear surgery. They have proven to be particularly appropriate for surgical situations which benefit from the bradytrophy and stiffness of the cartilage (adhesive otitis, retraction pockets, subtotal tympanic membrane defects, revision tympanoplasty). Of the numerous techniques available, the perichondrium-island technique and the palisade-cartilage technique are described in detail in this review, also regarding modifications and comments in the literature. Both methods show good functional and morphological results and should be chosen according to individual surgical requirements. The data of experimental investigations are involved in the decision which technique should be favored.

Cartilage↗
PubMed2004

Cardiovascular risk factors and probability for cardiovascular events in HIV-infected patients - part III: age differences.

OBJECTIVE: In recent years, concerns have been growing about an elevated rate of cardiovascular diseases in HIV-infected patients due to side effects of antiretroviral therapy. The present study analyses the cardiovascular risk profile and the probability of cardiovascular events with regard to the age of HIV-infected patients. METHODS: Cardiovascular risk factors of 309 HIV-infected adults were analysed. Patients were divided into four groups: 18-30 years (group 1), 31-40 years (group 2), 41-50 years (group 3), > 50 years (group 4). Overall 10-years probability for cardiovascular events was evaluated by the Framingham algorithm. RESULTS: Differences between the groups were detected in cardiovascular risk factors including changes in lipid- and glucose metabolism. Lipid values increased with elevated age, such as total cholesterol concentration (Mean +/- SEM in group 1 vs. group 4: 4.71 +/- 0.20 to 6.36 +/- 0.21 mmol/L, p < 0.05), LDL-cholesterol concentration (2.86 +/- 0.17 vs. 4.17 +/- 0.21 mmol/L, p < 0.05) and triglyceride concentration (1.56 +/- 0.14 vs. 3.48 +/- 0.40 mmol/L, p < 0.05). HDL-cholesterol concentration did not show a significant difference (1.15 +/- 0.03 mmol/L). Glucose concentration increased with elevated age in HIV-infected patients (5.28 +/- 0.19 vs. 6.46 +/- 0.24 mmHg, p < 0.05), but there was no significant difference in HbA1c - concentration, blood pressure and smoking rate between the groups. The overall 10-years probability for cardiovascular events was higher in group 1 (median: 1.9%) than in group 4 (20.5%; p < 0.01). CONCLUSIONS: The risk of cardiovascular events is related to the age in HIV-infected patients. Therefore, an increased duration of life due to a more effective antiretroviral therapy will have a significant impact on the rate of cardiovascular events in this patient population. In the future, further increase of cardiovascular events in HIV-infected patients may be expected.

Adolescent↗
PubMed2004

Cardiovascular risk factors and probability for cardiovascular events in HIV-infected patients. Part II: gender differences.

OBJECTIVE: Due to the side effects of antiretroviral therapy and long term survival there is an increasing concern of an elevated rate of cardiovascular diseases in HIV-infected patients. The present study analysed the cardiovascular risk profile and the probability of cardiovascular events in HIV-infected patients, due to differences of gender. METHODS: Cardiovascular risk factors of 309 HIV-infected adults, including 240 males were analysed. Overall 10-years probability for cardiovascular events was evaluated by the Framingham algorithm. RESULTS: Gender differences were detected in cardiovascular risk factors such as lipid values, blood pressure and the rate of smoking. Tobacco use was much more common in HIV-infected males compared with HIV-infected females (67.5% vs. 49.3%; p<0.001). Although no significant difference was noticed in total cholesterol (5.49 +/- 0.09 vs. 5.53 +/- 0.19 mmol/L, p = 0.84), the HDL-cholesterol concentration was significantly lower (1.09 +/- 0.03 vs. 1.36 +/- 0.06 mmol/L, p < 0.001) and the triglyceride concentration higher (3.01 +/- 0.21 vs. 2.06 +/- 0.26 mmol/L, p = 0.02) in HIV-infected males compared to HIV-infected females. Additionally, systolic blood pressure was higher in HIV-infected males compared with HIV-infected females (123.1 +/- 1.1 vs. 115.4 +/- 2.1 mmHg, p < 0.01). No significant differences were detected in HbA1c concentrations between both groups (5.15 +/- 0.07 vs. 5.31 +/- 0.11, p = 0.26). The overall 10-years probability for cardiovascular events was 8.7% (median) in HIV-infected males and 1.7% in HIV-infected females (p < 0.0001). CONCLUSIONS: In the present study, we observed gender differences in the cardiovascular risk profile of HIV-infected individuals. The risk of premature atherosclerosis and associated cardiovascular events was significantly higher in HIV-infected males.

Adult↗
PubMed2004

[Stenosing gastric laryngitis in infancy].

A 2 month old female infant presented an aphonic voice and increasing inspiratory stridor due to a stenosing granulating laryngitis. A pathologically elevated gastroesophageal reflux was measured by means of 24-h pH-metry. After antireflux therapy (Cisaprid, sodium alginate and upright body positioning), the laryngitis was completely healed. This case confirms that an elevated gastroesophageal reflux in infants can cause chronic inflammatory diseases of the upper respiratory tract, especially of the larynx.

Alginates↗
PubMed2004

Comparative investigation of the biocompatibility of various silicon nitride ceramic qualities in vitro.

There is a controversy about the biocompatibility of silicon nitride ceramics contained in the literature, which appears to be related to a factor of the individual chemical composition of different qualities of silicon nitride ceramics and of the different surface properties. This study attempts to investigate the cytotoxicity of different qualities of industrial silicon nitride ceramics applying an L929-cell culture model in a direct contact assay combined with a cell viability assessment. Five different qualities of industrial standard silicon nitride ceramics were chosen for in vitro testing. The chemical composition was determined by EDS analysis. Different biomedically approved aluminium oxide qualities, a titanium alloy, glass and polyvinylchloride (PVC) served as control materials. L929 mice fibroblasts were incubated directly on the materials for 24 h, stained with bisbenzimide and propidium iodine for double fluorochromasia viability testing, and evaluated by inversion-fluorescence microscopy to control cell morphology, viability and cell counts compared to empty well values. Scanning electron microscopy was applied to additionally investigate cell morphology. There was no observation of cytotoxic effects on the silicon nitride ceramic samples; moreover cell morphology remained the same as on aluminium oxide and titanium. Viability testing revealed the presence of avital cells exclusively on PVC, which served as a negative control. Cell counts on all polished surfaces showed significantly higher numbers, whereas some rough surface samples showed significantly lower numbers. We conclude that silicon nitride ceramics show no cytotoxic effects and should be considered for biomedical application owing to its favourable physiochemical properties, especially its superior resistance to mechanical stress, which would be useful for compression loaded conditions. Polished surfaces would appear to promote advanced biocompatibility.

Aluminum Oxide↗
PubMed2004

[Biocompatibilty of silicon nitride ceramic in vitro. A comparative fluorescence-microscopic and scanning electron-microscopic study].

BACKGROUND: With regard to its favorable physical properties, silicon nitride ceramic is considered as biomaterial for human medical application. Minor controversy exists about the biocompatibility of the material. METHODS: Cytotoxicity testing, cell viability and morphology assessment was performed applying the L929-mice fibroblast cell culture model in a direct contact assay. Testing materials were silicon nitride ceramics of different surface properties and titanium alloy as a reference. Polyvinylchloride served as a negative control. The cells were stained with bisbenzimide and propidium iodine for double fluorochromasia viability testing, and evaluated by inversion-fluorescence microscopy. Scanning electron microscopy was applied to additionally investigate cell morphology. RESULTS: No cytotoxic effects were observed on the silicon nitride ceramic samples; moreover cell morphology remained the same as on titanium. Avital cells were present exclusively on PVC. The cell growth in the silicon nitride samples showed no significant differences compared to titanium. Cell counts on all polished surfaces showed significantly higher numbers. Scanning electron microscopy revealed typical fibroblast morphology with filiform extensions. CONCLUSION: The current results indicate a favorable biocompatibility of silicon nitride ceramic. Cell growth, viability and morphology are comparable to parameters of titanium. Polished surfaces appear to promote cell growth. Further in vivo studies are mandatory prior to human medical application. Owing to its favorable physiochemical properties, especially its superior resistance to mechanical stress, silicon nitride could serve as a biomaterial for osteosynthesis of bone with mucosal attachment.

Alloys↗
PubMed2004

Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2.

INTRODUCTION: Pulmonary metastases of renal cell carcinoma (RCC) are associated with poor prognosis. Inhalation therapy with interleukin-2 (IL-2) is thus an appealing method for palliation. This multicenter study summarizes the national experience of IL-2 inhalation in patients with lung metastases of RCC. PATIENTS AND METHODS: Forty patients (median, 66.5 years of age) with radiologically documented progressing pulmonary metastases were enrolled. All patients had to be able to comply with inhalation technique, and were not candidates for other treatment options. Twenty-eight patients were systemic treatment-naïve. The protocol included three daily inhalations of IL-2 to a total dose of 18 MU. Treatment had to be continued until one of the following occurred: progression; a complete response; a life threatening toxicity; or patient refusal. Response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) system. RESULTS: The disease-control rate reached 57.5%, with a partial response rate of 2.5% and a disease stabilization rate of 55%. Median time to progression was 8.7 months. The main side-effects were cough and weakness. CONCLUSIONS: Inhalation of IL-2 for the treatment of pulmonary metastases in RCC is feasible, tolerable and beneficial in controlling progressive disease for considerable periods of time. The definition of response of biological therapy may need to be re-assessed and modified: stable disease should be regarded as a favorable response.

Administration, Inhalation↗
PubMed2004

Fluorouracil induces apoptosis and surface molecule modulation of peripheral blood leukocytes.

Little is known about the direct effect of chemotherapy on normal peripheral blood leukocytes (PBL) or its contribution to leukopenia. We examined 5'-fluorouracil's (5FU) effect on PBL apoptosis and adhesion molecules' expression in a single-drug solid-tumor model. Possible apoptosis mediators were examined. The study included 32 colorectal cancer patients; apoptosis was determined by annexin-V binding and light-scatter morphology before and after drug infusion. CD18, CD11a, CD11b, and CD63 membranal levels were assayed by flow cytometry. Apoptosis was increased post-5FU administration in neutrophils (PMN), monocytes and lymphocytes (P < 0.05). Levels of Fas receptor and activated caspase 3 did not vary indicating that the process was not mediated by caspase 3 in the timeframe studied. Reduced CD63 on monocytes and decreased CD18 expression on PMN and non-apoptotic monocytes were observed (P < or = 0.05). CD11a,b expression did not vary. Decreased CD18 and CD63 levels were demonstrated in apoptotic and non-apoptotic PBL implying a more direct association with the drug itself.

Antigens, CD↗
PubMed2004

Dose escalation study for defining the maximum tolerated dose of continuous oral trofosfamide in pretreated patients with metastatic lung cancer.

BACKGROUND: Trofosfamide is increasingly used in the treatment of patients with several types of malignancies. However, the optimal dose of trofosfamide for patients with advanced cancer has not been systematically investigated yet. The aim of this study was to define the maximum tolerated dose (MTD) of continuous oral trofosfamide. PATIENTS AND METHODS: 16 patients with advanced lung cancer (14 nonsmall cell lung cancer, 2 small cell lung cancer; 10 male, 6 female; median age 64 years (range 46-82); median Karnofsky status 70%; median number of organs involved 3 (range 1-6)) were enrolled. All patients were previously treated with chemotherapy (median 2x, range 1-6) and 8/16 (50%) with radiotherapy. Patients received trofosfamide p.o. administered in 3 doses per day for 3 weeks (1 cycle) using a 3-patient-cohort dose-escalation strategy. Toxicities were graded according to the WHO Criteria. RESULTS: Patients received a median of 2 cycles of trofosfamide (range 1-4) at 3 dose levels (90, 125, and 175 mg/m2). Grade 3 and 4 neutropenia, anemia, and thrombocytopenia were observed in 20, 13.3, and 6.6%, respectively. Dose-limiting toxicities during the first cycle were grade 3 muscle weakness and anorexia observed in 1/6 patients in cohort 1 (trofosfamide 90 mg/m2), grade 3 neutropenia in 1/6, and encephalopathy in 1/6 patients in cohort 3 (trofosfamide 175 mg/m2). Therefore, the dose level of 125 mg/m2 was defined as the MTD. CONCLUSION: Trofosfamide at 125 mg/m2 administered in 3 doses per day was well tolerated. This dose level is recommended for further clinical studies.

Administration, Oral↗
PubMed2003

Cardiovascular risk factors and probability for cardiovascular events in HIV-infected patients: part I. Differences due to the acquisition of HIV-infection.

OBJECTIVE: Due to side effects, such as hyperlipidaemia and insulin resistance, there is an increasing concern that antiretroviral drugs lead to an epidemic of cardiovascular diseases in HIV-infected patients. The present study characterizes the cardiovascular risk profile of HIV-infected individuals, due to the acquisition of HIV-infection. METHODS: Cardiovascular risk factors of 309 HIV-infected adults (HIV-acquisition: 59.2% by homosexual contact (group 1), 28.5% by heterosexual contact (group 2), 9.1% by intravenous drug abuse (group 3) and 3.2% by blood transfusion (group 4)) were analysed. Overall 10-years probability for cardiovascular events was analysed by the Framingham algorithm. RESULTS: Tobacco use was more common in group 1 subjects compared with group 2 subjects (67% vs. 52%; p<0.05). Additionally, group 1 subjects exhibited elevated total cholesterol (5.6 +/- 0.1 mmol/L vs. 4.8 +/- 0.3), LDL-cholesterol (3.6 +/- 0.1 mmol/L vs. 2.8 +/- 0.2) and triglyceride concentrations (3.2 +/- 0.3 mmol/L vs. 1.7 +/- 0.2) compared with group 3 (all p<0.05). No significant differences between the groups were detected in glucose metabolism. The overall 10-years probability for cardiovascular events was significantly higher in group 1 compared with group 2 and group 3 (12.2 +/- 0.8% vs. 6.6 +/- 0.9% and 7.9 +/- 1.6%, p<0.05). CONCLUSIONS: The cardiovascular risk profile differs between subgroups of HIV-infected individuals, leading to significant higher probability of cardiovascular events in group 1 subjects. The risk of premature atherosclerosis by HIV-infected individuals and therapeutic options remains to be established.

Adult↗
PubMed2003

Effect of filtration volume of continuous venovenous hemofiltration in the treatment of patients with acute renal failure in intensive care units.

OBJECTIVE: We evaluated the variable Kt/V, which has become established in the therapy of end-stage renal disease in acute renal failure, to assess the influence of the filtration volume of continuous venovenous hemofiltration on Kt/V. We measured the variables of acid-base balance and uremia control. DESIGN: Prospective interventional pilot study. SETTING: Medical intensive care unit of a university hospital. PATIENTS: Fifty-six patients with acute renal failure and continuous venovenous hemofiltration treatment. INTERVENTIONS: The patients were consecutively treated with a filtration volume of either 1 L/hr (group 1) or 1.5 L/hr (group 2). MEASUREMENTS AND MAIN RESULTS: Patients with a filtration volume of 1.5 L/hr achieved a Kt/V of 0.8 per day, which was significantly higher than in the patient group treated with 1 L/hr (0.53, p <.05). The filtration volume of 1.5 L/hr led to a markedly better control of blood urea nitrogen concentrations, 69.3 +/- 6.6 mg/dL vs. 52.1 +/- 5.2 (p <.05), and to a much quicker and longer lasting compensation of acidosis. Both groups had acidotic pH at the beginning of therapy (group 1, 7.29 +/- 0.02; group 2, 7.29 +/- 0.02, nonsignificant). In group 2, a significantly higher pH value than in group 1 was measured after 24 hrs of continuous venovenous hemofiltration (p < .001; 7.39 +/- 0.02 vs. 7.31 +/- 0.02). The pH values in group 1 did not normalize until after 4 days. The filtration volume of 1.5 L/hr led to a quicker increase in bicarbonate concentrations after 24 hrs of therapy (group 1, 2.8 +/- 3.2 mmol/L; group 2, 6.5 +/- 3.1 mmol/L, p <.001). CONCLUSIONS: The standardized urea clearance Kt/V is a valuable tool in the treatment of acute renal failure. Higher Kt/V levels were associated with a better control of uremia and acid-base balance. However, there were no differences in the clinical course, patient survival, percentage of patients with or without renal failure who were transferred from the intensive care unit, or Acute Physiology and Chronic Health Evaluation III scores.

APACHE↗