Biomedical subjects
Publications and source records attributed to K Stefansson.
A mother and son had peripheral neuropathy, abnormal elevation of serum IgM, and paraproteinemia. These patients may have a familial disorder of immune regulation with antibody-mediated neuropathy or a familial neuropathy with a secondary immune response.
The S100 protein has been found consistently in glial cells both in the central nervous system (CNS) and peripheral nervous system (PNS). However, in the retina we find substantial species variation in the distribution of this protein. Immunohistochemically, in the human retina we do not find any S100. In the rabbit retina it is present both in Müller cells and in astrocytes and in the chicken retina it is in neurons. This demonstrates how misleading it can be to use the distribution of a protein in one species to generalize about the distribution of the same protein in other species. It is also clear that even though immunohistochemical staining for the S100 protein could be used to study pathologic conditions that involve Müller cells in guinea pigs, hamster, rat, and rabbit retina it is going to be of limited value in investigations of the same conditions in the human eye.
The ganglioside content of formalin-fixed human spinal cords and fresh human spinal cords was found to be both quantitatively and qualitatively similar. However, the spinal cord was found to be heterogeneous with respect to ganglioside content. In particular, a gradient of GD1a was observed, increasing from a low content in the cervical region to a relatively high content in the sacral region. Comparison of the ganglioside content of nine normal spinal cords and nine spinal cords from clinically diagnosed amyotrophic lateral sclerosis (ALS) patients revealed no major quantitative differences, but the unique presence of three additional gangliosides in ALS spinal cords. One of these was tentatively identified as sialosylglobotetraosylceramide and was absent from eight of nine control spinal cord samples, the sole exception being the cord from a 97-year-old female.
We examined immunohistochemically the distribution of the neuronal-specific protein enolase (14-3-2) in normal human retina. We also examined the distribution of neuronal-specific enolase, glial fibrillary acidic protein, myelin-associated glycoprotein, and S-100 protein in seven human retinoblastomas. In normal retina neuronal-specific enolase was present in neurons but not in other cell types. The inner segments of cones stained darkly with antiserum to neuronal-specific enolase; the inner segments of rods stained either weakly or not at all. Most small round cells in all seven retinoblastomas studied stained with antiserum to neuronal-specific enolase but Flexner-Wintersteiner rosettes stained weakly or not at all. One retinoblastoma contained an area of cells that stained with antibodies to myelin-associated glycoprotein which in normal retina is found only in Müller's cells. Another retinoblastoma had an area of cells that stained with antiserum to glial fibrillary acidic protein, which in normal human retina is present only in astrocytes. All seven retinoblastomas lacked detectable S-100 protein. These results supported the conventional view that retinoblastomas are neuronal tumors although some may contain areas that show astrocytic or Müller's cell differentiation.
Monoclonal antibodies and polyclonal antisera were used to examine the distribution of S-100 protein in human retinas both immunohistochemically and immunochemically and to compare it to that of glial fibrillary acidic protein (GFAP). S-100 was not found in normal retinas nor in retinas with areas of reactive gliosis. GFAP was found in perikarya and processes of cells the nuclei of which were in the nerve fiber layer of normal retina. In areas of reactive gliosis there was intense staining with antiserum against GFAP extending from the internal limiting membrane to the external limiting membrane. Some of the glial cells in human retina and fibrillary astrocytes in the brain are identical in their expression of GFAP. However, absence of S-100 from both quiescent and reactive retinoglia distinguishes them from astrocytes in brain and spinal cord.
By the use of a rat IgG monoclonal antibody (mab), a mouse mab and human serum containing an IgM mab, all of which react with isolated human myelin-associated glycoprotein (MAG) on immunoblots and bind only to proteins with relative mobilities identical to MAG and dMAG on immunoblots of homogenates of adult human spinal cord, we demonstrated the following: in homogenates of central nervous system tissue from human fetuses of gestational ages that antedate myelination, the anti-MAG antibodies react only with proteins with molecular weights of 250,000 or larger. During myelination the molecular weights of proteins with which the anti-MAG antibodies react shift towards the lower molecular weights found in adult myelin. Amongst those central nervous system regions examined, the shift towards the low molecular weights occurred earliest in the region that is first to become myelinated and latest in the one that is the last to myelinate. Once myelination is completed, the antibodies react only with proteins with relative mobilities identical to those of MAG and dMAG. These developmental changes in molecular weights of "MAG-related proteins" may prove useful as an index of chemical processes on the basis of which myelination occurs.
A set of observations made on a patient with IgM lambda monoclonal gammopathy and neuropathy implicate humoral immunity in the pathogenesis of the neuropathy. A sural nerve biopsy from the patient showed a characteristic increase in the width of the intraperiod lines. Deposits of mu-heavy chains and lambda-light chains were found in myelin sheaths of the nerve biopsy. Immunohistochemically, it was demonstrated that mu-heavy chains and lambda-light chains from the patient's serum bound to myelin sheaths of normal peripheral nerves and to a lesser extent to myelin sheaths in the central nervous system (CNS). By immunoblots it was demonstrated that mu-heavy chains and lambda-light chains from the patient's serum bound to myelin associated glycoprotein but to no other antigens from the peripheral and central nervous systems. gamma and alpha heavy chains and chi light chains from the patient's serum were also shown to bind to myelin-associated glycoprotein but not as distinctly as the mu and lambda chains. It is postulated that the monoclonal gammopathy may have arisen on the background of polyclonal autoimmune attack directed against myelin-associated glycoprotein.
Outside the central nervous system S-100 is found only in Schwann cells and satellite cells of ganglia. It has also been demonstrated in Schwannomas and neurofibromas but is absent from soft tissue tumors of non-neural origin. S-100 protein was looked for in granular cell myoblastomas using an immunohistochemical technique in an attempt to further elucidate the histogenesis of these tumors. All tumor cells in the ten tumors studied were intensely stained with antiserum to S-100 including one with some malignant features. These results support the idea that granular cell myoblastomas arise from Schwann cells.
The distribution of S-100 outside the central nervous system in humans and rats was explored using antiserum to S-100 and the peroxidase anti-peroxidase method of Sternberger. In peripheral nerves the Schwann cells and the outermost part of the myelin sheaths were stained; axons were not. In dorsal root ganglia and ganglia of the autonomic nervous system only satellite cells were stained. In the adrenal medulla a considerable number of cells were stained. In all other organs studied Schwann cells and satellite cells of ganglia were the only elements that were stained. We conclude that S-100 could serve as a marker for Schwann cells in situ.
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A method for localization of glucose-6-phosphate dehydrogenase (G-6-PD; D-glucose-6-phosphate: NADP+ oxidoreductase; E.C. 1.1.1.49) activity has been applied to human nervous tissue. Intensely staining cells, not definable by conventional histologic techniques, have been identified in the human spinal cord, with highest numbers present in the substantia gelatinosa of the sacral region. The cells have a neuron-like morphology and express neuronal-specific antigen but are heterogeneous in size and shape. They are not detectable in infant spinal cord, but stain heavily in adults. We propose that these cells are homologous to the G-6-PD-active dorsal medullary cells first noted by Sakharova et al. (1979) and together with the latter group, may comprise a hitherto unrecognized system of neurons in the human central nervous system.
Acid protease activity was increased in skeletal muscle of patients with ALS. The highest levels of activity were found in individuals with the clinically and histologically most affected muscle. High levels of proteolytic activity correlated with the extent of muscle atrophy, the presence of target fibers and the overall severity of disease.
In soft tissues outside the central nervous system, S-100 protein is found normally only in Schwann cells. Using the peroxidase-antiperoxidase immunohistochemical method S-100 was also found in tumors derived from Schwann cells and melanocytes, including neurofibromas, neurilemomas, granular cell myoblastomas, cutaneous nevi, and malignant melanomas. S-100 was not detected in malignant Schwannomas, neuroblastomas, oat cell carcinomas, medullary carcinomas of the thyroid, paragangliomas, or meningiomas. S-100 was also absent from neoplasms of soft tissues not usually considered to arise from cells of neural crest origin. S-100 appears to be a useful marker for identifying neoplasms derived from Schwann cells and melanocytes.
The distribution of a neuronal specific enolase (14-3-2) in the central nervous system (CNS) lesions of tuberous sclerosis (TS) was examined using antiserum to 14-3-2 and the peroxidase antiperoxidase (PAP) method of Sternberger. In cortical tubers all the giant cells had intense cytoplasmic staining. Only occasional cells in the subependymal nodules were stained. All cells in the subependymal giant cell tumors were intensely stained. This indicates that the cortical giant cells and the giant cell subependymal tumors are of neuronal rather than astrocytic origin.
A new procedure for isolating oligodendrocytes from ovine white matter is described. The method separates oligodendrocytes into two bands on a linear sucrose gradient. Five criteria have been employed to classify the separated cells. It is shown by indirect immunofluorescence with specific antisera that 97% of the cells from both bands carry galactocerebroside, a specific surface marker for oligodendrocytes, on their plasma membranes and 95% of the cells retain myelin basic protein as distinct patches on their surfaces. Isolated cells conform ultrastructurally to current concepts of oligodendrocytes. The cells incorporate [3H]galactose into galactocerebroside and carrier free H2(35)SO4 into sulfatide, specific markers for oligodendrocytes. The specific activity of 2',3'-cyclic nucleotide-3'-phosphodiesterase in the two cell fractions is comparable to that reported for isolated oligodendrocytes by others. It is concluded that conservatively, 95% of the cells in both fractions are oligodendrocytes. Cells from both bands survive in culture for months. In vitro the cells extend two or more processes, contain 'gliosomes', and surround themselves with extensive sheet-like membranes; i.e. they exhibit the morphological characteristics ascribed to oligodendrocytes in explant cultures. Conservatively 90% of cultured cells stain with an antimyelin basic protein serum. The staining is localized in the cytoplasm and processes. The cells also stain with antigalactocerebroside and antioligodendrocyte sera. Cells remain differentiated for up to 70 days in vitro as evidenced by their incorporation of [3H]galactose and H2(35)SO4 into galactosyl and sulfogalactosylceramide, respectively.
Selected properties of peripheral blood lymphocytes (PBLs) from five ambulatory affected individuals of a kindred with autosomal dominant cerebrovascular amyloidosis were studied. The percentage of PBLs bearing surface membrane immunoglobulin (SmIg+ cells) was increased in the patient group (30 +/- 3% versus 20 +/- 2%; p less than 0.05). The percentage of PBLs forming early and total E-rosettes was comparable in patient and control groups. Mitogenic response to concanavalin A (Con A) was suggestively reduced in the patient group, measured both by total 3H-thymidine incorporation and by comparison of stimulation indices. Mitogenic response to phytohemagglutinin and pokeweed was comparable in the two groups. Capping of Con A by PBLs was significantly reduced in the patient group compared with the controls (13 +/- 1% versus 26 +/- 2%; p less than 0.01). The findings of reduced Con A response and increased SmIg+ cells support the hypothesis that immune dysfunction contributes to the development of amyloidosis. The reduced capping suggests altered membrane properties in this autosomal dominant disorder.
The distribution of glial fibrillary acidic protein (GFAP) in the central nervous system (CNS) lesions of tuberous sclerosis (TS) was examined using antiserum against GFAP and the peroxidase antiperoxidase method of Sternberger. In cortical tubers there were islands of gemistocytic astrocytes staining intensely for GFAP and occasional giant cells having some cytoplasmic staining. The majority of the cortical giant cells had no GFAP. The islands were separated by areas devoid of astrocytes with perikaryal staining. A faintly staining fibrous network was found between these islands. The majority of cells in the subependymal nodules stained. The retinal phakoma stained but not as intensely as the subependymal nodules. There was no staining whatsoever in the giant cell subependymal tumors. Absence of GFAP staining in the subependymal giant cell tumors makes their classification as astrocytomas less certain.
The human retina is unmyelinated, but structural similarities have been noted between Müller cells, the main glial cell type of retina, and oligodendrocytes, the myelin-forming cells of the central nervous system. We now show that antibodies against myelin-associated glycoprotein, a minor component of central and peripheral myelin so far found only in myelin and myelin-forming cells, also stain Müller cells. Immunoblot analysis of retinal proteins indicates that the antigen detected is myelin associated glycoprotein. These results suggest a closer relationship between Müller cells and oligodendrocytes than previously suspected and raise questions about the functional role of myelin-associated glycoprotein.