Biomedical subjects

W Cammer

Publications and source records attributed to W Cammer.

At least 37 records · Page 2Linked to original sources

PubMed1993

Atypical localization of the oligodendrocytic isoform (PI) of glutathione-S-transferase in astrocytes during cuprizone intoxication.

Immunocytochemical staining for the Pi and Mu isoforms of glutathione-S-transferase was used to investigate changes in the glial cells in the mouse forebrain. During early development in mouse forebrains the localizations of carbonic anhydrase, Pi and Mu were similar to the respective cellular localizations that had been observed in neonatal rat brain. That is, Pi was found in oligodendrocyte precursors, Mu in astrocytes, and carbonic anhydrase in both oligodendrocyte precursors and astrocytes. In forebrains of 6-week-old mice the neurotoxicant, cuprizone, induced oligodendrocyte degeneration, gliosis, and partial demyelination. Degeneration, gliosis, and partial demyelination. Degeneration of oligodendrocytes, and astrocytosis, began during the initial week of cuprizone feeding, and by the end of the eighth week some demyelination was observed. After mice were fed cuprizone for 4 to 7 weeks, Pi appeared in some of the reactive astrocytes, and Pi-positive astrocytes were present for at least 7 additional weeks. Normally, Pi appeared only in oligodendrocytes. Very few Pi-positive oligodendrocytes remained after the second week. During the eighth week healthy-looking carbonic anhydrase-positive oligodendrocytes reappeared and began to accumulate, and a few small patches of Pi-positive oligodendrocytes were also observed. In summary, some novel findings about glial cells were the observation of an enzyme (Pi) that is lost earlier from oligodendrocytes than is carbonic anhydrase, the apparently unique shift in Pi expression from oligodendrocytes to astrocytes and the greater temporal dissociation between loss of oligodendrocytes and demyelination in the older mice.

Animals↗

PubMed1993

Developmental changes in seizure susceptibility in carbonic anhydrase II-deficient mice and normal littermates.

Mice deficient in carbonic anhydrase II (CA II) were tested along with their normal littermates for susceptibility to seizures induced by flurothyl and loud sound at ages 10-180 days. In the flurothyl seizure model, CA II-deficient mice displayed increased resistance to clonic seizures from 32 to 90 days of age, whereas tonic-clonic seizures were suppressed at all ages. The mortality of CA II-deficient mice was significantly decreased at ages 19-40 days. The incidence of sound-induced seizures was very low and no difference between CA II-deficient and normal mice was found. The anticonvulsant effect of CA II deficiency appears to be dependent on seizure model and seizure type and to have age-specific characteristics.

Acoustic Stimulation↗

PubMed1993

Expression of CSF-1, c-fms, and MCP-1 in the central nervous system of rats with experimental allergic encephalomyelitis.

We have examined the expression of factors associated with the growth, differentiation, and chemotaxis of cells of the monocyte/macrophage series in the central nervous system of Lewis rats sensitized to develop experimental allergic encephalomyelitis. CSF-1 mRNA increased significantly over that found in control animals (sensitized with OVA in CFA or CFA alone). The elevation in the levels of this growth factor commenced immediately before the onset of early clinical signs and peaked immediately before maximal clinical incidence of disease. Expression of CSF-1 message declined to base-line values with resolution of the disease process. CSF-1 protein was also detected in the central nervous system at the height of clinical disease. Expression of the receptor for CSF-1, the proto-oncogene c-fms, also paralleled the early disease process. Elevated levels of c-fms mRNA were detected immediately before the onset and peaked at the height of clinical signs of disease. In contrast to CSF-1 levels, elevated c-fms message expression persisted after resolution of the acute phase of experimental allergic encephalomyelitis. Levels of macrophage chemotactic factor-1 message were also elevated immediately before the onset of clinical signs, peaked with the height of clinical disease, and declined with resolution of the disease. Unlike CSF-1 or c-fms, no endogenous macrophage chemotactic factor-1 message was detected in control animals. Macrophage chemotactic factor-1 protein was demonstrated by Western blot in the central nervous system at the height of clinical disease. The results support the conclusion that expression of factors that specifically target cells of the monocyte/macrophage series are an important component of the disease process in experimental allergic encephalomyelitis.

Animals↗

PubMed1993

Glial cell abnormalities in the CNS of the carbonic anhydrase II deficient mutant mouse.

The Car-2n/Car-2n mutant mouse is entirely lacking in carbonic anhydrase II (CA), which is normally found in myelin and glial cells in the CNS. CNS tissue from CA-deficient mutant mice was examined to see whether abnormalities could be detected which might help in understanding the function(s) of CA in the normal brain. Analyses of myelin yields and myelin proteins showed no differences between mutants and normal littermates. To visualize the oligodendrocytes and astrocytes in tissue sections, immunocytochemical staining was performed using antibodies against the Pi form of glutathione-S-transferase and glial-fibrillary acidic protein, respectively. In both gray and white matter from the mutants' brains the oligodendrocytes appeared to be shrinking and, possibly, degenerating. Hypertrophy of astrocytes occurred in the white matter, and the astrocytes in gray matter appeared swollen. It is suggested that imbalances in the HCO3-/CO2 ratios in various glial-cell compartments may produce abnormal distributions of water and ions in the brains of the CAII-deficient mice.

Animals↗

PubMed1993

Reduced susceptibility to seizures in carbonic anhydrase II deficient mutant mice.

The seizure susceptibility of carbonic anhydrase II (CA) deficient mice and their normal littermates was determined and compared. In flurothyl-induced seizures, CA deficient mice displayed longer latencies to the onset of both clonic and tonic-clonic seizures. In pentylenetetrazole-induced seizures mutant mice exhibited a lower incidence of clonic seizures than did their normal littermates. Acetazolamide (a CA blocker) was used for the pretreatment of normal mice to compare them to CA deficient littermates. The pretreated mice displayed a lower incidence of flurothyl-induced tonic-clonic seizures and of both types of pentylenetetrazole seizures. The attempts to elicit audiogenic seizure did not reveal any difference between normal and mutant littermates. However, when the mice were primed by a loud sound during the critical period and retested for audiogenic seizures again at age 1.5 months, the CA deficient mice displayed a significantly lower incidence of seizures. The similarity between the anticonvulsant action of CA deficiency and the anticonvulsant action of acetazolamide suggests an important role of CA in seizures. The exact mechanism of anticonvulsant action by CA inhibition, however, remains to be elucidated.

Acoustic Stimulation↗

PubMed1993

Lectin binding by macroglial and microglial cells in the brains of young normal and myelin-deficient (md) mutant rats.

To distinguish macroglia (oligodendrocytes and astrocytes) from microglia in the brain, 'markers' that have been used in previous studies include carbonic anhydrase II (CAII) immunoreactivity for macroglia, and Ricinus and Bandeiraea (BS-I) lectins for microglia. However, in rats < 1 week of age, many cells stained intensely with both anti-CAII and the labelled BS-I lectin. If some of the BS-I+/CAII+ cells were macroglia, and not microglia, BS-I should no longer be regarded as specific for microglia. To confirm or rule out that possibility, lectin histochemistry and double immunofluorescence staining were performed in tissue from the brains of normal young rats and from the microglial cell-enriched brains of myelin-deficient mutant rats. BS-I+/CAII- cells were found and examined. The BS-I+/CAII- cells resembled macrophages and microglia and did, indeed, differ in sizes and shapes from the BS-I+/CA+ cells. The BS-I+/CA+ cells appeared to represent CAII+ putative oligodendrocyte precursors described previously. Although less obvious, a lectin-binding structure was also observed in astrocytes. Lectins may cross-react with macroglial glycoproteins. For example, a glycoprotein found in oligodendrocytes and myelin, the myelin-associated glycoprotein (MAG), is related to the Ig superfamily and cell adhesion molecules. Therefore, it is cautioned that lectins and antibodies against members of the latter families of proteins should be used as cell-type specific markers only if other parameters are also examined.

Aging↗

PubMed1992

Localization of mu class glutathione-S-transferase in the forebrains of neonatal and young rats: implications for astrocyte development.

The Yb (Mu class) isoform of glutathione-S-transferase has recently been localized in ependymal cells, subependymal cells, and astrocytes in the forebrains of rats 3 weeks to adult in age. It was not known, however, at what age Mu might first be observed during postnatal development and whether the first cells in which it was found would be immature astrocytes or some less differentiated glial precursor cell, if the latter were present in vivo. Tissue sections from the forebrains of neonatal to 16 day old rats were immunostained with antibodies against Mu. In neonates Mu was observed in vimentin-positive cells and their processes adjacent to the lateral ventricles, and in the corpus striatum. The colocalization with vimentin suggested that these were subependymal cells and radial glia. In the corpus striatum the radial glia, while still vimentin-positive, rapidly lost Mu from their radial cell processes, whereas the cell-bodies remained Mu-positive. During the first postnatal week the Mu-positive, glial-fibrillary-acidic-protein (GFAP)-positive cell bodies of immature astrocytes appeared in the corpus striatum. The earliest Mu-positive cells in the immature white matter of the corpus callosum were vimentin-positive and had striking longitudinal processes that also were vimentin- and Mu-positive. Like the processes of radial glia, the longitudinal processes lost their Mu-immunoreactivity, only later and more gradually. Mu-positive, GFAP-positive cells appeared later in the corpus callosum than in the corpus striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1992

Localization of Pi class glutathione-S-transferase in the forebrains of neonatal and young rats: evidence for separation of astrocytic and oligodendrocytic lineages.

The Yp isoform (Pi class) of glutathione-S-transferase has recently been localized in oligodendrocytes in the brains of mature rats. To examine at what postnatal age Pi first appears in oligodendrocytes or precursor cells, antibodies against Pi were used to immunostain tissue sections from the forebrains of neonatal rats and young rats up to 17 days of age. In the brains of neonates Pi immunofluorescence was observed in ovoid cells in the subependymal layer, and in ovoid cells and cells bearing short, thick processes in the corpus callosum and cingulum. These cells did not immunostain for vimentin. During the first postnatal week Pi-positive cells showed positive immunostaining for ganglioside GD3, which is characteristic of oligodendrocyte precursors, and process-bearing Pi-positive cells appeared in the cingulum and at the lateral borders of the corpus callosum in increasing numbers. During the second postnatal week the cytoplasm of Pi-positive cells became more compact, and the processes thinner, and the Pi-positive cells and their processes began to immunostain for 2',3'-cyclic nucleotide-3'-phosphohydrolase, which is characteristic of immature and mature oligodendrocytes and myelin sheaths. By age 17 days Pi was observed in relatively mature oligodendrocytes. The observations suggest that Pi occurs in oligodendrocyte precursors, immature oligodendrocytes, and mature oligodendrocytes in the postnatal through 17 day old rat forebrain. In the accompanying paper (Cammer and Zhang, '92)--if references are permitted in the Abstract a different glutathione-S-transferase isoform, Yb (Mu class), was localized in cells of the astrocyte lineage, beginning in the forebrains of neonatal rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1992

Carbonic anhydrase in distinct precursors of astrocytes and oligodendrocytes in the forebrains of neonatal and young rats.

Carbonic anhydrase is present in oligodendrocytes and astrocytes in the mature rat brain. Whereas carbonic anhydrase-positive oligodendrocyte precursors had been identified during the first postnatal week, no information was available about the earliest occurrence of carbonic anhydrase in the astrocytic cell line, nor had carbonic anhydrase been detected in astrocytes in neonatal rat brains. Beginning on the first postnatal day, rat brains were double immunostained with anti-carbonic anhydrase II and respective 'markers' for immature and mature astrocytes and oligodendrocytes. During the first postnatal week there were intensely carbonic anhydrase-positive cells which were ovoid or had broad processes. On the basis of their shapes and antigen contents these were considered to be precursors of oligodendrocytes. Beginning on the first postnatal day carbonic anhydrase II was also observed in some vimentin-positive radial glia and in other vimentin-positive cells that differed in their appearance from the immature oligodendrocytes. The vimentin-positive, carbonic anhydrase-positive cells were less smooth-surfaced, and had much finer processes, than the oligodendrocyte precursors. By the third postnatal day there appeared carbonic anhydrase-positive, glial fibrillary acidic protein (GFAP)-positive cells that resembled the vimentin-positive cells. It is concluded that the latter are immature astrocytes and that carbonic anhydrase is in distinct precursors of oligodendrocytes and astrocytes as early as the first postnatal day.

Aging↗

PubMed1991

Depletion of glutathione interferes with induction of glycerolphosphate dehydrogenase in the brains of young rats.

In the rat brain hydrocortisone induces the enzyme, glycerolphosphate dehydrogenase (GPDH), during the first postnatal week. The present studies focused on a hypothetical role for glutathione-S-transferase (GST) in that phenomenon. Two forms of GST, Yb and Yp, had been detected in glial cells in mature rat brains, and it was suggested that they might function in hormone transport. Now GSTs have also been observed in the brains of 1-day-old rats. Two glutathione-depleting agents, buthionine sulfoximine and cyclohexene-1-one, were administered to rats, along with hydrocortisone, during the first postnatal week. Hydrocortisone or a depleting agent alone was administered to control animals. During the early days of the experiment there were lower GPDH specific activities in brains from the animals given hydrocortisone plus a depleting agent than in those from animals given hydrocortisone alone. Depleting agents alone did not affect the specific activities of GPDH. It is suggested that one function of the GST in rat brain is transport of hydrocortisone between or within glial cells.

Aging↗

PubMed1991

Immunostaining of carbamoylphosphate synthase II and fatty acid synthase in glial cells in rat, mouse, and hamster brains suggests roles for carbonic anhydrase in biosynthetic processes.

Double immunofluorescence staining showed carbonic anhydrase and glutamine synthetase in the same astrocytes. Carbamoylphosphate synthase II, which catalyzes the first committed step in pyrimidine biosynthesis, was also immunostained in astrocytes. The results suggested that in the astrocytes carbonic anhydrase and glutamine synthetase could provide the substrates, bicarbonate and glutamine, for pyrimidine biosynthesis. In the oligodendrocytes acetyl-CoA carboxylase was colocalized with carbonic anhydrase, and fatty acid synthase was immunostained in the same cell-type. As well as providing bicarbonate to initiate fatty acid synthesis in oligodendrocytes, the carbonic anhydrase in oligodendrocytes could recycle the carbon dioxide generated during this process.

Acetyl-CoA Carboxylase↗

PubMed1991

Comparison of immunocytochemical staining of astrocytes, oligodendrocytes, and myelinated fibers in the brains of carbonic anhydrase II-deficient mice and normal littermates.

Immunostaining for carbonic anhydrase (CA) was performed in paraffin sections from the brains of CA II-deficient mutant mice and their normal littermates. Double immunofluorescence staining showed CA in myelinated tracts and oligodendrocytes in the cerebellum of the normal but not the CA II-deficient mice, and also in astrocytes in the cerebral cortex of the normal mice but not the mutants. The data show that the CA in normal oligodendrocytes, astrocytes, and myelin is the II isoenzyme, because these structures in the mutants would be positively stained if the staining normally were due to a contaminant in the antiserum or an antibody against a different isoenzyme. The findings in normal gray matter also suggest that many neuronal cell bodies are surrounded by a network of fine, CA-positive astrocytic processes.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗

PubMed1991

A pi form of glutathione-S-transferase is a myelin- and oligodendrocyte-associated enzyme in mouse brain.

The pi form of glutathione-S-transferase (GST), previously found to be oligodendrocyte associated, has also been found in myelin. In the brains of adult mice, immunocytochemical staining for a pi form of GST was observed in myelinated fibers, as well as oligodendrocytes. In contrast, and as previously found in rats, positive immunostaining for mu forms occurred in astrocytes and not in oligodendrocytes or myelinated fibers. Double immunofluorescence staining strengthened the conclusion that pi was in oligodendrocytes and myelin in mouse brains. The results of enzyme assays performed on brain homogenates and purified myelin indicated that GST specific activities in mouse brain myelin were almost as high (0.8-fold) as those in mouse brain homogenates. Low, but reproducible, GST activities were also observed in myelin purified from rat brains, in which pi had been demonstrated in oligodendrocytes and mu in astrocytes. The pi form was also stained by the immunoblot technique in myelin purified from mouse brain. It was concluded that pi is a myelin associated, as well as oligodendrocyte associated, enzyme in mouse brain, and possibly also in rat brain. This is the first report of localization of GSTs in mouse brain and of GST in myelin.

Animals↗

PubMed1991

Glutamine synthetase in oligodendrocytes and astrocytes: new biochemical and immunocytochemical evidence.

The results of recent immunocytochemical experiments suggest that glutamine synthetase (GS) in the rat CNS may not be confined to astrocytes. In the present study, GS activity was assayed in oligodendrocytes isolated from bovine brain and in oligodendrocytes, astrocytes, and neurons isolated from rat forebrain, and the results were compared with new immunochemical data. Among the cells isolated from rat brain, astrocytes had the highest specific activities of GS, followed by oligodendrocytes. Oligodendrocytes isolated from white matter of bovine brain had GS specific activities almost fivefold higher than those in white matter homogenates. Immunocytochemical staining also showed the presence of GS in both oligodendrocytes and astrocytes in bovine forebrain, in three white-matter regions of rat brain, and in Vibratome sections as well as paraffin sections.

Animals↗

PubMed1991

Localization of the multifunctional protein CAD in astrocytes of rodent brain.

The CAD multidomain protein, which includes active sites of carbamyl phosphate synthetase II (CPS II, glutamine-dependent), aspartate transcarbamylase, and dihydroorotase, was immunostained in normal rat brains, the gliotic brains of myelin-deficient mutant rats, and brains from normal weanling hamsters. In each of these tissues CAD was observed in cells resembling astrocytes. In hamster brain, CAD immunofluorescence was also found in cells closely related to astrocytes, i.e., the Bergmann glia in cerebellum and the tanycytes surrounding the third ventricle. The astrocytic identity of the CAD-positive cells in rat brain was confirmed by double immunofluorescence staining with antibodies against glial fibrillary acidic protein (GFAP). The two enzymes carbonic anhydrase and glutamine synthetase occur in the cytoplasm of normal astrocytes in gray matter and of reactive astrocytes during gliosis. Products of each enzyme, i.e., bicarbonate and glutamine, are required for the CPS II reaction, which is the first step in the biosynthesis of pyrimidines. Therefore, the present results suggest roles for carbonic anhydrase and glutamine synthetase, as well as CAD, in pyrimidine biosynthesis in brain and a role for the astrocytes in the de novo synthesis of pyrimidines.

Animals↗

PubMed1991

Immunocytochemical staining of the RLM6 form of cytochrome P-450 in oligodendrocytes and myelin of rat brain.

We used immunocytochemical staining to localize the RLM6 form of cytochrome P-450 in rat brain. Immunofluorescence staining in vibratome sections was positive in cells that resembled oligodendrocytes, which are the cells that synthesize and maintain myelin. Double immunofluorescence staining with anti-RLM6, plus mouse monoclonal antibodies (MAb) against 2',3'-cyclic nucleotide-3'-phosphohydrolase or galactocerebrosides, showed localization of each of these oligodendrocyte "markers" in the same cells as RLM6. In vibratome sections from brains of adult rats there was faint RLM6 immunostaining in some of the myelinated fibers as well as in oligodendrocytes. In paraffin sections from adult rat brains, myelinated tracts were RLM6 positive, as were oligodendrocytes and myelinated fibers in the gray matter. Oligodendrocytes were also shown to contain glucose-6-phosphate dehydrogenase. We suggest that RLM6, which is constitutive to liver, is also constitutive to brain and, via the acetone monooxygenase reaction, which also utilizes NADPH, may contribute to the conversion of ketone bodies to substrates that could provide energy for the synthesis and maintenance of myelin.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗

PubMed1990

Reactive gliosis in the brains of Lewis rats with experimental allergic encephalomyelitis.

This paper assesses reactive gliosis in the optic tracts and other regions of brain in Lewis rats with experimental autoimmune encephalomyelitis (EAE). Enhanced immunostaining for glial fibrillary acidic protein (GFAP) in brains from rats with EAE occurred primarily in the white-matter tracts and was not restricted to sites of inflammation. Immunocytochemical staining for other putative astrocytic antigens demonstrated glutathione-S-transferase (Yb isoenzyme) to be localized extensively in GFAP-positive cells and vimentin to be present both in inflammatory cells and in some GFAP-positive astroglial cells. Positive staining for carbonic anhydrase and glutamine synthetase was observed in oligodendrocytes. In the optic tracts glutamine synthetase, but not carbonic anhydrase, was also observed in some astrocytes.

Animals↗

PubMed1990

Glutamine synthetase in the central nervous system is not confined to astrocytes.

Glutamine synthetase (GS) immunoreactivity is frequently used as an astroglial 'marker'. However, when sections of adult rat spinal cords were immunostained with antibodies against sheep glutamine synthetase, intense immunofluorescence was observed in cells resembling oligodendrocytes. In white matter in the rat brain GS immunostaining was also found in ovoid oligodendrocyte-like cells, whereas in gray matter in the same tissue sections GS immunostaining was found in astrocytes. Like the antibodies against sheep GS, antibodies against rat GS also immunostained putative oligodendrocytes, and colocalization with 2',3'-cyclic nucleotide-3'-phosphohydrolase in spinal cord supported the designation of the GS-positive cells as oligodendrocytes.

Animals↗