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Biomedical subjects

M B Bornstein

Publications and source records attributed to M B Bornstein.

At least 55 records · Page 3Linked to original sources
PubMed1981

Development of ganglion cells and their axons in organized cultures of fetal mouse retinal explants.

Retinas from 13-15 day fetal mice were explanted alone, with adjacent eyeball tissue, or with nearby superior colliculus explants. The organotypic structure of the retina developed in situ, including photoreceptors, interneurons, plexiform layers, ganglion cells, and an optic fibre layer. Electrophysiologic recordings demonstrated that functional synaptic networks developed resembling bioelectric response patterns seen in situ. Within half-retinas, arrays of optic fibers converged to the optic nerve head; in co-cultures with tectum they could become myelinated. Large bundles of long, naked neurites--1 degree primary retinal fibers--emerged from the explant in the first few days in vitro; these could often be traced back to the optic nerve head and a detailed survey of their properties using horseradish peroxidase (HRP) tracing methods identified tham as ganglion cell axons. When growing upon collagen substrata, 1 degree fibers began to disintegrate during the second week in vitro; however, many 1 degree fibers that grew into superior colliculus explants were maintained for at least 5 weeks in vitro, where they formed elaborate, functional terminal arborizations. In a few cases, 1 degree fibers grew across skeletal muscle fibers and appeared to induce them to contract. A second type of neuritic outgrowth pattern appeared after the first week in vitro: 2 degrees retinal fibers. This was composed of a mixed population of interneuronal neurites; a small percentage was catecholaminergic. Our characterization of the morphologic properties of retinal ganglion cells and their axons in organotypic cultures provides the necessary background to interpret electrophysiologic mapping and neural-specificity analyses of retino-CNS co-cultures. This in vitro model system may have biological relevance to understanding the cues that control the development of the retinotectal projection in situ.

Animals↗
PubMed1981

Catecholamine-containing neurons in cultures of fetal rat hypothalamus: distribution, morphology, and maturation.

The distribution, morphology, and maturation of catecholamine (CA) neurons have been studied in hypothalamic explants from late-gestation rats. CA-containing neurons were identified using the glyoxylic acid technique. CA-containing processes were present from all hypothalamic areas except the preoptic region. Several fiber types were identified. CA neurons in vitro resemble CA neurons in adult hypothalamus. This tissue culture system may be useful in the study of a number of properties of hypothalamus CA neurons.

Animals↗
PubMed1981

A marker for oligodendrocytes and its relation to myelinogenesis: an immunocytochemical study with experimental allergic encephalomyelitis serum and C.N.S. cultures.

To investigate a possible marker for oligodendrocytes and its relation to myelinogenesis, experimental allergic encephalomyelitis (EAE) serum has been used to study C.N.S. cultures from the time of explantation to maturity at 26 days in vitro (DIV). Cultures of foetal mouse spinal cord were exposed for 1 h to heated (complement-inactivated), rabbit anti-bovine white matter (WM-EAE) or control serum, fixed and processed by an immunoperoxidase technique for demonstrating bound immunoglobulin (Ig) by light and electron microscopy. From 5 to 26 DIV, cells morphologically identical to oligodendrocytes displayed binding of Ig to the plasmalemma of the cell body and its processes. At 5 DIV, immunoreactive oligodendrocytes had a large nucleus and nucleolus, prominent Golgi apparatus, and microtubules but no filaments. Occasionally a centriole was present, suggesting an early stage of differentiation. In myelinated cultures (from 11-12 DIV onwards), reaction product was present on the oligodendroglial outer plasmalemma apposed to myelin and along the outer loop. Sometimes it extended into the external mesaxon, outer layer of myelin, inner mesaxon and periaxonal space. No other structures were reactive, and oligodendroglia did not bind control Ig. These findings indicate that WM-EAE serum can be used as a marker for oligodendrocytes in cultures from 5 DIV onwards. The findings that oligodendrocytes acquire the antigen(s) prior to myelination and that the antigen(s) is localized on the plasmalemma of the inner and outer loops of actively myelinating oligodendroglial processes suggest that the antigen(s) may have a role in oligodendrocyte maturation and myelinogenesis. The antigen(s) involved is not yet established, but it is probably not myelin basic protein. This marker should prove useful in studies of C.N.S. development and the demyelinating diseases.

Animals↗
PubMed1981

Experimental allergic encephalomyelitis. Characterization of serum factors causing demyelination and swelling of myelin.

Serum factors in rabbits with white matter-induced experimental allergic encephalomyelitis (WM-EAE) were studied with respect to their role in demyelination in vitro in organotypic central nervous system (CNS) tissue cultures and in vivo in the myelinated retina of the rabbit eye. By absorption with staphylococcal protein A, IgG was quantitatively separated from the other serum proteins. No IgG was demonstrable in the absorbed IgG-depleted sera by Ouchterlony double diffusion, immunoelectrophoresis and SDS-polyacrylamide gel electrophoresis. Both the IgG-depleted WM-EAE sera and the IgG fractions had complement-dependent demyelinating activity on CNS cultures, and both contained immunoglobulin binding to myelin and oligodendroglia of the cultures, as demonstrated by an immunoperoxidase technique. However, only the purified IgG fractions in the absence of complement induced swelling of myelin and proliferation of oligodendroglial processes with redundant myelin in tissue cultures. The IgG-depleted complement-inactivated WM-EAE sera produced no morphological changes. In the rabbit eye model, antibody-dependent cell-mediated demyelination was observed only with the IgG fractions but not with the IgG-depleted EAE sera. No oligodendroglial proliferation occurred. These studies demonstrate for the first time that in CNS cultures, non-IgG immunoglobulins as well as IgG mediate complement-dependent demyelination and that these bind to myelin and oligodendrocytes, whereas only IgG causes myelin swelling and oligodendrocyte proliferation.

Animals↗
PubMed1981

Demyelination in vitro. Absorption studies demonstrate that galactocerebroside is a major target.

Myelinated cultures of mouse spinal cord have been exposed to sera raised in rabbits against whole white matter (anti-WM), myelin basic protein (anti-MBP) and galactocerebroside (anti-GC), the major glycolipid of CNS myelin, to determine which factor in central nervous system (CNS) tissue in vitro is the target of serum demyelinating and myelin swelling antibodies. The sera were tested by radioimmunoassay for activity against MBP and against GC and were also specifically absorbed with MBP, GC and control antigens. Studies were also performed with and without active complement. The findings show that demyelination and myelin swelling in vitro are caused by antibodies against GC and not against MBP. Ultrastructurally, the effects of anti-WM and anti-GC sera with and without complement were indistinguishable. This study demonstrates that GC is a major target in antibody-mediated demyelination.

Absorption↗
PubMed1981

Augmentation of immune-mediated demyelination by lipid haptens.

The encephalitogenic effects of bovine galactocerbroside and total myelin lipids given in the presence or absence of a known encephalitogenic dose of bovine myelin basic protein (MBP) in complete Freund's adjuvant have been examined in Hartley strain guinea pigs. The lipid haptens and MBP were given in the ratio in which they occur in intact myelin and were compared with experimental allergic encephalomyelitis (EAE) induced by whole bovine white matter in complete Freund's adjuvant. Clinically, bovine white matter- and MBP-induced EAE were similar, but in lesions in the central nervous system. Lipid/complete Freund's adjuvant emulsions were ineffective both clinically and histologically. In combination with MBP, galactocerebroside and total myelin lipids induced an EAE as severe as MBP-induced disease except that central nervous system lesions also showed demyelination. When given separately into opposite hindfeet, the lipid haptens and MBP produced EAE, but the lesions were not demyelinative. It appears, therefore, that lipid haptens have an augmenting effect on MBP when given in the same emulsion and produce central nervous system lesions which are both inflammatory and demyelinative.

Animals↗
PubMed1980

Plasmapheresis in multiple sclerosis: preliminary findings.

In seven of eight patients with progressive multiple sclerosis subjected to long-term plasmapheresis in combination with azathioprine and pulsed prednisone therapy, we found modest improvement of neurologic function. There was no change in auditory and visual evoked responses or serum demyelinating activity. In six of seven patients, cerebrospinal fluid IgG content decreased. Three additional patients in acute, severe exacerbation refractory to prednisone therapy made a substantial recovery, which commenced with plasmapheresis therapy. In two of them, the onset of clinical improvement after plasmapheresis was corroborated by decreased latency or increased amplitude of somatosensory evoked potentials. These results suggest that blood-borne factors, possibly autoantibodies, may play a role in the pathogenesis of the disease. The lesions may be at least partially reversible with plasmapheresis therapy, but a controlled trial is necessary to confirm these preliminary findings.

Adult↗
PubMed1980

Multiple sclerosis: serum gamma globulin and demyelination in organ culture.

Multiple sclerosis (MS) sera frequently demyelinate organotypic central nervous system (CNS) tissue cultures. To elucidate the possible role of gamma globulins in this form of experimental demyelination we depleted MS sera of all gamma globulins by immunoabsorption and then compared their demyelinating activity with that of the unabsorbed sera. In only 2 out of 16 patients was some demyelinating activity detected in the gamma globulin fraction. In all patients, most of the demyelinating activity was not associated with gamma globulins. In gel filtration experiments, this non-gamma globulin activity was detected in a high-molecular-weight and in a low-molecular-weight fraction.

Animals↗
PubMed1979

Effects of anti-white matter serum on myelin and lipid synthesis in brain prisms.

Tissue prisms prepared by choping whole mouse brain maintained respiratory capacity and ultrastructural integrity of 3 h in vitro. Normal rabbit serum (ca. 25%) caused no morphological change but inhibited the synthesis of galactolipids by the prisms. Heating the serum abolished the inhibition. Complement containing anti-white matter rabbit serum destroyed myelin and inhibited galactolipid synthesis to a greater degree than did normal serum. Structures other than myelin were unaffected by the antiserum. Incubation in the presence of heated anti-white matter serum eliminated the myelin destruction but resulted in specific morphological changes characterized by the doubling of the myelin lamellae at the intraperiod line. Immunoperoxidase studies suggest specific binding of immunoglobulin to components of myelin located at the intraperiod lone. These changes were similar to those found in organotypic cultures. Heated antiserum did not inhibit galactolipid synthesis but addition of complement (normal guinea pig serum) to the heated antiserum restored only that portion of the inhibition which exceeded that caused by normal serum. Heat labile factors in normal rabbit serum which inhibit myelin lipid synthesis in the prisms must be corrected for in studies in which the heating of serum is used to demonstrate that the effect is complement dependent. The prism system is simpler than that of organotypic cultures and may be useful in the study of myelinotoxic factors.

Animals↗
PubMed1979

Multiple sclerosis: immunochemical studies on the demyelinating serum factor.

Sera from patients with multiple sclerosis (MS) frequently produce demyelination of central nervous system tissue cultures. The nature of the factors responsible for demyelination is not as yet clearly established. However, several authors previously reported, in in vivo and in vitro models, demyelinating activity in IgG fractions isolated from sera and cerebrospinal fluid of MS patients14,42,48. We found the demyelinating activity of MS sera to be extremely labile to conventional biochemical treatments. Therefore, we isolated IgG from MS sera by absorption with staphylococcal protein A. Protein A binds specifically IgG1. IgG2 and IgG4. With this method we were able to remove most of the IgG, leaving only a small percentage, most probably IgG3, in the sera. Isolated IgG fractions from several sera of MS patients in the presence of human complement actively demyelinated central nervous system tissue cultures. Although a small, but significant, decrease in demyelinating activity could be observed in most of the sera absorbed in most of the sera absorbed with protein A, the majority of the demyelinating activity could not be removed by this treatment. From these studies, it appears that at least the majority of demyelinating activity in MS sera is not associated with IgG1, IgG2 or IgG4. If IgG is responsible for demyelination, IgG3 will most likely be the active factor.

Autoimmune Diseases↗
PubMed1979

Luteinizing hormone-releasing hormone (LH-RH) neurons in cultures of fetal rat hypothalamus.

Hypothalamic fragments from 21-day-old fetal rats were cultured in Maximow double-coverslip assemblies for 1 to 2 months. Neurons containing LH-RH were demonstrated immunohistochemically using an antiserum to LH-RH (Dermody; 1:500--1:4,000). LH-RH was demonstrable only in neuronal perikarya (8--13 micrometer) and in small (less than 1 micrometer) round structures nearby, primarily in explants of the median eminence-arcuate nucleus region. Reactive neurons were not found in explants of the preoptic area and could not be demonstrated in fetal hypothalami at the time of explantation. The presence of mature-looking LH-RH containing neurons in these cultures suggests that this tissue culture system can be used for the study of hypothalamic development.

Animals↗
PubMed1979

Experimental allergic neuritis. Ultrastructure of serum-induced myelin aberrations in peripheral nervous system cultures.

Mature myelinated cultures of mouse dorsal root ganglia (sometimes grown in combination with spinal cord tissue) have been exposed to unheated and heated (complement-inactivated) serum from rabbits with experimental allergic neuritis (EAN). Experimental cultures were examined for periods ranging from several hours to approximately 2 weeks of exposure. Some cultures were exposed to EAN serum for approximately 1 week then returned to normal medium for examination of the reversibility of the lesions. Unheated EAN serum induced demyelination of peripheral nervous system fibers within 96 hours of exposure. Following removal of the EAN serum, affected fibers remyelinated. Heated EAN serum produced a type of myelin swelling identical with that described previously in spinal cord explants exposed to serum from rabbits with experimental allergic encephalomyelitis. The lamellar spacing of the peripheral nervous system meylin was increased to approximately 23 nm. and the normal bifilar intraperiod line was increased to four leaflets. Some hypermyelination was seen. The swelling was incompletely reversible following removal of the heated serum. These findings are discussed in terms of their relevance to immunemediated demyelination and peripheral neuropathy associated with the hypergammaglobulinemic states.

Animals↗