Evidence of altered cardiac autonomic regulation in myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and meta-analysis

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition with no reliable diagnostic biomarkers. Studies have shown evidence of autonomic dysfunction in patients with ME/CFS, but results have been equivocal. Heart rate (HR) parameters can reflect changes in autonomic function in healthy individuals; however, this has not been thoroughly evaluated in ME/CFS.

METHODS

A systematic database search for case-control literature was performed. Meta-analysis was performed to determine differences in HR parameters between ME/CFS patients and controls.

RESULTS

Sixty-four articles were included in the systematic review. HR parameters assessed in ME/CFS patients and controls were grouped into ten categories: resting HR (RHR), maximal HR (HRmax), HR during submaximal exercise, HR response to head-up tilt testing (HRtilt), resting HR variability (HRVrest), HR variability during head-up tilt testing (HRVtilt), orthostatic HR response (HROR), HR during mental task(s) (HRmentaltask), daily average HR (HRdailyaverage), and HR recovery (HRR) Meta-analysis revealed RHR (MD ± 95% CI = 4.14 ± 1.38, P < .001), HRtilt (SMD ± 95% CI = 0.92 ± 0.24, P < .001), HROR (0.50 ± 0.27, P < .001), and the ratio of low frequency power to high frequency power of HRVrest (0.39 ± 0.22, P < .001) were higher in ME/CFS patients compared to controls, while HRmax (MD ± 95% CI = -13.81 ± 4.15, P < .001), HR at anaerobic threshold (SMD ± 95% CI = -0.44 ± 0.30, P = 0.005) and the high frequency portion of HRVrest (-0.34 ± 0.22, P = .002) were lower in ME/CFS patients.

CONCLUSIONS

The differences in HR parameters identified by the meta-analysis indicate that ME/CFS patients have altered autonomic cardiac regulation when compared to healthy controls. These alterations in HR parameters may be symptomatic of the condition.

[Clinical and instrumental characteristics of chronic neuroborreliosis]

The impairment of the nervous system is the main clinical presentation of chronic Lyme borreliosis. Frequency and characteristics of neuroborreliosis in Russia are still under-investigated. The article contains the analysis of 160 cases of chronic Lyme borreliosis with detailed descriptions of different neurologic syndromes - radiculopathy, polyneuropathy, encephalopathy and encephalomyelitis. Epidemiology of this disease as well as its laboratory and instrumental diagnosis are discussed. Extraneural signs and symptoms of late stages of neuroborreliosis are presented. The results of antibacterial treatment of different forms of chronic neuroborreliosis are outlined.

Reversible parainfectious bilateral "striatal necrosis"

Bilateral striatal necrosis is usually associated with either endogenous or exogenous toxins, and with poor neurodevelopmental outcomes. We describe two patients with acute bilateral striatal clinical syndrome and magnetic resonance signal changes who made a complete clinical and radiologic recovery within 3 months. After an uneventful pregnancy, normal birth, and normal development, both boys presented at ages 3 and 5 years, respectively, after a viral illness with slurring of speech, bradykinesia, and an extrapyramidal movement disorder. On examination, both manifested bilateral cog wheel rigidity, with a broad-based gait and flexor plantar response. Cranial magnetic resonance imaging in both children indicated bilateral, symmetric, high signal changes in the lentiform nucleus, predominately in the putamen, with sparing of the globus pallidi bilaterally. The brain parenchyma was otherwise normal. Neurometabolic investigations produced normal results in both patients. The pathogenesis is uncertain, but could be immune-mediated. Both children, at 3-year and 1-year follow-ups, respectively, are doing well neurologically and academically. Our patients demonstrate that abnormal imaging findings during acute stages do not preclude good clinical and radiologic recovery.

Pathogenic T cell responses against aquaporin 4

Inflammatory lesions in the central nervous system of patients with neuromyelitis optica are characterized by infiltration of T cells and deposition of aquaporin-4-specific antibodies and complement on astrocytes at the glia limitans. Although the contribution of aquaporin-4-specific autoantibodies to the disease process has been recently elucidated, a potential role of aquaporin-4-specific T cells in lesion formation is unresolved. To address this issue, we raised aquaporin-4-specific T cell lines in Lewis rats and characterized their pathogenic potential in the presence and absence of aquaporin-4-specific autoantibodies of neuromyelitis optica patients. We show that aquaporin-4-specific T cells induce brain inflammation with particular targeting of the astrocytic glia limitans and permit the entry of pathogenic anti-aquaporin-4-specific antibodies to induce NMO-like lesions in spinal cord and brain. In addition, transfer of aquaporin-4-specific T cells provoked mild (subclinical) myositis and interstitial nephritis. We further show that the expression of the conformational epitope, recognized by NMO patient-derived aquaporin-4-specific antibodies is induced in kidney cells by the pro-inflammatory cytokine gamma-interferon. Our data provide further support for the view that NMO lesions may be induced by a complex interplay of T cell mediated and humoral immune responses against aquaporin-4.

Chronic restraint stress during early Theiler's virus infection exacerbates the subsequent demyelinating disease in SJL mice: II. CNS disease severity

Theiler's murine encephalomyelitis virus (TMEV) infection is a well-characterized model of multiple sclerosis (MS). Previous research has shown that chronic restraint stress (RS) during early TMEV infection exacerbates behavioral signs of the disease. The present data suggest that RS-induced increases in CNS inflammation, demyelination, and axonal degeneration may underlie this exacerbation. In addition, we report that males exhibit greater CNS inflammation and higher numbers of demyelinating lesions while females show greater susceptibility to RS-induced exacerbation. These findings indicate that RS during early TMEV infection increases CNS lesion formation during the late phase and suggest that the effects of RS are sex-dependent.

Viliuisk encephalomyelitis in Eastern Siberia - analysis of 390 cases

Viliuisk encephalomyelitis (VE) is a unique disease occurring in the Yakut (Sakha) population of Eastern Siberia. VE is always fatal, with some patients dying during the acute encephalitic phase of illness; those surviving the acute phase develop progressive dementia, rigidity and spastic quadriparesis as part of a more prolonged pan-encephalitic syndrome. The disease is characterized neuropathologically by multiple widespread micronecrotic foci with marked inflammatory reactions and subsequent gliosis throughout the cerebral cortex, basal ganglia, cerebellum and brain stem. The acute febrile onset with cerebrospinal fluid pleocytosis and increased protein and neuropathology showing inflammatory reactions suggest that VE is an infectious disease, but the causative agent has not been identified. Initially detected in a small mixed Yakut-Evenk population of the mid-Viliui region, the disease subsequently spread south to densely populated areas around the capital city of Yakutsk. The occurrence of secondary VE cases in households and the introduction of the disease by migrants into new populations indicate that the disease is horizontally transmitted in a setting of a long intra-household contact. Although there has been a recent decline in the number of cases, increasing travel may result in further spread of this fatal disease to susceptible individuals in other regions of the world.

[Acute disseminated encephalomyelitis associated with mycoplasma pneumoniae infection]

A 20-year old man was hospitalized for acute urinary retention, headaches and mild fever. Neurological examination revealed a meningeal syndrome and a bilateral pyramidal syndrome of lower extremities with a C7 sensory level. The level of antibodies against Mycoplasma pneumoniae (Igm and IgG) suggested a recent unrecognized infection. Cerebral and medullar MRI showed T2-hyperintense lesions in the right thalamus and at the level of C1-C2 and C6. Evoked potentials were normal but EEG showed some bilateral theta waves. The cerebrospinal fluid analysis demonstrated 170 white cells/mm3 with 66% lymphocytes and proteins at 73 mg/dl. A few weeks after treatment with intravenous immunoglobulins at 0.4 g/kg/day for 5 days, the patient showed complete clinical recovery. MRI and urinary flowrate normalized after nine weeks. The authors are discussing the probable diagnosis of acute disseminated encephalomyelitis occurring after a mycoplasma unrecognized infection.

Dixièmes Journées des Maladies du Système Nerveux Périphérique

Sensory ganglionopathies have a frequent association with neoplastic disorders (paraneoplastic subacute sensory neuronopathy, or SSN) or dysimmune disorders, with drugs, such as cisplatin or pyridoxine, and with inherited disorders with degeneration of dorsal root ganglion cells. Unsteady gait and pseudoathetoid movements of the hand are the distinctive signs encountered in these disorders. The chronic disorders are characterized by non-length-dependent abnormalities of sensory nerve action potentials (SNAPs) and differ from other sensory neuropathies in showing a global, rather than distal, decrease in SNAP amplitudes. This review focuses on recent advances in defining the mechanisms involved in sensory ganglionopathies, and describes the differential diagnosis including the rarely encountered hereditary neuronopathies and the infectious causes.

Unusual reactions to insect stings

PURPOSE OF REVIEW

A variety of unusual or unexpected reactions have occurred in a temporal relationship to insect stings. This review will summarize these case history reports in recent years. As these reactions are very infrequent, the review will also include prior reported unusual reactions attributed to insect stings.

RECENT FINDINGS

Acute encephalopathy occurred 8 days after yellow jacket stings, without any other obvious cause. There have been prior reports of other neurological reactions, myasthenia gravis, peripheral neuritis and Guillain-Barré syndrome related to insect stings. Acute renal failure with tubular necrosis has occurred following massive numbers of stings from Africanized honeybees. Nephrotic syndrome has been reported in the past following single stings. Silent myocardial infarction has occurred, probably related to acute anaphylactic symptoms immediately following a sting. There are recent reports of other pathology, diffuse alveolar hemorrhage and rhabdomyolysis and prior reports of thrombocytopenic purpura and vasculitis. As the result of ocular stings, local reactions have occurred with corneal pathology leading to cataracts. Other prior reported reactions to ocular stings include conjunctivitis, corneal infiltration, lens subluxation, and optic neuropathy. There is scarce information regarding the pathogenesis of the majority of the unusual reactions and the subsequent allergic status or risk for sting anaphylaxis of people who have had these unusual reactions.

SUMMARY

This review includes a variety of reactions, particularly involving neurological, renal and cardiovascular symptoms, related to insect stings. It is important that clinicians be aware of this relationship when assessing people with these reactions and address future prophylaxis.

An equine protozoal myeloencephalitis challenge model testing a second transport after inoculation with Sarcocystis neurona sporocysts

Previous challenge studies performed at Ohio State University involved a transport-stress model where the study animals were dosed with Sarcocystis neurona sporocysts on the day of arrival. This study was to test a second transportation of horses after oral inoculation with S. neurona sporocysts. Horses were assigned randomly to groups: group 1, transported 4 days after inoculation (DAI); group 2, at 11 DAI; group 3, at 18 DAI; and group 4, horses were not transported a second time (controls). An overall neurologic score was determined on the basis of a standard numbering system used by veterinarians. All scores are out of 5, which is the most severely affected animal. The mean score for the group 1 horses was 2.42; group 2 horses was 2.5; group 3 horses was 2.75; and group 4 horses was 3.25. Because the group 4 horses did not have a second transport, they were compared with all other groups. Statistically different scores were present between group 4 and groups 1 and 2. There was no difference in the time of seroconversion between groups. There was a difference between the time of onset of first clinical signs between groups 1 and 4. This difference was likely because of the different examination days. Differences in housing and handling were likely the reason for the differences in severity of clinical signs. This model results in consistent, significant clinical signs in all horses at approximately the same time period after inoculation but was most severe in horses that did not experience a second transport.

Anti-Hu antibody neuropathy: a clinical, electrophysiological, and pathological study

OBJECTIVE

The objective is to report the clinical, electrophysiological, and histopathological features of 16 patients with anti-Hu antibody neuropathy.

METHODS

Clinical and electrophysiological data in 16 patients (11 females and 5 males) with positive anti-Hu antibody and nerve biopsy data in 9 cases were analyzed.

RESULTS

Cancer was detected in 11 patients, including 9 with small-cell lung cancer. Classical paraneoplastic subacute sensory neuronopathy (SSN) and/or encephalomyelitis (EM) was observed in 7 patients (44%), including 5 with SSN. The most common clinical feature was sensory-motor neuropathy (SMN), accounting for 50% of cases. Though sensory nerve conduction abnormality was the prominent feature in 14 (88%) cases, sensory and motor nerve conduction was abnormal in all cases. Motor nerve conduction findings were typical of axonal degeneration. The most common nerve conduction pattern was that of SMN, with a sensory neuronopathy pattern being observed in only 3 cases. Sural nerve biopsy in 9 patients showed axonal degeneration in all cases and inflammatory cells in 4 cases.

CONCLUSIONS

Classical sensory neuronopathy is rarer than expected, both clinically and electrophysiologically. Motor involvement is not uncommon and motor nerve conduction abnormality is frequently seen. A diverse clinical and electrophysiological, and histopathological spectrum was observed in this neuropathy.

SIGNIFICANCE

New guidelines for the selection of patients for anti-Hu antibody test are recommended.

Stiff-person syndromes: motor cortex hyperexcitability correlates with anti-GAD autoimmunity

OBJECTIVE

S: To investigate whether motor cortex excitability is enhanced in both stiff-person syndrome (SPS) and its "plus" variant, progressive encephalomyelitis with rigidity (PER), and related to autoimmunity against glutamic acid decarboxylase (GAD).

METHODS

The authors compared 21 patients with SPS or PER (7 untreated, 14 treated) with 14 age-matched healthy controls and used transcranial magnetic stimulation (TMS, paired-pulse paradigm) to investigate intracortical inhibition (ICI) and intracortical facilitation (ICF). GAD autoantibody levels in serum and CSF were determined by radioimmunoassay.

RESULTS

The authors found significantly enhanced motor cortex excitability in untreated SPS and PER patients. GABAmimetic medication significantly reduced ICF but did not affect ICI. Motor cortex excitability was more enhanced in patients with GAD antibodies than in patients without GAD antibodies and correlated positively with GAD antibody levels in CSF.

CONCLUSIONS

The motor cortex is hyperexcitable in SPS and PER patients. However, hyperexcitability is partly masked by GABAmimetic treatment. Correlation of elevated GAD antibody levels with enhanced ICF suggests that motor cortex hyperexcitability in SPS and PER is related to anti-GAD autoimmunity.

Fatal Acute Encephalomyelitis After a Single Dose of Intrathecal Methotrexate

A 40-year-old Hispanic man with acute lymphoblastic leukemia was treated with a single dose of intrathecal methotrexate 12 mg for prophylaxis against leptomeningeal spread of tumor. The day after methotrexate administration, the patient complained of severe back pain and urinary retention. The diagnosis of encephalomyelitis was made on day 3 after methotrexate administration, and by day 6 mechanical ventilation was begun secondary to ascending paralysis. By day 8 the patient was comatose, with minimal signs of brain activity and little hope for recovery; on day 12 he died. Although neurotoxicity is a frequent complication of methotrexate therapy, fatal acute neurotoxicity is extremely uncommon, especially in adults. The mechanisms of methotrexate toxicity remain unclear, and no effective treatment exists to prevent its occurrence. This patient rapidly progressed from mild neurotoxicity to fatal encephalopathy after one dose of intrathecal methotrexate during his third cycle of chemotherapy. Clinicians should be aware of the signs and symptoms of neurotoxicity during treatment, as well as predisposing factors that put patients receiving methotrexate at risk for neurotoxic effects.

Head retraction reflex in stiff-man syndrome and related disorders

The head retraction reflex (HRR) is a vestigial withdrawal reflex of the face and is suppressed in healthy subjects. We investigated the prevalence and electrophysiological patterns of the HRR in patients suffering from stiff-man syndrome (SMS, n = 28) and related disorders, stiff-limb syndrome (SLS, n = 2), and progressive encephalomyelitis with rigidity and myoclonus (PERM, n = 20). In patients with a positive HRR, the electromyographic (EMG) pattern was analyzed with surface recordings from the orbicularis oculi, sternocleidomastoid, trapezius, and the paraspinal extensor muscles at midthoracic and lumbar levels. On clinical testing, 17 of 28 SMS patients, 10 of 20 PERM patients, and 0 of 2 SLS patients had a positive HRR, ranging from a brief contraction of the neck extensors to violent retropulsion of the upper body. In all muscles, EMG reflex patterns elicited by gentle taps to the face or by electrical stimulation of the trigeminal nerve branches consisted of two components: an early, synchronous, brief burst with the shortest latency in trapezius (12.5-20.0 msec) and a late, asynchronous, longer response with latencies between 44 and 70 msec. We conclude that the HRR is an abnormal cutaneomuscular brainstem reflex that occurs in a considerable proportion of patients with SMS and related disorders. Although neither specific nor particularly sensitive for SMS, presence of the HRR in a setting with otherwise unexplained stiffness and spasms might help to avoid the otherwise frequent misdiagnosis of a psychogenic motor disturbance in patients with SMS.

Depression-like changes of the sleep-EEG during high dose corticosteroid treatment in patients with multiple sclerosis

Acute exacerbations of multiple sclerosis (MS) are commonly treated with high doses of corticosteroids that can influence sleep regulation and hypothalamo-pituitary-adrenal (HPA) activity. We examined the sleep-EEG (including conventional and spectral EEG analysis) in 9 female patients with relapsing-remitting MS (and no psychiatric disorder) just prior to and on days 2 and 10 of high dose corticosteroid treatment (500 mg/day methylprednisolone given IV for 5 days, then PO taper down) and age-matched healthy female controls. Before treatment with corticosteroids, MS patients compared to controls showed few changes of the sleep EEG, namely a significant increase in slow wave sleep (SWS) and a decrease in stage 2 sleep. In contrast, on day 10, but not day 2 of treatment, MS patients showed a number of sleep-EEG changes typically observed in patients with depression, including a reduction in REM latency, an increase in REM density, a decrease in the SWS and delta sleep ratio and a decrease in sigma EEG activity. However, no concomitant effect of treatment on mood was noted. In summary, unlike acute treatment with methylprednisolone, prolonged treatment induces several changes of the sleep-EEG in MS patients, that are also observed in patients with an acute depressive episode. Further prospective studies with longer-term follow-up are needed to examine the clinical relevance of our preliminary data.

Anatomical substrates for the central control of sympathetic outflow to interscapular adipose tissue during cold exposure

The thermogenic activity of interscapular brown adipose tissue (IBAT) in response to physiologic stimuli, such as cold exposure, is controlled by its sympathetic innervation. To determine which brain regions might be involved in the regulation of cold-evoked increases in sympathetic outflow to IBAT, the present study compared central nervous system (CNS) areas activated by cold exposure with brain regions anatomically linked to the sympathetic innervation of IBAT. Immunocytochemical localization of Fos was examined in the brains of rats exposed to 4 degrees C for 4 hours. In a separate group of rats, the neural circuit involved in IBAT control, including the location of sympathetic preganglionic neurons in the spinal cord, was characterized with pseudorabies virus, a retrograde transynaptic tracer. Central noradrenergic and serotonergic groups related to the sympathetic outflow to IBAT also were identified. Localization of viral antigens at different survival times (66-96 hours) revealed infection in circumscribed CNS populations, but only a subset of the regions comprising this circuitry showed cold-evoked Fos expression. The raphe pallidus and the ventromedial parvicellular subdivision of the paraventricular hypothalamic nucleus (PVH), both infected at early survival times, were the main areas containing sympathetic premotor neurons activated by cold exposure. Major cold-sensitive areas projecting to spinal interneurons or to regions containing sympathetic premotor neurons, which became infected at intermediate intervals, included lateral hypothalamic, perifornical, and retrochiasmatic areas, anterior and posterior PVH, ventrolateral periaqueductal gray, and Barrington's nucleus. Areas infected later, most likely related to reception of cold-related signals, comprised the lateral preoptic area, parastrial nucleus, dorsomedial hypothalamic nucleus, lateral parabrachial nucleus, and nucleus of the solitary tract. These interconnected areas, identified by combining functional and retrograde anatomic approaches, likely constitute the central circuitry responsible for the increase in sympathetic outflow to IBAT during cold-evoked thermogenesis.

Childhood chronic inflammatory demyelinating polyneuropathy with central nervous system demyelination resembling multiple sclerosis

Central nervous system demyelination has been described in adults but not in children with chronic inflammatory demyelinating polyneuropathy. We describe a patient with clinical and electrophysiological features consistent with chronic inflammatory demyelinating polyneuropathy who presented at age 5 with an intramedullary spinal cord tumor-like lesion and at age 8, represented with cerebral and spinal demyelinating lesions. Her clinical course and magnetic resonance imaging features were atypical for multiphasic disseminated encephalomyelitis and indistinguishable from multiple sclerosis. To our knowledge, this association has not been previously described in the English literature in childhood.

Stiff man syndrome and related conditions

The stiff man syndrome (SMS) and its variants, focal SMS, stiff limb (or leg) syndrome (SLS), jerking SMS, and progressive encephalomyelitis with rigidity and myoclonus (PERM), appear to occur more frequently than hitherto thought. A characteristic ensemble of symptoms and signs allows a tentative clinical diagnosis. Supportive ancillary findings include (1) the demonstration of continuous muscle activity in trunk and proximal limb muscles despite attempted relaxation, (2) enhanced exteroceptive reflexes, and (3) antibodies to glutamic acid decarboxylase (GAD) in both serum and spinal fluid. Antibodies to GAD are not diagnostic or specific for SMS and the role of these autoantibodies in the pathogenesis of SMS/SLS/PERM is the subject of debate and difficult to reconcile on the basis of our present knowledge. Nevertheless, evidence is emerging to suggest that SMS/SLS/PERM are manifestations of an immune-mediated chronic encephalomyelitis and immunomodulation is an effective therapeutic approach.

Remote neurologic manifestations of cancer

Paraneoplastic disorders may affect any part of the central or peripheral nervous systems. Although relatively uncommon, these disorders are a significant cause of neurologic morbidity for cancer patients. At least some paraneoplastic syndromes are believed to be caused by an autoimmune reaction against shared tumor-neural antigens. This article summarizes the clinical features of paraneoplastic disorders, the current evidence for autoimmunity, and guidelines for diagnosis and treatment.

Relation of clinical signs to pathological changes in 19 cases of canine distemper encephalomyelitis

In an attempt to associate the clinical neurological syndromes with the neuropathological features of canine distemper (CD), 19 spontaneous cases with neurological involvement were examined, before and after euthanasia. Seventeen dogs were less than one year of age and all except two (89.4%) were unvaccinated against CD. Various extraneural signs associated with CD encephalomyelitis (CDE) were seen in 15 dogs. Generalized or localized myoclonus was the most common sign observed (13/19). Seventeen of the dogs presented with signs suggestive of one neuroanatomical location of lesions. Of these animals, seven had signs of cerebral, two of cerebellar, four of cervical, one of cervicothoracic, two of thoracolumbar and two of lumbosacral syndrome. The diagnosis of CD was confirmed immunohistochemically (detection of CD viral antigen), serologically (neutralizing serum antibody titre > or = 16) and histopathologically (CDV inclusion bodies, type of central nervous system lesions). An association of the neuroanatomical lesion location and the histopathological findings was noted in 14 out of 17 dogs (82.3%). Myoclonus could be attributed to lower motor neuron damage in eight out of 13 dogs (61.5%).

Right medial thalamic lesion causes isolated retrograde amnesia

Pervasive retrograde amnesia without anterograde memory impairment has rarely been described as a consequence of circumscribed brain damage. We report this phenomenon in a 33 yr-old, right-handed man (JG) in association with the extension in the right thalamus of a previously small, bilateral thalamic lesion. JG presented with a dense amnesia for autobiographical material more than a few years old, with some sparing of recent memories. Furthermore, he was completely unable to recognise famous people or world events. Many other aspects of semantic knowledge were intact and there was no evidence of general intellectual impairment, executive dysfunction or loss of visual imagery. Magnetic resonance imaging revealed an acute lesion in the right thalamus and two small, symmetrical, bilateral non-acute thalamic lesions. Follow-up neuropsychological assessment indicated a stable pattern of impaired retrograde and spared anterograde memory over 18 months and psychiatric assessments yielded no evidence of confabulation, malingering or other symptoms to suggest psychogenic amnesia. JG's profile indicates that the division of declarative memory into just two categories - episodic and semantic - is inadequate. Rather, his case adds to the growing body evidence to suggest that world knowledge pertaining to people and events is stored or accessed similarly to autobiographical information and differently from other types of more general factual knowledge. We hypothesize that the right mediodorsal thalamic nucleus and immediately surrounding regions comprise the central processing mechanism referred to by McClelland (Revue Neurologique, 150 (1994) 570) and Markowitsch (Brain Research Review, 21 (1995) 117) as responsible for inducing and co-ordinating the recall of these sorts of cortically stored memory engrams.

Viability of Sarcocystis neurona sporocysts and dose titration in gamma-interferon knockout mice

Gamma-interferon knockout mice have become the model animal used for studies on Sarcocystis neurona. In order to determine the viability of S. neurona sporocysts and to evaluate the course of the disease in these mice, sporocysts were collected from opossums (Didelphis virginiana), processed, and stored for varying periods of time. Gamma-interferon knockout mice were then inoculated orally with different isolates at different doses. These animals were observed daily for clinical signs until they died or it appeared necessary to humanely euthanize them. 15 of 17 (88%) mice died or showed clinical signs consistent with neurologic disease. The clinical neurologic symptoms observed in these mice appeared to be similar to those observed in horses. 15 of 17 (88%) mice were euthanized or dead by day 35 and organisms were observed in the brains of 13 of 17 (77%) mice. Dose appeared not to effect clinical signs, but did effect the amount of time in which the course of disease was completed with some isolates. The minimum effective dose in this study was 500 orally inoculated sporocysts. Efforts to titrate to smaller doses were not attempted. Direct correlation can be made between molecularly characterized S. neurona sporocysts and their ability to cause neurologic disease in gamma-interferon knockout mice.

[Progressive encephalomyelitis with rigidity. Clinical and electrophysiological aspects]

A 72-year-old man presented with a chronic illness constituted by muscle rigidity affecting his lower limbs, trunk and neck, either spontaneous or triggered by stimuli, together with a spastic paraparesis, manual amyotrophy and pseudobulbar syndrome. The electrophysiologic study showed continuous motor unit activity integrated by normal motor unit potentials. Biochemical and imaging results were normal. These data suggest the diagnosis of idiopathic progressive encephalomyelitis with rigidity. Following administration of gabapentin (2000 mg daily), muscle rigidity and electromyographic continuous motor unit activity were suppressed. Transient drowsiness was the only side effect. The authors have tried to relate these findings to those found in the literature.

The pathogenesis of multiple sclerosis: a commentary

A series of recently published articles by a group of Austrian, German and American neuropathologists have proposed the existence of several different pathogenetic pathways in multiple sclerosis (MS). These studies were based on both biopsy and autopsy material. A review of the available published clinical, imaging and cerebrospinal fluid data suggest that some the cases used in those studies were more probably instances of disseminated encephalomyelitis rather than MS. This has serious implications regarding the specificity and significance of the findings in regard to MS pathogenesis. The specific myelinoclastic sequence and the variable clinical course of MS are determined by the individual's genetic endowment and immunologic history. Regardless of pathogenetic pathway and clinical course, the final pathologic picture of MS is always the same. The MS brain is genetically programmed to produce a unique, pathognomonic change, the plaque with sharply demarcated borders.

Anterior uveitis in murine relapsing experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS)

PURPOSE

To investigate whether anterior uveitis (AU), which often accompanies central nervous system (CNS) and systemic inflammatory diseases including multiple sclerosis (MS), also develops in a murine relapsing model of MS, experimental autoimmune encephalomyelitis (EAE) closely resembling relapsing-remitting MS, induced by immunization with myelin basic protein (MBP) in mice.

METHODS

(PL/J x SJL) F1 female mice were immunized with MBP in complete Freund's adjuvant (CFA) using Pertussis toxin as co-adjuvant. EAE was scored clinically on a scale of 0-5 based on the degree of paralysis. Uveitis was assessed by slit-lamp biomicroscopy. Histolological analysis of the CNS and eye were performed.

RESULTS

All immunized mice developed a characteristic relapsing paralysis. Evidence of AU was present late in the course of EAE, only after the resolution of the first clinical relapse, in 4 of 5 mice (80%) (clinical evidence) and 5 of 5 (100%) (histological evidence). AU was mild to moderate with the exception of one animal, in which it was severe. Involvement was invariably bilateral. Histology showed mononuclear infiltrates in the iris and ciliary body. Bilateral secondary cataracts were observed in the animal with severe inflammation. Paralytic episodes and the AU did not coincide. There were no clinical or histological eye abnormalities in control mice, either non-immunized or immunized with CFA and Pertussis toxin only.

CONCLUSION

We report AU in a mouse model of EAE which strongly resembles relapsing MS. These results further suggest shared antigenic determinants between the CNS and the eye, which likely become exposed to the immune system late in the course of CNS inflammation.

Detection of anterior horn lesions by MRI in central European tick-borne encephalomyelitis

We report a case of central European tick-borne encephalitis with cervical myelitis presenting clinically as a lower motor neuron syndrome of the upper limbs with proximal asymmetrical pareses and atrophies. There were no sensory deficits nor signs of lesions of the spinal pathways or signs of encephalitis or meningitis. The affected motor fibers of the upper limbs were electrically inexcitable, but sensory findings were normal. Electromyography of the paralyzed muscles revealed pathological denervation activity without voluntary activation. The initial magnetic resonance imaging (MRI) showed a large hyperdense lesion in the anterior part of the cervical cord from C3 to T1. Despite the fact that MRI changes disappeared completely within 6 weeks the patient showed only little improvement in the paralyzed muscles after 6 months. To our knowledge, these MRI changes in patients with tick-borne encephalitis, consistent with an isolated anterior horn lesion, have never been reported previously. The course may have been aggravated by an initial antibiotic treatment with cephalosporins.

Suppression of experimental allergic encephalomyelitis in rats exposed nocturnally to magnetic fields

After inoculation with spinal cord and complete Freund's adjuvant, female Lewis rats were exposed to weak, 7 Hz complex magnetic fields or to the control condition. The computer-generated magnetic field, whose amplitude varied from 15 nT to 60 nT every 6 to 12 sec, was presented for 6 min every hour between midnight and 0800 of the scotophase. In two replicates of the experiment, the rats exposed to the field displayed statistically significant suppression relative to sham-field controls (effect size = 55%) of the overt symptoms of experimental allergic encephalomyelitis which included hindleg paralyses.

Modulation of acute coronavirus-induced encephalomyelitis in gamma-irradiated rats by transfer of naive lymphocyte subsets before infection

Clinical course, recovery of infectious virus from brain tissue and histopathology of the central nervous system were examined in gamma-irradiated Lewis rats reconstituted by naive lymphocytes before infection with coronavirus MHV-4 (strain JHM). Up to 9 days past infection, no differences were seen between immunologically competent and immuno-deficient animals in terms of onset and progression of neurological disease. However, in the latter animals neurological symptoms were dominated by signs of encephalitis instead of paralytic disease as usually seen in immunocompetent animals. Nevertheless, despite high titers of infectious virus in the CNS of immunodeficient animals only mild histopathological changes were noticeable. In contrast, infectious virus in the CNS of immunologically competent animals was below the detection limit of the assay. Paralytic disease and tissue destruction were T lymphocyte mediated because gamma-irradiated rats that were reconstituted by CD4+ or CD8+ T lymphocyte enriched cells in the absence of B lymphocytes revealed an earlier onset of clinical symptoms and a more rapid deterioration of their clinical state compared to fully competent animals. Whereas in CD4+ T cell reconstituted animals infectious virus was moderately reduced and tissue destruction as well as inflammatory changes in the CNS were focal, in CD8+ T cell reconstituted animals vacuolizing white matter inflammation was diffuse without reduction of infectious virus in brain tissue. From the presented data we conclude that in the acute stage of JHMV-induced encephalomyelitis of Lewis rats: (i) tissue destruction and paralytic clinical symptomatology are mainly T cell-mediated; (ii) CD4+ T lymphocytes can directly contribute to reduction of viral load in the brain and (iii) only coordinated action of both, the T and the B cell compartment enables animals to survive the infection and recover from disease.

The pathophysiology of paraneoplastic neurological syndromes

Paraneoplastic neurological diseases are a group of neurological disorders associated with neoplastic tumors but not due to tumoral extension, metabolic, infectious, vascular or toxic complications of these tumors or their treatment. In the majority of paraneoplastic neurological disorders, circulating autoantibodies directed against neurons have been found in the serum and/or the CSF suggesting, and in some cases implicating, autoimmunity in the pathophysiology of these diseases. The finding of autoimmune phenomena during the course of paraneoplastic neurological disorders is of importance: from a practical point of view, since the detection of anti-neuronal autoantibodies is of great diagnostic help and should lead to the thorough search of the associated tumor often at an early stage of its development; from a theoretical point of view, these disorders represent a peculiar type of molecular mimicry. Tumoral neontigens having structural homology or identity with neuronal autoantigens elicit autoreactivity. The immunological effector mechanisms involved in the pathophysiology of paraneoplastic syndromes appear to differ according to the disease: autoantibodies are pathogenic in Lambert-Eaton syndrome whereas, in paraneoplastic cerebellar degeneration and in the Hu syndrome, the cellular immune response might play a greater role.

[A case report of steroid-responsive progressive encephalomyelitis with rigidity showing muscle stiffness limited to the upper body]

A 37-year-old female presented with progressive encephalomyelitis with rigidity for a period of about three months. Spasms began with several minutes of paroxysmal painful muscle stiffness in the left upper limb, followed by pain and muscle spasms in the upper limbs, shoulders, neck and back. The paroxysmal painful spasms were easily evoked by light touches and startling. The patient had contracture in the upper limbs and difficulty in relaxing the muscles. She also developed brain stem signs such as left sixth nerve palsy. The serum antinuclear antibody was positive (1 : 160). The cerebrospinal fluid examination revealed mild pleocytosis and protein elevation. Brainstem MRI, cervical MRI, and electroencephalography were normal. Surface electromyography in the arm and neck muscles showed continuous motor unit discharge elicited by passive movement of the right arm. Diazepam and baclofen were minimally beneficial. After treatment with intravenous injection of high-dose methylprednisolone and sequential oral prednisolone administration, the patient showed substantial improvement. This disorder may be part of a clinical spectrum that has an underlying autoimmune basis.

The role of IL-10 in mouse hepatitis virus-induced demyelinating encephalomyelitis

Interleukin 10 (IL-10) is an important anti-inflammatory cytokine. To examine its role in virus-induced encephalomyelitis, IL-10-deficient (IL-10 -/-) mice were infected with a neurotropic strain of mouse hepatitis virus (JHMV). JHMV-infected IL-10 -/- mice, compared to IL-4 -/- and syngeneic C57BL/6 mice, exhibited increased morbidity and mortality. Virus was cleared from the CNS of all groups of mice with equal kinetics by day 9 postinfection and the lack of either IL-4 or IL-10 did not alter the distribution of viral antigen, suggesting a lack of correlation between viral replication and the increased clinical disease in IL-10 -/- mice. In moribund IL-10 -/- mice, a moderate increase in mononuclear cell infiltration was correlated with increased expression of tumor necrosis factor-alpha, interferon-gamma, and inducible nitric oxide synthase mRNAs. In the small percentage of IL-10 -/- mice that survived, no differences in either demyelination or inflammation were observed. Together, these results suggest that IL-10 is not required for viral clearance, and although it appears to be one of the mechanisms responsible for inhibiting the extent of inflammation in the CNS during acute JHMV infection, it has little role in the eventual resolution of CNS inflammatory responses.

Vaccination with DNA encoding an immunodominant myelin basic protein peptide targeted to Fc of immunoglobulin G suppresses experimental autoimmune encephalomyelitis

We explore here if vaccination with DNA encoding an autoantigenic peptide can suppress autoimmune disease. For this purpose we used experimental autoimmune encephalomyelitis (EAE), which is an autoaggressive disease in the central nervous system and an animal model for multiple sclerosis. Lewis rats were vaccinated with DNA encoding an encephalitogenic T cell epitope, guinea pig myelin basic protein peptide 68-85 (MBP68-85), before induction of EAE with MBP68-85 in complete Freund's adjuvant. Compared to vaccination with a control DNA construct, the vaccination suppressed clinical and histopathological signs of EAE, and reduced the interferon gamma production after challenge with MBP68-85. Targeting of the gene product to Fc of IgG was essential for this effect. There were no signs of a Th2 cytokine bias. Our data suggest that DNA vaccines encoding autoantigenic peptides may be useful tools in controlling autoimmune disease.

Encephalomyeloradiculopathy associated with Epstein-Barr virus: primary infection or reactivation?

INTRODUCTION

Encephalomyeloradiculopathy (EMR) is a new syndrome, characterized by extensive involvement of the nervous system at different levels, including brain, medulla and spinal roots. We describe a patient presenting with prodromal febrile illness, followed by a wide infection of the nervous system with transverse myelitis and less severe meningitis, encephalitis and polyradiculopathy. The patient was treated with high-dose corticosteroids, antibiotics and acyclovir; in spite of therapy his condition improved very slowly, with severe neurological sequelae.

MATERIAL AND METHODS

Antiviral antibodies were searched for in serum and cerebrospinal fluid (CSF) by commercially available ELISA kits. Viral investigations were performed by cell culture isolation and search for viral antigens, and genomic nucleic acids were investigated by polymerase chain reaction (PCR).

RESULTS

Virological and serological studies evidenced a primary infection by cytomegalovirus (CMV), possibly responsible for the prodromal illness, persisting in the course of the disease. PCR performed in the peripheral blood mononuclear cells (PBMCs), DNA collected early and in the CSF drawn 30 days after the onset of the disease showed Epstein-Barr virus (EBV) DNA. The serum panel of EBV antibodies was typical of an intercurrent virus reactivation, more than of a primary infection.

CONCLUSION

EBV is known to be highly infectious for the nervous system, in this case of EMR the presence of DNA sequences in the PBMCs and CSF suggests that EBV plays a role in the development of this newly described syndrome.

Fulminant demyelinating encephalomyelitis associated with productive HHV-6 infection in an immunocompetent adult

Human herpesvirus 6 (HHV-6), the etiologic agent of roseola in young children, has been reported to be detectable in the brain of many neurologically normal adults, although regional localization to plaques of multiple sclerosis has also been demonstrated. Large amounts of this virus were present in multifocal demyelinating white matter lesions of fulminant encephalomyelitis with seizures in a 21-year-old woman with normal immune parameters. Brain biopsy after 3 weeks of neurologic deterioration revealed a viral etiology by light and electron microscopy; the virus was identified as HHV-6 by immunohistochemistry and by polymerase chain reaction (PCR) amplification in biopsy and autopsy specimens.

A new variant of progressive encephalomyelitis with rigidity associated with cerebellar ataxia and dementia: correlation of MRI and histopathological changes. A case report

A 27 year-old patient developed a progressive neurological multisystem disorder. Initial signs were cerebellar ataxia and dementia, followed by rigidity and oculomotor dysfunction. Myoclonus was not present. MRI showed a marked atrophy of the spinal cord, the cerebellum, and mild (sub)cortical atrophy. CSF contained oligoclonal bands, but no anti-glutamic acid dehydrogenase antibodies. He died 33 months after onset of symptoms. Autopsy revealed widespread neuropathological alterations including perivascular lymphocytic cutting, neuronal cell loss, and micro/astrogliosis the distribution of which corresponded to the changes seen in MRI. The diagnosis of progressive encephalomyelitis with rigidity was pathohistologically confirmed. Brain samples were negative for neurotrophic viruses tested by polymerase chain reaction. A new variant of this rare disorder is described initially presenting with ataxia and dementia, but without myoclonus.

Transgenic models to assess the pathogenic actions of cytokines in the central nervous system

In order to better understand the actions of proinflammatory cytokines in the mammalian CNS, a transgenic approach was employed in which the expression of IL-6, IL-3 or TNF-alpha was targeted to astrocytes in the intact CNS of mice. Transgenic mice exhibited distinct chronic-progressive neurological disorders with neurodegeneration and cognitive decline due to IL-6 expression, macrophage/microglial-mediated primary demyelination with motor impairment due to IL-3 expression and lymphocytic meningoencephalomyelitis with paralysis induced by TNF-alpha expression. Thus, expression of specific cytokines alone in the intact CNS results in unique neuropathological alterations and functional impairments, thereby directly implicating these mediators in the pathogenesis of CNS disease.

Experimental induction of equine protozoal myeloencephalitis in horses using Sarcocystis sp. sporocysts from the opossum (Didelphis virginiana)

Sarcocystis sp. sporocysts isolated from eight feral opossums (Didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (Melopsittacus undulatus), 14 wild-caught sparrows (Passer domesticus), one wild-caught slate-colored Junco (Junco hyemalis) and five weanling horses (Equus caballus). All budgerigars died within 5 weeks post inoculation (wpi). Histologic examination revealed meronts within the pulmonary epithelia and typical Sarcocystis falcatula sarcocysts developing in the leg muscles. Sparrows were euthanized 13 and 17 wpi and their carcasses were fed to four laboratory raised opossums. Sporocysts were detected in the feces of two opossums on 15 days post inoculation (dpi) and in a third opossum on 40 dpi. Fecal samples from the fourth opossum remained negative; however, sporocysts were found in intestinal digests from all four opossums. Sporocysts were not found in feces or intestinal digest of an additional opossum that was fed three uninoculated sparrows. Five foals were fed sporocysts (Foals 2, 3, 4, 5, and 7) and two foals were maintained as uninoculated controls (Foals 1 and 6). Sporocysts from two additional feral opossums also were fed to foals. Foal 5 was given 0.05 mg kg-1 dexamethasone sodium phosphate daily beginning 2 days before inoculation for a total of 2 weeks. Horse sera were tested three times per week, and cerebrospinal fluid (CSF) samples were tested biweekly for anti-Sarcocystis neurona antibodies by Western blot analysis. No foals had any S. neurona-specific antibodies by Western blot analysis prior to sporocysts ingestion. Seroconversion occurred in Foals 3, 5, and 7 by 24 dpi, followed by positive CSF tests on 28 dpi. Foals 2 and 4 seroconverted by 40 dpi. Cerebrospinal fluid from Foal 2 tested positive by 42 dpi, but Foal 4 remained seronegative throughout the study. Sera and CSF from control Foals 1 and 6 remained seronegative. All foals with positive CSF developed neurologic clinical signs. Neurologic disease was evident in Foals 2 and 3 by 42 dpi and in Foal 7 by 28 dpi. The severity of clinical signs progressed to marked spasticity, hypermetria and ataxia in Foal 7 by the end of the trial. Necropsy examination of inoculated foals did not reveal gross lesions; however, microscopic lesions consistent with equine protozoal myeloencephalitis (EPM) were found in Foals 2, 3, and 7. Protozoa were not observed in the tissue sections. Microscopic lesions consistent with EPM were not found in Foals 4 and 5 or in uninoculated control Foals 1 and 6. Foal 5 had unilateral non-inflammatory lesions in the cervical and thoracic spinal cord consistent with cord compression. These data indicate that the opossum is a definitive host of S. neurona.