Multiple sclerosis masquerading as a mass lesion

Six patients presenting with new neurological deficits underwent magnetic resonance imaging (MRI) that displayed mass lesions leading to diagnoses of tumor or abscess. Biopsy revealed demyelinating lesions.

Reorganization of organotypic cultures of mouse cerebellum exposed to cytosine arabinoside: a timed ultrastructural study

This study was designed to examine the sequential changes in the developing granuloprival cerebellar culture. In this model of anomalous cerebellar development, organotypic cultures derived from newborn Swiss-Webster mice were exposed to the DNA synthesis inhibitor, cytosine arabinoside, at explantation and were fixed for electron microscopic examination on successive days in vitro. Similar developmental stages were compared in control explants. Granule cell destruction began early, and was widespread by 2 days in vitro, when oligodendrocyte destruction also began in treated cultures. A few granule cells survived, but no recognizable oligodendrocytes remained by 7 days in vitro, at a time when myelin was initially evident in control explants. Purkinje cell recurrent axon collateral sprouting began at 3 days in vitro in cultures exposed to cytosine arabinoside, and the sprouted terminals initially synapsed with Purkinje cell somata, somatic spines and dendritic shafts. Synapses with Purkinje cell dendritic spines developed later, at approximately the same time as parallel fiber-Purkinje cell dendritic spine synapses formed in control cultures. Astrocytic ensheathment of control Purkinje cells was well underway by 6 days in vitro and Purkinje cell somata were relatively rounded and almost completely ensheathed by 9 days in vitro. Glial ensheathment did not occur in cytosine arabinoside treated cultures, and Purkinje cell somata were scalloped at 7 days in vitro by excess impinging recurrent axon collateral terminals, and never developed the smooth contours characteristic of control Purkinje cells. Purkinje cell somatic spines persisted in treated explants, and reduction of excess extracellular space was delayed until 12 days in vitro, when most of the developmental changes had been completed. The earlier development of synapses by excess recurrent axon collateral terminals with Purkinje cell somata, somatic spines and dendritic shafts, followed by the later development of heterotypical synapses with dendritic spines, in parallel with synapse formation by normal presynaptic elements, suggests that the sequence of development of synapses is a function of the maturational state of the postsynaptic components.

Lymphocytes from SJL/J mice immunized with spinal cord respond selectively to a peptide of proteolipid protein and transfer relapsing demyelinating experimental autoimmune encephalomyelitis

Relapsing experimental autoimmune encephalomyelitis (R-EAE) can be induced in SJL/J mice by immunization with spinal cord homogenate and adjuvant. The specific Ag(s) responsible for acute disease and subsequent relapses in this model is unknown. Myelin basic protein (BP), an encephalitogenic peptide of BP (BP 87-99), and proteolipid protein (PLP) can each induce R-EAE in SJL/J mice, and a peptide of PLP (PLP 139-151) has been reported to induce acute EAE. To determine the encephalitogens in cord-immunized mice with R-EAE, the in vitro proliferative responses of lymph node cells (LNC) and central nervous system mononuclear cells to BP, BP peptides, and PLP peptides were examined during acute EAE and during relapses. LNC responded only to PLP peptides 139-151 and 141-151 and did not respond to BP or its peptides during acute or chronic disease. Central nervous system mononuclear cells also preferentially responded to PLP 139-151 and 141-151 during acute and relapsing disease. A PLP 139-151 peptide-specific Th cell line was selected from LNC of cord-immunized donors. Five million peptide-specific line cells transferred severe relapsing demyelinating EAE to naive recipients. We conclude that PLP peptide 139-151 is the major encephalitogen for R-EAE in cord-immunized SJL/J mice. We demonstrate for the first time that Th cells specific for this peptide are sufficient to transfer relapsing demyelinating EAE. The predominance of a PLP immune response rather than a BP response in SJL/J mice suggests that genetic background may determine the predominant myelin Ag response in human demyelinating diseases such as multiple sclerosis.

Lymphocytes from SJL/J mice immunized with spinal cord respond selectively to a peptide of proteolipid protein and transfer relapsing demyelinating experimental autoimmune encephalomyelitis

Relapsing experimental autoimmune encephalomyelitis (R-EAE) can be induced in SJL/J mice by immunization with spinal cord homogenate and adjuvant. The specific Ag(s) responsible for acute disease and subsequent relapses in this model is unknown. Myelin basic protein (BP), an encephalitogenic peptide of BP (BP 87-99), and proteolipid protein (PLP) can each induce R-EAE in SJL/J mice, and a peptide of PLP (PLP 139-151) has been reported to induce acute EAE. To determine the encephalitogens in cord-immunized mice with R-EAE, the in vitro proliferative responses of lymph node cells (LNC) and central nervous system mononuclear cells to BP, BP peptides, and PLP peptides were examined during acute EAE and during relapses. LNC responded only to PLP peptides 139-151 and 141-151 and did not respond to BP or its peptides during acute or chronic disease. Central nervous system mononuclear cells also preferentially responded to PLP 139-151 and 141-151 during acute and relapsing disease. A PLP 139-151 peptide-specific Th cell line was selected from LNC of cord-immunized donors. Five million peptide-specific line cells transferred severe relapsing demyelinating EAE to naive recipients. We conclude that PLP peptide 139-151 is the major encephalitogen for R-EAE in cord-immunized SJL/J mice. We demonstrate for the first time that Th cells specific for this peptide are sufficient to transfer relapsing demyelinating EAE. The predominance of a PLP immune response rather than a BP response in SJL/J mice suggests that genetic background may determine the predominant myelin Ag response in human demyelinating diseases such as multiple sclerosis.

Myelination and glial ensheathment of Purkinje cells in cerebellar cultures are not inhibited by antibodies to the neural cell adhesion molecule, N-CAM

Mouse cerebellar cultures were exposed to anti-N-CAM antibodies throughout their in vitro development. Some cultures were stripped of myelinating oligodendrocytes and functionally competent astrocytes by treatment with cytosine arabinoside (Ara C), while others were left untreated and were potentially capable of forming myelin around axons and astrocytic sheaths around Purkinje cell somata and dendrites. As expected, the antibodies inhibited axonal fasciculation in the Ara C treated cultures. However, the same antibodies had no discernible effect on formation of myelin or astrocytic sheaths in cultures not treated with Ara C. N-CAM is expressed on the surfaces of neurons, oligodendroglia and astrocytes, and has been proposed as the signal molecule governing both kinds of neuron-glia interactions. The observations of the present study strongly suggest, however, that N-CAM does not have an indispensable role in such interactions.

Magnetic resonance imaging of experimental demyelinating lesions

An animal model of central nervous system demyelination was created by injecting rat internal capsules with lysophosphatidylcholine (LPC). The resulting chemically induced demyelinating lesions were readily visible in T1-weighted spin-echo, T2 weighted spin-echo, and inversion-recovery magnetic resonance imaging (MRI) sequences. Changes in lesions were followed over 8 weeks and correlated with histopathology. Histologically, lesions were characterized initially by an acute, inflammatory phase with edema and blood-brain barrier breakdown, followed by macrophage-mediated removal of myelin debris and finally by remyelination after 3 to 4 weeks. MRI can differentiate lesion stages in the LPC model and may be useful in investigating mechanistic aspects of the demyelinating process. In addition the well-localized lesions may be amenable to study by techniques of volume-localized NMR spectroscopy.

Myelination of axons within cytosine arabinoside treated mouse cerebellar explants by cultured rat oligodendrocytes

Cell suspensions of cultured purified rat oligodendrocytes prepared by the differential substrate adhesion method were applied to neonatal mouse cerebellar explant cultures in which myelination and oligodendrocyte maturation had been irreversibly inhibited by exposure to cytosine arabinoside. Myelination of Purkinje cell axons within 92% of the host explants was observed 2-5 days after oligodendrocyte application. Ultrastructurally, mature oligodendrocytes and axons surrounded by compact myelin, as well as spherules of compact myelin membranes without axons, were present within the cerebellar explants. It is evident that cultured dissociated purified oligodendrocytes retain the ability to myelinate appropriate axons. Such oligodendrocytes may be hyperreactive with regard to myelin membrane formation, as suggested by the presence of spheres of compact myelin without axons.

Brain dehydration and neurologic deterioration after rapid correction of hyponatremia

We made rats severely hyponatremic, varying the rate of onset and duration of the disturbance, and then compared rapid correction to slow correction. An acute fall in the plasma Na to 106 mEq/liter within seven hours caused seizures and coma, but these findings resolved and survival was 100% after either rapid or slow correction. A more gradual fall in plasma Na to 95 mEq/liter in three days caused neither seizures nor coma. Measurements of brain water and electrolytes showed that adaptive losses of brain Na and K (maximally depleted within seven hours) and slower losses of non-electrolyte solutes progressively reduced brain edema. After three days of hyponatremia, rapid correction to 119 mEq/liter with 1 M NaCl or to 129 mEq/liter by withdrawing DDAVP caused brain dehydration because lost brain K and non-electrolyte solutes were recovered slowly. This treatment was followed by a delayed onset of severe neurologic findings, demyelinating brain lesions and a mortality rate of over 40%. Slow correction (0.3 mEq/liter/hr) avoided these complications and permitted 100% survival. We conclude that the rat adapts quickly to hyponatremia and can survive with extremely low plasma sodium concentrations for prolonged periods. Although rapid correction is well tolerated when hyponatremia is of brief duration, it may cause brain damage in animals that have had time to more fully adapt to the disturbance.

Pulmonary function and dysfunction in multiple sclerosis

Pulmonary function was studied in 25 patients with clinically definite multiple sclerosis with a range of motor impairment. Forced vital capacity (FVC), maximal voluntary ventilation (MVV), and maximal expiratory pressure (MEP) were normal in the ambulatory patients (mean greater than or equal to 80% predicted) but reduced in bedridden patients (mean, 38.5%, 31.6%, and 36.3% predicted; FCV, MVV, and MEP, respectively) and wheelchair-bound patients with upper extremity involvement (mean, 69.4%, 50.4%, and 62.6% predicted; FVC, MVV, and MEP, respectively). Forced vital capacity, MVV, and MEP correlated with Kurtzke Expanded Disability Status scores (tau = -0.72, -0.70, and -0.65) and expiratory muscle weakness occurred most frequently. These findings demonstrate that marked expiratory weakness develops in severely paraparetic patients with multiple sclerosis and the weakness increases as the upper extremities become increasingly involved.

Immunoperoxidase labelling of rat brain sections with sera from patients with paraneoplastic cerebellar degeneration and systemic neoplasia

Sera from patients with systemic cancer found by immunofluorescence staining to have antibodies to human cerebellar cell populations were reacted with vibratome sections of rat cerebellum and examined by peroxidase-antiperoxidase (PAP) methods. Seven patients with clinically or pathologically confirmed paraneoplastic cerebellar degeneration and two neurologically normal patients with high titers of anticerebellar antibodies were studied. Sera from all antibody-positive patients, but not from controls, produced intense staining of brain sections. Sera from patients with ovarian adenocarcinoma reacted predominantly with Purkinje cells and neurons within brainstem nuclei. Sera from patients with oat cell carcinoma and one patient with ductal carcinoma of the breast produced nuclear and cytoplasmic staining of neurons throughout the central nervous system. Serum from a patient with Hodgkin's disease labeled the peripheries of Purkinje cells and Golgi II cells. Serum from a patient with mixed mesodermal sarcoma of the ovary labeled Purkinje cells, basket cells, and scattered astrocytes. Staining of extraneural tissues was not observed. This study confirms the presence of antineural antibodies in patients with systemic neoplasia with and without paraneoplastic cerebellar degeneration and suggests that the antigens recognized by this antibody response may vary with the associated neoplasm.

Movement disorders in multiple sclerosis

Movement disorders other than cerebellar tremor are rare clinical manifestations of multiple sclerosis (MS). Two cases of parkinsonism and a case of chorea associated with MS are reported, and the literature is reviewed.

Sodium channels in normal and regenerated feline ventral spinal roots

Regenerated and remyelinated nerve fibers have shorter internodes and thus more nodes than normal mature fibers. This requires either a decrease in the number of sodium channels per node or an increase in the number of channels per fiber or both. The purpose of this investigation was to determine what happens to sodium channel number, as estimated by 3H-saxitonin (STX) binding, in regenerated fibers and to relate this to nodal number. Five adult cats underwent cryoaxotomy of ventral root levels L5, L6, L7, and S1 on the left side. After regeneration for 16-45 weeks, binding parameters were determined. On the right (control) side, binding was consistent with that in unoperated animals (b = 1.3, Bmax = 10.2 +/- 0.4 fmol/mg wet, Kd = 0.6 +/- 0.1 nM). However, the regenerated nerves showed a 3.5-fold increase in maximal binding (b = 1.3, Bmax = 36.1 +/- 0.5, Kd = 0.45 +/- 0.4). Computer-aided histologic analysis of the regenerated roots revealed a decrease in fiber size; a significant decrease in internodal length for fibers in a given size class; and a 1.35-fold increase in total fibers per root. These factors account for a 2.36-fold increase in nodes per milligram (wet). The number of STX binding sites per regenerated node was calculated to be 1.95 X 10(6) (1.31, 3.07, 95% confidence limits), whereas it was 1.26 X 10(6) (0.78, 2.02) for the control roots. The difference was not significant (p greater than 0.05). It is concluded that, in regeneration, the increase in nodal number is accompanied by an increase in sodium channels, so that the number of channels per node is normal or slightly increased. There is a marked increase in channels per fiber and an even greater increase in channels per anterior horn cell. The implications of these data for nodal reorganization in remyelination are discussed.

Astrocytes play a role in regulation of synaptic density

Exposure of neonatal cerebellar explants to cytosine arabinoside destroys granule cells and arrests surviving glia in an early stage of maturation. Purkinje cells lack astroglial ensheathment and are hyperinnervated by sprouted Purkinje cell recurrent axon collateral terminals. Such granuloprival cultures were transplanted with optic nerve in order to supply mature glial cells. It was observed that not only were Purkinje cells almost completely ensheathed by astroglia, but there was a greater than 60% reduction in the number of somatic synapses compared to the non-transplanted granuloprival cultures. This astroglial ensheathment, which may be neuronally directed, could be the physical element provoking the reduction in the number of synapses.

Quantitative determination of MS-induced corpus callosum atrophy in vivo using MR imaging

To quantitate the extent of corpus callosum atrophy in multiple sclerosis, midsagittal corpus callosum areas were determined in 48 controls with normal MR scans and 41 patients with definite multiple sclerosis. The mean midsagittal corpus callosum area was 601 mm2 (range 405-791), 641 mm2, and 561 mm2 for all adult controls, for adult males, and for adult females, respectively. Control values were significantly greater than the means determined for all multiple sclerosis (MS) patients (508 mm2, range 281-758), for MS men (528 mm2), or for MS women (498 mm2). The degree of corpus callosum atrophy paralleled the estimated volume of periventricular and corpus callosum high-signal lesions, suggesting a possible cause-effect relationship. The results indicate that corpus callosum atrophy occurs commonly in patients with typical clinical forms of multiple sclerosis.

Corpus callosum and subcallosal-periventricular lesions in multiple sclerosis: detection with MR

Examination with magnetic resonance imaging of 40 patients with confirmed diagnoses of multiple sclerosis showed that corpus callosum involvement is common. Thirty percent of the patients had focal callosal lesions similar to those described in the pathology literature. Long, inner callosal-subcallosal lesions were found in 55% of patients. These lesions had signal characteristics similar to those of noncallosal periventricular lesions. Diffuse moderate to severe atrophy of the corpus callosum was noted in 40% of patients, with one exception concurrent with inner callosal lesions. The nature of the inner callosal lesions is not known, since these lesions are not typically described in the literature. These lesions may represent demyelination or increased water content and may be the precursor to atrophy that progresses from the ependymal surface toward the outer fibers of the corpus callosum.

Free kappa light chains in multiple sclerosis spinal fluid

Based on prior reports of free light chains of immunoglobulin G (IgG) in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS), we quantitated free kappa and lambda chains and whole IgG concentrations using sensitive and specific radioimmunoassays (RIAs). The RIA for free kappa chains had a sensitivity of 0.25 micrograms/ml and was capable of specifically measuring free kappa chains in whole CSF or serum even in the presence of a 4-log excess of whole IgG. By RIA, free kappa chains were detected in CSF samples from 33 (84%) of 39 MS patients but in only 1 (2.4%) of 42 controls. The control patients included 10 with noninfectious inflammatory diseases and 9 with central nervous system infections. The concentration of free kappa chains in the CSF of the MS patients was 1.40 +/- 1.21 micrograms/ml. Free kappa chains were concentrated in the CSF 71- to 120-fold relative to reference proteins. In contrast, increased levels of free lambda chains or of whole IgG were nonspecific; abnormalities were seen in controls with infections or inflammatory diseases as often as in MS patients. These studies suggest that the measurement of free kappa light chains may have important diagnostic usefulness, since the specificity of the finding for MS appears to be high.

Multiple sclerosis. The problem of incorrect diagnosis

Various neurologic disorders may be diagnosed incorrectly as multiple sclerosis (MS) since there is no test that is entirely specific for the disease. We report ten patients who met clinical criteria for probable or definite MS and who were given incorrect diagnoses. All of the patients were subsequently shown to have alternative diagnoses, three of which were directly treatable. From these illustrative cases, five characteristics were identified that alerted us to the possibility of an alternative diagnosis. We have called these characteristics "red flags," and suggest that they may be useful as features casting doubt on the diagnosis of MS if used judiciously in conjunction with clinical diagnostic criteria.