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Biomedical subjects

Peter Koch

Publications and source records attributed to Peter Koch.

22 records · Page 2Linked to original sources

Transscleral optical coherence tomography: a new imaging method for the anterior segment of the eye.

OBJECTIVE: To present a new imaging method for the anterior segment of the eye. METHODS: Transscleral optical coherence tomographic images were generated in healthy volunteers using a slitlamp-adapted prototype equipped with a superluminescence diode with an infrared wavelength of 1310 nm. RESULTS: The optical coherence tomographic system used allowed penetration of human sclera in vivo and high-resolution, cross-sectional imaging of the anterior chamber angle and the ciliary body. CONCLUSION: The 1310-nm optical coherence tomographic image shows a significant potential as a noninvasive diagnostic tool for the anterior segment of the eye.

Anatomy, Cross-Sectional↗

Transscleral optical coherence tomography--an experimental study in ex-vivo human eyes.

BACKGROUND AND OBJECTIVE: To evaluate the potentials of a 1310-nm optical coherence tomography (OCT) system to penetrate the highly backscattering sclera in enucleated human eyes and provide visualization of intraocular structures by transscleral imaging. STUDY DESIGN/MATERIALS AND METHODS: OCT-images were generated by an experimental prototype (Medical Laser Center, Lübeck, Germany) using a superluminescence diode with a wavelength of 1310 nm. OCT-images were taken from two enucleated human eyes using 100-200 axial scans with 60 Hz line scan frequency and compared to subsequent histologic sections. RESULTS: Transscleral OCT allowed penetration of the sclera and the anterior chamber angle could be completely identified. Some change within the anterior eye segment could be demonstrated with high accuracy. Additionally, limited demonstration of the ciliary body region was achieved. Due to limited signal intensity no detailed imaging of the pars plana and pars plicata region was possible. However, more posterior measurements allowed transscleral visualization of a retinal detachment. CONCLUSIONS: OCT using lightsources with a wavelength longer than that used in conventional OCT provides a promising imaging technique at high resolution allowing transscleral imaging of the anterior eye segment.

Anterior Chamber↗

Development of a decision-analytic model of stroke care in the United States and Europe.

OBJECTIVE: Stroke places a huge burden on society in terms of premature death, disability, and costs of care. Increasingly, the cost-effectiveness of new interventions needs to be demonstrated before their widespread implementation. Clinical trials are unable to measure the long-term impact of such new interventions in stroke care, and a modeling approach is necessary. The Stroke Outcome Model has been developed in four countries: France, Germany, the United Kingdom, and the United States as a flexible tool for this purpose. METHOD: The decision-analytic model represents the management of acute stroke and long-term care and prevention of recurrence for stroke survivors. The latter consists of semi-Markov state-transition processes, with health states defined by therapy, disability, and occurrence of further stroke. Sources of clinical data include trials, meta-analyses, and prospective cohort studies such as the Oxfordshire Community Stroke Project and the Northern Manhattan Stroke Study. Resource use data were obtained from published sources and expert clinician panels. Outcome measures used were strokes averted, life years, and quality-adjusted life-years gained. RESULTS: The model has been used to undertake economic analyses of antiplatelet therapy for the prevention of recurrent strokes, and of stroke unit care and thrombolytic therapy in acute stroke. From a health- and social-care perspective, new interventions were found to be cost saving or to provide health benefits at modest additional cost. Results were sensitive to the cost perspective, time horizon, baseline risk of stroke recurrence, and choice of effectiveness measure. CONCLUSION: The development of this model highlights the need for improved information on prognosis and resources used by stroke survivors and the importance of differentiating between economically distinct end points such as death, disabled survival and nondisabled survival, which may be combined as outcomes in clinical trials.

Acute Disease↗

Interleukin 8 and Flt3 ligand as markers of advanced disease in primary gastrointestinal non-Hodgkin's lymphoma.

Tumor angiogenesis plays a significant role in cancer growth and metastasis. This complex process is influenced by a variety of angiogenic factors. Elevated serum levels or high expression of some of these factors have been shown to correlate with stage and prognosis in certain human malignancies. This has been demonstrated most consistently for vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). We tried to establish, whether pre-treatment serum levels of the angiogenic factors VEGF, bFGF, interleukin 8 (IL-8) and Flt3 ligand (Flt3L) correlate with prognostic variables in 30 patients with primary gastro-intestinal non-Hodgkin's lymphoma. Our results suggest that higher pretreatment serum levels of IL-8 and Flt3L are associated with higher stage (>or= II) and high grade, respectively. Elevated pretreatment serum levels of VEGF and bFGF were not associated with advanced disease characteristics and carried no prognostic information.

Adult↗