[Solvent-induced chronic encephalopathy; the 'solvent team' project]

Long-term exposure to organic solvents can result in damage of the central nervous system. The WHO recognises the following stages: organic affective syndrome, mild chronic toxic encephalopathy (CTE), and severe CTE. There is no golden standard for the diagnosis of CTE. Mild CTE is characterised by fatigue, mood disturbances, memory and attention disorders. In the Netherlands, a so-called 'solvent team' consisting of an occupational physician, a neurologist, a neuropsychologist and an occupational hygienist, assesses patients suspected of having CTE. The diagnostic procedure consists of three steps: (a) interview and blood tests, (b) the computer-based Neurobehavioral Evaluation System, and (c) assessment of an exposure index, neuropsychological investigation, and clinical neurological examination. In the period 1997-1999 approximately 250 patients were assessed yearly in the Netherlands; resulting in 50 diagnoses of mild CTE a year. The real incidence is most likely higher at present, but will decline due to diminished exposure to organic solvents.

Clinical and genetic analysis of a four-generation family with a distinct autosomal dominant cerebellar ataxia

The autosomal dominant cerebellar ataxias (ADCAs) are a heterogeneous group of neurodegenerative disorders characterised by progressive cerebellar dysfunction in combination with a variety of other associative features. Since 1993 ADCAs have been increasingly characterised in terms of their genetic mutation and are referred to as spinocerebellar ataxias (SCAs). Some families with ADCA cannot be assigned to any of the known genotypes, which implies further genetic heterogeneity. We investigated the clinical symptoms of 12 patients of a four-generation family with ADCA and carried out mutation and genetic linkage studies. The family showed a relatively mild cerebellar ataxic syndrome with cognitive impairment, poor performance on the Wisconsin Card Sorting Test, myoclonus, and a postural irregular tremor of slow frequency. Age at disease onset and severity of cerebellar signs and symptoms suggest anticipation. The genetic loci implicated in ADCA were excluded by mutation analyses (SCA 1, 2, 3, 6, 7, 8, 12) and genetic linkage (SCA 4, 5, 6, 10, 11). We conclude that this family represents a clinically and genetically distinct form of SCA.

Non-secretion of mutant proteins of the glaucoma gene myocilin in cultured trabecular meshwork cells and in aqueous humor

Until recently, very little was known about the molecular mechanisms responsible for the development of glaucoma, a leading cause of blindness worldwide. Mutations in the glaucoma gene myocilin (MYOC, GLC1A) are associated with elevated intraocular pressure and the development of autosomal dominant juvenile glaucoma and a subset of adult-onset glaucoma. MYOC is expressed in the trabecular meshwork (TM), a tissue responsible for drainage of aqueous humor from the eye, and the tissue involved in elevated intraocular pressure associated with glaucoma. To better understand the role of MYOC in glaucoma pathogenesis, we examined the expression of normal and mutant myocilin in cultured ocular (TM) and non-ocular cells as well as in the aqueous humor of patients with and without MYOC glaucoma. Normal myocilin was secreted from cultured cells, but very little to no myocilin was secreted from cells expressing five different mutant forms of MYOC. In addition, no mutant myocilin was detected in the aqueous humor of patients harboring a nonsense MYOC mutation (Q368X). Co-transfection of cultured cells with normal and mutant myocilin led to suppression of normal myocilin secretion. These studies suggest that MYOC glaucoma is due either to insufficient levels of secreted myocilin or to compromised TM cell function caused by congestion of the TM secretory pathway.

Criteria for solvent-induced chronic toxic encephalopathy: a systematic review

In 1985, a WHO Working Group presented diagnostic criteria and a classification for solvent-induced chronic toxic encephalopathy (CTE). In the same year, the "Workshop on neurobehavioral effects of solvents" in Raleigh, N.C., USA introduced a somewhat different classification for CTE. The objective of this review is to study the diagnostic procedures that are used to establish the diagnosis of CTE, and the extent to which the diagnostic criteria and classification of the WHO, and the classification of the Raleigh Working Group, are applied. A systematic search of studies on CTE was performed, and the diagnostic criteria and use of the WHO and Raleigh classifications were listed. We retrieved 30 original articles published in English from 1985 to 1998, in which CTE was diagnosed. Only two articles did not report the duration of solvent exposure. The type of solvent(s) involved was described in detail in four articles, poorly in 17 articles, and not at all in nine articles. Tests of general intelligence were used in 19 articles, and tests of both attention and mental flexibility and of learning and memory were used in 18 articles. Exclusion, by interview, of potentially confounding conditions, such as somatic diseases with central nervous effects and psychiatric diseases, was reported in 21 and 16 articles, respectively. In only six of the articles were both the WHO diagnostic criteria and the WHO or Raleigh classifications used. In the future, parameters of exposure, psychological test results, and use of medication that possibly affects psychological test results should always be described. We list some advantages and disadvantages of the Raleigh and WHO classifications. To aid inter-study comparisons, the diagnosis of CTE should be categorized and reported according to an internationally accepted classification.

Similarities and differences in the phenotype, genotype and pathogenesis of different spinocerebellar ataxias

Historically, the differential diagnosis of the autosomal ataxias (ADCAs) has been difficult. In 1983 Harding proposed a useful clinical classification. Since 1983 ADCAs have been increasingly characterized in terms of their genetic locus and are referred to as spinocerebeller ataxia (SCA). The overlap between the SCA phenotypes and the high variability within SCA subgroups means that, for individual patients, the underlying mutation cannot be predicted reliable purely on the basis of clinical symptoms and so diagnosis should be made on the genotype. However, for executing DNA analyses in order of clinical likelihood, neurologists may try to deduce the underlying mutation by using a clinical algorithm. In this article we not only describe such an algorithm but also plot the pathway from clinical presentation, genetic classification and mutation, abnormal protein to common neuropathology in these disorders.

Early onset cerebellar ataxia with retained tendon reflexes: foot deformity in a first grade family member

Early onset cerebellar ataxia with retained tendon reflexes (EOCA) is a clinical syndrome characterised by progressive cerebellar ataxia with an onset before the age of 25 years and a wide spectrum of associated features. It is distinguished from Friedreich's ataxia (FA) mainly by the preservation of tendon reflexes, a better prognosis, and the absence of GAA expansion in the frataxin gene. Although EOCA is thought to be a hereditary disorder with an autosomal recessive mode of inheritance, genetic heterogeneity might underlie the spectrum of clinical features. In this case report we describe a patient with EOCA accompanied by pes cavus, hammer toes and peripheral neuropathy. The patient's father did not have any ataxia, but had the same foot deformities as his daughter and a slight peripheral neuropathy. The possible relationship between these clinical features is discussed.

Extended extradural spinal arachnoid cyst: an unusual cause of progressive spastic paraparesis

A 15-year old girl presented with a slowly progressive spastic paraparesis since the age of 12. Creatine kinase was slightly increased. Muscle biopsy carried out during tendon surgery for severe toe-walking showed 'myopathic' changes. Subsequent neurological evaluation and radiological studies revealed a large extradural arachnoid cyst extending from the 11th thoracic vertebra to the first lumbar vertebra. Her condition improved after operation. The 'myopathic' features turned out to be the result of chronic spinal compression. MRI is the method of choice to examine patients with non-hereditary progressive spastic paraparesis. Muscle biopsy and tendon surgery should not be performed, without careful neurological examination.

Antibacterial effect of garlic and omeprazole on Helicobacter pylori

The antibacterial effect of a home-made raw garlic extract and commercial garlic tablets alone and in combination with antibiotics or omeprazole was determined against clinical isolates of Helicobacter pylori. MIC values of raw garlic extract and three types of commercial garlic tablets ranged from 10,000 to 17,500 mg/L. When MIC values of the commercial tablets were based on the allicin content, no differences between the three types were observed. The combination of garlic and omeprazole, studied with killing curves, showed a synergic effect which was concentration dependent. Further clinical evaluation of garlic in combination with the conventional agents for H. pylori treatment seems warranted.

Parkinsonism, pyramidal signs, polyneuropathy, and cognitive decline after long-term occupational solvent exposure

It is well known that exposure to manganese, solvents, or carbon monoxide in an occupational setting may lead to central nervous system damage and parkinsonism. The most important solvents in this respect are methanol, toluene, carbon disulfide, and n-hexane. We describe three patients who had been exposed to various solvents for more than 20 years (25, 34, and 46 years). They presented with parkinsonism, pyramidal signs, mild cognitive decline, and unresponsiveness to levodopa. Two patients had a predominantly axonal and sensory polyneuropathy of the lower legs with fasciculations in one of them. Parkinsonian features were progressive, even after the patients had stopped work. We present clinical data, neuropsychological findings, and results of brain computed tomography or magnetic resonance imaging, electroneuromyography, evoked potentials, single photon emission computed tomography, and positron-emission tomography. There is growing evidence that various organic solvents give rise to a parkinsonism syndrome with pyramidal features in susceptible individuals.

Meningioma presenting as Tolosa-Hunt syndrome

A 23-year-old woman was admitted with headache, nausea, vomiting and blurred vision on the left side. Neurological examination showed ptosis with a complete internal and external ophthalmoplegia and a red fullness around the left orbita. Computed tomographic scanning of the brain revealed no abnormalities. As she improved on high doses of steroids a diagnosis of Tolosa-Hunt syndrome (THS) seemed to be indicated. However, magnetic resonance imaging (MRI) showed a lesion with intermediate signal intensity in the left cavernous sinus. Craniotomy was performed when symptoms of THS recurred. Histopathological examination revealed a meningioma with a papillary aspect and some mitoses. This case illustrates that: (1) THS is still a diagnosis by exclusion; (2) MRI and histopathological examination are important if there is any doubt about the diagnosis; and (3) also when there is no doubt, improvement after steroid therapy may be a diagnostic pitfall. Therefore, not only MRI but also orbital phlebography and angiography should seriously be considered.

Localisation of the gene for a dominant congenital spinal muscular atrophy predominantly affecting the lower limbs to chromosome 12q23-q24

Spinal muscular atrophies are a heterogeneous group of disorders. They differ in time of onset, clinical presentation, progression, severity and mode of inheritance. In 1985 a Dutch family was described with a dominant, non-progressive spinal muscular atrophy presenting at birth with arthrogryposis (MIM 600175). Linkage analysis was performed in this family. After having excluded the loci for Werdnig-Hoffmann's disease and for dominant distal spinal muscular atrophy with upper limb predominance, we were able to localise the gene to a 10 cM interval between the markers D12S78 and D12S1646 on chromosome 12q23-q24. Recently, dominant scapuloperoneal spinal muscular atrophy has been localised to an overlapping interval. However, the clinical appearances of scapuloperoneal spinal muscular atrophy and the present disorder make allelism unlikely. In 1994, a second Dutch family with a disorder similar to the present one was described. We excluded linkage to markers of the 12q23-q24 region in this family and thereby proved genetic heterogeneity of this type of dominant, congenital and nonprogressive spinal muscular atrophy.

Analysis of urinary caffeine metabolites to assess biotransformation enzyme activities by reversed-phase high-performance liquid chromatography

An isocratic high-performance liquid chromatography procedure was developed for the analysis of five urinary metabolites of caffeine; caffeine or 1,3,7-trimethylxanthine (137X), paraxanthine or 1,7-dimethylxanthine (17X), 1,7-dimethylurate (17U), 1-methylxanthine (1X), 1-methylurate (1U) and 5-acetylamino-6-formylamino-3-methyluracil (AFMU). A standardized procedure was used for oral intake of caffeine and for urine collection. Conditions for sample storage and preparation were optimized, resulting in no detectable loss of caffeine metabolites after storage of the urine samples for four months. Urine samples were extracted with chloroform-2-propanol (4:1, v/v) and separated on a reversed-phase column with acetic acid (33%)-tetrahydrofuran-acetonitrile-water (1:2.5:44:925.5, v/v) as the eluent. Peaks were monitored at 280 nm. Peak heights were measured and the five metabolites were quantified using calibration curves. Cytochrome P4501A2 (CYP1A2) activity was calculated from the molar ratio (AFMU+1X+1U)/17U, N-acetyltransferase (NAT) from the ratio AFMU/1X, XO from the ratio 1U/1X+1U and cytochrome P4502A6 (CYP2A6) from the ratio 17U/(17U+17X+1U+ 1X+AFMU). The inter-assay coefficients of variation ranged from 1.7% for 17U to 5.7% for IX. The intra-individual variation in metabolite ratios determined in two people, with intervals of a few days to several weeks between measurements, ranged from 2. 1% for XO to 11.0% for CYP2A6. Using this procedure, metabolic ratios were determined for four groups of subjects; healthy, non-smoking females using oral contraceptives (OC users, n=5) and non-users (n=5), healthy nonsmoking males (n=9) and children (n=7). Results found in this study were comparable to results reported in the literature for subjects with similar characteristics. A significantly higher CYP1A2 ratio was found for males (4.87+/-0.47) compared to females (3.62+/-0.91: p=0.005, Mann-Whitney). For the other enzyme activities, no significant differences were found between the groups of subjects in this study.

Adenylosuccinase deficiency with neonatal onset severe epileptic seizures and sudden death

We report a male infant with adenylosuccinase deficiency who developed epileptic seizures on the second day of life. Growth was normal and seizures were well controlled with anti-epileptic drugs. Despite axial hypotonia associated with peripheral hypertonicity he presented some development until seven months of age, when he developed high fever and died within a few hours. Although clinical heterogeneity in this disorder of purine synthesis and interconversion is well-known, in 14 out of 17 cases who experienced epilepsy seizures started after the first year of life. The early presentation in our index patient followed by his sudden death at the age of 7 months has not been described before. A search for disorders of purine metabolism should be included in the screening programme for every child with severe neonatal convulsions.

Prediction of recovery from upper extremity paralysis after stroke by measuring evoked potentials

Paralysis of the upper extremity is a severe motor impairment that can occur after stroke. Prediction of recovery from paralysis is difficult and is primarily based on subjective clinical evaluation. However, the integrity of the sensorimotor system can be assessed objectively and quantitatively by measuring evoked potentials. In this retrospective exploratory study, we evaluated the predictive value of motor and somatosensory evoked potentials for recovery from paralysis of the upper extremity. Motor and somatosensory evoked potentials were recorded in 29 patients who had had their first-ever infarction in the territory of the middle cerebral artery and who exhibited paralysis of the upper extremity. At follow-up, seven patients showed motor recovery. The evoked potential data were dichotomized into present or absent and related to the occurrence of motor recovery. Analysis revealed a significant association between the presence of evoked potentials early after stroke and the observed occurrence of motor recovery. These results suggest strongly that evoked potentials predict the occurrence of motor recovery of upper extremity paralysis in patients suffering from first-ever infarction in the territory of the middle cerebral artery.

Cerebellar ataxia, dementia, pyramidal signs, cortical cataract of the posterior pole and a raised IgG index in a patient with a sporadic form of olivopontocerebellar atrophy

Middle-aged patients who initially present with a progressive cerebellar ataxia, in the absence of a known familial pattern are often referred to under the descriptive diagnosis of 'idiopathic' late onset cerebellar ataxia. If these patients in time develop additional pyramidal or extrapyramidal features then they should be labeled as olivopontocerebellar atrophy (sOPCA). This case report describes a patient with OPCA with cerebellar ataxia as the presenting and most prominent feature in combination with dementia, pyramidal signs, cortical cataract of the posterior pole and a raised IgG index in cerebrospinal fluid. To the best of our knowledge this combination of signs and symptoms have not been described before.

The prognostic value of cortical magnetic stimulation in acute middle cerebral artery infarction compared to other parameters

The prognostic value of magnetic evoked potentials (MEP), somatosensory evoked potentials (SSEP), age and radiological parameters was determined in 50 patients with acute middle cerebral artery infarction. We performed MEP and SSEP within 4 days and after 6 weeks and 3 months of the infarction and assessed clinical improvement by using the Barthel index (BI) and the Rankin scale. The localization and extent of the infarction was investigated by CT scanning or NMR. All parameters were correlated to clinical outcome and the prognostic significance of each parameter in addition to BI was determined. MEP, SSEP, and age were valuable prognostic parameters in predicting stroke outcome when used together with the BI. However, in stepwise regression analysis using all parameters simultaneously, only MEP and age significantly contributed to clinical outcome in addition to BI. Patients showed a better outcome when their MEP was normal or delayed, measured within 4 days of the infarction, compared to patients with absent MEP. Clinical outcome was better at a younger age.

Nitrate contamination of drinking water: relationship with HPRT variant frequency in lymphocyte DNA and urinary excretion of N-nitrosamines

We studied peripheral lymphocyte HPRT variant frequency and endogenous nitrosation in human populations exposed to various nitrate levels in their drinking water. Four test populations of women volunteers were compared. Low and medium tap water nitrate exposure groups (14 and 21 subjects) were using public water supplies with nitrate levels of 0.02 and 17.5 mg/l, respectively. Medium and high well water nitrate exposure groups (6 and 9 subjects) were using private water wells with mean nitrate levels of 25 and 135 mg/l, respectively. Higher nitrate intake by drinking water consumption resulted in a dose-dependent increase in 24-hr urinary nitrate excretion and in increased salivary nitrate and nitrite levels. The mean log variant frequency of peripheral lymphocytes was significantly higher in the medium well water exposure group than in the low and medium tap water exposure groups. An inverse correlation between peripheral lymphocyte labeling index and nitrate concentration of drinking water was observed. Analysis of N-nitrosamine in the urine of 22 subjects by gas chromatography-mass spectrometry revealed the presence of N-nitrosopyrrolidine in 18 subjects. Analysis of the mutagenicity of well water samples showed that a small number of the well water samples were mutagenic in the Ames Salmonella typhimurium test after concentration over XAD-2 resin. In conclusion, consumption of drinking water, especially well water, with high nitrate levels can imply a genotoxic risk for humans as indicated by increased HPRT variant frequencies and by endogenous formation of carcinogenic N-nitroso compounds from nitrate-derived nitrite.

A Dutch family with benign hereditary chorea of early onset: differentiation from Huntington's disease

A large Dutch family of 88 members, running through five generations, is described with benign hereditary chorea of early onset. The clinical presentation was heterogeneous. The chorea manifested in late infancy or childhood, interfered with writing, was non-disabling, stable or even improved in adulthood in most cases, but was slowly progressive with gait impairment in some. There was mild dysarthria and normal intelligence. EEG brain CT-scanning and MRI were normal. Huntington's disease was excluded by analysis of the I T 15 gene, which showed a normal number of the CAG trinucleotide repeats in two patients. It is concluded that benign hereditary chorea of early onset is an entity different from Huntington's disease and that in cases of early onset chorea the diagnostic accuracy is markedly improved by DNA testing.

[Pyridoxine-dependent epilepsy in an infant]

A newborn girl with seizures was, after repeated conventional anticonvulsive treatment, cured by pyridoxine administration. Pyridoxine-dependent seizures are an uncommon disease with autosomal-recessive heredity and a variable clinical picture. The prognosis may be favourable when diagnosis is made early. Confusion with perinatal asphyxia, and initial good response to usual anticonvulsive treatment can lead to delay in diagnosis.

Influence of smoking behavior in relation to plasma retinol and alpha-tocopherol on sister chromatid exchanges in human peripheral blood lymphocytes

The present study was undertaken to evaluate the contribution of various individual characteristics and lifestyle factors on sister chromatid exchange (SCE) frequencies in human peripheral blood lymphocytes (PBLs). These also included associations between plasma retinol and alpha-tocopherol and SCE frequencies. The study population consisted of 50 healthy, smoking and nonsmoking, male and female volunteers, ages 22-49. SCE frequencies in PBLs were significantly higher in smokers than in nonsmokers. SCE frequencies correlated with variables of smoking habits and history, with the number of pack-years smoked correlating most strongly (r = 0.501; P < 0.001). Inverse but nonsignificant correlations were observed between plasma retinol and alpha-tocopherol levels and SCE frequencies in PBLs. In addition, with the use of multiple regression analysis, significant associations were found with age and possible occupational exposure after adjustment for smoking habits (r2 = 0.428; P = 0.0001). For males (n = 20), SCE frequencies were found to be associated significantly with the number of cigarettes smoked per day and possible occupational exposure (r2 = 0.485; P < 0.01). SCE frequencies in PBLs of females (n = 30) were associated positively with the number of pack-years smoked and age, and significantly inversely correlated with plasma alpha-tocopherol concentrations (r2 = 0.586; P = 0.0001). After exclusion of possible occupationally exposed persons (n = 8) from the study population and adjustment for the effects of age and smoking behavior, a weak inverse correlation was found between plasma alpha-tocopherol and SCE frequencies (r = -0.286; P = 0.0732).(ABSTRACT TRUNCATED AT 250 WORDS)

The association of cortical dysplasia and anterior horn arthrogryposis: a case report

We describe a 21-year-old woman with neurogenic congenital contractures (arthrogryposis) of the lower limbs, normal intelligence, hyper-reflexia and partial epilepsy. MRI revealed bilateral opercular (perisylvian) cortical dysplasia with infolding of cerebral cortex, a focal neuroblast migrational disorder. This type of migrational disorder is known to have a prenatal onset after the 20th fetal week, whereas the anterior horn cell degeneration responsible of neurogenic arthrogryposis originates at 12-14 weeks of gestation. A prenatal viral infection along the neural axis during both these gestational periods or a genetic defect could be responsible for both lesions in this case.