Biomedical subjects

A Lametschwandtner

Publications and source records attributed to A Lametschwandtner.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Lengths measurements in microvascular corrosion castings: two-dimensional versus three-dimensional morphometry.

In the present study we compared measurements of vessel lengths from (a) single-digital scanning electron microscope (SEM) images of microvascular corrosion casts (VCCs) of gill filters of tadpoles of Xenopus laevis Daudin by two-dimensional (2-D) morphometry (Optimas 6.5, Optimas Corp., Bothell, Wash., USA; planar measurements) and (b) digital stereopairs by three-dimensional (3-D) morphometry (3D-Morphometry, Minnich and Muska OEG, Salzburg). Depending on the spatial orientation of the vessels measured, we found a maximum difference of 58.84% (100 [3-D]-41.16 [2-D]) in vessel lengths by 3-D morphometry versus 2-D morphometry, which, in multiple (segmental) lengths measurements or when determining space angles, might be even higher. Based on results we consider 3-D morphometry of VCCs to be the method of choice for lengths measurements.

Animals↗

PubMedDate not supplied

Incorporation of beta-galactosidase-expressing endothelial cells into the skeletal muscle microvascular bed of mice.

Cloned murine endothelial cells (cEC) were used as a carrier system for introducing a foreign gene into the microvascular bed of the hind limb of inbred mice. cEC were transfected with a beta-galactosidase-neo fusion construct, which enables both selection for DNA uptake in the presence of G 418 and the staining of cells for beta-galactosidase activity. Transfected cEC adhered and integrated readily into confluent monolayers of nontransfected cEC (up to 26% of total cell number). Seeding lacZ-transfected cEC on explanted arteries revealed rapid adhesion of the cells (within minutes) to the intact endothelium. After injection of 10(6) transfected EC via the femoral artery into the microvascular bed of the hind limb their presence was documented by beta-galactosidase staining after various time periods (1 h to 4 wk). Implanted cEC were detected in numerous elements of the microcirculation both in frozen sections and in squash preparations of the hind limb muscle and in the femoral bone up to 4 wk after the injection. The microvascular bed of skeletal muscle of the mouse as a recipient site for transduced syngeneic endothelial cells is, thus, a suitable experimental model to study various strategies for somatic gene therapy.

Animals↗

PubMedDate not supplied

Corneal lathing using the excimer laser and a computer-controlled positioning system.

PURPOSE: To present the excimer laser corneal shaping system (ELCS-S), an add-on device to the Keratom, a commercially available 193-nm excimer laser built by Schwind. METHODS: The system is designed for the preparation of donor corneas under sterile conditions using the ultraviolet laser to offer greatest possible flexibility. Lenticules for planolamellar grafting and refractive epikeratoplasty, as well as donor buttons for penetrating keratoplasty can be computer-designed by the surgeon or technician and lathed with the system. RESULTS: Using the excimer laser corneal shaping system (ELCS-S) on human donor corneas, the central surface of the epikeratoplasty lenticule exhibited only narrow, flat concentric notches corresponding to the single lathing steps. Transmission electron microscopy revealed a damage zone of less than 0.3 microm in close approximation to the treated surface. The final thickness revealed a difference of less than +/-53 microm from the intended, initially programmed value. Ultrastructural studies showed the perpendicular stromal surface of the penetrating keratoplasty buttons to be smooth with minimal protrusion of Descemet's membrane. Endothelial injury was observed in a zone averaging between 40 and 100 microm adjacent to the cutting edge only. CONCLUSION: The excimer laser corneal shaping system (ELCS-S) allows a computer-controlled, surgeon-designed, sterile preparation of lamellar and penetrating corneal grafts with the use of the excimer laser. This could offer significant advantages in comparison to presently available systems for lamellar dissection and trephination.

Computers↗