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Biomedical subjects

M Müller

Publications and source records attributed to M Müller.

At least 109 records · Page 6Linked to original sources
PubMed2004

[A 52-year old female patient with recurrent shock of unclear origin, hemoconcentration and hypoalbuminemia].

Systemic capillary leak syndrome is a rare life threatening condition of unknown etiology. It was firstly described by Clarkson et al in 1960. It is characterised by recurrent attacks of severe hypovolemic shock, hemoconcentration and hypalbuminemia, caused by a sudden reversible increase in capillary permeability and shift of fluid and macromolecules to the extravascular compartment. A monoclonal paraprotein is always detectable in the serum of patients, without evidence of multiple myeloma. We describe the course of a patient, who died at a severe attack despite of prophylactic treatment after 25 months of illness. Application of cytostatics should be considered if prophylactic treatment fails even if there is no evidence of progression to multiple myeloma.

Capillary Leak Syndrome↗
PubMed2004

[Curative therapy in symptomatic atrial ectopy].

A female patient without underlying heart disease was highly symptomatic from short runs of atrial ectopy. Sustained atrial tachycardia or atrial fibrillation never occurred. Due to ineffective pharmacological therapy, catheter ablation combined with electroanatomic mapping (CARTO) was performed effectively. Characteristics of ectopic atrial tachycardia and the electrophysiological techniques are described.

Adult↗
PubMed2004

[Feasibilities and limitations of high field parallel MRI].

In medical magnetic resonance imaging (MRI) it is standard to use MR scanners with a field strength of 1.5 Tesla. Recently, an ongoing development to higher field strength can be observed and a new clinical standard at 3.0 Tesla seems to be established. High field MRI with its intrinsic higher signal to noise ratio (SNR) can enable new applications of MRI in medical diagnosis, or can serve to improve existing methods. It is important to note, that the use of high field MRI is not without its limitations. Besides the SNR, other unwanted effects increase with a higher field strength. Without correction, these high field problems cause a serious loss in image quality. An elegant way to address these problems is the use of parallel imaging. In many clinical applications, parallel MRI (pMRI) is part of the standard protocol, because pMRI can enhance virtually every MRI application, without necessarily affecting the contrast behavior of the underlying imaging sequence. In high field MRI, besides the speed advantage of pMRI, the positive influence on high field specific problems and therefore on the image quality will be of major importance.

Artifacts↗
PubMed2004

[Polyhexamethylbiguanid (PHMB) as preoperative antiseptic for cataract surgery].

BACKGROUND: We examined the efficacy and tolerability of Lavasept (polyhexamethylenbiguanid or PHMB)-an iodine-free antiseptic-in comparison to polyvinylpyrolidon iodine and Ringer's solution, as an alternative preoperative antiseptic. PATIENTS AND METHODS: In a randomized controlled double-blind trial 3 drops of Lavasept, 1.25%, PVP-iodine or Ringer's solution were applied preoperatively in 29 patients. The number of colony forming units (cfu) grown from conjunctival smears and conjunctival hyperaemia, corneal epitheliopathy and ocular surface pain were assessed preoperatively, intraoperatively and 1 day postoperatively. RESULTS: Despite intraoperative application of PVP-iodine, 40% of patients receiving Ringers solution still presented with more than 5 colony forming units (cfu) at the end of the procedure, while all patients that had additional preoperative Lavasept or PVP-iodine achieved relative sterility with less than 5 cfu (p < 0.05). While the effect of Lavasept lasted until the next day, conjunctival microbial colonisation recurred in eyes treated with PVP-iodine. As expected conjunctival hyperaemia and corneal epitheliopathy increased significantly postoperatively but no differences were observed between the 3 solutions tested. CONCLUSION: The preoperative application of Lavasept reduces the conjunctival flora safely and effectively. The microbicidal efficacy is equal to PVP-iodine, but potentially longer lasting. No signs of local or systemic intolerability were observed. Lavasept may be used as a potential alternative preoperative antiseptic and is suitable for iodine-intolerant patients.

Adult↗
PubMed2004

Identification and ablation of atypical atrial flutter. Entrainment pacing combined with electroanatomic mapping.

Differentiation between typical and atypical atrial flutter solely based upon surface ECG pattern may be limited. However, successful ablation of atrial flutter depends on the exact identification of the responsible re-entrant circuit and its critical isthmus. Between August 2001 and June 2003, we performed conventional entrainment pacing within the cavotricuspid isthmus in 71 patients with sustained atrial flutter. In patients with positive entrainment we considered the arrhythmia as typical flutter and treated them with conventional ablation of the cavotricuspid isthmus. As a consequence of negative entrainment we performed 3D-electroanatomic activation mapping (CARTO trade mark ). Conventional ablation of the right atrial isthmus was successful in all patients (n = 54) with positive entrainment. We performed electroanatomic mapping in the remaining 17 patients (14 male; age 60.9 +/- 16 years) resulting in the identification of 6 cases with typical and 11 cases with atypical flutter. Therefore, entrainment pacing was able to predict the true presence of typical atrial flutter in 91.5%. Atypical flutter was right sided in 4 patients and left sided in 7 cases. Electrically silent ("low voltage") areas probably demonstrating atrial myopathy were identified in all cases with left sided and in 2 patients with right sided flutter. In these patients targets for ablation lines were located between silent areas and anatomic barriers (inferior pulmonary veins, mitral respectively tricuspid annulus, or vena cava inferior). In 1 patient, the investigation was stopped due to variable ECG pattern and atrial cycle lengths. In the remaining cases, ablation was acutely successful. One patient, after surgical closure of a ventricular septal defect, demonstrated a dual-loop intra-atrial reentry tachycardia dependent on two different isthmuses. This arrhythmia required ablation of those distinct isthmuses to be interrupted. After a mean follow-up of 8.8 +/- 3.4 months, there was one patient with a recurrence of left-sided atrial flutter. Another patient developed permanent atrial fibrillation shortly after the procedure. Mean duration time of the procedure was 235.6 +/- 56.4 min (right atrium: 196 +/- 17.3 min; left atrium: 267.2 +/- 59.5 min), and average fluoroscopy time was 21.8 +/- 11.7 min (right atrium: 9.5 +/- 6 min; left atrium: 28.9 +/- 7 min). There was no incidence of serious complications associated with these procedures. In conclusion, conventional pacing in the cavotricuspid isthmus combined with electroanatomic mapping was an effective method to differentiate between typical and atypical atrial flutter. Electroanatomic mapping was a powerful tool both for identification of different atrial re-entrant circuits including their critical isthmuses as well as for effective application of individual ablation line strategies.

Adolescent↗
PubMed2004

[Clinical experiences with cooled radiofrequency ablation of ectopic atrial tachycardia employing an electroanatomic mapping system].

Due to its variable origin success for ablation of ectopic atrial tachycardia (EAT) has been difficult to achieve using conventional mapping and ablation strategies. In contrast, no information in the literature is available about the use of a nonfluoroscopic, 3-dimensional electroanatomic mapping system (CARTO) combined with the cooled ablation technology creating deeper lesions in experimental studies compared to standard catheters. In 20 consecutive patients (15 female; age 52.5 +/- 15.4 years), a single focus responsible for clinical EAT has been mapped. Twelve EATs were located in the right atrium, whereas 8 foci were left sided including 3 origins within a pulmonary vein (PV). Due to the reported development of PV stenosis in the ablative treatment of focal atrial fibrillation, direct ablation applied inside the PV was avoided. Instead, PV-disconnection achieved by the use of a Lasso trade mark catheter in 1 case and by circumferential ablation around the PV in 2 other patients was preferred. In 2 patients, ablation was not attempted because of an origin located directly in the area of the atrioventricular node. In another case, CARTO mapping was stopped due to persistent mechanical termination of the tachycardia with no possibility of reinduction. In the latter, ablation was performed in sinus rhythm at the earliest mapped site before terminating. Three weeks later another episode of EAT was noted in this patient. In the remaining 17 cases, ablation was associated with acute success and no recurrences of sustained tachycardia in all patients. Mean duration time was 192 +/- 53.3 min (right atrium 161 +/- 37.9 min; left atrium 229.6 +/- 46.2 min), and average fluoroscopic time was 22.8 +/- 9.7 min (right atrium 17.1 +/- 6.2 min; left atrium 29.8 +/- 8.9 min). There was no incidence of serious complications associated with this procedure. In conclusions, electroanatomical mapping including cooled ablation was a safe and feasible strategy in treating EATs. The benefit of this technique may imply the combination of both precise localization of the focus and effective applications of radiofrequency pulses, thereby minimizing acute failures or reablation. Due to the time consuming point by point data acquisition, the ability to generate precise maps demonstrating the earliest activation at their exact anatomical location can be limited by transient or persistent termination of the tachycardia.

Adult↗
PubMed2004

Effect of surface finish on the osseointegration of laser-treated titanium alloy implants.

It was the purpose of this study to examine the osseointegration of laser-textured titanium alloy (Ti6Al4V) implants with pore sizes of 100, 200, and 300 microm, specifically comparing 200-microm implants with polished and corundum-blasted surfaces in a rabbit transcortical model. Using a distal and proximal implantation site in the distal femoral cortex, each animal received all four different implants in both femora. The bone-implant interface and the newly formed bone tissue within the pores and in peri-implant bone tissue were examined 3, 6, and 12 weeks post-implantation by static and dynamic histomorphometry. Here we show that additional surface blasting of laser-textured Ti6Al4V implants with 200-microm pores resulted in a profound improvement in osseointegration, 12 weeks postimplantation. Although lamellar bone formation was found in pores of all sizes, the amount of lamellar bone within pores was linearly related to pore size. In 100-microm pores, bone remodeling occurred with a pronounced time lag relative to larger pores. Implants with 300-microm pores showed a delayed osseointegration compared with 200-microm pores. We conclude that 200 microm may be the optimal pore size for laser-textured Ti6Al4V implants, and that laser treating in combination with surface blasting may be a very interesting technology for the structuring of implant surfaces.

Alloys↗
PubMed2004

Biocompatibility of beta-stabilizing elements of titanium alloys.

In comparison to the presently used alpha + beta titanium alloys for biomedical applications, beta-titanium alloys have many advantageous mechanical properties, such as an improved wear resistance, a high elasticity and an excellent cold and hot formability. This will promote their future increased application as materials for orthopaedic joint replacements. Not all elements with beta-stabilizing properties in titanium alloys are suitable for biomaterial applications-corrosion and wear processes cause a release of these alloying elements to the surrounding tissue. In this investigation, the biocompability of alloying elements for beta- and near beta-titanium alloys was tested in order to estimate their suitability for biomaterial components. Titanium (grade 2) and the implant steel X2CrNiMo18153 (AISI 316 L) were tested as reference materials. The investigation included the corrosion properties of the elements, proliferation, mitochondrial activity, cell morphology and the size of MC3T3-E1 cells and GM7373 cells after 7 days incubation in direct contact with polished slices of the metals. The statistical significance was considered by Weir-test and Lord-test (alpha = 0.05). The biocompatibility range of the investigated metals is (decreasing biocompatibility): niobium-tantalum, titanium, zirconium-aluminium-316 L-molybdenum.

3T3 Cells↗
PubMed2004

Determination of Henry's law constant for methyl tert-butyl ether (MTBE) at groundwater temperatures.

The dimensionless Henry's law constant was determined for methyl tert-butyl ether (MTBE) at six temperatures (3, 5, 10, 15, 20 and 25 degrees C) by using a thermostatted flask (430 ml) containing an aqueous MTBE solution. The ratio between the gas phase and the water phase in the flask was approximately 1.7:1. The aim of this study was to acquire data needed to model the behaviour of MTBE at groundwater conditions. The dimensionless Henry's law constant at 10 degrees C is approximately 0.01 but is 0.03 at 25 degrees C. This is important for modelling MTBE because the variation of vaporization cannot be disregarded at groundwater temperatures. In a second experiment the water solubility of MTBE was determined to be 62.1 g/l at 5 degrees C and 35.5 g/l at 20 degrees C). The high solubility at low temperatures could cause MTBE plumes from spills (fuel accidents etc.) to spread rapidly.

Fresh Water↗
PubMed2004

Playing piano in the mind--an fMRI study on music imagery and performance in pianists.

Reading of musical notes and playing piano is a very complex motor task which requires years of practice. In addition to motor skills, rapid and effective visuomotor transformation as well as processing of the different components of music like pitch, rhythm and musical texture are involved. The aim of the present study was the investigation of the cortical network which mediates music performance compared to music imagery in 12 music academy students playing the right hand part of a Bartok piece using functional magnetic resonance imaging (fMRI). In both conditions, fMRI activations of a bilateral frontoparietal network comprising the premotor areas, the precuneus and the medial part of Brodmann Area 40 were found. During music performance but not during imagery the contralateral primary motor cortex and posterior parietal cortex (PPC) bilaterally was active. This reflects the role of primary motor cortex for motor execution but not imagery and the higher visuomotor integration requirements during music performance compared to simulation. The notion that the same areas are involved in visuomotor transformation/motor planning and music processing emphasizes the multimodal properties of cortical areas involved in music and motor imagery in musicians.

Adult↗
PubMed2004

Matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry in lipid and phospholipid research.

The interest in the analysis of lipids and phospholipids is continuously increasing due to the importance of these molecules in biochemistry (e.g. in the context of biomembranes and lipid second messengers) as well as in industry. Unfortunately, commonly used methods of lipid analysis are often time-consuming and tedious because they include previous separation and/or derivatization steps. With the development of "soft-ionization techniques" like electrospray ionization (ESI) or matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF), mass spectrometry became also applicable to lipid analysis. The aim of this review is to summarize so far available experiences in MALDI-TOF mass spectrometric analysis of lipids. It will be shown that MALDI-TOF MS can be applied to all known lipid classes and the characteristics of individual lipids will be discussed. Additionally, some selected applications in medicine and biology, e.g. mixture analysis, cell and tissue analysis and the determination of enzyme activities will be described. Advantages and disadvantages of MALDI-TOF MS in comparison to other established lipid analysis methods will be also discussed.

Brain Chemistry↗
PubMed2004

Prostate cancer metastatic to the stomach.

Metastatic prostate cancer has poor prognosis, with survival rates ranging from 1 to 3 years. Frequent sites for metastases are the skeletal system and lymph nodes; metastases to the gastrointestinal tract are rare. Although most patients become symptomatic with bone or flank pain, the patient we report initially presented with severe nausea and vomiting accompanied by moderate back pain. His prostate-specific antigen level was 171 ng/mL. Computed tomography and bone scan revealed retroperitoneal lymphadenopathy and bone metastasis. Cranial computed tomography was negative for metastasis but upper endoscopy and biopsy revealed a metastatic lesion from prostate cancer.

Adenocarcinoma↗
PubMed2004

Quantitative detection of cytokeratin 20 mRNA expression in bladder carcinoma by real-time reverse transcriptase-polymerase chain reaction.

OBJECTIVES: To determine cytokeratin 20 (CK 20) expression in tumor tissue, normal urothelial tissue, bladder washings, and urine from patients with urothelial carcinoma by real-time reverse transcriptase-polymerase chain reaction using the LightCycler Instrument. METHODS: Urine, bladder washings, tumor, and normal urothelial tissue were obtained from 33 patients with bladder carcinoma. RNA was subsequently extracted. Twenty tissue samples from healthy volunteers were used as controls. Real-time reverse transcriptase-polymerase chain reaction with the LightCycler was performed using fluorescence-labeled CK 20 primers as the target gene and the porphobilinogen deaminase housekeeping gene as the internal standard. RESULTS: CK 20 mRNA expression was detected in all samples investigated. CK 20 expression in the tissue and urine samples from patients with tumor was significantly increased compared with that in normal urothelial tissue (P = 0.028) or urine from the negative control group (P = 0.012). The average CK 20 expression was 70,140 arbitrary units (AU) in tumor tissue (30,533 AU in urine from patients with tumor) and 8460 AU in normal urothelial tissue (2234 AU in normal urine). A stage-related difference in CK 20 mRNA expression was observed in tumor tissue (P = 0.027) and for tumor grade G1-G2 versus G3 (P = 0.03). CONCLUSIONS: CK 20 mRNA expression levels in tissue and urine were elevated in patients with urothelial carcinoma compared with the levels in healthy individuals. CK 20 expression was also detectable in normal urine or normal urothelial tissue, but at significantly lower levels than in tumor samples. Fluorescence-labeled quantitative polymerase chain reaction using the LightCycler helped to differentiate between low-level CK 20 expression in normal urothelial tissue and the levels in tumor tissue samples. CK 20 might be an excellent and sensitive marker for tumor monitoring and routine follow-up in patients with transitional cell carcinoma.

Aged↗
PubMed2004

A coding mutation within the first exon of the human MD-2 gene results in decreased lipopolysaccharide-induced signaling.

MD-2 is an accessory protein of the Toll-like receptor (TLR)-4, necessary for assembling a receptor complex to sense low quantities of lipopolysaccharide in order to subsequently trigger innate immune responses. MD-2 and TLR-4 are expressed on a variety of immunocompetent cells. Mutations within the TLR-4 gene have been shown to attenuate immune responses against lipopolysaccharide in mice. In humans, a TLR-4 polymorphism has been associated with a higher risk for developing severe Gram-negative sepsis and with a lower risk for atherosclerosis. Since MD-2 is an essential part of the lipopolysaccharide receptor complex, we screened 20 patients that underwent surgical cancer therapy for novel MD-2 mutations by a single-strand conformation polymorphism technique. In one patient we found an A --> G substitution at position 103, resulting in an amino-acid exchange from Thr 35 to Ala. Reporter gene assays revealed that this mutation resulted in a reduced lipopolysaccharide-induced signaling. The patient displayed an uneventful postoperative course, with the exception of slightly decreased TNF-alpha levels after in vitro stimulation with LPS as compared to wt patients. Genotyping of a further 41 patients by a newly developed Lightcycler/FRET method failed to detect any additional polymorphism carriers, indicating that this is a rare mutation.

Alanine↗
PubMed2004

Locking compression plate loosening and plate breakage: a report of four cases.

The Locking Compression Plate (LCP) system offers a number of advantages in fracture fixation combining angular stability through the use of locking screws with traditional fixation techniques. This makes the implant particularly suitable for use in poor bone stock and complex joint fractures, especially in the epimetaphyseal area. However, the system is complex, requiring careful attention to biomechanical principles, and a number of potential pitfalls need to be considered. These pitfalls are illustrated in the 4 cases described herein, in which treatment was unsuccessful due to implant breakage or loosening. In each case, treatment failure could be attributed to the choice of an inappropriate plate and/or fixation technique, rather than to the features of the Locking Compression Plate system itself. Such experiences highlight the importance of detailed understanding of the biomechanical principles of plate fixation as well as careful preoperative planning for the successful use of the Locking Compression Plate system.

Aged↗
PubMed2004

Analysis of gyrA mutations in quinolone-resistant and -susceptible Campylobacter jejuni isolates from retail poultry and human clinical isolates by non-radioactive single-strand conformation polymorphism analysis and DNA sequencing.

AIMS: The aims of this study were to characterize the molecular variations in the quinolone resistance-determining region (QRDR) of gyrA among quinolone-resistant and -susceptible Campylobacter jejuni isolates originating from foods of animal origin and human infections and to evaluate the suitability of the single-strand conformation polymorphism (SSCP) method as a screening method for molecular characterization of fluoroquinolone resistance. METHODS AND RESULTS: Alterations in QRDR of gyrA from 182 C. jejuni isolates were determined by nonradioisotopic SSCP analysis and direct sequencing. A total of 13 types of nucleic acid sequence combinations within the QRDR of the gyrA gene resulted in 11 different SSCP patterns. All nalidixic acid resistant strains possessed nucleotide substitution at either codon Thr-86 or Asp-90. Silent mutations were detected additionally. Thr-86 to Ile mutation was detected in all 139 ciprofloxacin resistant strains, which showed cross-resistance to nalidixic acid. CONCLUSIONS: The SSCP method is suitable for a molecular screening of quinolone resistant C. jejuni isolates and in combination with DNA sequencing suitable to detect genetic variations of the QRDR of gyrA. SIGNIFICANCE AND IMPACT OF STUDY: This study provides data of the genetic variations of the QRDR of gyrA from C. jejuni isolates of foods and human beings.

Animals↗
PubMed2004

Optimizing open live-donor nephrectomy - long-term donor outcome.

INTRODUCTION: The technique of laparoscopic or retroperitoneoscopic donor nephrectomy has been increasingly propagated in recent years. The central advantage is supposed to be a reduction of perioperative discomfort. However, there have not been many reports describing the subjective feeling associated with an open donor nephrectomy, particularly with respect to the pain level in the perioperative and long-term course. This retrospective study examines the perioperative pain and morbidity and long-term outcome of living kidney donors from 35 yr of experience at the University Hospital Benjamin Franklin of the Free University of Berlin. METHODS: A total of 102 living kidney donors were asked to fill out a questionnaire. Five epidemiological questions were posed and the rest dealt mainly with lasting subjective and objective surgical impairments. There were also questions relating to the perioperative pain level (VAS/NAS-Score). In addition, basic information was obtained regarding the donor's current health status (physical examination, serum creatinine; sometimes also ultrasound, protein IU, blood pressure), and/or examinations were performed. RESULTS: The mean age at the time of donation was 45.5 and 55% were women. Donor nephrectomies were left-sided in 78 cases and right-sided in 24. There was a total complication rate of 53%, but serious complications only occurred in two cases (1.9%). A total of 53 donors could be reached. Although 41.5% felt they had a lasting impairment, somatic sequelae like respiratory, abdominal or scar problems were rare, affecting a maximum of only four patients in each case. Fifteen patients reported neurological problems such as sensory disturbances. The mean serum creatinine was 89.9 micromol/L in female and 114.2 micromol/L in male donors. Microalbuminuria was found in 22.6% of the donors, hypertension in 35.8%. Persistent pain was reported by 20.7%, its occurrence being permanent in two of the donors and very frequent in one. All the others rarely have pain. The median perioperative VAS/NAS score was 8 on the first day after surgery, 5 after 1 wk and 1 after 1 month. The analgesia was rated as good or very good by 71%. Everyday life was managed as well as before surgery after 2-4 wk by the highest percentage (42%) of patients, but working capacity was only regained after 1-3 months by a comparable percentage (44%). Forty-six percent had a very good and 33% a good feeling after the kidney donation. The relationship to the recipient had intensified in most cases. Ninety-one percent would again decide in favor of a donation. CONCLUSION: Donor nephrectomy in an open technique is a safe and reliable procedure with low morbidity. After a median post-operative period of 7 yr, however, 42% of the donors still report general impairment due to the intervention, although concrete somatic problems were only detected in a few cases. Nearly all these patients underwent surgery in a full flank position. Wound-healing impairments were also significantly more frequent with this surgical technique. This positioning should thus be avoided. The post-operative pain level was relatively high, but a marked improvement was achieved in the course of the observation period by optimizing analgesic management.

Female↗