Involvement of the Central Nervous System in Non-Hodgkin's Lymphoma

Fifteen of 146 (10 %) adult patients with non-Hodgkin's lymphoma showed clinical and pathologic evidence of involvement of the central nervous system (CNS); in 6 patients, the CNS lymphoma was present at the onset of disease, in 3 of them it was the only sign detected. In the remaining 9 cases, CNS involvement appeared during the course of systemic disease. In all cases symptoms related to infiltration of the CNS were associated with advanced disease (stage IV); bone marrow or bone involvement was found in 9 patients (60 %). The histologic subtypes were mostly of high-grade malignancy according to the Kiel classification: immunoblastic (3), centroblastic (3), Burkitt type (2), lymphoblastic (1), LP immunocytoma in polymorphic variant (3), unclassifiable (3). The prominent signs and symptoms of CNS lymphoma are listed: the cranial nerve palsies are the most common finding. The principal means of detecting CNS involvement are discussed: cerebrospinal fluid cytology, brain scan and CAT scan were the most useful diagnostic procedures. The reported data allow identification of patients at high risk of CNS lymphoma: this includes histologies of high-grade malignancy, advanced stage of disease, and bone marrow or bone infiltration. Therefore, either intensive systemic chemotherapy or CNS prophylaxis are recommended for patients with high risk of CNS disease.

Further evidence that mutations in FGD4/frabin cause Charcot-Marie-Tooth disease type 4H

BACKGROUND

Autosomal recessive demyelinating Charcot-Marie-Tooth neuropathy type 4H (CMT4H) manifests early onset, severe functional impairment, deforming scoliosis, and myelin outfoldings in the nerve biopsy. Mutations in the FGD4 gene encoding the Rho-GTPase guanine-nucleotide-exchange-factor frabin were reported in five families.

OBJECTIVE

To characterize a novel mutation in FGD4 and describe the related phenotype.

METHODS

A 20-year-old woman born of healthy consanguineous parents and affected with early-onset peroneal muscular atrophy underwent standard clinical, electrophysiologic, and pathologic (sural nerve biopsy) investigations. Mutational analysis of FGD4 was performed by direct sequencing of genomic DNA. Transcriptional analysis was done by reverse transcriptase PCR on leukocyte RNA.

RESULTS

The proband disclosed a moderately severe, scarcely progressive CMT, markedly slowed nerve conduction velocities, and a demyelinating neuropathy characterized by prominent myelin outfoldings. Mutational analysis disclosed a c.1762-2a>g transition in the splice-acceptor site of intron 14, which was predicted to cause a truncated frabin (p.Tyr587fsX14).

CONCLUSIONS

The report confirms genetic heterogeneity of FGD4, demonstrates that CMT4H has variable functional impairment, and suggests that frabin plays a crucial role during myelin formation.

Evaluating endothelial function of the common carotid artery: an in vivo human model

BACKGROUND AND AIMS

Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV).

METHODS AND RESULTS

In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10 microg/m(2) bs and 300 microg of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001).

CONCLUSIONS

ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy and right-to-left shunt: lack of evidence for an association in a prevalence study

BACKGROUND/AIMS

Up to more than 50% of cryptogenetic stroke patients and patients with migraine with aura (MA) are found to have a right-to-left shunt (RLS), which is usually due to a patent foramen ovale. Moreover, both MA and stroke are cardinal features of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Notch3 mutations have been suggested to induce an abnormally high incidence of atrial septal defects in a family harbouring an Arg141Cys pathogenetic mutation. We sought to determine the prevalence of RLS in CADASIL patients with different Notch3 mutations, both with and without migraine as a clinical feature.

METHODS

Subjects with a molecular diagnosis of CADASIL were tested for the presence of an RLS by means of contrast-enhanced transcranial Doppler (TCD). The diagnosis of migraine was made according to the 2004 International Headache Classification.

RESULTS

Sixteen CADASIL patients were tested; 6 had MA. Four patients displayed an RLS on contrast-enhanced TCD examination. Three of these patients had MA. Both patients with Arg141Cys displayed a large RLS.

CONCLUSION

We conclude that RLS is not necessarily linked to CADASIL as a comorbidity factor. Nevertheless, there could be a relation between RLS and specific Notch3 mutations, such as Arg141Cys.

A novel mutation of aprataxin associated with ataxia ocular apraxia type 1: Phenotypical and genotypical characterization

Ataxia oculomotor apraxia type 1 (AOA1) is the most common form of autosomal recessive ataxia in Japan, and the second in Portugal after Friedreich ataxia. AOA1 is typically characterized by early-onset cerebellar ataxia, oculomotor apraxia, hypoalbuminemia, hypercholesterolemia and late axonal sensori-motor neuropathy. AOA1 is associated with the aprataxin gene (APTX) encoding a protein involved in DNA repair. We characterized a novel homozygous missense mutation of APTX in a 34 year-old female patient born from consanguineous parents. The mutation, a Val230Gly caused by a c.689 T>G substitution, involved the histidine-triad (HIT) domain of the protein, affected a phylogenetically conserved amino acid and was absent in the control population. We described the clinical and neurophysiological features, the findings at structural and functional brain imaging, and the pathological picture of the sural nerve biopsy. The report emphasized the genetical and phenotypical heterogeneity of AOA1 by demonstrating atypical features such as absence of oculomotor apraxia and signs of pyramidal involvement. Expression studies by Western blotting on fibroblasts demonstrated that the homozygous Val230Gly mutation was associated with decreased levels of APTX indicating a loss-of-function mechanism.

Two novel mutations in dynamin-2 cause axonal Charcot-Marie-Tooth disease

BACKGROUND

Recently, mutations affecting different domains of dynamin-2 (DNM2) were associated alternatively with autosomal dominant centronuclear myopathy or dominant intermediate (demyelinating and axonal) Charcot-Marie-Tooth disease (CMT) type B.

OBJECTIVE

To assess the etiologic role of DNM2 in CMT.

METHODS

We performed a mutational screening of DNM2 exons 13 through 16 encoding the pleckstrin homology domain in a large series of CMT patients with a broad range of nerve conduction velocities and without mutations in more common genes.

RESULTS

We identified two novel DNM2 mutations that cosegregated with purely axonal CMT in two pedigrees without clinical evidence of primary myopathy.

CONCLUSION

Patients with axonal Charcot-Marie-Tooth disease type 2 neuropathy without mutations in more common genes should undergo investigation for DNM2 pleckstrin homology.

The role of muscle biopsy in investigating isolated muscle pain

OBJECTIVE

To evaluate the muscle biopsy findings from 240 patients who had isolated muscle pain.

METHODS

Histopathology, immunohistochemistry for dystrophin, dystrophin-related proteins, major histocompatibility complex type I, and biochemical analysis of glycolytic and mitochondrial respiratory chain enzymes were performed on muscle biopsies. An attempt was made to correlate pathologic data and clinical findings (sex, age, quality and distribution of symptoms, serum CK levels, and EMG recording).

RESULTS

We have described five groups of patients based on muscle biopsy findings: 51.6% had heterogeneous myopathic abnormalities; only 19% of them had a specific myopathic picture, i.e., central nuclei myopathy, central core disease, myopathy with tubular aggregates or with trabecular fibers or abnormalities of fiber typing; 20% had signs of respiratory chain dysfunction but only one patient had a probable mitochondrial disease; 7% had a neurogenic pattern; 2.4% had a metabolic myopathy (phosphorylase or phosphofructokinase deficiency); and 19% had normal muscle biopsy. No clear-cut correlation between muscle biopsy and clinical data was observed except for those patients with a metabolic myopathy.

CONCLUSIONS

The probability that a patient complaining only of muscle pain and with a normal neurologic examination has a definite muscle pathology is 2%. Only patients with sole exercise-related muscle pain and sCK seven times higher than the normal value are strongly suspected of having a metabolic myopathy. A rigorous selection of patients is needed before performing a muscle biopsy.

Variables influencing quality of life and disability in Charcot Marie Tooth (CMT) patients: Italian multicentre study

The purpose of this study was to assess the variables that influence quality of life (QoL) and disability in patients with Charcot-Marie-Tooth disease (CMT). We performed a prospective multicentre study using validated clinical disability and QoL measurements. Multivariate analysis was performed using QoL as a dependent variable and duration of symptoms, age, gender and CMT type, depression and disability measurements as independent variables. We enrolled 211 patients. QoL was highly significantly deteriorated with respect to the Italian normative sample. The physical aspect of QoL was mainly related to disability but it does not increase with the age, probably because of an adaptation between expectation and reality. The mental QoL is influenced by depression (hence we have to consider this aspect approaching CMT patients). Moreover, we observed that women complained of more severe symptoms than men. Finally, some CMT subtypes are related to more severe bodily pain symptoms than others. Multiperspective assessment of CMT showed new aspects of this disease, mainly regarding (1) differences between men and women and (2) the crucial role of pain and depression.

Hyperpyrexia-triggered relapses in an unusual case of ataxic chronic inflammatory demyelinating polyradiculoneuropathy

The ataxic form of chronic inflammatory demyelinating polyradiculoneuropathy (ataxic-CIDP) has been recently described as a subtype of chronic ataxic neuropathy, distinguished by steroid responsiveness and relative preservation of myelinated fibres at sural nerve biopsy. We report on a case of progressive, predominantly sensory, steroid-responsive neuropathy with clinical, laboratory, electrophysiological and pathological features of this uncommon form of CIDP. Moreover, the present case displays peculiar hyperpyrexia-triggered relapses leading to transitory severe tetraparesis, bilateral facial drooping, dysphonia, dysphagia and dyspnoea, which leave clinicians with some unresolved questions.

A novel missense mutation in the L1CAM gene in a boy with L1 disease

A novel missense mutation of the L1CAM gene (Xq28) is described in an adult patient affected with severe mental retardation, spastic paraparesis, adducted thumbs, agenesis of corpus callosum and microcephaly (L1 disease). We detected a transition c2308G-->A in exon 18 that caused an amino acid change in codon 770. The patient's mother and two sisters were heterozygous for the same mutation. This newly described mutation predicts the substitution of an aspartate by asparagine (D770N) in the second fibronectin (Fn2) domain of the extracellular portion of the mature L1 protein. Even if amino acid substitution does not significantly change the physico-chemical properties of the Fn2 domain, it seems clear that the integrity of this domain is required to maintain the biological functions of the protein. The feature peculiar to this patient is the decelerated head growth post-natally, leading to microcephaly. Mutations of L1CAM associated with prolonged survival may hamper post-natal brain and head growth.

Ataxia with oculomotor apraxia type 2: A clinical, pathologic, and genetic study

BACKGROUND

Ataxia with oculomotor apraxia type 2 (AOA2) is characterized by onset between age 10 and 22 years, cerebellar atrophy, peripheral neuropathy, oculomotor apraxia (OMA), and elevated serum alpha-fetoprotein (AFP) levels. Recessive mutations in SETX have been described in AOA2 patients.

OBJECTIVE

To describe the clinical features of AOA2 and to identify the SETX mutations in 10 patients from four Italian families.

METHODS

The patients underwent clinical examination, routine laboratory tests, nerve conduction studies, sural nerve biopsy, and brain MRI. All were screened for SETX mutations.

RESULTS

All the patients had cerebellar features, including limb and truncal ataxia, and slurred speech. OMA was observed in two patients, extrapyramidal symptoms in two, and mental impairment in three. High serum AFP levels, motor and sensory axonal neuropathy, and marked cerebellar atrophy on MRI were detected in all the patients who underwent these examinations. Sural nerve biopsy revealed a severe depletion of large myelinated fibers in one patient, and both large and small myelinated fibers in another. Postmortem findings are also reported in one of the patients. Four different homozygous SETX mutations were found (a large-scale deletion, a missense change, a single-base deletion, and a splice-site mutation).

CONCLUSIONS

The clinical phenotype of oculomotor apraxia type 2 is fairly homogeneous, showing only subtle intrafamilial variability. OMA is an inconstant finding. The identification of new mutations expands the array of SETX variants, and the finding of a missense change outside the helicase domain suggests the existence of at least one more functional region in the N-terminus of senataxin.

Phosphorylated 14-3-3zeta protein in the CSF of neuroleptic-treated patients

The authors describe 12 neuroleptic-treated patients with dementia of various etiologies who showed CSF elevation of phosphorylated 14-3-3zeta and normal tau protein levels. This contrasted with elevated amounts of 14-3-3 gamma, epsilon, and unphosphorylated zeta coupled to high tau protein levels in Creutzfeldt-Jakob disease and negative 14-3-3 assay in drug-free patients with dementia. Characterization of CSF 14-3-3 isoforms and determination of tau protein level can help to distinguish different etiologies of dementia.

Expression of late myogenic differentiation markers in sarcoplasmic masses of patients with myotonic dystrophy

Sarcoplasmic masses contain disorganized myofibrillar material and are a striking feature of myotonic dystrophy. However their significance is still unclear. Using immunocytochemistry we studied the expression of cytoskeletal proteins (desmin and vimentin), dystrophin, markers of myogenic differentiation (foetal myosin, neural cell adhesion molecule, bcl-2, insulin-like growth factor-I, fibroblast growth factor, retinoblastoma protein and myoD1), cell cycle regulators (Cdk2, p16, p27 and p57) and muscle proteases (ubiquitin, micro and m calpain and cathepsin D) in muscle biopsies from four patients with myotonic dystrophy. Sarcoplasmic masses were strongly positive for desmin, neural cell adhesion molecule, bcl-2, insulin-like growth factor I, retinoblastoma protein and p57, weakly positive for dystrophin and p16 and negative for vimentin, fibroblast growth factor, myoD1, Cdk2 and p27. Immunoreactivity for foetal myosin was detected only in a few fibres (< 1%). Our data suggest that the late myogenic differentiation programme is activated in sarcoplasmic masses although these areas do not reach complete maturation.

Segmental conduction abnormalities and myelin thickenings in Val102/fs null mutation of MPZ gene

The authors report in patients with Val102/fs null mutation a possibly age dependent variability of clinical and electrophysiologic phenotype, segmental conduction abnormalities mainly in ulnar nerves at the elbow, and excessive myelin foldings and thickenings. The authors hypothesize that myelin thickenings at the paranodal region, in concurrence with compression at usual entrapment sites or minor repetitive trauma, may induce segmental conduction abnormalities.

Expression of protein kinase C isoforms and interleukin-1beta in myofibrillar myopathy

BACKGROUND

The term myofibrillar myopathy refers to a rare and clinically heterogeneous group of muscle disorders. The pathogenesis of this myopathy is not well understood. The morphologic hallmark is myofibrillar destruction with abnormal expression of numerous proteins, most consistently of desmin.

METHODS

The authors investigated eight patients with myofibrillar myopathy belonging to four families. They studied the role of different protein kinase C isoforms and of interleukin-1beta, a cytokine that might activate protein kinase C and, in addition, mediate myofibrillar proteolysis.

RESULTS

Immunohistochemical analysis showed the expression of alpha, eta, and zeta isoforms of protein kinase C and of interleukin-1beta in abnormal muscle fibers. Immunoblots confirmed the immunohistochemical data and revealed the absence of protein kinase C delta and epsilon in muscle fibers from patients and controls.

CONCLUSIONS

These data suggest that protein kinase C and interleukin-1beta may play a role in the pathogenesis of myofibrillar myopathy.

Bovine spongiform encephalopathy and Creutzfeldt-Jakob disease: facts and uncertainties underlying the causal link between animal and human diseases

Following an outbreak of bovine spongiform encephalopathy (BSE) in dairy cows in the United Kingdom (UK), 153 definite and probable human cases of new variant Creutzfeldt-Jakob disease (nvCJD) have been reported, almost exclusively in the UK. Although exposure to the BSE agent is the most plausible interpretation for the occurrence of nvCJD, the causal link between the BSE prion and nvCJD is still debated. This review discusses the pros and cons of nvCJD as a separate nosographic entity, the scientific basis for a correlation between BSE and nvCJD, the validity of the current diagnostic criteria for CJD and nvCJD, the contribution of epidemiology to the detection of a causal relation between BSE and nvCJD, and the present and future directions of the epidemiological research on BSE, CJD and nvCJD.

Giant axon and neurofilament accumulation in Charcot-Marie-Tooth disease type 2E

The axonal type 2 Charcot-Marie-Tooth disease (CMT2) is phenotypically poorly characterized. Here the authors report a family with a Pro22Ser mutation in the neurofilament-light gene (NF-L; CMT2E) manifesting electrophysiologically as the demyelinating type 1 CMT (CMT1) and pathologically as an axonopathy with giant axons and accumulation of disorganized NF. NF-L should be investigated in CMT2 as well as in CMT1 not associated with the usual genes PMP22, Cx32, and P0.

Charcot-Marie-Tooth disease with giant axons: a clinicopathological and genetic entity

The authors report an Italian family with autosomal-dominant Charcot-Marie-Tooth disease (CMT) in which there were giant axons in the sural nerve biopsy. Linkage to the known CMT2 loci (CMT2A, CMT2B, CMT2D, CMT2F) and mutations in the known CMT2 genes (Cx32, MPZ, NEFL), GAN, NEFM, and CMT1A duplication/HNPP deletion were excluded. This family with CMT and giant axons has a pathologic and genetic entity distinct from classic CMT.

MELAS: clinical phenotype and morphological brain abnormalities

We describe the clinical and neuropathological findings of three unrelated autopsy cases of MELAS harboring the A3243G transition in the mitochondrial DNA (mtDNA). Using immunohistochemical techniques, we studied the expression of several subunits of the respiratory chain in various brain regions from the same cases. In all three cases there was a reduced immunocytochemical staining for mtDNA-encoded subunits of the respiratory chain, confirming the presence of a defective mitochondrial protein synthesis in this disease. Mitochondrial abnormalities were mostly confined to multiple areas of different size and shape, in agreement with the focal character of the brain pathology in MELAS, and were most prominent in the cerebral cortex, providing a morphological contribution to the explanation of the cognitive regression of the patients. Immunoreactivity for mtDNA-encoded subunits was reduced in the walls of many pial and intracerebral arterioles of different brain regions but there was no clear correlation between territories of affected vessels and distribution of the histological and immunohistochemical lesions. Cerebral focal lesions in MELAS might have a metabolic nature and several pathogenetic mechanisms might be involved in the genesis of stroke-like episodes when there is a local increased ATP demand.

Features of cell death in brain and liver, the target tissues of progressive neuronal degeneration of childhood with liver disease (Alpers-Huttenlocher disease)

Alpers-Huttenlocher disease (AHD) is a rare encephalopathy of infancy and childhood characterized by myoclonic seizures and progressive neurological deterioration, usually associated with signs and symptoms of liver dysfunction. There is no biological marker of the disease, and ultimate diagnosis still relies on pathological examination. Features of clinical progression and pathological findings suggest AHD to be secondary to a genetically determined disorder of mitochondrial function. We report on four AHD patients and focus on their pathological features in brain, liver and muscle. Liver and muscle biopsy specimens were examined using histochemical markers of the oxidative pathways, probes to immunodetect molecules of the apoptotic cascades and electron microscopy. In liver (but not in muscle) biopsy samples, activated caspases were detected by immunohistochemistry: foci of caspase-9-positive cells were seen in a child affected with chronic, progressive fibrosis. In an 18-year-old boy, who suffered from valproic acid-associated acute hepatitis, caspase-3 cells were clustered among the necrotic foci and the foamy cells. In both patients electron microscopy revealed apoptotic nuclei. Normal muscle biopsy specimens were observed in two children, 2 and 8 years-old respectively; in the 18-year-old patient cytochrome oxidase-negative fibers as well as ultrastructural findings of mitochondrial abnormalities were observed. In no patient was there biochemical evidence of impaired oxidative metabolism. Neuropathological examination of the brains of two patients (13 months and 19 years old, respectively) showed focal distribution of the lesions affecting the telencephalic cortex and, to a lesser extent, subcortical gray nuclei. Along with the necrotizing lesions, characterized by neuronal loss, neuropil microcysts and newly formed vessels, we also observed acutely shrunken neurons and features of apoptotic cell death in the cerebral cortex only. Severe neuronal loss without necrotizing features was observed in the cerebellar cortex. The presence of both anoxic and apoptotic nuclei in brain and liver, the target tissues of the disease, is consistent with the hypothesis that abnormal activation of mitochondrion-related cell death pathways might be involved in the pathogenesis of AHD.

Hereditary neuropathy with liability to pressure palsies: electrophysiological and genetic study of a family with carpal tunnel syndrome as only clinical manifestation

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disease characterized by recurrent sensory or motor manifestations. The molecular basis of HNPP is a deletion on chromosome 17p11.2. We studied a family (father, 61 years; mother, 55 years; 6 children of mean age 25.3 years) showing symptoms of carpal tunnel syndrome in 4 members (the parents and 2 sons). No one of them reported episodes of nerve palsy. In all the patients, except the mother and the younger son, electrophysiologic evaluation showed a sensorimotor polyneuropathy with delayed sensorimotor latencies. Genetic analysis was carried out in the parents and the eldest son. The 17p11.2 deletion was detected in the father and son, indicating paternal transmission of the disease. Clinical manifestations of HNPP may be atypical. Sometimes there is no history of acute nerve palsy, as in this family. For this reason, the frequence of HNPP might be underestimated. Electrophysiological examination is of great importance for the diagnosis of HNPP. Genetic analysis is a rapid and reliable diagnostic tool that can be combined with simplified electrophysiological examination, avoiding the need for nerve biopsy. In conclusion, the diagnosis of HNPP should be invoked in early onset entrapment neuropathies.

Peripheral and segmental spinal abnormalities of median and ulnar somatosensory evoked potentials in Hirayama's disease

OBJECTIVES

To investigate the origin of juvenile muscle atrophy of the upper limbs (Hirayama's disease, a type of cervical myelopathy of unknown origin).

SUBJECTS

Eight male patients were studied; data from 10 normal men were used as control.

METHODS

Median and ulnar nerve somatosensory evoked potentials (SEP) were recorded. Brachial plexus potentials at Erb's point (EP), dorsal horn responses (N13), and subcortical (P14) and cortical potentials (N20) were evaluated. Tibial nerve SEP and motor evoked potentials (MEP) were also recorded from scalp and spinal sites to assess posterior column and pyramidal tract conduction, respectively.

RESULTS

The most important SEP findings were: a very substantial attenuation of both the EP potentials and the N13 spinal responses; normal amplitude of the scalp N20; and normal latency of the individual peaks (EP-N9-N13-P14-N20). Although both nerves were involved, abnormalities in response to median nerve stimulation were more significant than those in response to ulnar nerve stimulation. There was little correlation between the degree of alterations observed and the clinical state. Latencies of both spinal and cortical potentials were normal following tibial nerve stimulation. The mean latency of cervical MEP and the central conduction time from the thenar eminence were slightly but significantly longer in patients than in controls.

CONCLUSIONS

The findings support the hypothesis that this disease, which is clinically defined as a focal spinal muscle atrophy of the upper limb, may also involve the sensory system; if traumatic injury caused by stretching plays a role in the pathogenesis, the damage cannot be confined to the anterior horn of the spinal cord.

Transcription factors c-Jun/activator protein-1 and nuclear factor-kappa B in oxidative stress response in mitochondrial diseases

Mitochondrial dysfunction leads to oxygen free radical (ROS) generation with consequent oxidative stress and cellular damage. Recently, activation of the cellular antioxidant system and apoptosis were demonstrated in skeletal muscle fibres from patients with mitochondrial diseases, but the underlying mechanisms remain unknown. Hydrogen peroxide, a by-product of ROS generation, is a chemical inducer of gene expression able to activate apoptosis and to promote the antioxidant response through the activation of nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1) transcription factor. Using immunohistochemistry and confocal microscopy, we evaluated the expression of NF-kappaB and AP-1 in muscle biopsies from patients with mitochondrial disease. In addition, we examined the expression of factors involved in their activation, such as NF-kappaB inducing kinase (NIK) and phosphorylated Jun-N-terminal kinase (p-JNK). Most fibres with respiratory chain dysfunction displayed nuclear staining for activated c-Jun/AP-1, but not for NF-kappaB. The same fibres reacted for p-JNK. Only some ragged red fibres immunoreacted for NIK. These data suggest that AP-1 is involved in the oxidative stress response in muscle fibres from patients with mitochondrial disease.

Paired transcranial magnetic stimulation for the early diagnosis of corticobasal degeneration

OBJECTIVE

To investigate cortical excitability in patients with corticobasal degeneration (CBD) and to find a reliable diagnostic technique for differentiating CBD from Parkinson's disease (PD).

METHODS

Using a paired transcranial magnetic stimulation technique, we studied motor cortex excitability at rest in 6 patients with clinically probable CBD, 10 patients with PD, and 10 normal subjects. The recovery cycle of the motor evoked potentials was tested by delivering paired magnetic stimulation over the hand area of the motor cortex at interstimulus intervals (ISIs) from 1 to 17ms.

RESULTS

In patients with CBD, paired magnetic stimuli delivered at short ISIs invariably elicited enlarged test MEPs. At ISIs of 1-10ms, the conditioned test MEPs were significantly larger in patients with CBD than in control subjects; and at ISIs of 1, 2, 4, and 6ms,they were also larger in patients with CBD than in patients with PD. At the other ISIs tested, patients and control subjects had similar amplitude conditioned test responses.

CONCLUSIONS

Our findings suggest that the unusual clinical manifestations of CBD might arise partly from motor cortex disinhibition. Paired magnetic stimulation could be a useful diagnostic test particularly in the early stages of the disease.

Hepatitis C virus infection and myositis: a virus localization study

We report a case of myositis associated with chronic hepatitis C virus infection. Muscle biopsy and immunohistochemistry showed perifascicular atrophy, few necrotic and regenerating fibres, scarce perivascular infiltrates, deposits of immunoglobulin G, C3, fibrinogen and MAC in muscle vessel walls, and non-uniform expression of major histocompatibility complex-I antigens among muscle fibres. Hepatitis C virus NS3 antigen and hepatitis C virus RNA were detected in infiltrating cells but not within muscle fibres or endothelial cells. Our findings suggest that humoral-mediated immune mechanisms, not directly related to hepatitis C virus infection of muscle structures, may sustain the local inflammatory reaction in this patient.

Myelin oligodendrocyte glycoprotein polymorphisms and multiple sclerosis

A detailed analysis of the coding sequences of myelin oligodendrocyte glycoprotei (MOG) gene was performed in multiple sclerosis (MS) patients and in control individuals and three new polymorphisms are described: T636C, nt 571+77C-->T (IVS 4), and nt 710-44A-->G (IVS 6). Screening studies demonstrated that T636C was present in three MS patients and in no control individual and that polymorphisms nt 571+77C-->T (IVS 4), and nt 710-44A-->G (IVS 6), were present with no significant frequency differences in MS patients and control individuals. No mutations were found after sequencing the coding sequences of the extracellular domain of MOG gene in 20 MS patients and 20 control individuals. Screening studies were also performed for known polymorphisms: G15A, Val142Leu, nt 571+68A-->G (IVS 4), and 571+92C-->G (IVS 4). Polymorphism Val 142 Leu, which is linked to nt 571+68A-->G (IVS 4), resulted under-represented in MS patients.

Prevalence of dementia and apolipoprotein e genotype distribution in the elderly of buttapietra, verona province, Italy

We investigated the prevalence of dementia and the apolipoprotein E (APOE) genotype distribution in the elderly of Buttapietra, a village near Verona, Italy. All residents over the age of 74 (n = 238), including those who were institutionalized, were studied using a direct-contact, single-phase design. The overall prevalence of dementia, clinically defined by DSM-III-R criteria, was 15.8 cases per 100 population, with age-specific figures increasing steeply with advancing age in both sexes. Alzheimer's disease (AD) was the most frequent dementing disorder (43%). APOE genotyping was determined after DNA amplification by restriction isotyping. We found that the epsilon4 allele and the epsilon3/epsilon4 genotype were associated with all types of dementia, although only the association of epsilon3/epsilon4 with AD reached statistical significance (odds ratio 4.5, 95% confidence interval 1.3-16.1). However, as reported in other Mediterranean countries, the frequency of the epsilon4 allele in our population was low (8.9%), suggesting that the population-attributable risk for AD, at least for elderly individuals (> or =75 years), could be small.

pH-dependent prion protein conformation in classical Creutzfeldt-Jakob disease

In transmissible spongiform encephalopathies, the cellular prion protein (PrP(C)) undergoes a conformational change from a prevailing alpha-helical structure to a beta-sheet-rich, protease-resistant isoform, termed PrP(Sc). PrP(C) has two characteristics: a high affinity for Cu(2+) and a strong pH-dependent conformation. Lines of evidence indicate that PrP(Sc) conformation is dependent on copper and that acidic conditions facilitate the conversion of PrP(C) --> PrP(Sc). In each species, PrP(Sc) exists in multiple conformations, which are associated with different prion strains. In sporadic Creutzfeldt-Jakob disease (sCJD), different biochemical types of PrP(Sc) have been identified according to the size of the protease-resistant fragments, patterns of glycosylation, and the metal-ion occupancy. Based on the site of cleavage produced by proteinase K, we investigated the conformational stability of PrP(Sc) under acidic, neutral, and basic conditions in 42 sCJD subjects. Our study shows that only one type of sCJD PrP(Sc), associated with the classical form, shows a pH-dependent conformation, whereas two other biochemical PrP(Sc) types, detected in distinct sCJD phenotypes, are unaffected by pH variations. This novel approach demonstrates the presence of three types of PrP(Sc) in sCJD.