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Biomedical subjects

E Weihe

Publications and source records attributed to E Weihe.

14 recordsLinked to original sources
PubMed1979

Met enkephalin-like immunoreactivity in Merkel cells.

The Merkel cells from sinus hair follicles of rats were investigated by immunohistochemistry using different antisera against neuropeptides and gastroenteropancreatic (GEP)-hormones. For the first time it has been demonstrated that Merkel cells exhibit an immunoreactivity towards metenkephalin (methionine-enkephalin). The met-enkephalin immunoreactivity was restricted to Merkel cells and was not found in associated nerve axons or terminals. Denervation of Merkel cells did not affect the met-enkephalin immunoreactivity. Antisera leu-enkephalin (leucine-enkephalin) and other polypeptides did not produce an immunoreaction. The demonstration of met-enkephalin-like immunoreactivity supports the concept that the Merkel cell is a member of the paraneuronal system and a potential neuroreceptor cell.

Animals↗
PubMed1979

Intercellular junctions in the full term human placenta. I. Syncytiotrophoblastic layer.

Inter- and intrasyncytiotrophoblastic junctions within the human full term placenta were electronmicroscopically investigated using thin sections and freeze-fracturing. Narrow clefts were occasionally situated between surface areas where adjacent chorionic villi exhibited close contact. Within these clefts, extensive zonulae and maculae occludentes and numerous maculae adherentes were found. The zonulae occludentes showed a continuous and irregular course on the membrane surface, and the maculae occludentes were irregularly distributed over extended membrane areas. Besides these areas, maculae occludentes and maculae adherentes were observed on infoldings and invaginations of the synctiotrophoblastic surface membrane. Investigations of the inner surface of the syncytiotrophoblastic layer, that is, the layer facing the villous stroma, also revealed invaginations joined by maculae adherentes. The functional significance of the inter- and intrasyncytiotrophoblastic junctions is discussed with respect to the differentiation of the trophoblast.

Female↗
PubMed1979

Horseradish peroxidase as a tracer for capillary permeability studies.

The permeability of capillaries was investigated utilizing an in vivo injection of horseradish peroxidase (HRP) and an in situ perfusion of a balanced salt solution containing HRP and lanthanum chloride. In the continuous capillaries of heart and muscle, HRP diffuses mainly through intercellular junctions, while in testicular capillaries, the transport is via micropinocytotic vesicles. The diffusion and micropinocytotic transport of HRP was demonstrated in both directions, i.e. from the capillary lumen to the interstitium and vice versa. Lanthanum can be used as a bidirectional inhibitor of micropinocytosis. The transport of HRP is then almost completely hindered in testicular capillaries. In heart muscle, the effect on HRP transport is not significant, due to second transport pathway, i.e. intercellular cleft passage.

Animals↗
PubMed1978

Ultrastructure of capillaries in the conduction system of the heart in various mammals.

The capillaries in the atrioventricular node and atriventricular bundle of the heart (mammals) were investigated by thin sections and freeze-etch replicas. Fenestrated endothelial cells were found to occur in all mammals examined in this study. These fenestrations (500 +/- 50 A diameter) are bridged by a diaphragm and occur in relatively small sieve areas. In contrast to the AV-node and AV-bundle, the non-specialized myocardium is supplied by continuous capillaries. The presence of the fenestrated capillary in the conduction system of the heart may serve to increase both permeability and passive transport capacity.

Animals↗
PubMed1977

The use of ionic lanthanum as a diffusion tracer and as a marker of calcium binding sites.

The distribution of ionic lanthanum (La3+) was studied after perfusion of the isolated rat heart with a buffered salt solution containing lanthanum chloride. We have demonstrated that the localization of lanthanum differed from that shown in previous studies in which hearts were exposed to ionic or colloidal lanthanum during or after fixation. La3+ passed rapidly through the intercellular cleft between endothelial cells. There was relatively little transport by micropinocytosis and no evidence of transendothelial passage through the cytoplasm. Perfusion with a solution containing 1 to 15 mM LaCl3 resulted in localization of La3+ on the entire cytoplasmic membrane system of muscle cells, i.e.: the non-specialized parts of the muscle cell membranes were stained by La3+ as well as the membranes of micropinocytotic vesicles, of the T-system and of the intercalated disc. The cytoplasmic leaflets of gap junctions were especially stained. However, the cell membranes of non-muscle cells were free of lanthanum precipitates. Freeze-fracturing of muscle cells showed concomitant alteration in the distribution of membrane-associated particles. The gap junction membranes also showed changes in particle aggregation. Intracellular binding of La3+ are restricted to muscle cells. Lanthanum was found in the cell nucleus associated with heterochromatin, in the nucleolus, and along the nuclear membrane. The myofibrils were stained mainly over the I-band.

Animals↗
PubMed1977

An improved perfusion fixation method for the testis.

A reliable and uniform vascular perfusion fixation method for the testis has been developed by using an initial washout solution containing a vasodilator and an anticoagulant. This is followed by a brief fixation with a sodium phosphate buffered formaldehyde-glutaraldehyde solution of conventional strenght, and then a second more concentrated aldehyde fixative solution containing picric acid. The method takes into account some of the unique features of the vascular supply of the male genital tract for its favorable perfusion and fixation. The advantages of this method are: (1) consistently favorable preservation of the testis; (2) simple and inexpensive apparatus; and (3) stable and relatively innocuous stock solutions.

Animals↗