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D Dahl

Publications and source records attributed to D Dahl.

At least 181 records · Page 10Linked to original sources
PubMed1981

Purified glial fibrillary acidic protein and desmin are distinct intermediate filament proteins exhibiting similar properties.

Glial fibrillary acidic (GFA) protein and desmin were purified from bovine brain and large intestine, respectively, and used in a comparison of the major protein components of two classes of intermediate filaments, the glial and smooth muscle filaments. The proteins are similar in size, charge, and amino acid composition, but clearly distinct. By sodium dodecyl sulfate-gel electrophoresis, GFA protein is about 5,000 daltons smaller than desmin. GFA protein is composed of three isoelectric variants which are all slightly more basic than the two variants observed for desmin. One-dimensional peptide mapping following limited proteolysis under denaturing conditions or following cyanogen bromide cleavage demonstrates that the proteins are not closely related in primary structure. Assembly-disassembly experiments reveal that the proteins share solubility properties and that negatively stained preparations of in vitro polymerized filaments are very similar. Limited proteolysis under native conditions demonstrates substructural similarities; comparative peptide mapping following digestion with chymotrypsin and trypsin suggests related core polypeptides of about 37,000 and 21,000 daltons. We conclude that GFA protein and desmin are distinct with respect to primary structure, but probably represent two of the more closely related classes of intermediate filament proteins.

Amino Acids↗
PubMed1981

Isolation of neurofilament proteins and of immunologically active neurofilament degradation products from extracts of brain, spinal cord and sciatic nerve.

This paper reports the isolation by immunoaffinity chromatography of neurofilament proteins from 1 mM sodium phosphate buffer extracts of brain, spinal cord and sciatic nerve in four mammalian species: human, bovine, rabbit and rat. Antisera were prepared against degraded chicken neurofilament proteins as previously described. The main polypeptides isolated in the fraction tightly attached to the column and eluted at pH 2.9 were at 72 and at approx. 150 kdaltons. In rat and rabbit the approx. 150-kdalton neurofilament polypeptide was apparently smaller compared with bovine and human as indicated by comigration experiments on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The 200-kdalton neurofilament polypeptide was less tightly attached to the immunoaffinity column and was preferentially eluted at pH 6.0 in 5 M urea. Variable amounts of degraded products were also present in most purified preparations. Degradation was markedly increased by the omission of EDTA in the extraction and column buffers. In the rat, degraded proteins isolated on the immunoaffinity column in the absence of EDTA were at 68 and 55 kdaltons.

Animals↗
PubMed1981

Expression of antigenic markers during the development of oligodendrocytes in mouse brain cell cultures.

The expression of myelin basic protein (MBP) and galactocerebroside (GC), two antigenic markers for oligodendrocytes, was checked on 7-, 14-, 21- and 28-day-old dissociated mouse brain cell cultures (BCC) by using the indirect immunofluorescence method with double staining. The number of GC positive cells increased between the 7th and the 14th day of culture before a steady state was reached. In contrast to this, the MBP-positive cells appeared only on the 14th day of culture, and their number increased with the age of the culture. In double staining, the serum produced against isolated oligodendrocytes shows the same picture as the anti-GC serum, while only a part of GC-positive cells showed also the presence of MBP. Our data suggest that the GC appears very early on the membrane of the oligodendrocytes during development while cells exhibiting both GC and MBP probably represent a more differentiated oligodendrocyte population.

Animals↗
PubMed1981

Immunohistochemical localization of the 150K neurofilament protein in the rat and the rabbit.

Antisera to the 150K-dalton polypeptide of the bovine neurofilament triplet and chicken neurofilament antisera reacting with the 70K protein in isolated bovine brain filaments stained the same structures in rat cerebellum by immunofluorescence and peroxidase-antiperoxidase methods, that is Purkinje cell baskets, thin nerve fibers in the lower half of the molecular layer and myelinated axons. The 150K bovine neurofilament antisera did not stain large motor neurons in the anterior horns of the spinal cord in rat and rabbit, nor aluminum-induced neurofibrillary tangles in the rabbit. All these structures were demonstrated by the chicken neurofilament antisera and by silver neurofibrillary methods. IDPN-induced axonal balloons containing accumulations of neurofilaments were equally well stained by bovine 150K and chicken neurofilament antisera. These data suggest that the 150K polypeptide of the neurofilament triplet is not a subunit of the neurofilament core and probably plays a role in axonal transport.

Animals↗
PubMed1981

The vimentin-GFA protein transition in rat neuroglia cytoskeleton occurs at the time of myelination.

Extraction with Triton, a nonionic detergent, is a common procedure to prepare intermediate filament enriched fractions from cells maintained in culture. The Triton-Insoluble fraction is called a cytoskeletal preparation. Using this procedure, we previously demonstrated that vimentin and glial fibrillary acidic protein (GFA) are major cytoskeletal proteins of neuroglia, in newborn and adult rat brain, respectively. In the present communication we report that the vimentin-GFA transition in rat brain occurs during the 2nd-3rd week, ie, at the time of rapid myelination when dividing glioblasts in white matter differentiate into oligodendroglia and interfascicular astrocytes.

Aging↗
PubMed1981

Glial and neuronal cells in amniotic fluid of anencephalic pregnancies.

Cultured amniotic fluid cells from four anencephalic pregnancies were characterized in indirect immunofluorescence (IIF) microscopy using specific antibodies against different types of cytoskeletal intermediate filaments. Most of the cells showed a fine fibrillar cytoplasmic fluorescence with antibodies against glial fibrillary acidic protein (GFA), indicating that amniotic fluid cells in anencephalic pregnancies are of glial origin. The GFA-positive cells were rapidly adhering and proliferating. They remained as the major cell type also in long term cultures, and could easily be recovered from liquid nitrogen without losing their GFA positivity. GFA-positive cells were pleomorphic in appearance, and occurred in several morphologically different shapes. Amniotic fluid from one of the anencephalic cases contained typical neuronal cells, which in IIF were GFA-negative but could specifically be stained with anti-neurofilament antibodies. Most of the GFA-negative cells in all the cases were fibroblasts, identified by their fluorescence only with antibodies against vimentin. Epithelial cells showing positive keratin-fluorescence in IIF, were seen only occasionally.

Adult↗
PubMed1981

Glial uptake of monoamines in primary cultures of rat median raphe nucleus and cerebellum. A combined monoamine fluorescence and glial fibrillary acidic protein immunofluorescence study.

Glial uptake of serotonin and dopamine was studied in primary cultures of the median raphe nucleus and cerebellum by using consecutive demonstration of monoamine fluorescence and glial fibrillary acidic protein immunofluorescence. Most of the glial cells taking up monoamines were glial fibrillary acidic protein positive. Astrocytes with a strong immunoreactivity exhibited monoamine fluorescence only occasionally, although such cells did take up L-dopa readily. Glial fibrillary acidic protein negative cells--morphologically identified as astrocytes--were seen to exhibit monoamine fluorescence after exposure. Glial uptake of serotonin at a concentration of 10(-4) M was detected in cerebellar cultures but not in cultures from the median raphe nucleus. When the concentration was 10(-3) M uptake of serotonin took place in both the areas but was weaker in cultures from the median raphe nucleus. At concentrations greater than 10(-5) M glial uptake of dopamine was detected in cultures from both the regions studied. No region dependent differences in glial uptake of dopamine was demonstrated, however. Based on these observations astrocytes and astrocyte-like glial cells take up dopamine and serotonin. Also glial cells with a remarkably high content of the glial fibrillary acidic protein are more resistant to monoamine uptake than cells exhibiting less intense or no glial fibrillary acidic protein immunofluorescence. The existence of regional differences in uptake of serotonin between the median raphe nucleus and cerebellum suggests that glial uptake of monoamines is not an entirely passive mechanism but may be actively controlled by glial cells in a region dependent manner.

Animals↗
PubMed1981

The fate of axonal debris in Wallerian degeneration of rat optic and sciatic nerves. Electron microscopy and immunofluorescence studies with neurofilament antisera.

Immunofluorescence demonstrated that axonal debris reacting with neurofilament antisera persist up to 4 months in rat optic nerves undergoing Wallerian degeneration. Antisera used in this study allowed the isolation of the 72,000- and 150,000-dalton neurofilament polypeptides from rat spinal cord by immunoaffinity chromatography. After 2 weeks of degeneration, proteins co-migrating with these neurofilament polypeptides were no longer identifiable in rat optic nerves, which suggests that immunofluorescent structures persisting in the nerves after this period contained neurofilament degradation products of different molecular weight. Additional evidence as to the persistence of axonal debris in degenerated optic nerves was obtained by electron microscopy. Two distinct types of axonal degeneration were observed in rat optic nerves by this method, floccular swelling and increased electron density of the axoplasm. In both types of degeneration, axoplasmic filaments and tubules were not identifiable. Although floccular material disappeared after 2 weeks of degeneration, so that only empty myelin sheaths remained, electron-dense axons persisted longer and were probably phagocytosed together with their myelin sheaths. In sciatic nerves, cross-reaction with neurofilament antisera had almost completely disappeared 10 days after transection. The same was true for nerves which had been tightly ligated to prevent axonal growth and to squeezed nerves which showed vigorous regeneration. A few scattered, brightly immunofluorescent fragments which persisted in nerves up to 2 weeks after transection were exception to these findings.

Animals↗
PubMed1981

Expression of glial and vimentin type intermediate filaments in cultures derived from human glial material.

Several cultures established from biopsies of apparently normal adult human glial material showed no cells positive for glial fibrillary acidic protein (GFA) when examined after seven or more cumulative population doublings (CPD), although the established glioma line U251 MG showed approximately 3% GFA-positive cells, and U333 CG/343 MG clone 3 showed greater than 98% GFA-positive cells. Both the human glia delivered cultures and the glioma lines were positive when assayed with sera specific for vimentin. We therefore investigated the expression of GFA as a function of cumulative population doublings after the establishment of primary cultures. Under our experimental conditions, although GFA-positive cells were clearly present in the primary cultures accounting for some 3%-14% of the cells present, the GFA marker was subsequently lost, and the proliferating cultures expressed only the vimentin type of intermediate filament. Those cells that were GFA-positive also appeared to be vimentin-positive. GFA expression was not reinduced in cultures that had lost the GFA marker by treatment with dibutyryl cyclic AMP. We discuss two alternate hypotheses for the origin of the GFA-negative cells: (1) the cultures area of astrocyte origin but lost the ability to express GFA on culturing; (2) the cultures originate from cells of nonastrocyte origin present in the primary material.

Cell Division↗
PubMed1981

Measurement of glial fibrillary acidic protein (GFAP) and anti-GFAP antibodies by solid-phase radioimmunoassays.

A solid-phase radioimmunoassay was developed for the detection of glial fibrillary acidic protein (GFAP) and GFAP-specific immunoglobulin G (IgG) antibodies. In antibody assays purified GFAP was absorbed onto polystyrene beads, followed by incubation in dilutions of serum. (125-I)-labelled human anti-IgG was used to quantify antibodies bound to solid-phase GFAP. GFAP in samples was measured by the inhibition of the binding of anti-GFAP antibody to solid-phase GFAP. The serum and CSF samples of 19 brain tumor, 40 multiple sclerosis and 66 control patients were assayed for anti-GFAP antibodies. The binding values in the serum and CSF samples of the brain tumor patient group were higher and the binding values in the CSF samples of the multiple sclerosis group lower than those of the control group. The differences were statistically significant.

Antibodies↗
PubMed1981

Vimentin, the 57 000 molecular weight protein of fibroblast filaments, is the major cytoskeletal component in immature glia.

Comparison of cytoskeletal preparations obtained from newborn and adult rat brain showed similar patterns on SDS-PAGE. However, coelectrophoresis of the newborn and adult preparations revealed distinct differences in the mobility of 2 major bands in the molecular weight range of 50--70 000. In adult brain cytoskeletons, the main band in the 50 000 range co-migrated with purified rat GFA protein (apparent molecular weight 53 000). No major band co-migrated with purified rat vimentin (apparent molecular weight 57 000). The reverse was true for newborn brain cytoskeleton. In adult and newborn brain cytoskeleton a major band co-migrated with the 150 000 neurofilament polypeptide isolated from rat spinal cord by immunoaffinity chromatography. Another neurofilament polypeptide (apparent molecular weight 72 000) was prominent in adult but not in newborn brain cytoskeleton. Conversely, newborn brain cytoskeleton comprised a band trailing behind the 72 000 neurofilament polypeptide. This band was not present in adult brain cytoskeleton. The distribution of vimentin in newborn rat brain was studied by immunofluorescence microscopy and compared to the distribution of GFA protein. As previously reported, a relatively limited number of GFA positive cells are present in the brain at this stage compared to later in development. Conversely, the large number of vimentin positive cells in newborn brain was well in keeping with the presence of a prominent vimentin band in cytoskeletal preparations obtained from this tissue. With the exception of meninges and blood vessels, vimentin appeared to be mainly localized in immature glia: periventricular glia; glia in non-myelinated white matter; radial glia in cerebral cortex and basal ganglia; Bergmann glia in cerebellum (Bergmann glia are still GFA negative in newborn rat). The neuroblastic germinal layers in hippocampus and cerebellum did not stain with vimentin antisera.

Animals↗
PubMed1980

Glial origin of rapidly adhering amniotic fluid cells.

Rapidly adhering cells (RA cells) from the amniotic fluid of a pregnancy with fetal anencephaly were investigated by immunofluorescence assay with an antiserum against glial cells. After 24 hours' cultivation a high proportion of the cells showed positive glial-specific fluorescence, whereas no staining was seen in cells from samples of normal amniotic fluid. At the 24th week the mother was delivered of a stillborn infant with anencephaly. Immunofluorescence staining of RA cells with glial-specific antiserum may be used for the differential diagnosis of fetal abnormalities associated with a high alpha-fetoprotein concentration in amniotic fluid.

Adult↗
PubMed1980

Astroglial and axonal proteins in isolated brain filaments. II. Isolation of a 70 000-dalton polypeptide from bovine brain filament preparations by immunoaffinity chromatography with antineurofilament antisera.

Antineurofilament antisera raised against chicken brain antigen were used to isolate neurofilament protein from bovine brain filament preparations by immunoaffinity chromatography. Glial fibrillary acidic protein, the subunit of glial filaments, passed unabsorbed through the column. The Mr 70 000 component of the neurofilament triplet was tightly absorbed to the column and essentially the only protein eluted at pH 2.5. The other two components of the triplet, of approximately 200 000 and 150 000 daltons, were less tightly attached to the column and eluted at pH 6.0 in 5 M urea.

Animals↗