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Biomedical subjects

A Bignami

Publications and source records attributed to A Bignami.

At least 91 records · Page 5Linked to original sources
PubMed1982

Immunostaining of neurofibrillary tangles in Alzheimer's senile dementia with a neurofilament antiserum.

Using anti-chicken brain neurofilament antisera, Alzheimer's neurofibrillary tangles from two patients with senile dementia were stained by immunofluorescence and by the peroxidase-antiperoxidase procedure in cryostat sections of hippocampus and frontal cortex. In sections of cerebellum obtained from the same patients, the distribution of immunostaining was the same as that observed in experimental animals: Purkinje cell baskets and nerve fibers in the inner half of the molecular layer were demonstrated selectively. The immunostaining of the tangles was abolished when the antisera were absorbed by their own antigen, by bovine brain filament preparations, or by the fraction of bovine brain filament preparations nonabsorbed on anti-glial fibrillary acidic (GFA) protein immunoaffinity columns. Absorption with a bovine microtubule preparation isolated by two cycles of the assembly-disassembly procedure did not abolish the staining. Immunostaining experiments conducted on bovine brain filament preparations resolved on sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the antisera staining the tangles reacted with the 200,000-, 150,000-, and 70,000-dalton neurofilament polypeptides. Antisera raised to the 150,000- dalton bovine neurofilament polypeptide isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis stained the tangle much less intensely, although Purkinje cell baskets in the cerebellum appeared well stained. No staining of neurofibrillary tangles was observed with antisera to other classes of 10-nm filament proteins (GFA protein, vimentin, and desmin).

Aged↗
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

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 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

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

Immunohistochemical characterization of neurofibrillary tangles induced by mitotic spindle inhibitors.

Neurofibrillary tangles were induced in the motor neurons of the rabbit spinal cord by the intrathecal injection of colchicine, vinblastine, and vincristine. The tangles stained intensely by immunofluorescence and by the peroxidase-anti-peroxidase procedure using neurofilament antisera raised against chicken brain antigen, as previously reported for aluminum-induced neurofibrillary tangles. No immunohistochemical reactivity could be demonstrated between the tangles and a 150,000 dalton bovine neurofilament antiserum, although the adjacent axons were intensely stained in cryostat sections of the spinal cord.

Animals↗
PubMed1980

Paraplegia following surgery in Foix and Alajouanine syndrome. (Arteriovenous malformation of the spinal cord).

Two patients with spinal cord arteriovenous malformation became paraplegic after removal of the abnormal vessels from the dorsal surface of the thoracolumbar spinal cord. Surgical exposure of a spinal cord arteriovenous malformation without an attempt at removal accelerated the pace of progressive paraparesis in two other patients. The poor outcome of our cases is, however, not representative of modern surgical techniques, since selective spinal angiography and the operating microscope were not used. We propose that the intramedullary vascular changes in this condition are an integral component of the arteriovenous malformation. Additionally, the phenomenon of nocturnal seminal ejaculation in spite of progressing impotence may be a clinical feature unique to spinal cord arteriovenous malformations.

Adult↗
PubMed1980

Neurofilaments in the chick embryo during early development. I. Immunofluorescent study with antisera to neurofilament protein.

The time of appearance of neurofilament protein was determined by indirect immunofluorescence in the chick. Immunofluorescence first appeared in 3-day embryos as a peripheral layer on the ventral and lateral surfaces of the spinal cord and hindbrain. Concomitant with a marked thickening of this layer on the ventrolateral surface of the neural tube, neurofibrils were seen emerging from the cord and the myelencephalon. The immunofluorescent layer could be followed rostrally on the surface of the brain up to the mesencephalic flexure. In this location a large bundle of fibrils was observed emerging from the ventral surface of the mesencephalon. The posterior root ganglia and inner layer of the retina were intensely immunofluorescent on day 4. In the following days of development the spinal cord and ganglia assumed a mature configuration. The appearance of the anterior horns on the 6th day was remarkably segmental, the anterior horns being detected in alternate sections in a series of transverse serial section.

Animals↗
PubMed1979

GFA expression in aggregation cultures of rat C6 glioma.

Few C6 glioma cells synthesize the astroglia-specific GFA protein in monolayer culture. A uniform population of GFA-positive cells was obtained by aggregation C6 cells in suspension culture, as previously reported for C6 glioma maintained on sponge foam matrices. These results strongly suggest that cell-to-cell interactions promote GFA expression.

Animals↗
PubMed1979

Astroglial and axonal proteins in isolated brain filaments. I. Isolation of the glial fibrillary acidic protein and of an immunologically active cyanogen bromide peptide from brain filament preparations of bovine white matter.

The glial fibrillary acidic protein and an immunologically active cyanogen bromide peptide were purified by immunoaffinity chromatography from 8 M urea extracts of brain filament preparations isolated from bovine white matter according to Norton's procedure. The protein accounted for approximately 30% of the total protein in this preparation and for the largest fraction in the 50 000 molecular weight range. The fraction not absorbed to the immuno-Sepharose column reacted with neurofilament antisera by double immunodiffusion. On sodium dodecyl sulfate gel electrophoresis the main bands in the non-adsorbed fraction were at 74 000 daltons and above 100 000. Several bands were seen in the 50 000 molecular weight range. It is concluded that glio- and neurofilaments co-purify together in Norton's procedure and that neurofilaments are probably heterogeneous in polypeptide composition.

Animals↗