Glutamate excitotoxicity--a mechanism for axonal damage and oligodendrocyte death in Multiple Sclerosis?

Glutamate excitotoxicity mediated by the AMPA/kainate-type of glutamate receptors is known not only to damage neurons but also the myelin-producing cell of the central nervous system (CNS), the oligodendrocyte. In Multiple Sclerosis (MS), myelin, oligodendrocytes and axons are lost or damaged as a result of an inflammatory attack on the CNS. Activated immune cells produce glutamate in large quantities by deamidating glutamine via glutaminase. Thus, we hypothesized that during inflammation in MS, glutamate excitotoxicity may contribute to the lesion. This was addressed by treating mice sensitized to develop acute experimental autoimmune encephalomyelitis (EAE) with an AMPA/kainate antagonist, NBQX. Treatment resulted in substantial amelioration of disease, increased oligodendrocyte survival and reduced axonal damage, as indicated by the levels of dephosphorylated neurofilament-H. Despite the clinical differences, NBQX-treatment had no effect on lesion size and did not reduce the degree of CNS inflammation. In addition, NBQX did not alter the proliferative activity of antigen-primed T cells in vitro, further indicating a lack of effect at the level of the immune system. In separate studies, infiltrating immune cells present in perivascular cuffs, commonly the site of entry for invading immune cells, were found to express glutaminase in abundance, supporting the production of glutamate in inflammatory lesions. Thus, glutamate excitotoxicity appears to be an important mechanism in autoimmune demyelination and its prevention with AMPA/kainate antagonists may prove to be an effective therapy for MS.

Development of severe longitudinal atrophy of thoracic spinal cord following lupus-related myelitis

A 26-year-old woman suffered from acute myelitis at Th 6 level associated with systemic lupus erythematosus. Methyl-prednisolone pulse therapy, intravenous high-dose immunoglobulin administration and plasmapheresis were not effective. Her neurological signs had persisted in spite of subsequent administration of oral prednisolone and azathiopurine. Magnetic resonance imaging (MRI) of spinal cord at the onset showed a marked swelling with intramedullary high intensity signals on T2WI along the whole thoracic cord. Three years later, MRI demonstrated a severe longitudinal and segmental atrophy of the mid to low thoracic cord which resulted in transverse spinal signs.

Differential microglial response to progressive neurodegeneration in the murine mutant Wobbler

Activated microglia is associated with neurodegenerative processes, but the precise role of this cell population is difficult to identify. Most experimental models employed to examine microglial responses involve acute alterations of neuronal integrity, in contrast to the progressive nature of neurodegenerative diseases. In order to approach the clinical situation better, the microglial response was analyzed in the murine mutant Wobbler, which exhibits a well-characterized neurodegenerative pathology, manifested by motoneuronal death following a period of cellular dysfunction with characteristic morphological features. Microglial cells were identified using anti-Mac1 or anti-IgG antibodies. Examination of the changes in density, localization, and phenotype of microglia differentiated two types of responses in Wobblers. A first type of response was observed as early as in the third week after birth, when the only apparent neuronal defect was the morphological alteration of a subset of motoneurons in the cervical spinal cord, which was maintained later on. The activated microglia extended long processes that selectively ensheathed vacuolated motoneurons. At later stages, when motoneuron death became prominent, an additional type of response was characterized by an increased density of reactive microglia that was seen extending throughout the cervical enlargement. This secondary microglial response occurred in parallel to the infiltration of T-lymphocytes. Thus, these results point to a differential response of microglial cells to a progressive neurodegenerative process.

Experimental myelitis in BALB/cN and C57BL/6N mice caused by herpes simplex virus type 1 compared with herpes simplex virus type 2

Intraperitoneal and footpad inoculations of herpes simplex virus type 1 (HSV) into BALB/cN (HSV-susceptible) and C57BL/6N (HSV-resistant) mice were carried out to induce experimental myelitis. Standard laboratory strains (McIntyre, F, RK, and recently Okinawa strain R1) were inoculated in mice. As a control, the HSV 2 standard laboratory strain SAV was also inoculated. The McIntyre strain was the most virulent, while the F strain was the least. RK and R1 were both moderately virulent. Myelitis was induced in BALB/cN mice after intraperitoneal and footpad inoculations of low to high doses of the McIntyre strain, and intraperitoneal inoculation of moderate and high doses of the RK and R1 strains. Symptoms of paraplegia of the hind legs and rectal and urinary incontinence were observed, but not until 3-5 hours before death. The symptoms caused by footpad inoculation were slightly different from those following intraperitoneal inoculation; rectal incontinence, in particular, was inconspicuous in the former. In the case of footpad inoculation of RK and R1, only one mouse inoculated with R1 showed symptoms and histology of myelitis. The F strain caused no symptoms. In the case of C57BL/6N mice, high dose intraperitoneal and footpad inoculations of the McIntyre strain also caused myelitis, and the symptoms were observed about 6-7 hours before death. In only one C57BL/6N mouse intraperitoneally inoculated with a high dose of R1 did symptoms appear about 6 hours before death. The same symptoms caused by intraperitoneal and footpad inoculations of HSV 2 (SAV) were observed more clearly and for a longer period (half to one day) than those caused by HSV 1 inoculation. Spinal cord necrosis was noted with McIntyre, RK and R1 inoculations, but it was not marked with randomly located foci, when compared with that caused by SAV. Further, the foci of necrosis in C57BL/6N mice were smaller than in BALB/cN mice, even when high dose McIntyre strain was used. Nuclear pyknosis and edema of the brain in the dead mice following HSV 1 inoculation were more marked than in those killed by SAV.

MRI of radiation myelitis: a report of a case treated with hyperbaric oxygen

Radiation therapy is commonly applied as a primary or adjuvant therapy for malignancies. One of the major complications following radiation therapy is the necrosis of the otherwise normal surrounding soft tissues and/or bone. Post-radiation myelopathy rarely occurs when the spinal cord is included within the radiation field, in cases of high total radiation doses or for high radiation doses per fractionation. Up until the present, no tolerance dose for the spinal cord has accurately been defined and no treatment has proved satisfactory. Hyperbaric oxygen therapy is already currently used as adjuvant treatment for osteoradionecrosis and for radionecrosis of soft tissues with satisfactory results, whereas results for the treatment of post-attinic myelitis were contradictory. The aim of our report is to describe a case of radiation myelitis with a progressive improvement in the clinicoradiologic picture following hyperbaric oxygen treatment.

Neurodegeneration and glial activation patterns after mechanical nerve injury are differentially regulated by non-MHC genes in congenic inbred rat strains

Ventral root avulsion in the rat leads to a retrograde response, with activation of glia and up-regulation of immunologic cell surface molecules such as major histocompatibility complex (MHC) antigens, and the subsequent degeneration of a large proportion of the lesioned motoneurons. Herein, we examined several inbred congenic rat strains previously known to react differently to experimentally induced autoimmune diseases and demonstrate a substantial genetic diversity in the regulation of glial activation and neuron death in this injury model. The panel of examined inbred rat strains included DA(RT1AV1), PVG.1AV1, LEW.1AV1, LEW.1N, BN(RT1N) and E3(RT1U), and the following parameters were determined: (1) MHC class II expression on glia; (2) expression of glial fibrillary acidic protein, C3 complement, and microglial response factor-1 mRNAs in glia; (3) levels of the tumor necrosis factor-alpha and interleukin-1beta cytokine mRNAs; (4) degree of motoneuron loss. The findings of considerable strain-dependent differences in all parameters studied demonstrate important polymorphisms in the genetic regulation of these events. Furthermore, some of the studied features segregated from each other, suggesting independent regulatory mechanisms. Genes outside of the MHC complex are mainly implicated as being of importance for the phenotypic differences, as significant differences were recorded between the MHC congenic strains differing in the non-MHC genes but not vice versa. These results contribute new important insights into the genetic regulation of glial reactivity and neuron death after mechanical nerve injuries. In addition, the finding of conspicuous strain-dependent differences makes it necessary to consider the genetic background when designing and interpreting animal experiments involving noxious insults to the central nervous system resulting in glial activation and nerve cell loss.

Spinal cord lesions of myelitis with hyperIgEemia and mite antigen specific IgE (atopic myelitis) manifest eosinophilic inflammation

We report the neuropathological findings of spinal cord specimens obtained from two patients who had localized myelitis with hyperIgEemia and mite antigen specific IgE (atopic myelitis). Both cases showed mild spinal cord dysfunction, and the gadolinium-enhanced area of the isolated spinal cord lesion observed on MRI was biopsied, respectively. Neuropathologically, both cases showed many perivascular lymphocyte cuffings associated with disrupted vessels, and the infiltration of eosinophils in the spinal cord lesions. Both myelin and axons were lost in the lesions, which were associated with astrogliosis. These findings suggest that an allergic mechanism may play a role in this condition.

Sustained induction of heme oxygenase-1 in the traumatized spinal cord

Oxidative stress contributes to secondary injury after spinal cord trauma. Among the consequences of oxidative stress is the induction of heme oxygenase-1 (HO-1), an inducible isozyme that metabolizes heme to iron, biliverdin, and carbon monoxide. Here we examine the induction of HO-1 in the hemisected spinal cord, a model that results in reproducible degeneration in the ipsilateral white matter. HO-1 was induced in microglia and macrophages from 24 h to at least 42 days after injury. Within the first week after injury, HO-1 was induced in both the gray and the white matter. Thereafter, HO-1 expression was limited to degenerating fiber tracts. HSP70, a heat shock protein induced mainly by the presence of denatured proteins, was consistently colocalized with HO-1 in the microglia and macrophages. This study to demonstrates long-term induction of HO-1 and HSP70 in microglia and macrophages after traumatic injury and an association between induction of HO-1 and Wallerian degeneration. White matter degeneration is characterized by phagocytosis of cellular debris and remodeling of surviving tissue. This results in the metabolism, synthesis, and turnover of heme and heme proteins. Thus, sustained induction of HO-1 and HSP70 in microglia and macrophages suggests that tissue degeneration is an ongoing process, lasting 6 weeks and perhaps even longer.

Toxoplasma gondii myelitis in a patient with adult T-cell leukemia-lymphoma

Adult T cell leukemia-lymphoma (ATL) caused by HTLV-I may be associated with severe immunosupression and several opportunistic infections. Toxoplasmic encephalitis is a common central nervous system opportunistic infection in severely immunosupressed patients, however spinal cord involvement by this parasite is rare. In this paper, we report a case of toxoplasmic myelitis in a patient with ATL.

Persistent accumulation of cyclooxygenase-1 (COX-1) expressing microglia/macrophages and upregulation by endothelium following spinal cord injury

Acute inflammation following spinal cord injury results in secondary injury and pathological reorganisation of the central nervous system (CNS) architecture. Cyclooxygenases (Prostaglandin Endoperoxide H Synthases, PGH) are key enzymes in the conversion of arachidonic acid into prostanoids which mediate immunomodulation, mitogenesis, apoptosis, blood flow, secondary injury (lipid peroxygenation) and inflammation. Here, we report cyclooxygenase-1 (COX-1) expression following spinal cord injury. In control spinal cords, COX-1 expression was localized by immunohistochemistry to ependymal cells, some neurons, inclusive dorsal and ventral root ganglion cells, few endothelial cells but rarely to brain microglia/macrophages. In injured spinal cords, COX-1(+) microglia/macrophages accumulated highly significantly (P<0.0001) at peri-lesional areas and in the developing necrotic core early after injury. Here numbers of COX-1(+) cells remained persistently elevated up to 4 weeks following injury. Further, COX-1(+) cells were located in perivascular Virchow-Robin spaces, between spared axons and in areas of Wallerian degeneration. Double labeling experiments confirmed co-expression of COX-1 by ED-1(+) and OX-42(+) microglia/macrophages. Transiently after infarction most COX-1(+) microglia/macrophages coexpress the activation antigen OX-6 (MHC class II). However, the prolonged accumulation of COX-1(+) microglia/macrophages at the lesion site enduring the acute post injury inflammatory response points to a role of COX-1 in tissue remodeling or secondary injury. We have identified and localized persistent accumulation of COX-1 expressing cells which might be a potential pharmacological target following spinal cord injury. Therefore, we suggest that approaches based on: (i) short-term; and (ii) selective COX-2 blocking alone might not be a sufficient tool to suppress the local synthesis of prostanoids.

Antibodies to chondroitin sulfates A, B, and C: clinico-pathological correlates in neurological diseases

Anti-chondroitin sulfates (ChSs) antibodies have been reported in neuropathy and neurodegenerative diseases. Differences in specificities may account for their association with different diseases. Sera from 303 neurological patients were tested for antibodies to ChSs A, B, C. Titers >/=51,200 were found in 16 patients (eight peripheral neuropathy, three motor neuron disease, four multiple sclerosis, one myelitis). Three patients also had anti-sulfatides antibodies, which in two cases cross-reacted with ChSs. By indirect immunofluorescence, positive sera stained nuclei on normal human peripheral nerve sections. These findings indicate that human anti-ChSs antibodies are broadly reactive and not specific to any neurological disease.

Poliomyelitic-like illness in central European encephalitis

Central European encephalitis (CEE) may be accompanied by myeloradiculitic symptoms in up to 5% of patients. The authors report six patients with a myelitic form of CEE mimicking acute poliomyelitis with bulbar and arm predominance and a poor prognosis. Three patients died. Of the survivors, only one can perform most activities of daily living, but still needs assisted ventilation at night. Autopsy in one patient showed severe cervicothoracic inflammation with changes almost exclusively in anterior horn cells and roots, as typically seen in poliomyelitis.

Post-radiotherapy myelitis observed in an AIDS patient with a meningioma: case report and review of the literature

Radiation myelitis is an uncommon but serious complication of radiation therapy. Although the definitive threshold to cause myelitis is unknown, it is believed that less than 50 Gy when given in 25 or more fractions is highly unlikely to cause myelopathy. This report describes a case of myelitis within the radiotherapy portal in an HIV infected patient who received radiation therapy for an atypical meningioma located in the cervical spine. A complete resolution of the meningioma was also noted in this case. The possible contributing roles of HIV infection and concomitant administration of antiviral drugs are discussed.

Nerve growth factor in glia and inflammatory cells of the injured rat spinal cord

Nerve growth factor (NGF) is crucial for the development of sympathetic and small-diameter sensory neurons and for maintenance of their mature phenotype. Its role in generating neuronal pathophysiology is less well understood. After spinal cord injury, central processes of primary afferent fibers sprout into the dorsal horn, contributing to the development of autonomic dysfunctions and pain. NGF may promote these states as it stimulates sprouting of small-diameter afferent fibers and its concentration in the spinal cord increases after cord injury. The cells responsible for this increase must be identified to develop a strategy to prevent the afferent sprouting. Using immunocytochemistry, we identified cells containing NGF in spinal cord sections from intact rats and from rats 1 and 2 weeks after high thoracic cord transection. In intact rats, this neurotrophin was present in a few ramified microglia and in putative Schwann cells in the dorsal root. Within and close to the lesion of cord-injured rats, NGF was in many activated, ramified microglia, in a subset of astrocytes, and in small, round cells that were neither glia nor macrophages. NGF-immunoreactive putative Schwann cells were prevalent throughout the thoracolumbar cord in the dorsal roots and the dorsal root entry zones. Oligodendrocytes were never immunoreactive for this protein. Therapeutic strategies targeting spinal cord cells that produce NGF may prevent primary afferent sprouting and resulting clinical disorders after cord injury.

Spinal cord involvement in pediatric systemic lupus erythematosus: case report and literature review

Transverse myelitis is a rare but serious complication of systemic lupus erythematosus (SLE). We describe the youngest patient with transverse myelitis ever recorded in SLE. Clinical improvement was observed after prednisone and cyclophosphamide therapy. The English language literature from 1966 to the present on the subject are reviewed.

Regeneration in sarcoglycanopathies: expression studies of sarcoglycans and other muscle proteins

We have studied the immunohistochemical expression of 14 different muscle proteins of the basal lamina, sarcolemma and cytoskeleton in primary sarcoglycanopathies (13 cases) and compared it with Duchenne dystrophy (6 cases) and myositis (5 cases). Sarcolemmal proteins (i.e. 4 sarcoglycans, beta-dystroglycan, dystrophin, beta-spectrin) were reduced both in sarcoglycanopathies and Duchenne dystrophy, because of structural and functional impairment of the plasma membrane. Sarcolemmal proteins are poorly expressed in regenerating fibers of all muscle disorders, due to a developmental delay or to an abnormal assembly. Laminins (alpha2 and beta chains) were preserved in all cases while utrophin was expressed in Duchenne muscle but not in sarcoglycanopathies. Regenerating fibers were studied with different markers (i.e. fetal myosin, desmin, vimentin, laminin alpha1). Fetal myosin positive fibers (as well as desmin and laminin alpha1), were significantly higher in Duchenne dystrophy (25%) than in age-matched sarcoglycanopathies (7%). Vimentin, a marker of early regeneration, was expressed at higher level in sarcoglycanopathies than in Duchenne dystrophy, suggesting in the former a lower extent of regeneration or a shorter regeneration cycle.

Intramedullary increased MR signal intensity and its relation to clinical features in cervical myelopathy

BACKGROUND

Areas of intramedullary hyperintensity in patients with cervical spondylogenetic myelopathy (CSM) have been described and studied by several authors.

METHODS

In the present study, 100 patients were reappraised and divided into 2 groups according to whether or not MRI detected areas of hyperintensity on T2-weighted images.

RESULTS

Statistical analysis demonstrated that intramedullary hyperintensity is most frequently associated with severe impairment of deambulation, muscular hypotonus-hypotrophy and hypoesthesias of the upper limbs.

CONCLUSIONS

These radiological findings probably correspond to various types of lesions which, when irreversible, may influence postoperative neurological recovery.

[Progressive muscular weakness due to subacute postinfectious polyradiculitis and myelitis]

In a 67-year-old patient, generalised stable muscular weakness preexisting for several years became rapidly progressive within a few weeks prior to hospitalisation. He died one month after admission from acute cardiocirculatory failure. There was no history of muscular pain, clinical examination showed weak or absent tendon reflexes, hyposensibility of the dorsa of his feet, fasciculations and myocloni of the muscles of the lower limbs as well as a generalised muscular atrophy. Polyneuropathy due to diabetes mellitus and monoclonal IGG-kappa-type gammopathy were preexisting. CSF examination showed inflammatory cerebral fluid changes and further investigations revealed inflammatory polyradiculopathy affecting mainly motor nerve fibres. There was evidence of a reactivated varicella-zoster infection in serum and in the cerebrospinal fluid samples. The search for a tumour, vasculitis or a drug-related cause for this syndrome remained negative. Neuropathological examination at autopsy showed subacute polyradiculitis accompanied by myelitis. The most probable cause of this disorder is immune-mediated polyradiculitis after varicella-zoster infection.

Myelinolytic lesions in spinal cord of cobalamin-deficient rats are TNF-alpha-mediated

Repeated intracerebroventricular (i.c.v.)microinjection of tumor necrosis factor-alpha (TNF-alpha) into normal rats causes intramyelin and interstitial edema in the white matter of the spinal cord (SC). This response is identical to that observed in the SC white matter of rats made cobalamin (Cbl) deficient by total gastrectomy (TG). Immunoblot analysis showed that: 1) the level of the biologically active form of the TNF-alpha protein (17 kDa) is higher in the SC of totally gastrectomized (TGX) rats 2 months after TG, i.e., at the postoperative time when edema is observed; 2) SC levels of TNF-alpha protein (17 kDa) in 2-mo-TGX-, Cbl-treated rats are reduced to control. Repeated i.c.v. microinjections of anti-TNF-alpha antibodies, transforming growth factor-beta1 (TGF-beta1) or interleukin-6 (IL-6) into TGX rats, begun shortly after TG, substantially reduced both intramyelin and interstitial edema in the SC white matter. This study provides the first evidence that the hallmark myelin damage of Cbl-deficient central neuropathy, which is a pure myelinolytic disease, is not caused directly by the withdrawal of the vitamin itself, but reflects enhanced production of the biologically active form of TNF-alpha by SC cells. This study thus supports the view that TGF-beta1 and IL-6 may act as neuroprotective agents in Cbl deficiency central neuropathy.

Clinical, immunological and MRI features of myelitis with atopic dermatitis (atopic myelitis)

In order to clarify the characteristic features of myelitis with atopic dermatitis (AD), we compared the clinical, immunological and MRI findings between 14 myelitic patients with AD and 12 myelitic patients without AD. The myelitic patients with AD showed the following distinct features, compared with those without AD. (1) A preferential involvement of the cervical cord, as shown by neurologic as well as MRI examinations (14/14 vs. 5/12; P=0.0012), (2) paresthesia/dysesthesia as the predominant symptoms and a rare occurrence of definite muscle weakness (0/14 vs. 5/12; P=0.0120) and dysuria (1/14 vs. 8/12; P=0.0029), (3) a lower Expanded Disability Status Scale score (mean, 1.5 vs. 3.5; P=0.0018), (4) normal cerebrospinal fluid (CSF) findings including those for the IgG index and oligoclonal IgG bands and (5) a persistence of neurologic symptoms and MRI lesions during the follow-up periods (mean, 17 months). In addition, both the serum total IgE level and the frequency of specific IgE to Dermatophagoides farinae were significantly higher in the myelitic patients with AD (median IgE=1266 U/ml, specific IgE 14/14) than in those without AD (145 U/ml, P=0.0034 and 8/12, P=0.0331, respectively) and in 40 healthy controls (86 U/ml, P<0.0001 and 12/40, P<0.0001, respectively). Since myelitis with AD has distinct features and atopy to mite antigens appears to be the underlying cause of this condition, it may therefore be a distinct subtype of myelitis.

[HIV myelopathy as the presenting symptom of acquired immunodeficiency syndrome]

INTRODUCTION

Spinal lesions in the acquired immunodeficiency syndrome (AIDS) occur in 22% of all neurological complications, although their occurrence as the first sign of the disease is very uncommon. First place amongst the myelopathies described as associated with HIV is taken by vacuolar myelopathy, followed by the myelites.

CLINICAL CASE

We studied a 65 year old homosexual man who had previously been free of symptoms and signs of HIV infection. He was seen for progressive paraparesia which had begun some days previously, followed by altered sense of position and of vibration. Complementary tests showed that the patient was a carrier of HIV antibodies in high titre (P-24) with a high viral load of 907 x 1,000 copies RNA/ml. Testing with evoked potentials showed changes compatible with involvement of the sensory pathways of the spinal cord. After treatment with dexamethasone there was obvious improvement with partial recovery of his symptoms.

CONCLUSIONS

The neurological condition described was compatible with vacuolar type myelopathy due to HIV, appearing in the initial stages of the illness and coinciding with a marked increase in the viraemia. Although necropsy is necessary for confirmation of the diagnosis, more and more evidence is being found on which to base clinical suspicion. We discuss various hypotheses regarding possible pathogenic mechanisms arising in these circumstances.

Clinical and laboratory features of myelitis patients with anti-neutrophil cytoplasmic antibodies

Although perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) are associated with vasculitic neuropathy, their association with central nervous system (CNS) disorders has not been studied except for one report on optic-spinal type of multiple sclerosis associated with serum pANCA. We examined pANCA in sera from 98 patients with various CNS disorders, such as 58 MS, 17 myelitis, 12 HTLV-1 associated myelopathy, and 11 other CNS diseases using indirect immunofluorescence methods. The results showed serum pANCA to be positive in five patients with a peculiar type of myelitis, including two with MS and three with etiology unknown myelitis. All of these ANCA-positive patients were women and had acute or subacute myelopathy with various severities. MRI revealed segmental swelling of the spinal cord with T2 hyperintensity in the acute stage of the disease. Marked pleocytosis (227.8+/-101/mm3) and elevated protein level (128.8+/-52 mg/dl) in CSF were noted. Four of the patients had anti-nuclear antibodies and two had previous histories of symptoms suggesting autoimmune disorders. In a search for target antigens of pANCA, myeloperoxidase reactivity was found in the sera from two myelitis patients. Clinical and laboratory features of myelitis patients with pANCA in the present study are different from those of typical MS patients. Further study will be needed to delineate the role of pANCA in the pathogenesis of a specific type of myelitis.

Myelitis: a rare presentation of mumps

We report a rare case of mumps myelitis in which parotid swelling appeared 3 days after the symptoms of myelitis. A 10-year-old boy presented with acute paraplegia of grade I-II on MRC (Medical Research Council) scale and retention of urine with normal sensations. Central motor conduction to tibialis anterior (CMCT-TA) on the right side was 32 ms and 24 ms on the left side. Spinal MRI revealed hyperintense signal changes extending from C3 to T12. After 5 days of methylprednisolone therapy, there was marked improvement in weakness, micturition normalized and CMCT-TA also returned to normal. MRI repeated after 1 month was also normal. This response seems to be due to antiedema and to the antiinflammatory effect of methylprednisolone, because of a temporal relationship between MPS and clinical improvement. However, the possibility of natural recovery cannot be ruled out.

Computed tomography-guided biopsy of the spine. A review of 103 patients

STUDY DESIGN

A retrospective study of 103 computed tomography-guided biopsies of the spine. These represent a consecutive series of patients with spinal lesions or disorders observed over a 32-month period.

OBJECTIVES

To determine the diagnostic accuracy and clinical usefulness of computed tomography-guided biopsies with respect to major influencing variables.

SUMMARY OF BACKGROUND DATA

Computer tomographic-guided biopsy of the spine is considered a safe, accurate, and relatively inexpensive examination technique. A study comparing its diagnostic accuracy with respect to all the variables of age, gender, radiographic appearance, spinal level, tissue type, or pathologic diagnosis has not been done.

METHODS

Biopsy specimens were sent for cytologic and histologic analysis. Bacteriologic studies were performed when clinically indicated. The biopsy results were analyzed for adequacy and diagnostic accuracy, i.e., the ability to generate a tissue sample adequate for pathologic examination and one that yields diagnostic information.

RESULTS

The mean age of patients was 60 years, with a range of 4-91 years. The spines of 52 males and 51 females were studied. There were eight cervical, 28 thoracic, 53 lumbar, and 14 sacral lesions used as biopsy sites. The radiographic appearance of spinal lesions were lytic in 74 cases, blastic in four cases, and mixed in two cases. Tissues undergoing biopsy included bone (63 cases), soft tissue (35 cases), and mixed specimens (five cases). The pathologic examinations revealed 18 infections, 23 primary neoplasms, 34 metastases, and 19 normal tissues. An adequate specimen for pathologic examination was obtained in 90 biopsies (87%). A diagnosis was achieved in 67 of 94 patients (71%). Diagnostic rates obtained in thoracic level biopsies were lower than those from biopsies of other spinal levels (P = .007).

CONCLUSION

Computed tomography-guided biopsy is an important tool in the evaluation of spinal lesions. A positive biopsy result may preclude the need for open surgical intervention. This study included one of the largest series of patients in the medical literature. In addition, it determined the diagnostic rates of this procedure with respect to the major influencing variables. Thoracic-level biopsies have a diagnostic rate that is significantly lower than that of other spinal levels. No significant correlation was found between diagnostic accuracy and age, gender, radiographic appearance, tissue type, or eventual diagnosis.

Spinal rigidity following acute myelitis

A patient with a 2(1/2)-year history of painful spasms and rigidity of both lower limbs is described. Symptoms began after an episode of acute myelitis. The spasms--which were spontaneous and stimulus sensitive and occurred on voluntary action--involved the repetitive grouped discharge of motor units. Continuous motor unit activity was present at rest in the muscles of both legs, and cutaneomuscular reflexes were abnormal. This patient is similar to those recently reported as having stiffness and spasms of the legs due to a possible chronic spinal interneuronitis and provides further evidence that this kind of movement disorder may be caused by spinal cord pathology.

Neuropathology of myelitis, myelopathy, and spinal infections in AIDS

In AIDS, pathology in the spinal contents usually follows that in the brain but is less frequent. Opportunistic infections are found in an average of 9.5% of spinal AIDS autopsies but in 54% of autopsies of the whole CNS. Necrotizing CMV radiculomyelitis is a rare (3.4% in spinal autopsies) but very characteristic opportunistic spinal lesion. The most prominent spinal cord disease in AIDS is vacuolar myelopathy, occurring in greatly differing frequencies according to different geographical areas, with a mean of about 22.5% in AIDS spinal cord autopsies. Its pathogenesis and clinicopathologic correlation need clarification; it appears to develop mainly in severely ill AIDS patients with significant viral load, advanced immunosuppression, and confounding metabolic imbalance.

Acute Myelitis after hepatitis B vaccination

We report a case of myelitis after plasma-derived hepatitis B vaccination. The patient was a 31-year-old man who presented with progressive sensory symptoms in extremities that developed 2 weeks after a third vaccination. MRI of the cervicothoracic region revealed swelling and T2 high signal at the level of C4 to C5 cord, and isolated enhancement in the posterior columns between C4 and C5 cord. The significance of MRI findings and HLA haplotype of the patient will be briefly discussed.

Toxoplasmosis of the spinal cord in a patient with AIDS: case report and review

We present the case of a patient whose acute myelopathy almost completely resolved with empirical therapy for toxoplasmosis, and we review thirteen previously reported cases of myelopathy thought to have been caused by Toxoplasma gondii in patients with AIDS. The most common symptoms and abnormal physical findings were motor loss (usually paraparesis), bilateral sensory loss, urinary bladder dysfunction, and local pain. The majority of patients had magnetic resonance images that showed abnormalities of the spinal cord and brain in association with positive serology for Toxoplasma. Therapy for toxoplasmosis, when administered soon after the onset of symptoms, has resulted in clinical and radiographic improvement in the conditions of patients with toxoplasmosis.

Zoster myelitis: improvement with antiviral therapy in two cases

This report describes two patients with acquired immunodeficiency syndrome (AIDS) and herpes zoster myelopathy. Patient one had a T-8 myelitis that preceded the onset of T-8-distribution zoster and was followed by cervical myelopathy. Antibody to varicella zoster virus (VZV) was present in the CSF. He never received steroids or other immunosuppressive drugs, and his condition improved dramatically after treatment with intravenous acyclovir. The second patient had a rapidly progressive myelitis with paralysis of both legs. Detection of VZV DNA and antibody to VZV in his CSF led to successful treatment with famciclovir despite discontinuation of dexamethasone and earlier treatment failure with acyclovir. These cases support the idea that VZV myelopathy in the immunosuppressed host is caused by virus invasion. CSF analysis for antiviral antibody and for VZV DNA by polymerase chain reaction are helpful in establishing the diagnosis. Aggressive antiviral therapy is advised.

Ascending paralysis due to myelitis in a newborn with congenital toxoplasmosis

We present a female neonate in her second week of life with borderline microcephaly, microphthalmia and progressive ascending sensory and motor deficit leading to complete paralysis with respiratory failure and death at 27 days of age. Neurological imaging revealed, in addition to cerebral atrophy, marked hydrocephalus, ependymal basal ganglia calcification, leptomeningeal enhancement, and patchy myelitis throughout the entire spinal cord. CSF cytological examination revealed the presence of a mononuclear pleocytosis with Toxoplasma gondii trophozoites free in the CSF and within the cytoplasm of some macrophages, and a 100-fold raised protein content. To our knowledge, this is the first reported case of clinical acute spinal cord involvement in congenital toxoplasma infection, proven by the presence of toxoplasma trophozoite in the CSF.

Primary angiitis of the central nervous system associated with Hodgkin's disease

An unusual case of primary angiitis of the central nervous system associated with Hodgkin's disease in a 55-year-old-man is reported. After a 10-month history of acute transverse myelitis, the patient was diagnosed as having nodular sclerosing-type Hodgkin's disease involving the retroperitoneal lymph nodes. The patient died of a brainstem hemorrhage 1 week after a 15-day course of chemotherapy. Primary angiitis was documented on autopsy examination. To our knowledge, only nine similar cases have been reported in the literature, and none of them was associated with a sole initial spinal cord presentation. Owing to the rarity of this disease entity, a high index of suspicion and awareness of the association between primary angiitis and Hodgkin's disease are essential for early diagnosis.

A mathematical model of the volume effect which postulates cell migration from unirradiated tissues

PURPOSE

In order to simulate the large variation in tolerance doses for very small treatment volumes, we introduce a model which assumes the presence of cells which have migrated from unirradiated tissues.

METHODS AND MATERIALS

In order to represent serial architecture, the new model adds a new parameter to the familiar expression for serial architecture. Data derived from the model is fitted to the dose-response data developed by Hopewell et al. (Hopewell, J.W., Morris, A.D. and Dixon-Brown, A. The influence of field size on the late tolerance of the rat spinal cord to single doses of X rays. Br. J. Radiol. 60: 1099-1108, 1987) using white matter necrosis of rat spinal cord.

RESULTS

The new model with a cell-migration term more accurately describes the large differences in threshold doses for a very small treatment volume than a model without a cell-migration term.

CONCLUSION

Although these results do not prove that cell migration is the mechanism behind the volume effect for very small volume, they do suggest that the probability of normal tissue complication is more accurately predicted by the new model.

Necrotizing myelopathy--a report of two cases with review of literature

Necrotizing myelopathy is an uncommon neurological disorder. Till 1991, only 31 cases have been described in the literature. In this report, clinical and neuropathological features in two patients with necrotizing myelopathy are described. The precise aetiological agent in first patient was undetermined, However in the second patient there was serological evidence, suggestive of Herpes simplex virus infection.

Herpes simplex myelitis as a cause of acute necrotizing myelitis syndrome

We report a patient with herpes simplex virus (HSV) myelitis with a clinical history of rapidly progressive spinal cord dysfunction and extensive necrosis of the lumbosacral spinal cord at autopsy. The etiologic agent was HSV type 2. The close resemblance of the clinical features of this case to the syndrome of acute necrotizing myelitis emphasizes the need to recognize HSV myelitis as a cause of this syndrome, since it is diagnosable during life by culturing the CSF and is treatable.

Varicella-zoster virus infection of the central nervous system in the acquired immune deficiency syndrome

Productive varicella-zoster virus (VZV) infection of the central nervous system (CNS) was demonstrated in 11 acquired immune deficiency syndrome (AIDS) patients using immunocytochemistry and in situ hybridization. A characteristic zoster skin eruption was seen in only four cases. From our own series and 11 other cases in the literature, we identified five clinico-pathological patterns of VZV infection of the CNS in AIDS patients which could occur simultaneously. (i) Multifocal encephalitis predominantly involving the white matter, likely to be due to haematogenous spread of the infection was found in four cases. (ii) Ventriculitis was found in three cases. In two cases there was complete acute or chronic necrosis of the ventricular wall with marked vasculitis; in the third, the ependymal lining appeared irregular with foci of VZV-infected ependymal cells, some of which protruded into the ventricular lumen. (iii) Acute haemorrhagic meningo-myeloradiculitis with necrotizing vasculitis was observed in two cases. In one, this was associated with ventriculitis and was possibly due to shedding of infected ependymal cells into the ventricular lumen and secondary seeding of the CSF. (iv) Focal necrotizing myelitis was seen in one case. It followed cutaneous herpes zoster and was considered to result from neural spread from the diseased dorsal root ganglion similar to cases previously described of encephalitis limited to the visual system following VZV ophthalmicus, or bulbar encephalitis following a trigeminal zoster. (v) Vasculopathy involving leptomeningeal arteries and causing cerebral infarcts was seen in four cases, it was associated with meningitis in most cases. These findings are in keeping with the observation in non-AIDS patients that VZV spread to the CNS may follow different routes. Our study tends to show that VZV infection of the CNS occurs more frequently in AIDS than previously suspected and suggests that it must be considered as a diagnosis in cases of encephalitis, ventriculitis, focal myelitis, acute myeloradiculitis and cerebral infarcts in these patients.

MRI of AIDS-related polyradiculomyelitis

OBJECTIVE

We describe the unusual syndrome of cytomegalovirus (CMV) polyradiculomyelitis and its MR findings in two patients with AIDS.

MATERIALS AND METHODS

The clinical records and MRI studies of two patients with AIDS and CMV polyradiculomyelitis were reviewed. The MR images were performed on a Picker 1.0 or 1.5 T MR unit. Axial and sagittal T1-weighted images of the lumbar spine were obtained, pre- and post-Gd-DTPA (0.1 mmol/kg) administration. Gradient echo sagittal images were also obtained.

RESULTS

Precontrast images demonstrated a thickened cauda equina in both patients. In one patient the conus was ill defined on precontrast images. Post-contrast images demonstrated diffuse enhancement of the cauda equina in both patients as well as enhancement along the surface of the conus. In one patient the nerve roots were clumped and adherent to the walls of the thecal sac as well as to other nerve roots.

CONCLUSION

The clinical presentation of urinary retention, flaccid paraparesis, back and/or leg pain, and "saddle anesthesia" in a patient with AIDS should suggest the diagnosis of CMV polyradiculomyelitis. Although diffuse enhancement of the cauda equina on postcontrast MRI is a nonspecific finding, it would strongly support this diagnosis in the appropriate clinical setting. The diagnosis may be easily missed without the use of a contrast agent.

Myelitis following chickenpox: a case report

An 18-year-old woman presented with myelopathic symptoms and a T-8 sensory deficit during a primary varicella infection. There were significant MRI changes in both the cervical and thoracic regions. Following treatment with steroids and intravenous acyclovir, the patient improved clinically and the abnormalities on MRI improved.

Differential time course and spatial expression of Fos, Jun, and Krox-24 proteins in spinal cord of rats undergoing subacute or chronic somatic inflammation

We have used the evoked expression of both immediate early gene (IEG)-encoded proteins (Krox-24, c-Fos, Fos B, Jun D, Jun B, c-Jun), and dynorphin to monitor sensory processing in the spinal cords of rats undergoing subacute or chronic somatic inflammation (i.e., subcutaneous inflammation of the plantar foot and monoarthritis, respectively). Behavioral and immunocytochemical approaches were conducted in parallel up to 15 weeks postinjection in order to detect possible relationships between clinical evolution and spatiotemporal pattern of IEG-encoded protein expression. Each disease had specific characteristics both in terms of their clinical evolution and pattern of evoked protein expression. All IEG proteins were expressed in both cases. Most of the staining was observed in both the superficial layers of the dorsal horn and deep dorsal horn (laminae V-VII and X). Monoarthritis was distinguished by a high level of total protein expression. Staining was especially dense in the deep dorsal horn. More labelled cells were observed at 1-2 days and at 2 weeks postinjection, corresponding to the initiation and progressive phases of the disease, respectively. Subcutaneous inflammation was characterized by a moderate level of total IEG expression. More labelled cells were observed in the first day following injection. It is the relative degree of expression of each IEG-encoded protein with regard to the others that characterized the progression of the diseases. Early stages of the diseases coincided with the expression of all Fos and Jun proteins, while late stages showed an increase in Jun D and Fos B involvement; Krox-24 was induced mostly during the early phases and/or periods of paroxysm of the diseases. Persistent stimulation was characterized by a predominant expression in deep versus superficial layers of the dorsal horn. Evoked expression of c-Jun in motoneurons was only observed in monoarthritis. The peak of dynorphin expression was late in regard to both the induction of inflammation and period of maximal IEG-encoded protein expression. The present work indicates that the neural processing that takes place during progression of these diseases can be monitored well at the spinal cord level by using the expression of an array of IEG-encoded proteins. Study of long term evolutive diseases and especially those that evolve into chronicity can largely benefit from such an approach.