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A Gansmuller

Publications and source records attributed to A Gansmuller.

31 records · Page 2Linked to original sources
PubMed1991

Tracing transplanted oligodendrocytes during migration and maturation in the shiverer mouse brain.

Fragments of neural tissue from normal newborn mouse were stained with Hoechst 33342 dye before transplantation into the newborn shiverer mouse brain. Combination of this technique with immunohistochemistry demonstrated that, after transplantation, these cells are able to survive as long as unstained cells and to myelinate in the shiverer mouse host brain. Stained cells express the normal sequence of differentiation in terms of chronology of differentiation marker expression [04, galactocerebroside (GalC), myelin basic protein (MBP)], as normal cell do in situ. It has thus been possible by this technique to show the migration pathways of transplanted cells and to correlate them with the expression of specific markers: long distance migration along white matter axonal pathways occurs when cells are o4-positive, GalC-negative. By contrast, only GalC-positive cells are able to migrate across the grey matter in the absence of radial glia. Finally, it has been possible to propose a migration and differentiation sequence of these cells, suggesting that MBP-positive oligodendrocytes divide after migration in the target zone.

Animals↗
PubMed1991

A nuclear marker for mammalian cells and its use with intracerebral transplants.

The Hoechst dye staining method has been successfully applied to the central nervous system in mammals and its use has been demonstrated in intracerebral transplantation. The technique is rapid, simple and based on intrinsic nuclear properties. It was found to be permanent and valid whatever the animal strains or ages, allowing the distinction of rat cells from those of mouse, studied either separately or in a cross-transplantation model. It permitted the detection of grafted cells in the area of transplantation and the observation of early dispersion around the implantation site. Moreover, it can be combined with immunohistochemistry as demonstrated by a myelin marker in a relevant model. Immunodetection can thus help to directly observe grafted cells, at distance from the locus of transplantation, confirming their presence in the graft-type myelin patches. Because of its rapid performance, this technique can be used systematically after transplantation to check for the presence of grafted cells in the host.

Animals↗
PubMed1990

Short-term post-grafting morphological alterations of glia from an adult brain transplant.

Fragments of corpus callosum from adult rabbit have been implanted into the brain of newborn mice. Previous studies had shown that under such conditions transplant-derived astroglial cells differentiate in the host and survive for at least 2 months. The present study was devised to clarify the fate of the differentiated astrocytes present in the adult transplant by using combined ultrastructural and immunohistochemical approaches. These mature cells are shown to degenerate and die within 2 days after the implantation. Therefore, we suggest that stem cells present in adult tissue would account for the surviving population of transplant-derived glial cells.

Animals↗
PubMed1990

Patchy myelination pattern in the jimpy mouse brain: immunohistochemical study.

The jimpy (jp) mutation of the mouse leads to a dramatic decrease of myelination in the hemizygous mutant central nervous system (CNS). Several descriptions based on classical histology, immunohistochemistry, and electron microscopy (EM) have demonstrated the scarcity of myelin formation in the different parts of the CNS. The immunohistochemical study presented here showed a very singular patchy pattern of myelin distribution in the different areas of the whole mutant brain. The myelin patches are randomly dispersed without bilateral symmetry, and their density and location vary from one animal to another. No reproducible pattern of myelination could be found among the population observed. This distribution has been compared with observations on young heterozygotes and wild-type homozygotes from the same strain. A similar patchy and random distribution of myelin could be observed in heterozygotes, which present an intermediate level of myelination. This strongly suggests that a migration of precursors or immature oligodendrocytes (ODCs) from the periventricular zone followed by local multiplication of colonies of ODCs before myelination is a general feature in normal as well as pathological conditions.

Animals↗
PubMed1989

Myelination and remyelination in the central nervous system by transplanted oligodendrocytes using the shiverer model. Discussion on the remyelinating cell population in adult mammals.

In the early sixties, remyelination was first observed in animal models of demyelination and described a few years later in multiple sclerosis. The spontaneous remyelination process is now well documented. Remyelination by transplantation of myelin-forming cells has been attempted. Transplanted Schwann cells can myelinate a central nervous system lesion but the remyelination is limited to the area of implantation. Oligodendrocytes or precursor cells are much more invasive and have been shown to migrate from the implantation site to the lesion at a distance of several millimeters. Thus, remyelination by transplantation of myelin-forming cells is possible at least in animal models, the oligodendrocytes being more efficient.

Animals↗
PubMed1988

Remyelination by transplanted oligodendrocytes of a demyelinated lesion in the spinal cord of the adult shiverer mouse.

Fragments of normal newborn mouse central nervous system (CNS) were transplanted into the spinal cord of adult shiverer mice at distance of 1, 2 or 3 intervertebral spaces from a lysolecithin-induced demyelinating lesion. Remyelination by grafted oligodendrocytes was observed by electron microscopy (EM). This result showed the capability of grafted oligodendrocytes or precursor cells to migrate to a demyelinated lesion and to remyelinate naked axons in an adult host, even in presence of host spontaneous remyelination.

Animals↗
PubMed1987

Antibody-dependent in-vitro cytotoxicity of newborn Trichinella spiralis larvae: nature of the cells involved.

The cytotoxic reaction of normal peritoneal mouse cells, containing less than 3% eosinophils, against newborn Trichinella spiralis larvae, in the presence of antibody, was studied using newborn worms less than 2 h of age, or newborn worms that had been maintained in culture at 37 degrees C for 20 h. Newborn worms 2 h old were killed, whereas 20 h newborn worms were not. The cells that initially adhered to the larvae were examined by electron microscopy. Only eosinophils adhered to 2 h newborn worms and only macrophages to 20 h ones. The attached eosinophils degranulated and died after a few hours. The macrophages that adhered to, but did not kill the 20 h newborn worms were morphologically in good state and no lysis of the larvae was observed. These results suggest that different antibody classes are involved in eosinophil and macrophage adherence, and strongly support the hypothesis that eosinophils mediate larval destruction. They also show that rapid changes are taking place after birth in the structure of the larval cuticle and that the age of Trichinella newborn worms is a major factor in the antibody-dependent cellular cytotoxicity reaction.

Adhesiveness↗
PubMed1986

Correspondence of two nuclear networks observed in situ with the nuclear matrix.

In resting lymphocytes, three well defined networks are observed and attempts were made to superimpose them upon the networks described in isolated nuclear matrices. These three nuclear structures are seen after DNase and RNase treatment. They are digested by pepsin but their sensitivity to this enzyme is different. The more resistant network corresponds to the outer lamina of the isolated nuclear matrix. The second network is located in the inter-chromatin area. It is more sensitive to pepsin than the lamina and this sensitivity is increased ten-fold when digestion with pepsin is preceded by RNase digestion. This network corresponds to the internal network of isolated nuclear matrices. The third network is located in the intrachromatin area and is the most sensitive to pepsin action.

3,3'-Diaminobenzidine↗
PubMed1986

Transplantations of newborn CNS fragments into the brain of shiverer mutant mice: extensive myelination by transplanted oligodendrocytes. II. Electron microscopic study.

As already demonstrated by immunohistochemistry, oligodendrocytes from newborn normal mice are able to survive, migrate and myelinate when transplanted into the newborn shiverer (shi/shi) mouse brain. The survival of the grafted cells and their interaction with the host brain were studied at different times after transplantation. Normal myelin was found in the host parenchyma basing our observation on the morphological difference between normal and shiverer myelin: the shiverer myelin deprived of major dense line appears uncompacted as compared to normal myelin. Myelin formed by transplanted oligodendrocytes was detected around the graft and, after immunohistochemical prelocalization, at considerable distance from the site of implantation. Normal and shiverer myelin were detected around axons adjacent to each other or around the same axon. These results confirm and extend at the ultrastructural level our previous data obtained by immunohistochemistry.

Animals↗
PubMed1984

Nucleolus and large nucleolar aggregates of condensed chromatin in interphase nuclei of L 929 cells.

Three-dimensional reconstructions show that the nucleoli from L 929 cells are associated with one or several large aggregates of chromatin displaying a honeycomb-like structure. The form and the number of both nucleoli and honeycomb structures vary as the cells emerge from the resting state and enter exponential growth. Quantitative data show that the number of honeycomb structures decreases as the number of nucleoli diminishes; both numerical regressions are significant. In addition, the nucleoli and the honeycomb structures enlarge when the cells enter the exponential growth phase. In resting cells the number of honeycomb structures is correlated to the number of nucleoli. Therefore we conclude that the large nucleolar mass of condensed chromatin, which in L 929 cells displays a honeycomb structure, contains a portion of the nucleolar organizing region.

Animals↗
PubMed1983

[Nucleolar lesions induced by ribonuclease in living cultured cells].

The nucleolar lesions provoked by the action of ribonuclease (RNase) on living chick embryo fibroblasts were studied by means of microcinematographic analysis and at the ultrastructural level using oxidized diaminobenzidine as a differentially contrasting stain for nucleic acids. This study has shown that the induction of nucleolar dispersion by RNase was only the beginning of a series of discrete steps. The following sequences are described: dispersion of the nucleolus into fragments, their reassembly, and the emission of spherules which appear of chromatin origin. At that step nucleoli are typically segregated. The alteration of the nucleolar associated chromatin seemed to be primordial in these processes. Moreover, the large mass of heterochromatin intimately associated with the nucleolus and which has been considered to be a part of the nucleolar organizer region apparently plays a chief part in the reassembly of the nucleolar fragments into a segregated nucleolus. Ribonuclease is compared to other drugs known to act on nucleolar DNA.

3,3'-Diaminobenzidine↗