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Biomedical subjects

W Eberhardt

Publications and source records attributed to W Eberhardt.

At least 19 recordsLinked to original sources
PubMed2006

Induction chemotherapy, concurrent chemoradiation and surgery for Pancoast tumour.

The traditional treatment of Pancoast tumour with local approaches (surgery, radiotherapy or a combination of both) leads to a poor outcome due to the high rate of incomplete resection and the lack of systemic control. The aim of the present prospective feasibility study was to determine whether a trimodality approach improves local control and survival. Patients with stage IIB-IIIB Pancoast tumour received induction chemotherapy (three courses of split-dose cisplatin and etoposide or paclitaxel) followed by concurrent chemoradiotherapy (a course of cisplatin/etoposide combined with 45 Gy hyperfractionated accelerated radiotherapy). After restaging, eligible patients underwent surgery 4-6 weeks post-radiation. A total of 31 consecutive patients with T3 (81%) or T4 (19%) Pancoast tumour were enrolled in the study. Induction chemoradiotherapy was completed in all patients without treatment-related deaths. Grade 3-4 toxicity was observed in 32% of cases. In total, 29 (94%) patients were eligible for surgery. Complete resection was achieved in 94% of patients. The post-operative mortality rate was 6.4% and major complications arose in 20.6% of the patients. The median survival was 54 months with 2- and 5-yr survival rates of 74 and 46%, respectively. In conclusion, this intensive multimodality treatment of Pancoast tumour is feasible and improves local resectability rates and long-term survival as compared with historical series.

Adult↗
PubMed2006

Molecular and electronic structure in NaCl electrolytes of varying concentration: identification of spectral fingerprints.

Near edge x-ray absorption spectra at the Na K edge in aqueous NaCl electrolytes are presented as a function of concentration. The spectra are modeled by electronic structure calculations. We find and identify the orbital origin of two spectral fingerprints with sensitivity to the Na+-H2O distance and the Na+-Cl- distance in the electrolyte. Interionic interaction is found to be crucial for the description of the electrolytes at high concentrations.

Journal Article↗
PubMed2004

Lensless imaging of magnetic nanostructures by X-ray spectro-holography.

Our knowledge of the structure of matter is largely based on X-ray diffraction studies of periodic structures and the successful transformation (inversion) of the diffraction patterns into real-space atomic maps. But the determination of non-periodic nanoscale structures by X-rays is much more difficult. Inversion of the measured diffuse X-ray intensity patterns suffers from the intrinsic loss of phase information, and direct imaging methods are limited in resolution by the available X-ray optics. Here we demonstrate a versatile technique for imaging nanostructures, based on the use of resonantly tuned soft X-rays for scattering contrast and the direct Fourier inversion of a holographically formed interference pattern. Our implementation places the sample behind a lithographically manufactured mask with a micrometre-sized sample aperture and a nanometre-sized hole that defines a reference beam. As an example, we have used the resonant X-ray magnetic circular dichroism effect to image the random magnetic domain structure in a Co/Pt multilayer film with a spatial resolution of 50 nm. Our technique, which is a form of Fourier transform holography, is transferable to a wide variety of specimens, appears scalable to diffraction-limited resolution, and is well suited for ultrafast single-shot imaging with coherent X-ray free-electron laser sources.

Journal Article↗
PubMed2004

Oscillatory magnetic anisotropy in one-dimensional atomic wires.

One-dimensional Co atomic wires grown on Pt(997) have been investigated by x-ray magnetic circular dichroism. Strong changes of the magnetic properties are observed as the system evolves from 1D- to 2D-like. The easy axis of magnetization, the magnetic anisotropy energy, and the coercive field oscillate as a function of the transverse width of the wires, in agreement with theoretical predictions for 1D metal systems.

Journal Article↗
PubMed2004

New targeted treatments in lung cancer--overview of clinical trials.

Combination chemotherapy has been established as the cornerstone of systemic treatment for advanced lung cancer in the last ten to fifteen years. However, improvements with new drug combinations in recent years have been rather small and a general outcome plateau has been reached with one-year survival rates of about 40% and two-year survival rates of less than 15%. Survival over three to four years is still a rare event in this disease, and more and more efforts are being made to develop innovative systemic treatment strategies with mechanisms of action different from conventional cytotoxic drugs. These molecular targeted agents have made a strong move forward in the management of this disease since Gefitinib--a small molecule EGF-receptor tyrosine kinase inhibitor--was registered in 2003 by the FDA and a number of further countries for the third-line treatment of non-small-cell lung cancer. Since then, every month findings have been reported about new cellular targets on lung-cancer cells and, consequently, new agents aiming at these molecular targets are being developed, preclinically. Some of these agents have already been tested in the clinics within phase-I, phase-II and some even within randomised phase-III trials. In this review we will try to summarise the current knowledge and data on the clinical activity of these new drugs in lung cancer and to give a perspective on the future for these new treatment principles. The most promising strategies have been aiming at the EGF-receptor family, serum-VEGF and the VEGF-receptor family (VEGF-1 and -2, respectively). Results from pivotal registration trials are expected within the next one or two years for a number of these new drugs, and the standards of care for advanced lung cancer may change dramatically, comparable to what we have seen in other solid tumours such as metastasised breast and colon cancer.

Antibodies, Monoclonal↗
PubMed2003

Femtosecond electron and spin dynamics in Ni/W(110) films.

The collapse of the magnetic exchange splitting in 7 monolayer thick epitaxial Ni/W(110) films following a femtosecond laser pulse was measured using time-resolved photoemission spectroscopy. Ultrafast demagnetization during the laser induced hot electron cascade proceeds via spin-flip excitations with a relaxation time constant of 300+/-70 fs. At longer times the electronic system cools down and the magnetization is finally reestablished with a time constant of 3.2+/-0.2 ps.

Journal Article↗
PubMed2002

Ferromagnetism in one-dimensional monatomic metal chains.

Two-dimensional systems, such as ultrathin epitaxial films and superlattices, display magnetic properties distinct from bulk materials. A challenging aim of current research in magnetism is to explore structures of still lower dimensionality. As the dimensionality of a physical system is reduced, magnetic ordering tends to decrease as fluctuations become relatively more important. Spin lattice models predict that an infinite one-dimensional linear chain with short-range magnetic interactions spontaneously breaks up into segments with different orientation of the magnetization, thereby prohibiting long-range ferromagnetic order at a finite temperature. These models, however, do not take into account kinetic barriers to reaching equilibrium or interactions with the substrates that support the one-dimensional nanostructures. Here we demonstrate the existence of both short- and long-range ferromagnetic order for one-dimensional monatomic chains of Co constructed on a Pt substrate. We find evidence that the monatomic chains consist of thermally fluctuating segments of ferromagnetically coupled atoms which, below a threshold temperature, evolve into a ferromagnetic long-range-ordered state owing to the presence of anisotropy barriers. The Co chains are characterized by large localized orbital moments and correspondingly large magnetic anisotropy energies compared to two-dimensional films and bulk Co.

Journal Article↗
PubMed2002

Photon-induced thermal desorption of CO from small metal-carbonyl clusters.

Thermal CO desorption from photoexcited free metal-carbonyl clusters has been resolved in real time using two-color pump-probe photoelectron spectroscopy. Sequential energy dissipation steps between the initial photoexcitation and the final desorption event, e.g., electron relaxation and thermalization, have been resolved for Au2(CO)(-) and Pt2(CO)5-. The desorption rates for the two clusters differ considerably due to the different numbers of vibrational degrees of freedom. The unimolecular CO-desorption thresholds of Au2(CO)(-) and Pt2(CO)5- have been approximated by means of a statistical Rice-Ramsperger-Kassel calculation using the experimentally derived desorption rate constants.

Journal Article↗
PubMed2002

Induction chemotherapy followed by concurrent chemotherapy and definitive high-dose radiotherapy for patients with locally advanced non-small-cell lung cancer (stages IIIa/IIIb): a pilot phase I/II trial.

BACKGROUND: Overall prognosis of patients with locally advanced non-small-cell lung cancer (LAD-NSCLC) is still unfavourable. Different attempts to improve treatment results have been made using combinations of chemotherapy and radiotherapy. The aim of this pilot phase I/II investigation was to test the feasibility and toxicity of a definitive multimodality protocol in patients with irresectable NSCLC stages IIIA (N2) and IIIB. PATIENTS AND METHODS: Thirty LAD-NSCLC patients (stages IIIA/IIIB: 3/27; median age: 54 years, range 34-70; male/female: 17/13) who were consecutively enrolled onto our ongoing neoadjuvant multimodality protocol from October 1996 to February 1999 remained inoperable after induction treatment. Three cycles of cisplatin/etoposide (PE) were followed by hyperfractionated accelerated radiotherapy (HF-RTx: 1.5 Gy bid up to a total dose of 45 Gy in 3 weeks) concurrent with one cycle of PE. Definitive local treatment was completed with a small volume boost of 20 Gy (qd), adding up to a total dose of 65 Gy to the primary. Patients were routinely offered prophylactic cranial irradiation (PCI; 30 Gy; 2 Gy qd). RESULTS: Overall toxicity of the definitive CTx/RTx protocol-the main endpoint of this investigation-turned out to be acceptable (oesophagitis grade 3/4: 6/4 patients; pneumonitis grade 3/4: 0/1 patients; no treatment-related deaths). Actuarial survival at 2 years was 31% with a loco-regional control rate of 21%. CONCLUSIONS: This regimen turned out to be feasible with acceptable toxicity and will serve as a reference arm in a planned randomised trial in stage IIIB NSCLC, testing the value of surgery in this setting: preoperative induction CTx/RTx followed by surgery versus definitive CTx/RTx.

Adult↗
PubMed2002

[Heart assist systems with integrated microsensors (HIM 2)].

The use of intracardiac pump systems is leading to more physiological support for coronary surgery patients. But the currently available micro blood pump with an integrated micro pressure sensor and an outer diameter of 6.5 mm is not suitable for a transfemoral placement of the device. Therefore a significantly smaller pump with an outer diameter of 4 mm (12F) is been developed and tested. To transfer the sensor technology in this, for the first time the MID (moulded interconnected device) technology is applied in a medical device. In a first step MID is used to integrate a smaller pressure sensor on the existing blood pump. The result should help to find a new packaging and connecting solution for integration of the miniaturized sensor on the 4 mm pump.

Assisted Circulation↗
PubMed2001

Downregulation of integrin-linked kinase mRNA expression by nitric oxide in rat glomerular mesangial cells.

Inflammatory glomerular diseases are accompanied by changes in the expression patterns of growth factors, mediators and matrix-associated proteins in mesangial cells and by the production of nitric oxide via the cytokine-inducible form of the nitric oxide synthase. Nitric oxide has been shown to act potently on gene transcription. To identify genes that are differentially expressed by endogenously produced nitric oxide, we forced rat mesangial cells to produce high amounts of nitric oxide by exposure to inflammatory cytokines and compared the mRNA expression patterns of cytokine-stimulated mesangial cells with cells that were additionally treated with the nitric oxide synthase inhibitor L-NMMA to block endogenous NO synthesis. We used a modification of a low stringency RT-PCR approach designated as RNA arbitrarily-primed polymerase chain reaction (RAP-PCR). In this way, we identified among others the integrin-linked kinase (ILK) as an NO-regulated gene. The NO-mediated changes in the mRNA and protein expression patterns of ILK were compared to that of "secreted protein acidic and rich in cystein" (SPARC), a gene that was identified as NO-regulated in the same set of experiments (Walpen et al., J. Am. Soc. Nephrol., 11, 468-476). ILK and SPARC mRNA levels by were downregulated by cytokines via endogenously produced nitric oxide in a comparable manner as verified by Northern blot analysis. In contrast, cytokine- induced NO production or administration of exogenous NO-donors strongly reduced SPARC protein levels without altering ILK protein content in mesangial cells over a period up to 72 hours. Blocking de novo protein synthesis showed a short halflife of SPARC (< 2 hours) whereas ILK-protein was stable over a period of 7 hours, indicating that NO-mediated reduction of ILK mRNA levels does not influence protein content of ILK in mesangial cells under the time limitations given under cell culture conditions. However, a role for cytokines/NO in ILK-long-term regulation in chronic inflammatory diseases that may influence phenotypic responses such as apoptosis or cell proliferation remains to be elucidated.

Animals↗
PubMed2001

Nitric oxide and mechanisms of redox signalling: matrix and matrix-metabolizing enzymes as prime nitric oxide targets.

One of the greatest biomedical breakthroughs of the twentieth century was the discovery of endothelium-derived relaxing factor and its identification as nitric oxide (NO). NO has received special attention ever since: besides its potent vasodilatory and vasoprotective effects, NO was identified as a key player in innate immunity and was found to act as an unconventional type of neurotransmitter. This article focuses on mechanisms of NO signalling that form the basis of functional cell responses to accommodate changes in the cellular microenvironment. Redox-based regulation of signal transduction and, on a more long-term scale, changes in gene expression will be exemplified by NO-modulation of matrix components and matrix-metabolizing enzymes. It seems to be a safe bet that ongoing analyses of NO signalling and gene expression will provide a wealth of promising therapeutic targets in human diseases.

Animals↗
PubMed2001

Nitric oxide induces MIP-2 transcription in rat renal mesangial cells and in a rat model of glomerulonephritis.

Nitric oxide is a crucial mediator of several forms of glomerulonephritis. We examined the effects of NO on the mRNA expression pattern in glomerular mesangial cells by using a low-stringency reverse transcriptase-polymerase chain reaction method and detected a cDNA fragment that was induced by interleukin 1b (IL-1b) and further up-regulated by the NO donor diethylenetriamine-nitric oxide (DETA-NO). Each respective cDNA fragment was found to match with the cDNAs of rat macrophage inflammatory protein 2 (MIP-2) and GRO/cytokine-induced neutrophil chemoattractant 2b (CINC-2b). Further characterization of MIP-2 regulation by Northern blot analysis confirmed an NO- and IL-1b-dependent increase in MIP-2 mRNA levels. Moreover, inhibition of IL-1b-induced endogenous NO formation by the NO-synthase (NOS) inhibitor L-NMMA markedly attenuated MIP-2 protein expression. We cloned 770 bp of the 5'-flanking region of rat MIP-2 and fused this fragment to a luciferase reporter gene. Transfection of the construct into mesangial cells resulted in a 3.5-fold increase in luciferase activity in cells treated with DETA-NO when compared to controls, suggesting a transcriptional mechanism for NO-induced MIP-2 expression. Deletion and mutational analysis identified critical nuclear factor (NF)-kB and NF-IL-6 binding sites required for NO regulation of MIP-2. In vivo, inhibition of NO synthesis in the Thy-1.1 model of mesangioproliferative glomerulonephritis by the specific inducible-NOS inhibitor L-NIL resulted in a marked reduction of MIP-2 mRNA expression. Furthermore, infiltration of neutrophils into the glomerulus was dramatically attenuated in L-NIL-treated rats.

Amidines↗