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Biomedical subjects

T Schneider

Publications and source records attributed to T Schneider.

At least 19 recordsLinked to original sources
PubMed2007

[Polypharmacy, compliance and non-prescription medication in patients with cardiovascular disease in Germany].

BACKGROUND AND OBJECTIVE: The expenses of health insurances are continuously raising. With implementation of evidence-based medicine resulting in polypharmacy, compliance is decreasing and patients as well as physicians are facing unintentional drug interactions. Furthermore the arbitrary use of additional drugs apart from prescribed medication has to be considered. The objective of this study was to analyse polypharmacy, compliance and utilisation patterns for non-prescription medications (OTC) in patients with cardiovascular diseases. METHODS: 100 patients with cardiovascular diseases (45 women, 55 men, 58 - 87 years) were interviewed using a questionnaire. The compliance was determined by the Morisky-Score. RESULTS: 78 % of the patients received more than four pills every day (median 8.34). Most common products were beta-blockers (89 %), ACE-Inhibitors/Sartans (69 %) and aspirin (65 %). Only 52 % of the patients knew the indications of their medication. Although 83 % of the patients claimed to be absolutely compliant concerning their medication, the Morisky-Score revealed a high compliance only in 52 %. The compliance decreased significantly if the number of prescribed medication increased to more than four pills a day. 48 % of the patients took regularly non-prescription products, 35 % more than three additional products daily. Most commonly multivitamins, minerals, herbals and non-steroidal anti-inflammatory drugs were used. This non-prescription medication did not affect the compliance of the patients. CONCLUSIONS: Polypharmacy with more than four pills daily leads to a lower compliance and can therefore influence the implementation of guideline-medicine. Non-prescription medication is widely used and should be considered because of their potential side-effects and drug interactions.

Adrenergic beta-Antagonists↗
PubMed2007

[The morphologic variants of KSHV/HHV 8-associated lymphoproliferations].

KSHV/HHV 8 infection is associated with primary effusion lymphoma, multicentric Castleman disease (MCD) and MCD-associated plasmablastic lymphoma. We report the case of an HIV-infected male with Kaposi sarcoma, MCD in the lymph node and development of a KSHV/HHV 8-associated plasmablastic lymphoma in the liver. Immunohistochemistry revealed an HHV 8 infection of plasmablasts showing cytoplasmic IgM/lambda expression. To the best of our knowledge, liver infiltration by a MCD-associated HHV 8 positive plasmablastic lymphoma has not been documented previously. The differential diagnosis is discussed.

Adult↗
PubMed2006

A new method for an improved determination of continuous photon fluence spectra for X-ray tube voltages up to 150 kV.

The experimental determination of bremsstrahlung spectra used in radiation protection dosimetry as well as in medical physics is generally composed of the following steps: acquisition of pulse-height spectra, determination of the detector's inherent response function and unfolding of the measured pulse-height spectra with this function. On the whole, this procedure leads to photon fluence spectra of good quality. It is, however, generally not completely free of artefacts. These occur at both the low- and high-energy sides of the spectrum, with a predominance at the low-energy side. In this work, a new method to overcome this problem is presented. It consists of reconstructing the distorted part of a spectrum on the basis of the total filtration pertinent to the radiation quality considered. The formalism is derived and the ability of the method to provide spectra free of artefacts is demonstrated.

Algorithms↗
PubMed2006

Effects of bevacizumab on retinal function in isolated vertebrate retina.

BACKGROUND: Bevacizumab (Avastin) is a recombinant protein that targets vascular endothelial growth factor (VEGF). In vitro, bevacizumab inhibits VEGF induced cell proliferation and tissue factor production. Abnormal angiogenesis involving VEGF is a central event during the development of choroidal neovascularisation (CNV). The present study was designed to evaluate the short term toxic effects of bevacizumab on retinal function for a therapeutic intraocular application. METHODS: Isolated bovine retinas were perfused with an oxygen pre-incubated nutrient solution. The electroretinogram (ERG) was recorded as a transretinal potential using silver/silver chloride electrodes. Bevacizumab was added in different concentrations to the nutrient solution for 45 minutes. Thereafter the retina was reperfused for 60 minutes with normal nutrient solution. The percentage of a-wave and b-wave reduction during the application of bevacizumab was calculated and compared to control recordings. RESULTS: During the application of three different concentrations of bevacizumab (0.08 mg/ml, 0.25 mg/ml, 0.8 mg/ml) no significant reduction of the a-wave and b-wave amplitude was observed. During the washout, the ERG amplitudes were unchanged. CONCLUSION: The present study suggests that an intraocular application of 0.25 mg/ml bevacizumab for the treatment of CNV is reasonable. No significant short term effects of bevacizumab on retinal function were detected, but long term effects cannot be excluded.

Angiogenesis Inhibitors↗
PubMed2006

Bland-White-Garland syndrome and atrial septal defect - rare association and diagnostic challenge.

We report on a 40-year-old woman referred for evaluation of a cardiac murmur and dyspnea on exertion. The electrocardiogram (ECG) showed incomplete right bundle branch block, and echocardiography revealed a large atrial septal defect (ASD, ostium secundum type) with dilated right-sided heart chambers. At cardiac catheterization, a large left-to-right shunt (78% of the pulmonary blood flow) was found, and surprisingly, the additional diagnosis of anomalous origin of the left coronary artery from pulmonary artery (ALCAPA) was established. After ASD closure and left coronary artery ligation with implantation of a vein graft to the left anterior descending artery, she had an uneventful 18-years follow-up. We discuss the interaction of the two associated conditions, and based on the herein reported unusual combination, we highlight typical features of non-invasive examinations including auscultation, ECG, and echocardiography in adult patients with ALCAPA.

Adult↗
PubMed2006

Effects of patent blue on human retinal function.

BACKGROUND: Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. Lately, the application of patent blue for staining of the internal limiting membrane has been proposed as an alternative to the standard procedures during macular hole surgery. In the present study we investigated the effects of patent blue 0.48% on human retinal function. METHODS: An isolated human retina preparation was perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by a commercially available patent blue solution. The duration of retinal exposure to the dye solution was varied between 15 s and 4 min. Thereupon, the preparation was reperfused with standard solution for 2 h. The percentage of b-wave reduction after exposition was calculated. RESULTS: No effects on the human ERG were seen after 15 and 30 s of dye application. Reversible reductions of the b-wave amplitude were found for an exposure period of 60 and 120 s, respectively. After 4 min of patent blue application a persistant b-wave amplitude reduction by 40% was found. CONCLUSIONS: Patent blue affects human retinal function when applied for at least 1 min. However, no irreversible effects on the human ERG were seen even after 2 min of retinal exposure to patent blue. Thus, toxic effects on retinal function after intraoperative short-term application of patent blue 0.48% appear unlikely to occur.

Coloring Agents↗
PubMed2006

[Norovirus infections in Germany].

Noroviruses are responsible for the majority of acute viral gastroenteritis infections worldwide. Transmission may be faecal-oral or through contaminated food and water or airborne by virus-containing aerosols. Characteristics of noroviruses that facilitate their spread are their high concentration in stool and vomitus, their extreme environmental stability, their low infectious dose as well as the lack of long-lasting immunity. The majority of norovirus infections occur in large outbreaks among persons living in institutional settings, such as hospitals and nursing homes, although sporadic cases also occur. Children and elderly persons are most often affected. Illness is characterized by acute onset of projectile vomiting. For prevention and control of norovirus outbreaks strict control management is necessary. Based on the high genomic variability new variant noroviruses with different pathogenic factors can arise. Depending on the circulating variant the extent of the usual winter peak can vary enormously. Available diagnostic methods include RT-PCR assays for detection of viral RNA, electron microscopy and enzyme immunoassays (EIA) for detection of viral antigens. The implicated virus can be subtyped through nucleotide sequencing and linked to a specific outbreak. With the enactment of the Protection against Infection Act in January 2001 a mandatory reporting system of norovirus infections was established. Analysis of surveillance data from this system permits a detailed overview of the nationwide epidemiology of this disease in Germany.

Caliciviridae Infections↗
PubMed2006

[27-year-old man with high fever and septic shock after returning from vacation].

A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema. In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.

Adult↗
PubMed2006

Autochthonous hepatitis E virus infection in Germany with sequence similarities to other European isolates.

Hepatitis E virus (HEV) is a common cause of acute hepatitis in endemic areas. Yet reports on autochthonous cases in other areas such as middle Europe are increasing. Here we report on a patient, who obviously acquired his HEV infection in Germany. Sequence analysis of the virus gained from his serum revealed homologies to other European isolates and swine isolates.

Communicable Diseases↗
PubMed2005

Characterization of microbial particle release from biomass and building material surfaces for inhalation exposure risk assessment.

A conceptual approach including measurements of materials at rest (step 1), measurements using a large rotating drum (step 2) or a Particle-FLEC (step 2) and measurements at a workplace (step 4) has been used to characterize the release of microbial components (bacteria, fungi, actinomycetes, endotoxin or enzymes) and particles from straw, wood chips or fungal cultures of different ages on gypsum boards. Repeated agitation or handling periods were included in step 2 and step 4. There was a low similarity between the amount of microbial components measured in step 1 and the aerosolized amount (step 2) from gypsum boards, wood chips and straw. Ratios between some microbial components measured at the workplace (step 4) and measured in step 2, showed similarities. Less than 1.3% of the total amount of microorganisms and endotoxin becomes airborne during 5 min of agitation of straw or wood chips. Most microbial components were released at higher rates during the first agitation period than during the following periods. However, differences were seen between different microbial components, and endotoxin from straw was released at the same rate in two successive agitation periods. Fungal particles smaller than spores were released from fungal colonized gypsum boards at amounts that were up to 30 times higher in the first agitation period compared with that in the following period, while fungal spores were released at amounts that were five times as high in the first period compared with that in the following period. In addition to differences between microbial components, the release patterns of microbial components were different for wood chips and straw. The time for maximum particle release to half particle release was longer for straw than for wood chips. The observation that some components, e.g. endotoxin, are released at the same rate in two successive handling steps, and that others (e.g. fungi) are mainly released initially, shows that the exposure period to different components from the same material differs in duration. The observed differences in the release patterns of different components and the differences between materials are important when preventive steps are to be taken, and it stresses the importance of applying a relevant sampling time and period in exposure assessments.

Air Microbiology↗
PubMed2005

Partial photoionization cross sections and angular distributions for double excitation of helium up to the N = 13 threshold.

Partial photoionization cross sections sigmaN(Egamma) and photoelectron angular distributions betaN(Egamma) were measured for the final ionic states He+ (N > 4) in the region between the N = 8 and N = 13 thresholds (Egamma > 78.155 eV) using the cold target recoil ion momentum spectroscopy technique (COLTRIMS). Comparison of the experimental data with two independent sets of theoretical predictions reveals disagreement for the branching ratios to the various HeN(+) states. The angular distributions just below the double ionization threshold suggest an excitation process for highly excited N states similar to the Wannier mechanism for double ionization.

Journal Article↗
PubMed2005

[Fever of unknown origin in the 21st century: infectious diseases].

Fever of unknown origin (FUO) is a rare but important disease. The definition of FUO has not changed in the last 50 years. Classical FUO is defined by an illness of at least 3 weeks duration with fever greater than 38 masculine C, and no established diagnosis after 1 week of hospital investigation. The causes of FUO can be divided in four categories: infectious diseases, noninfectious inflammatory diseases, neoplasms, and others (miscellaneous). Recent studies have surprisingly shown that despite improved diagnostic procedures the percentage of patients with FUO, in which no diagnosis after intensive investigations in specialized centres can be found, has increased. However, finding the correct diagnosis in FUO is essential for these patients for psychological and vital reasons. Therefore and because of economic reasons patients with FUO should be investigated in specialized centres with a department for rheumatology and infectious diseases.

Aged↗
PubMed2005

Do early injections of bulking agents following radical prostatectomy improve early continence?

Bulking agents belong to the treatment options of stress urinary incontinence in both genders for a long time, but early injection of bulking agents following radical prostatectomy to improve early continence is a new treatment modality and the results of the first years will be presented in this study. From 1996 to 2001, 55 incontinent patients, of whom 44 suffered from post-prostatectomy incontinence (PPI), have been treated by bulking agents in our clinic and evaluated later on, using a semistandardized questionnaire. Mean age was 65.5 years and the mean follow-up was 32 months. Of 44 patients with PPI, 29 suffered from incontinence of the third, 10 from incontinence of the second and 5 from incontinence of the first degree. We examined the influence of transurethral injection of bulking agents on direct postoperative continence (short-term results) and on continence at the time of follow-up (long-term results) (mean 32 month). An improved early continence (short-term result) was achieved in 30 patients. At follow-up, 19 patients were completely dry, 18 reported an improved continence. Especially the time of treatment, referring to radical prostatectomy, had a significant influence on treatment results with better results in the subgroup of 34 patients that have been treated early (mean 23 days) compared to 10 patients that received delayed treatment (mean 26 months) following radical prostatectomy. The preoperative degree of incontinence had a significant influence on short-term results, and not on long-term results. The amount of bulking material and the number of injections had no significant influence on short-term results, but repeated injections resulted in statistically worse long-term results. In summary, early transurethral injection of bulking agents is an effective and minimal invasive therapy option to improve early continence in patients with PPI. Time to improved continence due to training of the sphincter externus muscle cannot be shortened, but the quality of life during this time can be improved. In case of a severe lesion of the sphincteric muscle, continence cannot be improved for a longer period and the results are poor. In these cases, procedures like implantation of an artificial urinary sphincter may be required.

Adult↗
PubMed2005

Optical characterization of the nematic lyotropic chromonic liquid crystals: light absorption, birefringence, and scalar order parameter.

We report on the optical properties of the nematic (N) phase formed by lyotropic chromonic liquid crystals (LCLCs) in well aligned planar samples. LCLCs belong to a broad class of materials formed by one-dimensional molecular self-assembly and are similar to other systems such as "living polymers" and "wormlike micelles." We study three water soluble LCLC forming materials: disodium chromoglycate, a derivative of indanthrone called Blue 27, and a derivative of perylene called Violet 20. The individual molecules have a planklike shape and assemble into rodlike aggregates that form the phase once the concentration exceeds about 0.1 M. The uniform surface alignment of the N phase is achieved by buffed polyimide layers. According to the light absorption anisotropy data, the molecular planes are on average perpendicular to the aggregate axes and thus to the nematic director. We determined the birefringence of these materials in the N and biphasic N-isotropic (I) regions and found it to be negative and significantly lower in the absolute value as compared to the birefringence of typical thermotropic low-molecular-weight nematic materials. In the absorbing materials Blue 27 and Violet 20, the wavelength dependence of birefringence is nonmonotonic because of the effect of anomalous dispersion near the absorption bands. We describe positive and negative tactoids formed as the nuclei of the new phase in the biphasic N-I region (which is wide in all three materials studied). Finally, we determined the scalar order parameter of the phase of Blue 27 and found it to be relatively high, in the range 0.72-0.79, which puts the finding into the domain of general validity of the Onsager model. However, the observed temperature dependence of the scalar order parameter points to the importance of factors not accounted for in the athermal Onsager model, such as interaggregate interactions and the temperature dependence of the aggregate length.

Journal Article↗
PubMed2005

Bone plug length and loading angle determine the primary stability of patellar tendon-bone grafts in press-fit ACL reconstruction.

The present study was conducted to evaluate the influence of bone-plug length on the primary stability of patellar tendon-bone grafts, using a femoral press-fit fixation technique. Forty-eight human PTB grafts with a patellar bone-plug length of 15 mm and 25 mm were obtained from 24 human cadavers (mean age 72 years) and implanted to porcine femora in a press-fit fixation technique. Tensile loading was performed at 10 mm/s until failure at varying loading angles of 0 degrees, 30 degrees and 60 degrees. Compared to 25 mm, a significant decrease of primary graft stability was recorded in the testing of 15-mm bone plugs. For both plug lengths, the ultimate load to failure increased with rising the loading angles. While axial graft loading exclusively caused plug dislocation, the predominant mode of failure was tendon rupture at 60 degrees loading angle. We conclude that 15-mm bone plugs do not result in a sufficient stability for early aggressive rehabilitation and therefore 25-mm bone plugs are recommended for the femoral press-fit technique.

Aged↗
PubMed2005

On multiscale approaches to three-dimensional modelling of morphogenesis.

In this paper we present the foundation of a unified, object-oriented, three-dimensional biomodelling environment, which allows us to integrate multiple submodels at scales from subcellular to those of tissues and organs. Our current implementation combines a modified discrete model from statistical mechanics, the Cellular Potts Model, with a continuum reaction-diffusion model and a state automaton with well-defined conditions for cell differentiation transitions to model genetic regulation. This environment allows us to rapidly and compactly create computational models of a class of complex-developmental phenomena. To illustrate model development, we simulate a simplified version of the formation of the skeletal pattern in a growing embryonic vertebrate limb.

Animals↗