Biomedical subjects

J Offermann

Publications and source records attributed to J Offermann.

3 recordsLinked to original sources

PubMed1990

Switched array coils.

Switched array coils (SACs) are a useful tool in local coil imaging since they allow in a user-friendly manner one to make the best choice in the trade-off between field of view and signal-to-noise ratio. This is done by selecting the current path within a conductor array equipped with suitable switches. Since the switching can be controlled by the system, this allows changing of the coil dimensions within multislice sequences. Thus image quality can be improved due to smaller coil dimensions for a given slice and a larger area can be covered by electronically shifting this sensitive area. The principle can be applied to surface--as well as volume--coil designs.

Electronics, Medical↗

PubMed1987

Surface coil with variable geometry: a new tool for MR imaging of the spine.

A switchable-array surface coil for magnetic resonance (MR) imaging of the spine has been built that enables the user to change the working size of the coil depending on the volume of interest. The prototype has achieved similar image quality to that obtained with conventional coils of equal size. This type of antenna may reduce the number of individual coils necessary for a high-quality MR imaging study.

Humans↗

PubMed1986

Cognin distribution during differentiation of embryonic chick retinal cells in vitro.

Differentiation of individual retina neurons is closely linked to development of retina function. This differentiation may be intrinsic to the cell or determined by the position of the cell within the developing tissue. Retina cognin, a cell-cell recognition protein, which may itself mediate position-dependent cell interactions in vivo exhibits a characteristic change in distribution during embryonic chick development. Cognin is progressively lost from the outer retina in a manner which appears position-dependent. We asked if this change in cognin distribution was actually position-dependent or intrinsic to the retina cells. Neural retina cells from 8-day-old chick embryos were cultured in vitro. Continued differentiation of the cultured cells was demonstrated by neurite outgrowth and characteristic increases in choline acetyltransferase and glutamic acid decarboxylase activity. In such cultures, the characteristic developmentally related disappearance of retina cognin occurred as in vivo. This indicated that this aspect of retina neuronal differentiation was independent of position within the tissue and likely intrinsic to individual cells after 8 days of embryonic development.

Animals↗