Bickerstaff's brainstem encephalitis associated with anti-GM1 and anti-GD1a antibodies

Bickerstaff's brainstem encephalitis (BBE) is a Guillain-Barré syndrome (GBS) spectrum disorder associated with predominantly central nervous system predilection. Patients exhibit a variable constellation of depressed consciousness, bilateral external ophthalmoplegia, ataxia and long tract signs. Although the pathophysiology is not fully understood, it has been associated with anti-GQ1b antibodies in two-thirds of patients. We present a patient with clinical features consistent with BBE and positive anti-GM1 and anti-GD1a antibodies. A diagnostic approach to the acutely unwell patient with brainstem encephalitis is explored in this clinical context with a literature review of the aforementioned ganglioside antibody significance. Intravenous immunoglobulin therapy is highlighted in BBE using up-to-date evidence-based extrapolation from GBS.

Allopregnanolone Treatment Improves Plasma Metabolomic Profile Associated with GABA Metabolism in Fragile X-Associated Tremor/Ataxia Syndrome: a Pilot Study

Currently, there is no effective treatment for the fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder. In this pilot study, we evaluated whether allopregnanolone, a natural neurosteroid that exerts beneficial effects in neurodegenerative diseases, nervous system injury, and peripheral neuropathies, could improve lymphocytic bioenergetics and plasma pharmacometabolomics in six males with FXTAS (68 ± 3 years old; FMR1 CGG repeats 94 ± 4; FXTAS stages ranging from 3 to 5) enrolled in a 12-week open-label intervention study conducted at the University of California Davis from December 2015 through July 2016. Plasma pharmacometabolomics and lymphocytic mitochondria function were assessed at baseline (on the day of the first infusion) and at follow-up (within 48 h from the last infusion). In parallel, quantitative measurements of tremor and ataxia and neuropsychological evaluations of mental state, executive function, learning, memory, and psychological symptoms were assessed at the same time points. Allopregnanolone treatment impacted significantly GABA metabolism, oxidative stress, and some of the mitochondria-related outcomes. Notably, the magnitude of the individual metabolic response, as well as the correlation with some of the behavioral tests, was overwhelmingly carrier-specific. Based on this pilot study, allopregnanolone treatment has the potential for improving cognitive and GABA metabolism in FXTAS aligned with the concept of precision medicine.

Antineuronal Antibody in a Patient with Neuroblastoma and Opsoclonus-Myoclonus-Ataxia: A Case Report

We describe the case of a patient with neuroblastoma and opsoclonus-myoclonus-ataxia displaying serum and CSF anti-Hu antibodies that were able to recognize antigens of the patient's own tumor.

Novel Blood Biomarkers Are Associated with White Matter Lesions in Fragile X- Associated Tremor/Ataxia Syndrome

BACKGROUND

The need for accessible cellular biomarkers of neurodegeneration in carriers of the fragile X mental retardation 1 (FMR1) premutation (PM) alleles.

OBJECTIVE

To assess the mitochondrial status and respiration in blood lymphoblasts from PM carriers manifesting the fragile X-associated tremor/ataxia syndrome (FXTAS) and non-FXTAS carriers, and their relationship with the brain white matter lesions.

METHODS

Oxygen consumption rates (OCR) and ATP synthesis using a Seahorse XFe24 Extracellular Flux Analyser, and steady-state parameters of mitochondrial function were assessed in cultured lymphoblasts from 16 PM males (including 11 FXTAS patients) and 9 matched controls. The regional white matter hyperintensity (WMH) scores were obtained from MRI.

RESULTS

Mitochondrial respiratory activity was significantly elevated in lymphoblasts from PM carriers compared with controls, with a 2- to 3-fold increase in basal and maximum OCR attributable to complex I activity, and ATP synthesis, accompanied by unaltered mitochondrial mass and membrane potential. The changes, which were more advanced in FXTAS patients, were significantly associated with the WMH scores in the supratentorial regions.

CONCLUSION

The dramatic increase in mitochondrial activity in lymphoblasts from PM carriers may represent either the early stages of disease (specific alterations in short-lived blood cells) or an activation of the lymphocytes under pathological situations. These changes may provide early, convenient blood biomarkers of clinical involvements.

Ataxia and the Role of Antigliadin Antibodies

Background:

Although it is acknowledged that patients with celiac disease can develop neurological complications such as ataxia, the association of antigliadin antibodies in the etiology of sporadic ataxia and the usefulness of this testing in diagnosis of ataxia is controversial.

Methods:

We investigated this association by testing for the presence of IgG and IgA antigliadin antibodies in 56 ataxic patients and 59 controls. The ataxia patients were subsequently classified into three groups: sporadic, hereditary and MSA.

Results:

Of the total ataxic patients, 6/56 (11%) were positive for either IgG or IGA antigliadin antibodies compared to the controls of which 5/59 (8%) were positive (p = 0.68). In a subgroup analysis, 4/29 (14%) of the samples in the sporadic ataxic subgroup were positive for antigliadin antibodies (IgG or IgA) compared to control (p = 0.44). Similar negative results were found in the remaining subgroup analyses.

Conclusions:

These results do not support an association between antigliadin antibodies and sporadic ataxias.

Progressive ataxia and myoclonic epilepsy in a patient with a homozygous mutation in the FOLR1 gene

Several unrelated disorders can lead to 5-methyltetrahydrofolate (5MTHF) depletion in the cerobrospinal fluid (CSF), including primary genetic disorders in folate-related pathways or those causing defective transport across the blood-CSF barrier. We report a case of cerebral folate transport deficiency due to a novel homozygous mutation in the FOLR1 gene, in an effort to clarify phenotype-genotype correlation in this newly identified neurometabolic disorder. A previously healthy infant developed an ataxic syndrome in the second year of life, followed by choreic movements and progressive myoclonic epilepsy. At the age of 26 months, we analyzed CSF 5MTHF by HPLC with fluorescence detection and conducted magnetic resonance (MR) imaging and spectroscopy studies. Finally, we performed mutational screening in the coding region of the FOLR1 gene. MR showed a diffuse abnormal signal of the cerebral white matter, cerebellar atrophy and a reduced peak of choline in spectroscopy. A profound deficiency of CSF 5MTHF (2 nmol/L; NV 48-127) with reduced CSF/plasma folate ratio (0.4; NV 1.5-3.5) was highly suggestive of defective brain folate-specific transport across the blood-CSF/brain barrier. Mutation screening of FOLR1 revealed a new homozygous missense mutation (p.Cys105Arg) that is predicted to abolish a disulfide bond, probably necessary for the correct folding of the protein. Both parents were heterozygous carriers of the same variant. Mutation screening in the FOLR1 gene is advisable in children with profound 5MTHF deficiency and decreased CSF/serum folate ratio. Progressive ataxia and myoclonic epilepsy, together with impaired brain myelination, are clinical hallmarks of the disease.

Ataxia with vitamin E deficiency associated with deafness

Ataxia with vitamin E deficiency (AVED) is a rare autosomal recessive disorder, usually with a phenotype resembling Friedreich ataxia, caused by selective impairment of gastrointestinal vitamin E absorption. Vitamin E supplementation improves symptoms and prevents disease progress. In North Africa and Southern Europe, AVED is as common as Friedreich ataxia. There are no reported cases from Turkey. We herein report a 16-year-old Turkish girl with AVED, who was found to have total deletion of the TTPA gene as well as sensorineural deafness, and we present her follow-up data after vitamin E therapy.

Gluten ataxia: passive transfer in a mouse model

Gluten sensitivity is an autoimmune disease that usually causes intestinal atrophy resulting in a malabsorption syndrome known as celiac disease. However, gluten sensitivity may involve several organs and is often associated with extraintestinal manifestations. Typically, patients with celiac disease have circulating anti-tissue transglutaminase and anti-gliadin antibodies. When patients with gluten sensitivity are affected by other autoimmune diseases, other autoantibodies may arise like anti-epidermal transglutaminase in dermatitis herpetiformis, anti-thyroid peroxidase antibodies in thyroiditis, and anti-islet cells antibodies in type 1 diabetes. The most common neurological manifestation of gluten sensitivity is ataxia, the so-called gluten ataxia (GA). In patients with GA we have demonstrated that anti-gliadin and anti-tissue transglutaminase antibodies cross-react with neurons but that additional anti-neural antibodies are present. The aim of the present article is to review the knowledge on animal models of gluten sensitivity, as well as reviewing the role of anti-neural antibodies in GA.

Acute sensory ataxic neuropathy with antibodies to GD1b and GQ1b gangliosides and prompt recovery

Three patients developed acute pure sensory ataxic neuropathy. Two of the three patients had a recent Campylobacter jejuni infection. Patient 1 had monospecific IgG anti-GD1b. Patients 2 and 3 had cross-reactive IgG anti-GQ1b and anti-GD1b and patient 2 also had IgG anti-GT1a. Motor nerve conduction studies were completely normal. Sensory conductions showed reduced amplitude or absent sensory nerve action potentials with normal or slightly slowed conduction velocities. In patient 2, serial electrophysiological studies showed reappearance and improvement of sensory nerve potential amplitudes in 4 weeks. All patients recovered completely in 2 months and sensory potential amplitudes normalized in 3-5 months. Our findings: (1) confirm the existence of a pure acute sensory ataxic neuropathy with cross-reactive IgG anti-GQ1b and anti-GD1b as a variant of Guillain-Barré syndrome; (2) expand the clinical presentation of Guillain-Barré syndrome after C. jejuni infection and suggest that molecular mimicry is at the basis of acute sensory ataxic neuropathy; and (3) indicate that, in acute sensory ataxic neuropathy with prompt recovery, the site of the lesion is not in the primary sensory neurons and the pathophysiological mechanism may be functional in nature.

Copper deficiency myelopathy (human swayback)

The hematologic manifestations of copper deficiency are well known and include anemia and neutropenia. In the past few years, the neurological manifestations of acquired copper deficiency in humans has been recognized, the most common being a myelopathy presenting with a spastic gait and prominent sensory ataxia. The known causes of acquired copper deficiency include prior gastric surgery, excessive zinc ingestion, and malabsorption; however, often the cause is unclear. Hyperzincemia may be present even in the absence of exogenous zinc ingestion. The clinical features and neuroimaging findings are similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Copper and vitamin B12 deficiency may coexist. The neurological syndrome may be present without the hematologic manifestations. Copper supplementation resolves the anemia and neutropenia promptly and completely and may prevent the neurological deterioration. Improvement, when it occurs, is often subjective and preferentially involves sensory symptoms. This article describes patients with copper deficiency myelopathy seen at the Mayo Clinic in Rochester, Minn, and reviews the literature on neurological manifestations of acquired copper deficiency in humans.

A possible variant of neuro-Behçet disease presenting chronic progressive ataxia without mucocutaneo-ocular symptoms

Behçet disease (BD) is a chronic relapsing multisystem disorder of unknown etiology, which preferentially affects the oral and genital mucous membranes, skin, and eyes. Neurological involvement is one of the most serious manifestations of BD, known as neuro-Behçet disease (NBD). We here describe clinical, radiological, and neuropathological findings for two patients with a possible variant of NBD, who manifested progressive ataxia in the absence of mucocutaneo-ocular signs characteristic for BD. Both patients presented a slowly progressive cerebellar phenotype, accompanied by behavioral changes and sphincter disturbance. Brain MRI scan revealed mild atrophy in pons and cerebellum. Both patients showed a mild CSF pleocytosis, and were positive for HLA-B51. The post-mortem examination performed in one patient, showed widespread foci of chronic encephalitis, consistent with the diagnosis of NBD. Steroid pulse therapy was effective in one patient. Identifying the progressive ataxia phenotype of NBD without mucocutaneo-ocular symptoms is important, because these patients may benefit from early steroid therapy.

Antiganglioside antibodies in serum of patients with chronic sensory ataxic neuropathy

Recent studies have shown that antiganglioside antibodies, particularly those associated with the disialosyl group, may be involved in immune-mediated sensory peripheral neuropathies. We report the results of plasma screening for antiganglioside antibodies in two patients with chronic ataxic neuropathy. We found reactivity against gangliosides GD3, GD1b, and GT1b in one of them and against GD1a in the other, even though both had nearly identical clinical pictures. Results suggest that anti-GD1a antibodies, which are usually associated with motor polyneuropathy, may also be involved in the pathogenesis of clinically pure sensory polyneuropathy.

Elevation of carbamazepine-10,11-epoxide by quetiapine

A 52-year-old woman and a 56-year-old man who were receiving carbamazepine experienced markedly elevated levels of its active metabolite, carbamazepine-10,11-epoxide (CBZ-E), after starting quetiapine therapy. The CBZ-E:carbamazepine ratio increased 3-4-fold in each patient. Levels of CBZ-E returned to baseline after discontinuing this drug combination. The metabolite can accumulate and cause neurotoxicity. The woman experienced ataxia and agitation while receiving quetiapine, which resolved after carbamazepine was switched to oxcarbazepine. The man was asymptomatic. To our knowledge, these are the first two case reports describing this interaction. Quetiapine may inhibit epoxide hydrolase and/or glucuronidation of carbamazepine-10,11-trans-diol in the same way as valproate and possibly lamotrigine do. If carbamazepine and quetiapine are administered concurrently, clinicians should consider monitoring CBZ-E concentrations.

Screening for autoantibodies in children with opsoclonus-myoclonus-ataxia

Various paraneoplastic autoantibodies have been linked to discrete neurologic syndromes and tumors in adults, but little is known about their incidence in children. We report a cross-sectional study of known paraneoplastic antibodies in 59 children with opsoclonus-myoclonus-ataxia, 86% of whom were moderately or severely symptomatic, and 68% of whom had relapsed at the time of testing. This total number of patients includes 18 children with low-stage neuroblastoma (tested after tumor resection), six of whom had never been treated with immunosuppressants. All were seronegative for anti-Hu, anti-Ri, and anti-Yo, the three paraneoplastic antibodies most associated with opsoclonus-myoclonus or ataxia in adults. These data contrast with reports of anti-Hu-positive sera in children with high-stage tumors and suggest that anti-Hu, anti-Ri, and anti-Yo do not explain relapses in pediatric opsoclonus-myoclonus-ataxia. They underscore the need to search for unique autoantibodies, as well as cellular mechanisms of pediatric paraneoplastic disease.

Antibodies to squalene in recipients of anthrax vaccine

We previously reported that antibodies to squalene, an experimental vaccine adjuvant, are present in persons with symptoms consistent with Gulf War Syndrome (GWS) (P. B. Asa et al., Exp. Mol. Pathol 68, 196-197, 2000). The United States Department of Defense initiated the Anthrax Vaccine Immunization Program (AVIP) in 1997 to immunize 2.4 million military personnel. Because adverse reactions in vaccinated personnel were similar to symptoms of GWS, we tested AVIP participants for anti-squalene antibodies (ASA). In a pilot study, 6 of 6 vaccine recipients with GWS-like symptoms were positive for ASA. In a larger blinded study, only 32% (8/25) of AVIP personnel compared to 15.7% (3/19) of controls were positive (P > 0.05). Further analysis revealed that ASA were associated with specific lots of vaccine. The incidence of ASA in personnel in the blinded study receiving these lots was 47% (8/17) compared to an incidence of 0% (0/8; P < 0.025) of the AVIP participants receiving other lots of vaccine. Analysis of additional personnel revealed that in all but one case (19/20; 95%), ASA were restricted to personnel immunized with lots of vaccine known to contain squalene. Except for one symptomatic individual, positive clinical findings in 17 ASA-negative personnel were restricted to 4 individuals receiving vaccine from lots containing squalene. ASA were not present prior to vaccination in preimmunization sera available from 4 AVIP personnel. Three of these individuals became ASA positive after vaccination. These results suggest that the production of ASA in GWS patients is linked to the presence of squalene in certain lots of anthrax vaccine.

Clinical, electrophysiological, and serological overlap between Miller Fisher syndrome and acute sensory ataxic neuropathy

We report a patient with severe sensory ataxia, areflexia, and ophthalmoplegia with preservation of limb muscle strength. Electrophysiological examinations revealed peripheral sensory nerve involvement. A serological examination showed the elevation of IgG antibodies to various b-series gangliosides as well as GT1a. These indicated that this case is an overlap between acute sensory ataxic neuropathy and Miller Fisher syndrome. Autoantibody is implicated as potential pathogenic agents in some cases of acute sensory ataxic neuropathy.

Antiganglioside antibodies in acute self-limiting ataxic neuropathy: incidence and significance

Antidisialosyl antibodies have been previously associated to chronic and acute ataxic neuropathies. We studied the presence of these antibodies in nine patients with acute self-limiting ataxic neuropathy (ASLAN) using ELISA and TLC immunodetection. One patient showed serum IgG immunoreactivity against gangliosides GD3 and GQ1b. The patient's IgG was able to bind to the nodes of Ranvier on frozen human dorsal root. Our studies confirmed that antidisialosyl reactivity is associated to ataxic neuropathy and its specific binding to the dorsal root could explain the predominant sensory involvement. Nevertheless, the low incidence of this reactivity indicates that a different pathogenic mechanism should be involved in most ASLAN patients.

An examination of the synergistic interaction of ethanol and thiamine deficiency in the development of neurological signs and long-term cognitive and memory impairments

BACKGROUND

The prolonged and heavy consumption of ethanol has been associated with thiamine deficiency and a wide range of cognitive and memory impairments. The present study was undertaken to test the hypothesis that ethanol and thiamine deficiency act synergistically, producing more severe clinical neurological disturbances and cognitive and memory impairments than either thiamine deficiency or chronic ethanol alone.

METHODS

The acute neurological and long-term behavioral consequences of combined chronic (32 weeks) ethanol consumption (20% v/v in drinking water) and three separate 4-week long episodes of dietary thiamine deficiency (ET/TD) versus ethanol (ET) or thiamine deficiency (TD) treatments alone were examined in male Sprague Dawley rats aged 12 weeks at the start of treatment.

RESULTS

The ET/TD group lost less weight than the TD group during each episode of thiamine deficiency. Contrary to expectations, the progression and severity of ataxia, impaired righting reflexes, and opisthotonic posturing were similar in the ET/TD and TD groups. None of the ET animals displayed any neurological or behavioral symptoms during treatment. After withdrawal from ethanol and a 7-week recovery period, none of the groups differed in spontaneous activity. On subsequent testing, the ET group displayed a significant increase in perseverative responding in a spontaneous alternation task. A small but significant proportion of ET/TD (23%), ET (17%), and TD (8%) animals were unable to reach criterion on an initial nonmatching-to-position task (NMTP) or in two subsequent reversals of the matching and NMTP tasks, which indicated persistent learning impairments. A large proportion of animals in each of the three groups demonstrated significantly reduced accuracy compared with controls at longer delays of matching-to-position tasks (MTP), but only the ET group was consistently impaired at the shorter delays. There were no significant correlations between blood ethanol concentration and any of the learning and memory measures.

CONCLUSIONS

These results indicate that the interaction of chronic ethanol consumption and bouts of TD is both domain specific and not always synergistic. Learning and reference memory appear to be sensitive to a synergistic interaction of ET and TD, whereas short-term working memory disturbances are most affected by ET and neurological symptoms are most associated with TD. Furthermore, neither the presence of neurological symptoms nor blood ethanol concentrations appear to be good predictors of learning and memory deficits.

Phenotypic and genotypic relationships between ethanol tolerance and sensitivity in mice selectively bred for initial sensitivity to ethanol (SS and LS) or development of acute tolerance (HAFT and LAFT)

BACKGROUND

Genetically based risk for development of alcoholism in humans seems to be related to initial sensitivity and/or acute tolerance to ethanol. The genetic basis for the development of tolerance has received less attention than other ethanol-related behaviors. We have selected lines of mice, according to genetics, which are differentially sensitive to the initial hypnotic effect of ethanol (Short Sleep and Long Sleep, SS and LS) and other lines that differentially develop acute functional tolerance to ethanol (High and Low Acute Functional Tolerance, HAFT and LAFT). We review reports of the relationship between initial sensitivity and two forms of tolerance as measured using different behavioral measures and different time scales. The goal of the study was to investigate alcohol tolerance as measured by different behavioral tests conducted over different time periods and relate these variables to hypnotic sensitivity.

METHODS

We investigated the phenotypic and genotypic relationships between different measures of tolerance to ethanol in the SS and LS mice. We used two measures of tolerance: (a) The time an animal can remain on a stationary dowel or roto-rod at 5-min intervals up to 30 minutes after a single low dose of ethanol (Acute Single Dose Tolerance, ASDT-dowel or ASDT-roto-rod); and (b) The difference in blood ethanol levels taken when a mouse could repeatedly regain balance on a stationary dowel or roto-rod after successive doses of ethanol (Acute Functional tolerance, AFT-dowel or AFT-roto-rod). The time course in AFT was much longer, up to 2 hours. We carried out the same studies on the High and Low Acute Functional Tolerance (HAFT and LAFT) mice.

RESULTS

SS and LS mice differ in hypnotic sensitivity as measured by sleep time, and they differ in all forms of acute tolerance that were measured except in AFT-dowel. Although there were phenotypic correlations between AFT-dowel and ASDT-roto-rod in the Heterogeneous Stock (HS) of mice, provisional Quantitative Trait Loci (determined with Recombinant Inbred mice from a SS X LS cross) for the two phenotypes did not overlap, which indicated that there was little or no genetic correlation between the measures. HAFT and LAFT mice do not differ in hypnotic sensitivity as measured by sleep time measurements nor in ataxic sensitivity as measured on the dowel. The HAFT and LAFT mice both developed tolerance when tested in the 30-minute time frame, but the differences between the lines was largely in the rate of development of tolerance and not the amount developed. On the other hand, when tolerance was measured over 2 hr on the dowel or roto-rod, the HAFT and LAFT animals developed different levels of tolerance.

CONCLUSIONS

We concluded that measures of tolerance depended on both the time of ethanol's action and the behavioral task used. It seemed that the measures of tolerance used in this study had different genetic bases in mice. Presumably, tolerance will also vary in humans depending on the behavioral measure, and tolerance will also have different genetic bases for the different behavioral measures in humans.

The genetics of acute functional tolerance and initial sensitivity to ethanol for an ataxia test in the LSxSS RI strains

BACKGROUND

It has been proposed that development of tolerance to the behavioral effects of ethanol depends on the degree of impairment produced by the drug; that is, more sensitive individuals should develop greater tolerance. Tests of this hypothesis with respect to acute functional tolerance have produced contradictory results. We tested the hypothesis by examining the genetic relationship between initial sensitivity and acute functional tolerance in the LSXSS recombinant inbred mice.

METHODS

We tested mice for initial sensitivity to the ataxic effects of 1.75 g/kg of ethanol in a stationary dowel balance test by determining blood and brain ethanol concentrations at fall. Acute tolerance to the ataxic effects of ethanol was determined by measuring blood ethanol concentration (BEC) at regain of dowel balance ability after the first injection (BEC1RB) and after a second ethanol injection of 2.0 g/kg (BEC2RB). Acute tolerance was quantified by the difference in ethanol concentration at the two regains of balance (BEC2RB - BEC1RB) or by the difference between the second regain and one of the initial sensitivity measures (BEC2RB - initial sensitivity).

RESULTS

Four different measures of initial sensitivity were taken: two that used BEC values and two that used forebrain or hindbrain ethanol concentrations. We calculated acute tolerance values by using each of these initial sensitivity measures plus BEC2RB. No evidence of a genetic relationship between initial sensitivity and acute tolerance was found, which suggests that these are two independent phenomena with respect to stationary dowel balance.

CONCLUSIONS

Three conclusions can be drawn from this work: (1) Orbital sinus BEC at early time points (<5 min postinjection) may or may not accurately reflect brain EC in mice, dependent on genotype; (2) there is no genetic relationship between initial sensitivity and acute tolerance to stationary dowel ataxia in the LSXSS RIs; and (3) sex-specific factors affect low-dose ethanol responses on the stationary dowel.

Orphenadrine poisoning in a child: clinical and analytical data

Orphenadrine is an anticholinergic drug used mainly in the treatment of Parkinson's disease. It has a peripheral and central effect and a known cardiotoxic effect when taken in large doses. We report the successful outcome of the treatment of a 2 1/2-year-old girl who accidentally ingested 400 mg of orphenadrine hydrochloride (Disipal). One hour after ingestion she presented neurological symptoms: confusion, ataxic walking, and periods of severe agitation. Generalized tonic-clonic seizures appeared resistant to the administration of multiple antiepileptics. They ceased after a supplementary dose of intravenous diazepam, endotracheal intubation, and mechanical ventilation. An episode of ventricular tachycardia responded well to i. v. lidocaine. Physostigmine was administered in three successive doses. The initial orphenadrine plasma level (3,55 microg/ml) was in the toxic range, associated with high mortality. The calculated elimination half-life was 10.2 h and the molecule and/or its metabolites were found up to 90 h after ingestion.

An apparent case of human T-cell lymphotropic virus type II (HTLV-II)-associated neurological disease: a clinical, molecular, and phylogenetic characterisation

Several studies have reported an association between HTLV-II and a neurological condition which has come to be called HTLV-II-associated myelopathy and is similar, in some cases, to HTLV-I-associated myelopathy. To further explore the establishment of an etiological link between this virus and neurological disease, we determined the HTLV status of three individuals, one of which presented with symptoms of progressive ataxia. Since the patient with neurological disease and her husband were HTLV-II positive, we had the potential to study one of few cases of an HTLV-II-associated neurological disorder, and the first case in Canada. However, although the individual with the neurological disease was HTLV-II positive, we discovered that her brother, who displays the same clinical symptoms, was not positive for either HTLV-II or HTLV-I. Thus, disease association with HTLV-II became unsupportable. We present here, nevertheless, the first sequence and phylogenetic analysis of an HTLV-II isolate in Canada. This study suggests that cases of HTLV-II and neurological disease must be carefully investigated before any etiological conclusions can be made.

New insights into the in vivo function of heterotrimeric G-proteins through gene deletion studies

A huge number of receptors signals through heterotrimeric G-proteins to regulate a wide variety of physiological processes. The ability to modify G-protein expression in vivo provides a powerful new tool to analyze the function of G-protein-mediated signalling pathways. Genetic ablation of G-protein alpha-subunit genes is continuing to give new insights into the physiological roles of heterotrimeric G-proteins. This review highlights recent advances resulting from such genetic approaches to the study of G-protein-mediated signalling.

Immunotoxicological assessment of cyclosporin A by conventional pathological techniques and immune function testing in the rat

1. Groups of male rats were given different doses of cyclosporin A, ranging from the maximum tolerated dose (20 mg/kg/day) downwards, 7 days a week for 28 days using a protocol derived from OECD test guideline 407. 2. At the end of the test, one set of animals underwent a detailed necropsy and histopathological examination of lymphoid tissues. Immune function was assessed using the lymphoproliferative response and natural killer cell activity of their spleen cells. Another set of animals was immunised with sheep erythrocytes on day 25 and used to evaluate the ability to produce specific anti-sheep red blood cell antibody. 3. Cyclosporin A produced detectable effects on the immune system at all doses and at doses lower than other toxic effects. Both histopathological techniques and one of the immune function tests were able to identify changes at the lowest dose, 1.25 mg/kg/day. 4. The results of this investigation suggest that conventional histopathological techniques, if applied to a range of lymphoid organs, are sufficient to identify potential immunotoxicants without recourse to immune function tests.

Tryptophan-immobilized column adsorbs immunoglobulin G anti-GQ1b antibody from Fisher's syndrome: A new approach to treatment

Sera from patients with Fisher's syndrome in the acute phase contain immunoglobulin (Ig)G anti-GQ1b ganglioside antibody. Removal of the autoantibody should lead to earlier recovery with less residual neurologic involvement. A tryptophan- or phenylalanin-immobilized polyvinyl alcohol gel column (IM-TR 350 or IM-PH 350) semiselectively adsorbs such autoantibodies as rheumatoid factor, anti-DNA antibody, or anti-acetylcholine receptor antibody. A batchwise adsorption test showed that an IM-TR gel adsorbed a larger amount of the IgG anti-GQ1b antibody than did an IM-PH column. Several patients with Fisher's syndrome therefore were given immunoadsorbent therapy using the IM-TR column without adverse reactions. An ex vivo plasma perfusion study done with the IM-TR column confirmed that it effectively adsorbs the IgG anti-GQ1b antibody. Results of adsorption tests done with various amino acid-immobilized gels suggest that both the hydrophobic force of the side chain and the anionic charge of the carboxylic acid in tryptophan are important in the adsorption of the autoantibody by the IM-TR gel. Immunoadsorption using the IM-TR column, which does not need replacement fluids, offers an alternative type of plasmapheresis for Fisher's syndrome.

Acute ataxic neuropathy with cross-reactive antibodies to GD1b and GD3 gangliosides

We report a patient with an acute, self-limiting neuropathy consisting of ataxia and areflexia, but without ophthalmoplegia or limb weakness, with transient, high-titer serum IgG antibodies to a single NeuAc(alpha 2-8)NeuAc-linked disialosyl epitope, as found on GD1b and GD3 gangliosides. The serum did not react with GQ1b, GT1a, or GT1b. This atypical case, which most closely represents an incomplete Miller Fisher syndrome, indicates that anti-GD1b/GD3 antibodies may be able to induce sensory ataxia.

A comparison of euthanasia methods in rats, using carbon dioxide in prefilled and fixed flow rate filled chambers

The two methods (prefilled and fixed flow rate filled chambers) recommended in the 1993 AVMA Euthanasia Panel report for using carbon dioxide to euthanatize rats were evaluated in terms of their effect on behavior and selected blood gas values. Responses were videotaped during exposure to > or = 90% carbon dioxide in a prefilled chamber or a gradually filled chamber, using a fixed flow rate of 20% chamber volume/min. Arterial blood samples were taken to determine partial pressure of oxygen, partial pressure of carbon dioxide, pH, and oxygen saturation prior to entering the chamber and at time points determined by rats' responses to carbon dioxide. Rats showed similar reactions when exposed to carbon dioxide by either method. Significant differences in mean time for each response to occur were seen between euthanasia methods. Maintaining a near atmospheric oxygen chamber concentration by using a 75% CO2: 20% O2: 5% N2 gas mixture to gradually fill the chamber did not change rats' reactions upon exposure. Significant differences were found between pre-exposure values and values from samples obtained when rats became immobile after entering the prefilled chamber. Partial pressure of carbon dioxide significantly increased, and pH and percent oxygen saturation significantly decreased from pre-exposure values in all samples obtained after rats entered the gradually filled chamber. Partial pressure of oxygen in these rats was greater than or equal to pre-exposure levels in all samples. Rats appeared sedated because of the anesthetic effects of carbon dioxide when immobility was observed. Distress was not observed in the rats when either method of euthanasia was used.

Serum anti-GQ1b IgG antibody is associated with ophthalmoplegia in Miller Fisher syndrome and Guillain-Barré syndrome: clinical and immunohistochemical studies

To determine the significance of serum anti-GQ1b IgG antibody, we studied the disease spectrum associated with this antibody and GQ1b epitope in the human nervous system. We examined sera from 19 patients with typical Miller Fisher syndrome (MFS), five patients with acute postinfectious ophthalmoplegia without ataxia (atypical MFS), six patients with Guillain-Barré syndrome (GBS) with ophthalmoplegia (GBS-OP[+]), and 23 patients with GBS without ophthalmoplegia (GBS-OP[-]). We also examined sera from 84 patients with other neurologic or non-neurologic disorders and from 16 normal control subjects. Eighteen of the 19 patients with typical MFS, all the patients with atypical MFS, and five of the six patients with GBS-OP(+) had increased anti-GQ1b IgG activity in ELISA, but none of the patients in the other groups, including GBS-OP(-), had it. All the patients' sera that had anti-GQ1b IgG antibody showed anti-GT1a IgG activity. Results of absorption studies suggested that the same antibody reacted with GQ1b and GT1a. An anti-GQ1b mouse monoclonal antibody immunostained the paranodal regions of the extramedullary portion of the human oculomotor, trochlear, and abducens nerves. Biochemical analysis showed that the human oculomotor nerve contained a larger amount of GQ1b than did the ventral and dorsal roots of the spinal cord. We conclude that serum IgG antibody against GQ1b is very closely associated with acute postinfectious ophthalmoplegia in MFS and GBS.

Delayed hyperbaric oxygen therapy for carbon monoxide intoxication--two case reports

The severity of signs and symptoms following carbon monoxide intoxication often does not relate to admission carboxyhaemoglobin levels. Two cases are presented with severe neurological impairment despite carboxyhaemoglobin levels of 2% and 1.7% on admission to hospital, who responded well to hyperbaric oxygen therapy. In one case, symptoms recurred several days later, but responded to further hyperbaric oxygen therapy. The role of and possible mechanism of action of late hyperbaric oxygen treatment in carbon monoxide intoxication are discussed.

Primordial birdheaded nanism associated with progressive ataxia, early onset insulin resistant diabetes, goiter and primary gonadal insufficiency. A new syndrome

A new syndrome in two siblings with primordial birdheaded nanism, progressive ataxia, goiter, primary gonadal insufficiency and insulin resistant diabetes mellitus is presented. Plasma concentrations of TSH, PTH, LH, FSH, ACTH, glucagon and insulin all working through cell membrane receptors were elevated. A generalized cell membrane defect was suggested to be the pathophysiological abnormality in these patients.

Genetic correlation of ethanol-induced ataxia and cerebellar Purkinje neuron depression among inbred strains and selected lines of rats

In the present study, we compared phenotypic differences in behavioral and neurophysiological responses to acute ethanol administration among six inbred rat strains. Genetic variation was found both for ataxia, as measured by loss of righting response (sleep time) after a hypnotic dose of ethanol, and for the depressant action of ethanol on the spontaneous discharge of cerebellar Purkinje neurons. Results from an analysis of covariance of these phenotypes, measured among the inbred strains, provided strong evidence for a high genetic correlation between sleep time and inhibition of cerebellar Purkinje neuron discharge in response to acute ethanol administration. However, ethanol metabolism was also found to correlate with the behavioral sensitivity of rats to ethanol. Preliminary data from the third generation of replicate lines of rats currently being selectively bred for high and low acute sensitivity to ethanol shows a trend toward divergence of both ethanol sleep time and neuronal sensitivity to acute ethanol. The conclusion from these data supports the hypothesis that the cerebellum is an important locus of ethanol action, and suggests that neuronal sensitivity to ethanol will continue to diverge between these rat lines as selection for the sleep time phenotype progresses.

Vitamin B nutrition in the Nigerian tropical ataxic neuropathy

Assessment of nutritional status of vitamin B components by plasma or blood levels indicated riboflavin deficiency and possibly thiamine deficiency in Nigerian patients who suffered from tropical ataxic neuropathy and neurologically normal Nigerians who subsisted on predominant cassava diet. Serum levels of folate, niacin, pyridoxine and panthothenic acid were normal. Vitamin deficiencies probably are minor factors, if any, in the pathogenesis of tropical ataxic neuropathy in Nigerians.

Plasma cholesteryl sulfate in Friedreich's ataxia

Alteration of membrane fluidity and anomalies of membrane structural proteins have been suspected in Friedreich's ataxia. Plasma lecithin:cholesterol acyltransferase (LCAT) activity is also lowered in this disease, presumably because of a substrate effect. The membrane-stabilizing effect of cholesteryl sulfate (CS) and its inhibitory effect on LCAT activity prompted us to measure this substance in the plasma of Friedreich's ataxia patients as well as in normal subjects and in patients with Charlevoix-Saguenay disease. Plasma cholesteryl sulfate concentrations were significantly higher in Friedreich's ataxia, with levels above the upper limit of normal in nearly half of the cases. This increase was unrelated to age, sex or plasma cholesterol levels, but closely associated with the severity of the disease and thus considered to be secondary. A similar phenomenon (except the association with severity) was observed in Charlevoix-Saguenay ataxia. Levels also tended to be higher in first-degree relatives of Friedreich cases. The significance of these findings is discussed in the light of recent knowledge and experimental data obtained in this laboratory on rats made deficient in essential fatty acids. The highest concentrations of CS observed in Friedreich's ataxia (1097 micrograms/dL, 6 times the normal mean) was only 25% as high as the concentrations reported to inhibit LCAT activity.

Excess rumen product anions in cattle. II. Toxic and lethal effects with butyrate

Toxicity to butyrate was observed in 100-250 kg male Holstein calves following intravenous injection of 0.7-3.6 mmole/kg body weight, intravenous infusion with 0.12-0.53 mmole/min/kg body weight and intraruminal dosage with 19.4 mmole/kg body weight butyrate. Lower doses produced ataxia and serous nasal discharge. Higher doses produced sudden flaccid paralysis and death from asphyxia. No postmortem lesions, gross or histological, were observed. Plasma K+ was reduced to 2.2-2.5 mEq/L. When infusions were stopped, rapid recovery preceded clearance of butyrate and low K+ remained. Nerve depolarization in the central nervous system may be the cause of the toxic effects. Butyrate acidosis is suggested as a factor in unexplained sudden deaths in ruminants.

Truncal ataxia in chronic anticonvulsant treatment. Association with drug-induced folate deficiency

The association of truncal ataxia with a number of different factors has been studied in a group of 95 epileptic outpatients on chronic anticonvulsant treatment. The 28 patients showing truncal ataxia had been epileptic for a longer period of time, received a significantly larger number of drugs, and had higher serum levels of phenobarbital than the non-ataxic group. Serum folate levels were significantly lower in the ataxic group. A role is postulated for anticonvulsant-induced folate deficiency in the appearance of truncal ataxia presenting after prolonged anti-convulsant therapy, either by increasing the serum levels of the anticonvulsants or through other, unknown mechanisms. The presence of tonic-clonic seizures, presumably associated with brain anoxia, was not associated with the appearance of truncal ataxia.

Erythrocyte protoporphyrin levels in patients with Friedreich's and other ataxias

Of 13 patients with Friedreich's ataxia (Type Ia) and 17 with type IIa recessive ataxias, all were found to have levels of "free erythrocyte protoporphyrin" (FEP) above the normal range. The rise in FEP in Friedreich's ataxia correlated well with the age of the individual and thus appears to be related to the course of the disease. Subjects with olivo-ponto-cerebellar atrophy, Charlevoix syndrome, Duchenne muscular dystrophy, and Parkinson's disease were also found to have significantly elevated FEP, although the distribution overlapped with the normal range. The finding of elevated FEP may indicate a relative heme deficiency in ataxia due to inhibition of ferrochelatase leading to a state of ineffective, persistent erythropoiesis. The possibility of a prostaglandin abnormality being related to this defect and to the pathogenesis of ataxia is considered.

Platelet taurine uptake in spinocerebellar degeneration

The uptake of 14C-taurine was studied in the platelets of 20 ataxic patients and 20 age-matched normal control subjects. No significant differences were found in uptake or kinetics of taurine between the two groups of subjects. If a transport defect in taurine exists in Friedreich's ataxia, it is not present in all tissues. Preliminary indication was obtained in favor of heterogenity of the uptake pattern between ataxic individuals.

Plasma lipids and lipoproteins in Friedreich's ataxia and familial spastic ataxia--evidence for an abnormal composition of high density lipoproteins

A systematic study of plasma lipids and lipoproteins was carried out in 11 cases of Friedreich's ataxia and 6 cases of familial spastic ataxia (Charlevoix-Saguenay disease) using 11 healthy normolipidemic volunteers of comparable age and sex as controls. No differences were noted in the fatty acid profile of the total lipid fraction, in the total cholesterol and phospholipids or in the percentage distribution of the individual phospholipid classes. The triglycerides were significantly higher in Friedreich's ataxia, but remained within the normal range. Although no systematic abnormalities could be detected in the electrophoretic pattern of plasma lipoproteins or in the apolipoprotein profile on polyacrylamide gel electrophoresis, major differences were found in the high density lipoprotein (HDL) fraction. Their total amount was reduced and their composition was abnormal in both neurological diseases. In Friedreich patients, the relative proportion of cholesterol and triglycerides was increased while the relative protein content was greatly reduced. In Charlevoix disease, a similar abnormality was seen except for the excess of triglycerides. The proportion of phospholipids in HDL was the same in the three groups of patients. In addition, the low density lipoprotein (LDL) fraction was slightly reduced in both diseases. This anomaly of the HDL fraction could indicate that the HDL apolipoprotein moiety has a greater affinity for cholesterol and triglycerides in Friedreich's ataxia than its normal counterpart.

Swayback (enzootic ataxia) in Alberta lambs

Swayback (enzootic ataxia), a disease not previously described in Canada, occurred in newborn lambs in Alberta in 1972. Of 100 lambs born in one flock, over 60 succumbed in the enzootic. The diagnosis was based on the presence of a) gross cavitations and gelatinous lesions of the cerebral white matter in 16 of 24 (66.67%) lambs examined, b) central chromatolysis and hyalinization of neurons of the red and vestibular nuclei and reticular formation and of the lateral and ventral horns of the spinal cord, c) myelin deficiencies of the dorsolateral and sulcomarginal funiculi of the spinal cord and d) low hepatic and serum copper levels in affected lambs and low serum copper levels in the ewes. The feeding of sugar beet-(beta saccharifera) top silage to the ewes during pregnancy, lambing and lactation, and its relationship to the enzootic is discussed.

Biochemical studies in Tanzanian patients with ataxic tropical neuropathy

Data on thiocyanate and vitamin B(12) concentrations in plasma from Tanzanian patients with ataxic tropical neuropathy are presented and support the hypothesis that, as in Nigeria, the condition may result from chronic exposure to cyanide or cyanogens from a diet including large amounts of cassava.

Controlled trial of hydroxocobalamin and riboflavine in Nigerian ataxic neuropathy

The results are presented of a double-blind therapeutic trial of hydroxocobalamin and riboflavine in Nigerian patients suffering from a degenerative neuropathy. Although no benefit from either vitamin was demonstrated, this may reflect the inadequacy of the dosages used. The results are discussed in relation to the hypothesis that dietary cyanide and cyanogens are responsible, at least in part, for the occurrence of this disease in a malnourished population.

Plasma amino-acids in the Nigerian nutritional ataxic neuropathy

Investigation of nine patients with tropical ataxic neuropathy showed an absence or diminution of sulphur-containing amino-acids-cysteine and methionine-and a variable concentration of most other essential amino-acids. The pattern was unlike that found in kwashiorkor. The levels of serum cholesterol and total protein were normal, and the serum vitamin B(12) levels were normal or high. Plasma thiocyanate concentration was high.All the patients gave a history of a monotonous diet of cassava derivatives. Cassava contains a cyanogenetic glycoside (linamarin) from which cyanide is released on hydrolysis. The excessive cyanide detoxication may be responsible for the low concentration of the sulphur-containing amino-acids.