Search PubMed⌕ Search

Biomedical subjects

M A Konerding

Publications and source records attributed to M A Konerding.

46 records · Page 3Linked to original sources
PubMed1989

The vasculature of xenotransplanted human melanomas and sarcomas on nude mice. I. Vascular corrosion casting studies.

The vascular system of xenotransplanted human melanomas and sarcomas on nude mice was studied by means of microorrosion casting. In summary, the vascular system of xenotransplants can be described in termes of a simply structured system, lacking not only a hierarchy with respect to wall formation but also to vascular distribution. Thus, the vasculature clearly differs from that in normal tissues.

Animals↗
PubMed1989

The vasculature of xenotransplanted human melanomas and sarcomas on nude mice. II. Scanning and transmission electron microscopic studies.

The tumor-inherent vasculature plays a major role with respect to tumor sensitivity to ionizing radiation. Ultrastructural studies of the tumor vasculature are necessary in order to obtain more detailed information on the architecture and structure and on the sites affected by tumor therapy. The vasculature of xenotransplanted human tumors on nude mice was investigated in this study by means of scanning and transmission electron microscopy. Structurally complete, real arteries or veins are neither to be seen in the periphery nor in the center. Large-caliber vessels basically have a capillary wall structure. The endothelial cells show a very alternating height and electron density. Frequently, different cell types and tumor cells themselves are apparently involved in the formation of the vessel wall. The endothelium is characterized by very simple, immature cell contacts. In some tumors, the amount of vessels without or with incomplete endothelium seems to be higher than the number of structurally real capillaries. This has consequences as well for radiotherapy as for hyperthermia and chemotherapy.

Animals↗
PubMed1989

The vascular system of xenotransplanted tumors--scanning electron and light microscopic studies.

A widely used model for investigating basic tumor characteristics and different treatment modalities preclinically is the immune-deficient, athymic nude mouse. This model offers many morphological parallelisms to the clinical situation. The aim of this study is to demonstrate the vascularization pattern of xenotransplanted human melanomas and sarcomas using different methods. Xenotransplanted tumors of 62 congenital thymus-aplastic nude mice were examined ultrastructurally and topographically after corrosion cast and tissue preparation. Quantitative measurements of tumors injected with India ink were carried out to obtain comparable information on the vascular densities in the tumors. Quantitative measurements showed that there is no zonal, topographic arrangement of the vascular densities. Comparisons of the vascular densities in the centers of tumors with the densities in the periphery showed an extreme heterogeneity in tumor vessel distribution, which does not generally support the idea of a better vascularisation in the tumor periphery. Neither in the periphery nor in the center of the tumor regular vessels are to be seen consisting of intimal, medial and adventitial layers. Even the largest peripheral vessels, which often take a tortuous course, consist mainly of an endothelial layer and some perivascular connective tissue only. Areas with high vascular densities could be seen just beneath areas almost free of vessels. Besides endothelial-lined vessels numerous irregular, tumor cell-lined sinusoids are visible both in sarcomas and melanomas. The morphology of the vessels found scanning electron microscopically is generally in agreement with many features described transmission electron microscopically.

Animals↗
PubMed1988

The vascularization of the peripheral nerve of chicken and rat.

The vascular system of the sciatic nerve of chicken and rats was examined by means of the microcorrosion casting technique and freeze-broken specimens. The main epineural vessels form two lateral and interfascicular vascular bundles which anastomose with one another and also with the peri- and endoneural plexuses. On epi- and perineural vessels one can find morphological correlates for regulative means such as sphincters. Even the endoneural vessels depict numerous anastomoses. The proximity of the vessels as well as the great number of anastomoses suggests a considerable compensatory potential with an adaptable perfusion rate in case of a partial breakdown of a plexus.

Animals↗
PubMed1987

The vascularization of the vertebral column of rats.

The intrinsic and extrinsic blood supplies of the vertebral column of rats have been examined by corrosion cast with Mercox CL2B(R). The close functional and topographic relationship of vessels to supplied structures were exposed by fractionated maceration of the soft tissues. The segmental arteries diverge into an anterior, median and posterior group with various anastomoses between their branches. Vertebral bodies and intervertebral discs are preferably supplied by branches of the anterior and median section. The vessels reaching the vertebral body from the dorsal side diverge in a treelike branching mode into the direction of the vertebral endplate. The venous drainage takes place by the segment-overlapping internal and external vertebral venous plexuses. Bloodflow regulating sphincters can be identified within all parts of the arterial and venous system. This fact seems to be of great importance regarding pathophysiological processes of degeneration and likewise regeneration even of the intervertebral discs.

Aging↗