Search PubMed⌕ Search

Biomedical subjects

D Dahl

Publications and source records attributed to D Dahl.

At least 109 records · Page 6Linked to original sources
PubMed1986

Coexpression of neurofilament and keratin proteins in cutaneous neuroendocrine carcinoma cells.

Four cases of neuroendocrine carcinomas (NECA) of the skin were studied by indirect immunofluorescence, using a monoclonal antikeratin antibody and a polyclonal antineurofilament antibody. Fifty to ninety percent and 80 to greater than 95% of the NECA cells stained with the antineurofilament antibody and the antikeratin antibody, respectively. Using double-labeling indirect immunofluorescence we could also demonstrate that, in 3 cases studied, some of the NECA cells, but not all, stained with both antikeratin and antineurofilament antibodies. These results, together with the recent knowledge of the intermediate filament protein type of normal Merkel cells (MC), tend to support the hypothesis that NECA cells do not originate from epithelial MC but from dermal neuroendocrine cells. A dual concept of intraepithelial MC and extraepithelial intradermal neuroendocrine cells, "from possible distinct origin," is proposed. Such a system has already been suggested for the neuroendocrine cells of the appendix and bronchial mucosae.

Adenocarcinoma↗
PubMed1986

Visualization of regenerating sciatic nerve fibres by neurofilament immunohistochemistry.

Regeneration of injured sciatic nerve in rats was studied with an immunohistochemical technique visualizing neurofilaments in nerve fibres as well as S-100 protein in Schwann cells. Outgrowing axons with delicate sprouts could be demonstrated along pathways formed by Schwann cells. In contrast, axons which had stopped growing or were degenerating showed bulb-like swellings in their terminal parts. The use of immunohistochemical techniques offers advantages over conventional neurohistochemical staining methods, enabling more detailed observations of nerve regeneration mechanisms in animals.

Animals↗
PubMed1986

Anti-neurofilament antibodies in the sera of patients with small cell carcinoma of the lung and with visual paraneoplastic syndrome.

The sera of patients with small cell carcinoma of the lung (SCCL) and an associated visual paraneoplastic syndrome (VPNS) have high titer immunoglobulins that react with retinal ganglion cells and with cloned lines of the SCCL. The immunoglobulins in the sera of two patients with SCCL and VPNS reacted with at least one common antigen shared by neural cells and cloned lines of the SCCL. The molecular weights of the predominant neural and tumor antigens were 205,000, 145,000, 65,000, and 20,000-24,000 as determined by Western blots. Three of the antigens from neural tissue copurify and comigrate electrophoretically with neurofilament proteins. Polyclonal antibodies prepared against authentic neurofilament proteins react with antigens having molecular weights identical to those of proteins that react with immunoglobulins from the SCCL-VPNS patients. Polyclonal antibodies that were prepared against isolated retinal ganglion cells and that were shown previously to cause the immunoablation of the ganglion cells in vivo reacted most intensely with the Mr 205,000 antigen and weakly with the Mr 145,000 and Mr 70,000 antigens. Treatment of the Western blots with alkaline phosphatase from Escherichia coli did not affect the immunoreactivity between the immunoglobulins and the purified neurofilament proteins. It is proposed that the immunoglobulins in the sera of patients with SCCL-VPNS may be involved etiologically in the development of the VPNS.

Animals↗
PubMed1986

Neurofilament antibodies in systemic lupus erythematosus.

Autoantibodies against neuronal antigens occur in sera of patients with systemic lupus erythematosus (SLE). These antibodies may have significance in the pathogenesis of neurological complications of SLE. However, the neuronal structures containing the corresponding autoantigens are poorly known. In our study we assayed circulating antibodies against defined neuronal components--neurofilaments--by an enzyme-linked immunosorbent assay (ELISA) using purified neurofilament polypeptides as targets. Circulating neurofilament antibodies (anti-NF) of IgG class were detected in 21% of 28 patients with SLE and in 6% of 17 patients with rheumatoid arthritis and in none of the 14 patients with primary sicca syndrome and 40 blood donors. The presence of anti-NF could also be confirmed by the indirect immunofluorescence technique using frozen sections of rat spinal cord. In one serum, anti-NF cross reacted with vimentin type of intermediate filaments. The antibodies bound both to the 70 kilodalton and the 200 kilodalton polypeptides of neurofilaments as judged by the immunoblotting technique. Two of 6 anti-NF positive patients had neurological complications.

Animals↗
PubMed1985

Glial fibrillary acidic (GFA) protein in vertebrates: immunofluorescence and immunoblotting study with monoclonal and polyclonal antibodies.

We report a comparative immunofluorescence and immunoblotting study of GFA protein, the subunit of glial filaments, in nonmammalian vertebrates. The study was conducted with polyclonal antibodies raised to human and shark antigen and with monoclonal antibodies isolated from mice immunized with chicken and bovine antigen. With the exception of cyclostomes, glial filaments appeared remarkably conserved in vertebrate phylogeny, both with respect to the molecular weight and immunoreactivity of their protein subunit. In most species, the antibodies decorated a single band in brain, spinal cord, and optic nerve extracts by the immunoblotting procedure. This band had the same molecular weight in the different CNS regions. With the exception of the turtle, species differences in the molecular weight of the band were not greater than those observed among mammalian vertebrates (human, bovine, and rat). However, there were some exceptional findings in fish. In goldfish and trout brain and spinal cord extracts, the antibodies decorated with the same intensity two bands. In accordance with previous immunofluorescence findings, goldfish optic nerve extracts were negative by the immunoblotting procedure. In four fishes (sea bass, tautog, trout, and scup), optic nerves reacted with the antibodies. However, the band decorated by the antibodies was higher in molecular weight than that obtained from brain and spinal cord extracts. Glial fibers were demonstrated by immunofluorescence in the brain, spinal cord, optic nerve, and retina of most species studied. In amphibia immunofluorescent structures were comparatively few, probably accounting for the negative results by immunoblotting. A comparative immunohistological study of the cerebellum showed the presence of perpendicular glial fibers in the molecular layer of most species examined. Birds and amphibia were different in this respect. Bergmann glia in chicken were GFA negative. In the frog and the toad, immunofluorescent fibers in the molecular layer of the cerebellum were haphazardly oriented. Ependymal radial glia was GFA-negative in the cerebellum of subavian vertebrates. Antisera raised in rabbit to shark GFA protein reacted with the same bovine GFA fragments recognized by polyclonal and monoclonal antibodies raised to human and bovine antigens, respectively, i.e., 30-kDa N-bromosuccinimide fragment (tryptophan cleavage); 35-kDa 2-nitro-5-thiocyanobenzoic acid fragment (cysteine cleavage); 18-kDa cyanogen bromide fragment (methionine cleavage). Conversely, the chicken GFA monoclonal antibodies selected for this study only reacted with noncleaved protein.

Animals↗
PubMed1985

Cytochemical relationships in the paracervical ganglion (Frankenhäuser) of rat studied by immunocytochemistry.

Vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) immunoreactivities have been demonstrated in the paracervical ganglion of the rat using immunocytochemistry. Dopamine beta-hydroxylase (D beta H) and neurofilament protein triplet immunoreactivities have also been demonstrated in this region. The VIP, NPY, D beta H and neurofilament immunoreactivities were located in ganglion cells and nerve fibres, while CGRP immunoreactivity was localized only in nerve fibres. Many cells immunoreactive with D beta H antiserum were also immunoreactive with NPY antiserum. A small number of cells immunoreactive with VIP antiserum were also immunoreactive with NPY antiserum. CGRP-immunoreactive nerve fibres were distributed in certain regions of the ganglion only.

Animals↗
PubMed1985

Immunohistochemical demonstration of glial fibrillary acidic protein in normal rat Müller glia and retinal astrocytes.

The presence of glial fibrillary acidic protein (GFA)-positive Müller glia and retinal astrocytes were studied immunohistochemically in normal rat retina. Using GFA antiserum both Müller glia and separate star-shaped cells were observed in spread-preparations as well as cryostat sections. The retinal astrocytes were also visualized using two different monoclonal GFA antibodies. These cells were found to be located in the nerve fiber and ganglion cell layers. In contrast, Müller glia were not normally visualized with any of the monoclonal GFA antibodies but could be stained 4 days after an optic nerve crush. Our results demonstrate that normal rat Müller glia expresses GFA-like immunoreactivity.

Animals↗
PubMed1985

Image analysis of GFA-positive astrocytes from adolescence to senescence.

Smears of fresh rat brain tissue combined with immunohistochemistry using antiserum to glial fibrillary acidic protein (GFA) were used to visualize individual astrocytes in different cortical regions of rats ranging in age from 1 to 30 months. By computerized image analysis, the cell area and the cell perimeter were determined. Using 4-month-old male Sprague-Dawley rats, it was found that GFA-positive astrocytes from cerebellum and hippocampus were significantly larger, both in terms of cell area and cell perimeter, than similar cells from cortex cerebri. The temporal development was carefully followed in smears of the hippocampal formation where a continuous increase in cell size was observed from 1 to 30 months of age. During the first few postnatal months a rapid increase in both cell area and cell perimeter was observed using Sprague-Dawley rats. For studies of senescent animals, Fisher 344 rats specifically bred for aging studies were obtained. Using such animals, a second, highly significant slower growth phase which continued until the longest time points studied was observed. A separate experiment using Sprague-Dawley rats also showed large differences in both cell area and cell perimeter of GFA-positive cerebellum and cortical astrocytes taken from 6-week- and 18-month-old animals. In conclusion, the present study shows that maturation of GFA-positive astrocytes is a process which continues for several months postnatally. This relatively rapid growth phase is followed by a slower increase in cell size, probably continuing throughout life.

Age Factors↗
PubMed1985

Action of norepinephrine in the dentate gyrus. I. Stimulation of locus coeruleus.

The effect of stimulating locus coeruleus (LC) on the response of dentate gyrus granule cells to medial perforant pathway stimulation was studied in anesthetized rats. Field responses were recorded simultaneously at the mid-dendritic and granule cell levels. Two types of responses were recorded: those due to the synchronous firing of granule cell action potentials (population spikes) and those produced by excitatory synaptic activity (evoked synaptic potentials or ESPs). Stimulation of LC prior to stimulating the perforant pathway resulted in a decrease in the ESP (inward current) measured at the dendrites and, in most animals, an increase of the population spike measured at the granule cell level. Although LC stimulation decreased the ESP at the dendrites, the ESP at the granule cell body level (outward current) was not affected. The changes in granule cell responses following LC stimulation are discussed in relation to previous findings in freely moving rats.

Animals↗
PubMed1985

Action of norepinephrine in the dentate gyrus. II. Iontophoretic studies.

The effects of iontophoretic application of 1-norepinephrine (NE) and related drugs on granule cell responses evoked by a stimulus pulse applied to the medial perforant pathway were studied in anesthetized rats. Drugs were applied and responses recorded at successive dorso-ventral positions along the dendrites and at the cell body layer. 1. Reciprocal actions of alpha and beta receptors were revealed in the cell body region. The beta agonist isoproterenol decreased the population spike while the beta antagonist sotalol increased it. In contrast, the alpha agonists phenylephrine and clonidine increased the population spike whereas the alpha antagonist prazosin decreased it. The action of the drugs was rapid, dose dependent and reversible. NE itself had no effect when applied in the granule cell layer. 2. In contrast to the failure of NE to elicit a short term response, and in confirmation of a previous report (Neuman and Harley 1983), the prolonged application of NE in the granule cell layer produced a longterm enhancement of the population spike. However, this effect was also observed after the application of d-NE. 3. NE affected granule cell responses in the middle third of the dendrites where it reduced the evoked synaptic potential (ESP, current flow produced by excitatory synaptic activity) in a dose-dependent manner. Recordings taken simultaneously in the cell body region revealed a reduction of the population spike and no change in the ESP at the cell body layer (the positive-going ESP reflecting an outward current flow from the cell). In an attempt to delineate receptor specificity, a series of alpha and beta agonists and antagonists were applied to the mid-dendritic region. All drugs reduced the ESP in a manner similar to NE. Such lack of specificity in the action of NE has been previously reported in the spinal motoneuron (Engberg et al. 1976; Marshall 1983). The function of NE in the dentate gyrus is discussed in the light of these and previous results.

Animals↗
PubMed1985

Antibodies to neurofilament protein and other brain proteins reveal the innervation of peripheral organs.

Monoclonal and polyclonal antibodies to neurofilament proteins, neuron-specific enolase, glial fibrillary acidic protein and S-100 have been used to demonstrate nerves, ganglion cells and the supportive glial system of the innervation of various organs. The female genitalia, the urinary tract, the respiratory system, the pancreas, the heart and the skin of several mammalian species, including rat, mouse, guinea pig, cat, pig, monkey and man were fixed in para-benzoquinone and portions of each organ were snap frozen. Serial or free-floating thick cryostat sections were stained using indirect immunofluorescence and peroxidase anti-peroxidase immunocytochemistry. In addition, the newly described and highly sensitive immunogold-silver staining technique was used on Bouin's-fixed and wax-embedded tissues. Antibodies to neurofilament proteins seemed to react with neuronal structures in all the species studied. Alternately stained serial sections showed a similar distribution of neurofilament proteins and neuron-specific enolase-containing nerves. Neuron-specific enolase staining had a diffuse appearance and was found to be highly variable, indicating that the neuron-specific enolase content might be related to the physiological state of the nerves and ganglion cells, whereas antibodies to neurofilament protein gave a consistently intense and very clear picture of the ganglion cells and nerve fibres. Antibodies to S-100 stained supportive elements of the peripheral nervous system in all tissues examined, whereas antibodies to glial fibrillary acidic protein were more selective.

Animals↗
PubMed1985

Combined immunostaining of neurofilaments, neuron specific enolase, GFAP and S-100. A possible means for assessing the morphological and functional status of the enteric nervous system.

Neurofilaments, part of the cytoskeletal network, and neuron specific enolase, a major enzyme in glycolysis, are both present in central and peripheral neurons. Glial fibrillary acidic protein and S-100, on the other hand, are soluble proteins which are found exclusively in the supportive cells of the nervous system, i.e. the glial cells. Examination was made, using immunocytochemistry, of all main areas of the gastrointestinal tract of three mammalian species, rat, pig and man. By applying serial tissue sectioning, it was possible to study the relative occurrences of the two neuronal markers in the same cell bodies and to examine the relationships of the neurons with the glial cells as revealed by the antibodies to glial fibrillary acidic protein and S-100. Both neurofilaments and neuron specific enolase were localised to an extensive system of enteric nerves, with the level of neuron specific enolase-immunoreactivity showing greater variability than that observed using antibodies to neurofilaments. Comparison of the occurrence of neuron specific enolase and neurofilament immunoreactivity in serially sectioned neuronal cell bodies revealed that a minor population stained only with antibodies to neurofilaments. The equivocal or absent neuron specific enolase-immunoreactivity in some perikarya may reflect variations in functional status within the nervous system. Glial fibrillary acidic protein- and S-100-immunoreactivities were confined to glial cells which, in this normal tissue, were always in close association with the neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Immature and mature neurofilament-immunoreactive trigeminal fibers can innervate the iris as studied by intraocular grafting of iris and trigeminal ganglia.

Using immunohistochemistry on stretch-prepared whole mounts of adult rat irides, a dense, well-organized plexus of neurofilament-positive nerves originating in the trigeminal ganglion can be visualized. Such a two-dimensional tissue preparation is well-suited for studies on sensory and autonomic nerve fiber growth. In the present study the growth capacity of such neurofilament-positive nerves has been studied immunohistochemically. In irides homologously transplanted to the anterior eye chamber of adult albino rats, the intrinsic neurofilament-positive network had almost completely disappeared 4 days postoperatively. In whole mounts of iris grafts after 15 days and 4 weeks in oculo a gradually increasing plexus of nerves was observed. After 3.5 months in oculo a dense, regular network of fluorescent fibers had formed in the iris grafts to the same magnitude as in situ. However, whereas large axon bundles constituted a prominent feature of the distribution of neurofilament-positive nerves in situ, only a few and relatively thin axon bundles were seen in the grafts. The growth capacity of the neurofilament-positive trigeminal nerves was also studied by grafting fetal trigeminal ganglia to the anterior eye chamber. As visualized in cryostat sections, trigeminal grafts contained a large number of strongly fluorescent perikarya and a high density of positive fibers after intraocular maturation. Such grafts readily innervated the host iris. In the area immediately adjacent to the grafts, thin, parallel, rather weakly fluorescent fibers radiated out from the ganglia. When mature trigeminal grafts with attached host iris were regrafted to the anterior eye chamber of adult animals for a few days, in order to remove the intrinsic host iris innervation, such irides showed outgrowing fibers, often organized in small axon bundles, at long distances from the ganglion graft. The present report shows that both mature and immature neurofilament-immunoreactive neurons are capable of innervating the iris. Furthermore, this ingrowth can occur both in the presence and absence of normal intrinsic neurofilament-positive nerve fibers.

Animals↗
PubMed1985

Glial fibrillary acidic protein (GFAP)-like immunoreactivity in the rodent eye. Comparison between peripheral glia of the anterior uvea and central glia of the retina.

Immunohistochemistry with antiserum raised against glial fibrillary acidic protein (GFAP) revealed a dense plexus of GFAP-positive fibers in normal rodent iris. These fibers were not stained with 2 monoclonal GFAP antibodies which readily stain astrocytes, suggesting that they contain a polypeptide closely related, but not identical, to CNS GFAP. The GFAP-positive iris fibers did not disappear after short-term intraocular grafting or culturing of irides; instead a conspicuous system of fluorescent, star-shaped cells appeared. In the retina Müller glia were intensely fluorescent using GFAP antiserum whereas positive staining was observed with GFAP monoclonals only after injury to the retina. These antibodies, however, readily stained astrocytes in the inner layers of the normal retina. Taken together, these findings support the idea of GFA proteins as a group of closely related but not identical polypeptides.

Animals↗