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Biomedical subjects

W Brysch

Publications and source records attributed to W Brysch.

32 records · Page 2Linked to original sources
PubMed1993

Autoinduction of platelet derived growth factor (PDGF) A-chain mRNA expression in a human malignant melanoma cell line and growth inhibitory effects of PDGF-A-chain mRNA-specific antisense molecules.

Autoinduction of PDGF-A-chain mRNA's was demonstrated in cells of a human malignant melanoma cell line (HTZ 19), indicating a PDGF-induced amplification of an autocrine growth factor loop mechanism. PDGF-alpha receptors were detected by immunocytochemistry in HTZ 19 melanoma cells. Exogenously administered PDGF-AA exerted an increase in cell proliferation by 70% at 200 ng/ml PDGF in serum-supplemented cell culture medium. Antisense phosphorothioate-oligodeoxynucleotides (S-ODN's), specifically targeted against PDGF-A-chain mRNA, reduced cell proliferation of HTZ 19 melanoma cells by 62% at a concentration of 5.0 microM, also only in serum-enriched medium. These findings strongly suggest that PDGF-AA homodimers may be an autocrine growth factor for HTZ 19 melanoma cells but require synergistic interaction with serum components.

Base Sequence↗
PubMed1993

Opposite functions of jun-B and c-jun in growth regulation and neuronal differentiation.

Induction of the jun-B and/or c-jun transcription factors is part of the immediate early response to diverse stimuli that induce alterations in cellular programs. While c-jun is a protooncogene whose expression is required for induction of cell proliferation, jun-B has recently been found to be induced by stimuli inducing differentiation in various cell lines. Furthermore, its expression is largely restricted to differentiating cells during embryogenesis. To determine the functional significance of these findings, we used antisense phosphorothioate oligodeoxynucleotides to inhibit expression of the two genes in proliferating and neuronally differentiating cells. While selective inhibition of c-jun expression reduced proliferation rates, inhibition of jun-B protein synthesis markedly increased proliferation in 3T3 fibroblasts, human mammary carcinoma cells and PC-12 pheochromocytoma cells, suggesting jun-B involvement in negative growth control. Neuronal differentiation of PC-12 cells induced by nerve growth factor (NGF) was prevented by inhibition of jun-B protein synthesis. PC-12 cells not only failed to grow neurites but also remained in the proliferative state. Furthermore, in cultured primary neurons from rat hippocampus, inhibition of jun-B expression, again, markedly reduced morphological differentiation. Conversely, inhibition of c-jun protein synthesis enhanced morphological differentiation of both primary neurons and PC-12 tumor cells. Thus, jun-B expression is required for neuronal differentiation and its balance with c-jun activity is involved in regulating key steps in proliferation and differentiation processes.

3T3 Cells↗
PubMed1993

Transient expression of PKC gamma mRNA in cerebellar granule cells during rat brain development.

The localization of PKC gamma mRNA expression during the maturation of rat cerebellum has been studied by in situ hybridization. We found a transient expression over the granule cell layer and persistent high expression in the Purkinje cells during postnatal development. Expression in granule cells appeared as early as postnatal day 5 over the external granule cell layer, when Purkinje cells are multiply innervated by climbing fibres in contrast to their mono-innervation in the adult. As the regression of the poly-innervation during the following weeks is known to require granule cell input, our findings suggest that the PKC gamma expression over the migrating granule cell layer is linked to the process of selective stabilization of synapses during the maturation of the cerebellum.

Aging↗
PubMed1993

Ca2+/calmodulin protein kinase and protein kinase C expression during development of rat hippocampus.

The expression of the genes encoding the alpha subunit of type-II calcium/calmodulin-dependent protein kinase (CAM-KII alpha) and the gamma subspecies of protein kinase C (PKC gamma) was examined throughout postnatal rat brain development by in situ hybridization histochemistry. CAM-KII alpha was found to be expressed sequentially over the different hippocampal subregions, beginning with expression in the pyramidal cells of CA3 at birth, followed by expression in the external blade of the dentate gyrus and in CA1 on postnatal day (PND) 5 and, finally, on PND 8 in the internal blade of the dentate gyrus. PKC gamma expression, in contrast, rose simultaneously in the hippocampal subregions CA1 and CA3, with little expression over the dentate gyrus. This fashion of expression corresponds to the similar maturational state of the pyramidal cells in CA1 and CA3, whereas CAM-KII alpha expression during development of the rat hippocampus follows the time table of afferent lamination, which is delayed in CA1 compared to CA3. Furthermore, we found a temporal overexpression of CAM-KII alpha in the hippocampal subfields CA1 and CA3 at the end of the second postnatal week which coincides with the development of N-methyl-D-aspartate receptor binding.

Animals↗
PubMed1993

Autocrine growth regulation in neuroectodermal tumors as detected with oligodeoxynucleotide antisense molecules.

The cell lines of three neuroectodermal tumors, two glioblastomas (HTZ-146, HTZ-17) and one melanoma (HTZ-19) were established and screened for the expression of growth factors by northern blotting and immunochemical methods. All three tumors were positive for platelet-derived growth factor- (PDGF-) A-, -B-chain, and basic fibroblast growth factor (bFGF) messenger ribonucleic acids. Cultured cells as well as original tumor material were also positive for PDGF-AA-, PDGF-BB, and bFGF protein, as shown by immunochemistry. To investigate the possible pathophysiological role of PDGF and bFGF, antisense technology was employed with chemically modified nuclease-stable 14-mer phosphorothioate oligodeoxynucleotides. Proliferation of all three tumors was reduced to a different extent with antisense phosphorothioate oligodeoxynucleotides in vitro, targeted against PDGF-A-chain-, -B-chain-, and -bFGF-messenger ribonucleic acid. These data indicate autocrine stimulatory loops for PDGF and bFGF, which may be blocked, may have different relevance in neuroectodermal tumors in vitro, and may have conceivable future therapeutic implications.

Biopsy↗
PubMed1993

The effect of transforming growth factor-beta 2-specific phosphorothioate-anti-sense oligodeoxynucleotides in reversing cellular immunosuppression in malignant glioma.

This in vitro study was aimed at restitution of transforming growth factor (TGF)-beta 2-mediated suppression of T-lymphocyte activation within malignant gliomas. In early-passage tumor cell cultures of two glioblastomas (HTZ-153 and HTZ-209) and one malignant astrocytoma classified as World Health Organization Grade III (HTZ-243), autologous peripheral blood mononuclear cells were activated by interleukin-1 alpha and interleukin-2 in vitro (lymphokine-activated killer cells) and tested for cytotoxic and proliferative activity. In expression studies (Western blot and Northern hybridization) of all three tumors, TGF-beta could be detected at the protein and messenger ribonucleic acid (mRNA) levels. A polyclonal anti-TGF-beta neutralizing antibody did not enhance lymphocyte proliferation upon stimulation with tumor targets (3H-thymidine incorporation) and slightly stimulated lymphocyte cytotoxicity against autologous target cells. Preincubation of target cells for 12 hours with TGF-beta 2-specific phosphorothioate-anti-sense oligodeoxynucleotides (S-ODN's) did, however, enhance lymphocyte proliferation up to 2.5-fold and autologous tumor cytotoxicity up to 60%, compared to controls not treated with S-ODN's. Incubation of tumor cells with TGF-beta 2-specific S-ODN's resulted in decreased TGF-beta-specific immunoreactivity in cultured glioma cells, in reduced TGF-beta 2 protein concentration (Western blot), and in a change in the expression pattern of TGF-beta 2 mRNA's. These observations may have implications for in vivo and in vitro activation of a cellular immune response against autologous malignant glioma cells.

Antigens, CD↗
PubMed1992

Neuronal plasticity depending on a glycoprotein synthesized in goldfish leptomeninx.

Transcription of a calcium and zinc binding, nervous system-specific cell adhesion glycoprotein, ependymin, in goldfish leptomeninx was significantly enhanced after active avoidance conditioning, followed by enhanced translation and secretion. Inactivation of secreted ependymin by injected antisera interfered with behavioral adaptations. In addition to the site of synthesis in reticular cells of the leptomeninx electronmicroscopic immunochemistry localized the protein to tectal neurons of the superficial plexiform and the periventricular cell layers. Detection of ependymin in cells where it is not synthesized, namely in neurons, suggests a re-uptake during functional activity of the CNS and assigns a pivotal role to the cerebrospinal and interstitial brain fluids for the distribution of protein factors that support axonal growth and neuronal plasticity.

Animals↗
PubMed1992

Antisense bFGF oligodeoxynucleotides inhibit DNA synthesis of rat astrocytes.

Basic fibroblast growth factor (bFGF) is a multifunctional protein that stimulates proliferation, migration and differentiation of various cell types of the mammalian brain. In rat astrocyte cell cultures bFGF stimulates DNA synthesis after exogenous addition. This article will focus on the endogenous pathway of bFGF in rat astrocytes in cell cultures. After a single administration of bFGF antisense phosphorothioate oligodeoxynucleotide (PTO) a significant inhibition of DNA synthesis was observed. A control oligodeoxynucleotide does not inhibit DNA synthesis, while specific antisense c-myc PTO did inhibit DNA synthesis. Addition of anti bFGF PTO suppresses the expression of bFGF protein in Western blot analysis. These results suggest that bFGF may be an endogenous growth signal in developing astrocytes.

Animals↗
PubMed1992

bFGF induces its own gene expression in astrocytic and hippocampal cell cultures.

Basic FGF mRNA induction by bFGF was investigated in cell cultures from rat brain, i.e. postnatal day 2 cortex and embryonic day 18 hippocampus. In situ hybridization shows that after bFGF treatment (10(-10) M) for 14 h neurones and glial cells show a remarkable increase in bFGF mRNA production. Incubation of astrocytes with antisense bFGF phosphorothioate oligodeoxynucleotides (bFGF-PTOs) resulted in an inhibition of both bFGF induced and serum induced proliferation. The results indicate that bFGF is capable of inducing its own mRNA production. This induction, i.e. new synthesis of bFGF mRNA, seems to be essential for the mitogenic effect of both bFGF and serum components.

Animals↗
PubMed1991

High basal expression of the zif/268 immediate early gene in cortical layers IV and VI, in CA1 and in the corpus striatum--an in situ hybridization study.

The localization of zif/268 gene expression in adult rat and mouse brain was studied with in the situ hybridization, using 32P-labeled 30 mer oligonucleotide probes. Basal expression without intentional neuronal stimulation was examined. Distribution of zif/268 mRNA was highly differential. In the neocortex a layer specific expression was seen with high levels in layers IV and VI, most prominent in the visual and somatosensory cortices. In the hippocampus labeling was strongest in CA1 but very low in the dentate gyrus. Strong expression was also seen in the primary olfactory cortex, the corpus striatum, the nuclei amygdaloidei, the nucleus accumbens and the cerebellar cortex.

Animals↗
PubMed1991

Regional and temporal expression of sodium channel messenger RNAs in the rat brain during development.

The distribution of mRNA expression for three types of voltage gated neuronal sodium-channels was studied in the rat brain at different developmental stages (embryonal day E18, postnatal day P5 and adult). With the in-situ hybridization technique, using synthetic DNA-oligomer probes, pronounced regional and temporal variations in the expression levels of the different channel subtypes could be detected. In comparison with types I and III, sodium channel II mRNA was the most abundant subtype at all developmental stages. Maximal expression of sodium channel II mRNA was seen at P5 in virtually all parts of the grey matter, except for the cerebellum. In adult rat brain in contrast, sodium channel II mRNA levels were maximal in the granular layer of the cerebellum, whereas in all other regions expression had decreased to roughly 50% of postnatal levels. Na channel I expression was virtually absent at E18 and showed highest levels at P5, with maxima in the caudate nucleus and hippocampus. In the adult brain, expression of Na-channel I was nearly absent in the neocortex, but well detectable in the cerebellum and, at lower levels in the striatum and thalamus. Sodium channel III was mainly expressed at the embryonal stage and showed a decrease to very low levels with little regional preferences in the adult.

Animals↗
PubMed1990

The topology of the thalamo-cortical projections in the marmoset monkey (Callithrix jacchus).

This paper addresses the question of a general topological principle of thalamo-cortical projections. In the lissencephalic primate brain of the common marmoset (Callithrix jacchus), large injections of horseradish peroxidase were made in various parts of the neocortex. These injections were placed in different animals and hemispheres along various caudo-rostral and medio-lateral gradients. Labelled cells in the thalamus were plotted and the labelling-zones resulting from several injections along a medio-lateral and two caudo-rostral cortical vectors were drawn into semi-schematic thalamic maps. These composite maps reveal a topological organization of the whole thalamo-cortical projection. The thalamic representation of the caudo-rostral and medio-lateral gradients indicate a rotation of the posterior relative to the anterior thalamus. An attempt is made to relate the organization of the thalamo-cortical projection to the development of the thalamus and the cortex. The cortex is divided into concentric zones around the sensory-motor and insular cortex. The thalamus is divided into corresponding projection zones. The topology of thalamo-cortical connections can then be regarded as a consequence of corresponding thalamic and cortical growth gradients. This is not only consistent with the general thalamo-cortical topology and the inversion of maps from thalamus to cortex, but also explains the continuity and overlap of thalamic projection zones in the pulvinar to widely separated cortical areas as the parietal, temporal and frontal association cortex.

Animals↗
PubMed1984

The second, intralaminar thalamo-cortical projection system.

In the marmoset (Callithrix jacchus), HRP and 3H-apo-HRP were injected into various cortical regions and the positions of labelled neurons in the non-specific, intralaminar thalamic nuclei (N. centralis and centre m edian ) were investigated. Although neuron populations projecting to the different cortical regions overlap widely, a coarse topology exists inasmuch as intralaminar neurons projecting to the posterior cortex were located more rostrally and those projecting to the anterior cortex were located more caudally in the intralaminar complex. With injections into nearby cortical regions of the parieto-temporal association cortex with HRP and 3H-apo-HRP, respectively, no double labelled cells were found in the intralaminar nuclei, although the fields of labelled cells completely overlapped. Also in the specific projection nuclei no double labelled cells were encountered. About 10-20% of the thalamo-cortical projection cells are located in the intralaminar nuclei. Some functional aspects of this second thalamo-cortical projection system are discussed.

Animals↗