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Biomedical subjects

A Müller

Publications and source records attributed to A Müller.

At least 55 records · Page 3Linked to original sources
PubMed2004

[Prospective comparison of the new indentation tonometer TGdC-01, the non-contact tonometer PT100 and the conventional Goldmann applanation tonometer].

BACKGROUND: This study aimed to compare the results of newer tonometric techniques with standard tonometry for the examples of the Goldmann applanation tonometry (GAT), the indentation tonometer "TGDc-01" and the non-contact tonometer "PT 100". PATIENTS: The study was conducted on a total of 52 healthy subjects. The IOP was measured in each subject on both eyes with all three methods. There were 27 males (51.9 %), 25 females (48.1 %) with an average age of 28.5 years, with a minimum of 13 and a maximum of 79 years. RESULTS: There was no statistically significant difference between the non-contact and the Goldmann applanation tonometry. The measurements were 0.4 mmHg lower, no difference for the left or right side was seen. For IOP higher than 15 mmHg - 0.88 mmHg lower and for IOP lower 15 mmHg - 0.15 mmHg. The results for the "TGDc01" were 0.82 mmHg lower than GAT, the standard deviation was a little higher with 2.9 mmHg compared to 2.67 mmHg for GAT. For IOP higher than 15 mmHg they rose up to - 2.28 mmHg, for IOP lower than 15 mmHg the results for "TGDc-01" were only - 0.2 mmHg lower. There was also an effect with respect to the side, on the right eye the difference was significant with 3.03 mmHg (p = 0.006), in contrast to the left eye with 2.69 mmHg (p = 0.235). For "TGDc01" the standard deviation was higher with 2.9 mmHg compared to 2.6 mmHg for "PT 100". CONCLUSIONS: The non-contact tonometer showed no clinical relevant difference compared with GAT for measuring IOP. The indentation tonometer showed differences for precision, for higher tension IOP the measurement was lower compared with GAT. There was also a significant side difference using the "TGDc-01".

Adolescent↗
PubMed2004

[Multi-center study of the Jenaer model of the temporal bone].

BACKGROUND: Preparing exercises at the temporal bone are a prerequisite for the knowledge of the anatomical special features of this region and for learning the fundamentals of the tympanic cavity surgery. Since however fewer human temporal bones are available, the search for back-up models already took place in the last years. METHODS: Based on the experiences of the handling and visualization of CT data for the 3D-implant construction in the ent department Jena a temporal bone model was developed. The model was sent away to surgeons of different training. On the basis of identification of anatomical structures and evaluation of general parameters by means of a point system the model was evaluated. RESULTS AND CONCLUSIONS: The Jenaer temporal bone model is suitable as entrance into the preparing exercises. The anatomical structures are good to identify for the beginner. The handling with drill and chisel can be learned.

Attitude of Health Personnel↗
PubMed2004

[Modern diagnostics of tracheal stenosis].

BACKGROUND: Numerous new modalities in computertomography (CT), in particular Multislice-Spiral-CT and Virtual Endoscopy, and novel developments in endoscopy and spirometry gave us reason to review the current state of the art in diagnostics of tracheal stenosis (TS). METHODS: This review evaluates the literature of the last decade regarding new trends and methods in diagnostics of tracheal stenosis. Pros and cons are discussed, and the future trends are highlighted. CONCLUSIONS: Spiral-CT scans at collimated slices of < or = 3 mm, PITCH < or = 1.5 and a segmentation level of - 350 HE permit a valid measurement of tracheal lumina. The flow-volume-plot is still the most important investigation to evaluate respiratory function in TS. Peak-Flow-Meters are suitable for patient self monitoring. The selective estimation of the TS related airway resistance using in situ measurements and numerical flow simulation studies are likely to reach importance in future. The ability to obtain exact measures from endoscopic recordings using EndoScan serves quality control in endoscopy. An objective comparison of different treatments becomes possible. Endosonography and methods for in-vitro tissue analysis (Optical Coherence Tomography) are more focused on the early diagnosis of malignant lesions. The Synopsis of endoscopy, CT-scan and spirometry provides the highest diagnostic accuracy today.

Bronchoscopes↗
PubMed2004

Carbon balance in leaves of young poplar trees.

In the present study, important components of carbon metabolism of mature leaves of young poplar trees (Populus x canescens) were determined. Carbohydrate concentrations in leaves and xylem sap were quantified at five different times during the day and compared with photosynthetic gas exchange measurements (net assimilation, transpiration and rates of isoprene emission). Continuously measured xylem sap flow rates, with a time resolution of 15 min, were used to calculate diurnal balances of carbon metabolism of whole mature poplar leaves on different days. Loss of photosynthetically fixed carbon by isoprene emission and dark respiration amounted to 1% and 20%. The most abundant soluble carbohydrates in leaves and xylem sap were glucose, fructose and sucrose, with amounts of approx. 2 to 12 mmol m(-2) leaf area in leaves and about 0.2 to 15 mM in xylem sap. Clear diurnal patterns of carbohydrate concentration in xylem sap and leaves, however, were not observed. Calculations of the carbon transport rates in the xylem to the leaves were based on carbohydrate concentrations in xylem sap and xylem sap flow rates. This carbon delivery amounted to about 3 micromol C m(-2) s(-1) during the day and approx. 1 micromol C m(-2) s(-1) at night. The data demonstrated that between 9 and 28 % of total carbon delivered to poplar leaves during 24 h resulted from xylem transport and, hence, provide a strong indication for a significant rate of carbon cycling within young trees.

Biological Transport↗
PubMed2004

Temporal modulation of an autoprotease is crucial for replication and pathogenicity of an RNA virus.

Pestiviruses belong to the family Flaviviridae, and their genome is a single-stranded RNA of positive polarity encoding one large polyprotein which is further processed into mature proteins. Noncytopathogenic (noncp) strains of the pestivirus bovine viral diarrhea virus (BVDV) can establish persistent infection. In persistently infected animals, noncp BVDVs occasionally acquire mutations in viral nonstructural protein 2 (NS2) that give rise to cytopathogenic (cp) BVDV variants, and, eventually, lead to the onset of lethal disease. A molecular marker of cp BVDV infection is a high-level expression of the replicative NS3 protease/helicase that together with NS2 is derived from NS2-3. Here, we present evidence for NS2-3 autoprocessing by a newly identified cysteine protease in NS2 that is distantly related to the NS2-3 autoprotease of hepatitis C and GB viruses. The vital role of this autoprotease in BVDV infection was established, implying an essential function for NS3 in pestiviral RNA replication which cannot be supplied by its NS2-3 precursor. Accordingly, and contrary to a current paradigm, we detected almost complete cleavage of NS2-3 in noncp BVDV at early hours of infection. At 6 to 9 h postinfection, NS2-3 autoprocessing diminished to barely detectable levels for noncp BVDV but decreased only moderately for cp BVDV. Viral RNA synthesis rates strictly correlated with different NS3 levels in noncp and cp BVDV-infected cells, implicating the NS2 autoprotease in RNA replication control. The biotype-specific modulation of NS2-3 autoprocessing indicates a crucial role of the NS2 autoprotease in the pathogenicity of BVDV.

Amino Acid Sequence↗
PubMed2004

The effects of corneal parameters on the assessment of endothelial cell density in the elderly eye.

BACKGROUND: The possible impact of corneal thickness, curvature, and size on the measurement of endothelial cell density (ECD) has largely been ignored in the normal eye. The aim of this study was to investigate the possible impact of the main corneal parameters on the analysis of ECD values at the central, superior, and temporal parts of the corneal surface. METHODS: All 75 participants (52 females, 23 males) were assessed as part of a pre-cataract surgery investigation. The mean age was 75.7 (SD 10.9) years. Confocal microscopy was used to measure ECD and the percentage of six sided cells at the central, superior, and temporal parts of the cornea. The Orbscan II topography system was used to measure corneal thickness, topography, and horizontal corneal diameter. RESULTS: The mean central ECD measured was 2488 (SD 301) cells/mm(2), compared with 2525 (SD 505) cells/mm(2) in the temporal cornea and 2639 (SD 398) cells/mm(2) in the superior cornea. The regional differences in ECD were not significant (p>0.14). The central ECD was significantly correlated to the central (mean 0.593 (SD 0.039) mm, p = 0.021) as well as the temporal (0.628 (SD 0.039) mm, p<0.001) and the superior corneal thickness (SD 0.644 (SD 0.048) mm, p = 0.018). The mean corneal curvature at the centre (7.7 (SD 0.34) mm, p = 0.002) as well as 3 and 5 mm from the apex was significantly related to ECD (p = 0.008 and p = 0.009, respectively). CONCLUSIONS: The study suggests that in an older population, lower ECD values would be expected in thinner and/or steeper corneas.

Aged↗
PubMed2004

Antioxidant intervention does not affect the response of plasma erythropoietin to short-term normobaric hypoxia in humans.

Recent research has demonstrated that reactive oxygen species (ROS) participate in intracellular signaling processes initiated during hypoxia. We investigated the role of ROS in the response of plasma erythropoietin (Epo) to short-term normobaric hypoxia in humans. Twelve male subjects were exposed twice to 4 h of normobaric hypoxia (H; inspired oxygen fraction 12.5%) with a period of 6 wk between both experiments (H1 and H2). With the use of a randomized placebo-controlled crossover design, the subjects received orally a combination of the antioxidants all-rac-alpha-tocopherol (800 mg/day for 3 wk) and alpha-lipoic acid (600 mg/day for 2 wk) or placebo before H1 and H2, respectively. Three weeks before H1, the subjects underwent one control experiment in normoxia (N; inspired oxygen fraction 20.9%) without any treatment. Serum alpha-tocopherol was significantly higher after treatment with antioxidants compared with placebo. Capillary Po(2) declined during H without significant differences between antioxidants and placebo. Plasma peroxide levels were lower under antioxidant treatment but not affected by hypoxia. The response of Epo to H did not show significant differences between antioxidant [maximum increase (means, 95% confidence interval): +121%, +66 to +176%] and placebo conditions (+108%, +68 to +149%). Similarly, hypoxia-induced increase of Epo corrected for diurnal variations, as revealed during N, did not differ between antioxidants and placebo. Individual variability of Epo in response to H was not related to the individual degree of hypoxemia during H. Our results do not support the assumption that ROS play a major modulating role in the response of Epo to short-term normobaric hypoxia in humans.

Antioxidants↗
PubMed2004

Management of primary breast cancer: an update.

Based on results of trials emerged during the last 2 years and on data presented at the 8th International Conference on Primary Therapy of Early Breast Cancer held in 2003 in St. Gallen, a summary of current knowledge and controversies in the management of breast cancer is given. The following topics are covered: screening, biology, surgery, radiation therapy, primary systemic therapy, and adjuvant therapy (biological therapies, chemotherapy, endocrine therapies including ovarian ablation, and their interactions).

Antineoplastic Agents↗
PubMed2004

Influence of hemodialysis membrane permeability on serum levels of advanced glycation end products (AGEs) and homocysteine metabolites.

BACKGROUND: [corrected] Advanced glycation end products (AGEs), total homocysteine (tHcy) and the homocysteine metabolites cystathionine (Cysta) and dimethylglycine (DMG) are increased in serum of patients with end-stage renal disease. The aim of this prospective randomized study was to compare the efficacy of polysulfone high-flux vs. polysulfone low-flux hemodialysis (HD) treatment regarding removal of AGEs, tHcy, Cysta and DMG. PATIENTS AND METHODS: Twenty-nine patients on chronic HD treatment were randomly assigned to 2 groups in a 3-period 2-treatment design with low flux (A)--high flux (B)--low flux (A) for group I and B-A-B for group II, 6 weeks each period. The following parameters were measured in pre- and postdialytic serum samples at baseline and the end of each period: total serum fluorescence, Nepsilon-carboxymethyllysine (CML), free and protein-bound pentosidine, tHcy, Cysta and DMG. RESULTS: There was increased removal of free pentosidine during high-flux HD treatment compared to low-flux HD treatment, attaining significance between the second and third treatment periods (group 1: 86.0 +/- 4.7% vs. 79.2 +/- 8.8%, p = 0.007; group II: 84.0 +/- 6.3% vs. 79.8 +/- 9.8%, p = 0.049 for high vs. low flux). The intradialytic reduction rates for total serum fluorescence, tHcy, Cysta, DMG did not differ between high- and low-flux HD treatment. Protein-bound pentosidine and CML did not decrease during the dialysis sessions, neither with high-flux nor with low-flux HD membrane. Despite a strong decrease during single HD session, the predialytic levels of free pentosidine, tHcy, Cysta and DMG remained unchanged during the study period both for high- and low-flux HD treatment. CONCLUSION: The more pronounced effect of high-flux dialysis on the removal rate of free pentosidine, found in this randomized crossover study, could not translate into a significant difference in predialysis levels after a 6-week treatment period. We could not find any differences between polysulfone high- and low-flux membranes for lowering predialytic serum concentrations of the measured AGEs, which are mainly bound on albumin.

Arginine↗
PubMed2003

[Psychosocial factors in a fibromyalgia syndrome patient. Assessment by means of electron pain diaries--casuistics and multivariate time series analysis].

OBJECTIVE: Fibromyalgia syndrome (FMS) is a condition of chronic widespread pain. In its process of chronification psychosocial factors play an important role. A multimodal treatment including integrated group therapy has been proved to be effective. Yet little attention has been paid so far to the exact sequence of changes and interrelation between psychosocial factors, functional capacity, and level of pain under integrated group therapy for FMS patients. METHODS: One FMS patient was exemplarily monitored with an electronic diary over 13 weeks while undergoing integrated group therapy. On a daily basis we assessed the level of pain, functional capacity, and other disease-related variables (anxiety, depression, quality of sleep, self-efficacy) via visual analog scales. By the means of multivariate time series analysis the timing of changes in psychosocial factors and their effects on perceived functional capacity was identified. RESULTS: Under integrated group therapy all assessed variables gradually changed in the predicted way. Pain, depression, anxiety could be reduced, whereas self-efficacy, quality of sleep, and functional capacity improved. 71% of the variance could be explained by the multiple regression model. Self-efficacy was, beside pain intensity and depression, an important predictor for functional capacity on the same day. High self-efficacy correlated negatively with the level of functional capacity 3 days later. CONCLUSION: Integrated group therapy proved to be effective. Self-efficacy played an important role regarding the improvement of functional capacity. Depicting the exact timing of changes in the assessed variables helped to detect patterns of influence and indicate directions for further treatment.

Electronics↗
PubMed2003

Precise determination of the 2s(1/2)-2p(1/2) splitting in very heavy lithiumlike ions utilizing dielectronic recombination.

The 2s(1/2)-2p(1/2) energy splittings DeltaE(L) of the lithiumlike ions 19779Au76+, 20882Pb79+, and 23892U89+ have been measured at the Experimental Storage Ring, utilizing low energy dielectronic recombination. The resonance energies in total 41 different 1s(2) 2p(1/2)nl(j(')) (n > or =20) autoionizing Rydberg states populated in the dielectronic capture process have been determined. The 2s(1/2)-->2p(1/2) excitation energies have been obtained by extrapolation of these resonance energies to the associated series limits n--> infinity. The combined analysis of the experimental data for all three ions yields DeltaE(L)=216.134(96) eV for Au76+, 230.650(81) eV for Pb79+, and 280.516(99) eV for U89+.

Journal Article↗
PubMed2003

Effect of smoking on risk factors for cardiovascular disease in patients with diabetes mellitus and renal insufficiency.

BACKGROUND: Many studies have been published demonstrating a strong correlation between smoking, renal lesions and cardiovascular morbidity and mortality. Possible contributing factors are elevated blood pressure values, changes in vascular reactivity, concentrations of lipids, fibrinogen and carboxyhemoglobin, in patients with diabetes mellitus, the quality of diabetes control and insulin resistance. Other possible risk factors may include advanced glycation end (AGE)-products, total plasma homocysteine and metabolites as well as symmetrical (SDMA) and asymmetrical (ADMA) dimethylarginine. It was the goal of the present trial to investigate the serum concentrations of these >new<, possible risk factors in a selection free population of patients with type 1 and insulin-treated type 2 diabetes mellitus, in patients with chronic renal insufficiency and in renal transplant recipients. The second aim was to analyse the effect of cigarette smoking on the levels of these laboratory parameters. PATIENTS AND METHODS: A total of 544 subjects (n = 98 patients with chronic renal insufficiency without hemodialysis, n = 84 patients with hemodialysis, n = 50 renal transplant recipients, n = 114 patients with type 1 and n = 147 patients with insulin treated type 2 diabetes mellitus, n = 51 healthy controls) participated in the trial. RESULTS: Patients with renal insufficiency had significantly higher concentrations of the AGE-products N-epsilon-Carboxymethyllysine (CML) and pentosidine compared with both groups of patients with insulin-treated diabetes mellitus and the healthy controls. In patients with type 1 diabetes there was a positive correlation between HbA1c and the concentration of CML (r = 0.405, p = 0.017) and between the pentosidine-concentration and the serum creatinine-level (r = 0.482, p = 0.001). In type 2 diabetes there was a correlation between CML and diastolic blood pressure (r = 0.239, p = 0.039). In comparison to the healthy controls, patients with renal diseases and patients after kidney transplantation had higher concentrations of total plasma homocysteine and its metabolites. Similar results were found for SDMA and ADMA: Patients with chronic renal insufficiency both with and without hemodialysis had significantly higher values than the renal transplant recipients and healthy controls. A clear influence of cigarette smoking on the levels of the laboratory parameters measured could not be determined in any group; neither in the patients with diabetes mellitus, nor in the patients with renal diseases, nor in the healthy controls. CONCLUSIONS: The present trial demonstrates an increase in the parameters linked to the development of cardiovascular diseases including total plasma homocysteine, its metabolites, the dimethylarginines SDMA and ADMA and advanced glycation end-products depending on the degree of renal insufficiency. Moreover, in patients with insulin-treated diabetes mellitus, the concentrations of the AGE-products CML and pentosidine seem to be strongly influenced by the quality of diabetes control and blood pressure levels. There was no influence of cigarette smoking on the levels of the laboratory parameters measured.

Adult↗
PubMed2003

Observation of trielectronic recombination in Be-like Cl ions.

Recombination involving the core excitation of two electrons, which may be termed trielectronic recombination, has been experimentally identified for the first time. Using Cl13+ ions circulating in the TSR heavy-ion storage ring, we have observed surprisingly strong low-energy trielectronic recombination resonances, comparable to the dielectronic process. At higher electron-ion collision energies, trielectronic recombination is suppressed due to the autoionization of the triply excited intermediate state into excited final states. The formation of the intermediate state depends sensitively on configuration mixing, making trielectronic recombination a challenge to atomic-structure calculations.

Journal Article↗
PubMed2003

[Video-assisted endoscopic sinus revision for treatment of chronic, unilateral odontogenic maxillary sinusitis].

BACKGROUND: The proportion of dental causes of maxillary sinusitis is estimated between 10% and 40%. The mechanisms are manifold and originate from the close relation of the side teeth and the maxillary sinus. In the past, the transantral approach was commonly used by maxillofacial surgeons as their first choice. PATIENTS AND METHODS: Between 01/1999 and 10/2001 38 patients underwent endoscopic surgery controlled via the fossa canina. Apart from the mandatory treatment of the dental focus and the mucosal pathologies, a fenestration to the middle meatus of the nose was performed in 7 cases. RESULTS AND CONCLUSION: The dental medical history, OPG, CT scans in coronary plane, endoscopic findings, and histology showed the commonly "silent" course of dental sinusitis. Typical findings in CT scans are unilateral basal maxillary opacities adjacent to the molar and premolar teeth. In 20% of the cases there was also a blockade of the infundibulum. All patients were reexamined 6-12 months postoperatively. The patients are free of symptoms, but sometimes suffer from headaches. An exact diagnosis and the clear separation of rhinogenic causes are vital points for the therapy of dental sinusitis. In cases of unilateral sinusitis, a comprehensive investigation by the maxillofacial surgeon should be recommended. Video-assisted endoscopic sinus revision is preferable to the transantral approach and is especially suitable for the treatment of mucosal retention cysts, the removal of foreign bodies, endoscopically controlled resections of apical roots, elevations of the sinus floor, and dental implants. If the ethmoidal infundibulum and maxillary ostium are open, no fenestration is needed. In cases of blockade, fenestration to the middle nose canal is indicated.

Bicuspid↗
PubMed2003

Hyperhomocysteinemia as a new risk factor for brain shrinkage in patients with alcoholism.

Chronic alcohol consumption can induce brain atrophy, whereby the exact mechanism of brain damage in alcoholics remains unknown. There is evidence that chronic alcoholism is associated with hyperhomocysteinemia. Homocysteine is an excitatory amino acid which markedly enhances the vulnerability of neuronal cells to excitotoxic and oxidative injury in vitro and in vivo. The present volumetric magnetic resonance imaging study included 52 chronic alcoholics and 30 non-drinking healthy controls. Patients were active drinkers and had an established diagnosis of alcohol dependence. We investigated the influence of different variables on the hippocampal volume of patients suffering from chronic alcoholism. We observed that pathological raised levels of plasma homocysteine showed the most significant correlation to hippocampal volume reduction (P<0.001, multiple regression analysis). Raised plasma levels of homocysteine are associated with hippocampal (brain) atrophy in alcoholism.

Adult↗
PubMed2003

[Extravasation: a rare complication of central venous cannulation? Case report of an imminent erosion of the common carotid artery].

Extravasation is the non-intentional leakage of substances/solutions into the perivascular or subcutaneous space that can result in significant tissue damage. The extent of destruction depends on the properties of the substance, its concentration, and the amount applied. Substances known to cause severe tissue damage include certain chemotherapeutic agents, vasoactive substances, concentrated electrolytes, and other hyperosmolar solutions. Extravasation can be avoided by meticulous monitoring of venous access. When extravasation occurs, the infusion should be stopped immediately. Substances known to cause tissue damage should be removed from perivascular or subcutaneous space within 24 hours by local incision and irrigation. A delay in early treatment may necessitate more extensive surgical debridement and skin coverage operations. Since the extent of deep soft tissue damage is difficult to predict and is often underestimated, a magnetic resonance imaging should be performed before surgery. We report here on a 73-year-old patient, in whom extravasation of potassium-chloride from a dislocated multi-lumen central venous catheter led to a life-threatening skin and soft-tissue necrosis of the neck. This article provides an overview of common vesicants, theories of tissue destruction, potential risk factors, guidelines for prevention, and current treatment strategies.

Aged↗
PubMed2003

[Effect of topical dexamethasone treatment on antigen-presenting cells in murine corneas].

OBJECTIVE: To determine the influence of dexamethasone treatment on APCs and the time of graft survival of MHC-disparate grafts. METHODS: Flatmounts of the ocular surface prepared with EDTA and tangential frozen sections of the remaining corneal stroma from untreated eyes of normal mice (n=6) and from eyes treated for 7 days with dexamethasone ( n=6) were immunohistologically examined for content of F4/80+ and MHC II+ cells.Furthermore, corneas of C(3)H mice without and with 7-day dexamethasone eye drop treatment (n=8) were grafted into BALB/c mice receiving the same treatment. RESULTS: The number of positive cells within the epithelial flatmounts showed a dramatic reduction in the dexamethasone-pretreated group (p<0.01 compared to the untreated control group). The number of positive cells in the corneal stroma remained unchanged. The grafts of untreated control mice survived 16+/-4 days, the treated grafts 16+/-3 days. CONCLUSIONS: Most investigators assume that normal murine corneas contain no APCs such as macrophages and Langerhans cells. For the first time we were able to detect APCs in flatmounts of the ocular surface and frozen sections of corneal stroma. Our investigations show that, in contrast to the ocular surface, the number of F4/80+ cells in the corneal stroma is not influenced by dexamethasone treatment. Transplantation of corneas containing donor-derived APCs promotes acute rejection (direct pathway of allorecognition).Thus,dexamethasone treatment did not prolong the time of allograft survival.

Administration, Topical↗