Radon Exposure and Neurodegenerative Disease

Background: To carry out a systematic review of scientific literature about the association between radon exposure and neurodegenerative diseases. Methods: We performed a bibliographic search in the following databases: Pub med (Medline), Cochrane, BioMed Central and Web of Science. We collected the data by following a predetermined search strategy in which several terms werecombined. After an initial search, 77 articles were obtained.10 of which fulfilled the inclusion criteria. Five of these 10 studies were related to multiple sclerosis (MS), 2 were about motor neuron diseases (MND), in particular amyotrophic lateral sclerosis (ALS) and 3 were related to both Alzheimer's disease (AD) and Parkinson's disease (PD). Results: The majority of the included articles, suggested a possible association between radon exposure and a subsequent development of neurodegenerative diseases. Some of the studies that obtained statistically significant resultsrevealed a possible association between radon exposure and an increase in MS prevalence. Furthermore, it was also suggested that radon exposure increases MND and AD mortality. Regarding AD and PD, it was observed that certainde cay products of radon-222 (²²²Rn), specifically polonium-210 (²¹⁰Po) and bismuth-210 (²¹⁰Bi), present a characteristic distributionpattern within the brain anatomy. However, the study with the highest scientific evidence included in this review, which investigated a possible association between the concentration of residential radon gas and the MS incidence, revealed no significant results. Conclusions: It cannot be concluded, although it is observed, that there is a possible causal association between radon exposure and neurodegenerative diseases. Most of the available studies are ecological so, studies of higher statistical evidence are needed to establish a causal relationship. Further research is needed on this topic.

Geographic Analysis of Motor Neuron Disease Mortality and Heavy Metals Released to Rivers in Spain

The etiology of motor neuron disease (MND) is still unknown. The aims of this study were to: (1) analyze MND mortality at a fine-grained level; and (2) explore associations of MND and heavy metals released into Spanish river basins. MND deaths were extracted from the Spanish nationwide mortality registry (2007⁻2016). Standardized mortality ratios (SMRs) for MND were estimated at a municipal level. Sites that emitted quantities of heavy metals above the regulatory thresholds were obtained from the European Pollutant Release and Transfer Register database (2007⁻2015). The relative risks for non-exposed and exposed municipalities (considering a downstream 20 km river section) by type of heavy metal were analyzed using a log-linear model. SMRs were significantly higher in central and northern municipalities. SMRs were 1.14 (1.10⁻1.17) higher in areas exposed to heavy metals than in non-exposed areas: 0.95 (0.92⁻0.96). Considering the different metals, we found the following increased MND death risks in exposed areas: 20.9% higher risk for lead, 20.0% for zinc, 16.7% for arsenic, 15.7% for chromium, 15.4% for cadmium, 12.7% for copper, and 12.4% for mercury. This study provides associations between MND death risk and heavy metals in exposed municipalities. Further studies investigating heavy metal exposure are needed to progress in MND understanding.

Motor neuron disease mortality and lifetime petrol lead exposure: Evidence from national age-specific and state-level age-standardized death rates in Australia

BACKGROUND

The age standardized death rate from motor neuron disease (MND) for persons 40-84 years of age in the Australian States of New South Wales, Victoria, and Queensland increased dramatically from 1958 to 2013. Nationally, age-specific MND death rates also increased over this time period, but the rate of the rise varied considerably by age-group. The historic use of lead (Pb) additives in Australian petrol is a candidate explanation for these trends in MND mortality (International Classification of Disease (ICD)-10 G12.2).

METHODS

Leveraging temporal and spatial variation in petrol lead exposure risk resulting from the slow rise and rapid phase-out of lead as a constituent in gasoline in Australia, we analyze relationships between (1) national age-specific MND death rates in Australia and age-specific lifetime petrol lead exposure, (2) annual between-age dispersions in age-specific MND death rates and age-specific lifetime petrol lead exposure; and (3) state-level age-standardized MND death rates as a function of age-weighted lifetime petrol lead exposure.

RESULTS

Other things held equal, we find that a one percent increase in lifetime petrol lead exposure increases the MND death rate by about one-third of one percent in both national age-specific and state-level age-standardized models of MND mortality. Lending support to the supposition that lead exposure is a driver of MND mortality risk, we find that the annual between-age group standard deviation in age-specific MND death rates is strongly correlated with the between-age standard deviation in age-specific lifetime petrol lead exposure.

CONCLUSION

Legacy petrol lead emissions are associated with age-specific MND death rates as well as state-level age-standardized MND death rates in Australia. Results indicate that we are approaching peak lead exposure-attributable MND mortality.

Effectiveness of wetting method for control of konzo and reduction of cyanide poisoning by removal of cyanogens from cassava flour

BACKGROUND

Konzo is an irreversible paralysis of the legs that occurs mainly among children and young women in remote villages in tropical Africa and is associated with a monotonous diet of bitter cassava. Konzo was discovered in 1938 by Dr. G. Trolli in the Democratic Republic of Congo (DRC). It also occurs in Mozambique, Tanzania, Cameroon, Central African Republic, and Angola. It was first controlled in Kay Kalenge village, DRC, in 2011 with the use of a wetting method to remove cyanogens from cassava flour. Fourteen months later, another visit was made to Kay Kalenge.

OBJECTIVE

To determine whether Kay Kalenge women were still using the wetting method, whether there were new cases of konzo, and whether the wetting method had spread to other villages.

METHODS

Meetings were held with chiefs, leaders, and heads of mothers' groups, women from 30 households were interviewed, and three nearby villages were visited. Total cyanide and thiocyanate were analyzed in cassava flour and urine samples, respectively.

RESULTS

The women in Kay Kalenge village still used the wetting method. There were no new cases of konzo. The mean cyanide content of the flour samples was 9 ppm, and no child had a mean urinary thiocyanate content greater than 350 micromol/L. The use of the wetting method had spread naturally to three adjacent villages.

CONCLUSIONS

The wetting method has been readily accepted by rural women as a simple and useful method to control konzo by removing cyanide from cassava flour, and its use has spread to nearby villages. The wetting method should be promoted by health authorities to control konzo and reduce cyanide poisoning from high-cyanide cassava flour.

On the biomarkers and mechanisms of konzo, a distinct upper motor neuron disease associated with food (cassava) cyanogenic exposure

Konzo is a self-limiting central motor-system disease associated with food dependency on cassava and low dietary intake of sulfur amino acids (SAA). Under conditions of SAA-deficiency, ingested cassava cyanogens yield metabolites that include thiocyanate and cyanate, a protein-carbamoylating agent. We studied the physical and biochemical modifications of rat serum and spinal cord proteins arising from intoxication of young adult rats with 50-200mg/kg linamarin, or 200mg/kg sodium cyanate (NaOCN), or vehicle (saline) and fed either a normal amino acid- or SAA-deficient diet for up to 2 weeks. Animals under SAA-deficient diet and treatment with linamarin or NaOCN developed hind limb tremors or motor weakness, respectively. LC/MS-MS analysis revealed differential albumin carbamoylation in animals treated with NaOCN, vs. linamarin/SAA-deficient diet, or vehicle. 2D-DIGE and MALDI-TOF/MS-MS analysis of the spinal cord proteome showed differential expression of proteins involved in oxidative mechanisms (e.g. peroxiredoxin 6), endocytic vesicular trafficking (e.g. dynamin 1), protein folding (e.g. protein disulfide isomerase), and maintenance of the cytoskeleton integrity (e.g. α-spectrin). Studies are needed to elucidate the role of the aformentioned modifications in the pathogenesis of cassava-associated motor-system disease.

Impaired neuromotor functions in hospital laboratory workers exposed to low levels of organic solvents

Solvents are ubiquitous in industrial societies in a wide range of processes, and long-term exposure to these organic compounds may impair neuromotor functions such as equilibrium function. However, there is limited knowledge of effects on posture and gaze control after organic solvent exposures below workplace threshold limit values. The aim of this study was to evaluate the consequences of low-level co-exposure to organic solvents on balance and gaze control in hospital laboratory workers. Twelve hospital laboratory female subjects mainly exposed to toluene and ethanol, with median exposure duration of 24 years, and 12 non-exposed female controls were submitted to posturography and oculomotricity testings including sensory organization and motor control tests and saccade and smooth pursuit tests. Although current measured exposure values to toluene and ethanol were much below workplace threshold limit values (current median exposure levels of 32.5 mg/cubic meter and 39.9 mg/cubic meter, respectively), exposed workers displayed a weaker balance and a less precise gaze control. They presented, on the one hand, a reduced ability to resolve sensorial conflict situations compared to controls, particularly when situations were managed by the vestibular information, and, on the other hand, longer saccadic reaction time. Organic solvents might have an impact on vestibular pathways involved in postural control and exert a depressant central pathway effect implicated in the management of oculomotor response. Evaluating balance control in sensory conflicting situations and saccadic reaction time is proposed as a way to reveal subclinical neurotoxicological effects due to low-level exposure to organic solvents.

Excitotoxic motoneuron disease in chick embryo evolves with autophagic neurodegeneration and deregulation of neuromuscular innervation

In the chick embryo, in ovo application of NMDA from embryonic day (E) 5 to E9 results in selective damage to spinal cord motoneurons (MNs) that undergo a long-lasting degenerative process without immediate cell death. This contrasts with a single application of NMDA on E8, or later, which induces massive necrosis of the whole spinal cord. Chronic MN degeneration after NMDA implies transient incompetence to develop programmed cell death, altered protein processing within secretory pathways, and late activation of autophagy. Chronic NMDA treatment also results in an enlargement of thapsigargin-sensitive Ca(2+) stores. In particular MN pools, such as sartorius-innervating MNs, the neuropeptide CGRP is accumulated in somas, peripheral axons and neuromuscular junctions after chronic NMDA treatment, but not in embryos paralyzed by chronic administration of curare. Intramuscular axonal branching is also altered severely after NMDA: it usually increases, but in some cases a marked reduction can also be observed. Moreover, innervated muscle postsynaptic sites increase by NMDA, but to a lesser extent than by curare. Because some of these results show interesting homologies with MN pathology in human sporadic ALS, the model presented here provides a valuable tool for advancing in the understanding of some cellular and molecular processes particularly involved in this disease.

ALS and mercury intoxication: A relationship?

We report the case of an 81-year-old woman in whom clinical signs and features of electromyographic activity patterns were consistent with amyotrophic lateral sclerosis (ALS). Increased blood level and massive urinary excretion of mercury proved mercury intoxication. Despite a chelation treatment with Meso 2-3 dimercaptosuccininc acid (DMSA), she died after 17 months. The pathophysiology of sporadic ALS remains unclear. However, the role of environmental factors has been suggested. Among some environmental factors, exposure to heavy metals has been considered and ALS cases consecutive to occupational intoxication and accidental injection of mercury have been reported. Although no autopsy was performed, we discuss the role of mercury intoxication in the occurrence of ALS in our case, considering the results of experimental studies on the toxicity of mercury for motor neuron.

Downregulation of glutaredoxin but not glutathione loss leads to mitochondrial dysfunction in female mice CNS: Implications in excitotoxicity

Oxidative stress, excitotoxicity and mitochondrial dysfunction play synergistic roles in neurodegeneration. Maintenance of thiol homeostasis is important for normal mitochondrial function and dysregulation of protein thiol homeostasis by oxidative stress leads to mitochondrial dysfunction and neurodegeneration. We examined the critical roles played by the antioxidant, non-protein thiol, glutathione and related enzyme, glutaredoxin in maintaining mitochondrial function during excitotoxicity caused by beta-N-oxalyl amino-L-alanine (L-BOAA), the causative factor of neurolathyrism, a motor neuron disease involving the pyramidal system. L-BOAA causes loss of GSH and inhibition of mitochondrial complex I in lumbosacral cord of male mice through oxidation of thiol groups, while female mice are resistant. Reducing GSH levels in female mice CNS by pretreatment with diethyl maleate or L-propargyl glycine did not result in inhibition of complex I activity, unlike male mice. Further, treatment of female mice depleted of GSH with L-BOAA did not induce inhibition of complex I indicating that GSH levels were not critical for maintaining complex I activity in female mice unlike their male counterpart. Glutaredoxin, a thiol disulfide oxidoreductase helps maintain redox status of proteins and downregulation of glutaredoxin results in loss of mitochondrial complex I activity. Female mice express higher levels of glutaredoxin in certain CNS regions and downregulation of glutaredoxin using antisense oligonucleotides sensitizes them to L-BOAA toxicity seen as mitochondrial complex I loss. Ovariectomy downregulates glutaredoxin and renders female mice vulnerable to L-BOAA toxicity as evidenced by activation of AP1, loss of GSH and complex I activity indicating the important role of glutaredoxin in neuroprotection. Estrogen protects against mitochondrial dysfunction caused by excitotoxicity by maintaining cellular redox status through higher constitutive expression of glutaredoxin in the CNS. Therapeutic interventions designed to upregulate glutaredoxin may offer neuroprotection against excitotoxicity in motor neurons.

Statins, Neuromuscular Degenerative Disease and an Amyotrophic Lateral Sclerosis-Like Syndrome

BACKGROUND

The WHO Foundation Collaborating Centre for International Drug Monitoring (Uppsala Monitoring Centre [UMC]) has received many individual case safety reports (ICSRs) associating HMG-CoA reductase inhibitor drug (statin) use with the occurrence of muscle damage, including rhabdomyolysis, and also peripheral neuropathy. A new signal has now appeared of disproportionally high reporting of upper motor neurone lesions.

AIM AND SCOPE

The aim of this paper is to present the upper motor neurone lesion cases, with other evidence, as a signal of a relationship between statins and an amyotrophic lateral sclerosis (ALS)-like syndrome. The paper also presents some arguments for considering that a spectrum of severe neuromuscular damage may be associated with statin use, albeit rarely. The paper does not do more than raise the signal for further work and analysis of what must be regarded as a potentially very serious and perhaps avoidable or reversible adverse reaction, though it also suggests action to be taken if an ALS-like syndrome should occur in a patient using statins.

METHODS

The 43 reports accounting for the disproportional reports in Vigibase (the database of the WHO Programme for International Drug Monitoring) are summarised and analysed for the diagnosis of an ALS-like syndrome. The issues of data quality and potential reporting bias are considered.

RESULTS

'Upper motor neurone lesion' is a rare adverse event reported in relationship to drugs in Vigibase (a database containing nearly 4 million ICSRs). Of the total of 172 ICSRs on this reported term, 43 were related to statins, of which 40 were considered further: all but one case was reported as ALS. In 34/40 reports a statin was the sole reported suspected drug. The diagnostic criteria were variable, and seven of the statin cases also had features of peripheral neuropathy. Of a total of 5534 ICSRs of peripheral neuropathy related to any drug in Vigibase, 547 were on statins. The disproportional reporting of statins and upper motor neurone lesion persisted after age stratification, and such disproportionality was not seen for statins and Parkinson's disease, Alzheimer's disease, extrapyramidal disorders, or multiple sclerosis-like syndromes.

DISCUSSION

Because the cases were sometimes atypical we propose the use of the term 'ALS-like syndrome' and speculate whether this is part of a spectrum of rare neuromuscular damage. The diagnosis of ALS is often problematic, and the insidiousness and chronicity of the disease make causality with a drug difficult to assess. The disproportionally high reporting makes this an important signal nevertheless, since ALS is serious clinically and statins are so widely used. Wide use of the statins also makes a chance finding more probable, but is unlikely to cause disproportional reporting when there are no obvious biases identified.

CONCLUSION

We emphasise the rarity of this possible association, and also the need for further study to establish whether a causal relationship exists. We do advocate that trial discontinuation of a statin should be considered in patients with serious neuromuscular disease such as the ALS-like syndrome, given the poor prognosis and a possibility that progression of the disease may be halted or even reversed.

Motor dominant neuropathy induced by adjuvant therapy with adriamycin and cyclophosphamide followed by dose-dense paclitaxel in a breast cancer patient

A 38-year-old woman underwent mastectomy and axillary lymph node dissection for invasive ductal carcinoma with multiple lymph node involvement. The patient received adriamycin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) followed by weekly paclitaxel 80 mg/m(2) (without interruption) as adjuvant treatment. After receiving ten courses of paclitaxel, the patient developed motor neuropathy, with difficulty in ascending stairs and rising from a chair. A nerve conduction study demonstrated impairment of bilateral peroneal nerve function, although the sural sensory nerves were intact. After 2 weeks of withholding paclitaxel treatment, the motor neuropathy was alleviated and the scheduled doses were completed. A pharmacokinetic study of paclitaxel showed the possibility of elimination delay at the last infusion. We suggest that a dose-dense schedule of paclitaxel may be a significant risk factor for this kind of motor neuropathy.

Levodopa, motor fluctuations and dyskinesia in Parkinson’s disease

Parkinson's disease (PD) is one of the most frequent, chronic, progressive degenerative disorders of the CNS, characterised by altered neurotransmission of dopamine in the basal ganglia. This may result in disturbances of movement, mobility and posture symptoms, all of which cause severe disability in PD patients. There is no cure for PD. Current treatment approaches aim at symptomatic improvement with a balance of the altered neurotransmission, particularly in striatal dopaminergic neurons. Levodopa, the metabolic precursor of active dopamine, is the most effective compound in the drug treatment of PD. However, chronic exposure to levodopa and related dopaminergic agents supports an onset of movement behaviour fluctuations and dyskinesia in the long term. Dyskinesia is unwanted, sometimes excessive and causes abnormal facial, body and limb movements that appear in many PD patients who are often dependent on the overall dosage of dopaminergic substitution. This complication of anti-Parkinsonian drug therapy supports disability and reduces quality of life in PD patients and their caregivers. This review focuses on the major clinical features and knowledge on the aetiology of these treatment-associated, long-term side effects of dopaminergic drug treatment in PD. It also gives an overview of existing and potential future treatment-strategies for the management of these troublesome treatment complications that affect motor behaviour in PD patients.

Geographic isolates of atypical Parkinsonism and tauopathy in the tropics: Possible synergy of neurotoxins

Over the last 60 years an abnormally high prevalence of atypical Parkinsonism has been reported in 5 different geographic isolates. It was first described on Guam, later in New Guinea and in the Kii peninsula, on Guadeloupe, and in New Caledonia. We investigated the phenotype of atypical Parkinsonism in three of these foci and observed several similarities with dementia in most and amyotrophic lateral sclerosis in some. This disappearance of this disease in two places--Guam and New Guinea--suggested an environmental origin which has not been clarified before the disease ended. The exposure to annonaceae acetogenins and/or rotenone has been documented in four of these places, and experimental studies in animals demonstrated annonaceae acetogenins neurotoxicity, which is similar to rotenone neurotoxicity. Simultaneous exposure to acetogenins and rotenone could produce a synergistic toxicity on neurons.

Pharmacological induction of heat-shock proteins alleviates polyglutamine-mediated motor neuron disease

Spinal and bulbar muscular atrophy (SBMA) is an adult-onset motor neuron disease caused by the expansion of a trinucleotide CAG repeat encoding the polyglutamine tract in the first exon of the androgen receptor gene (AR). The pathogenic, polyglutamine-expanded AR protein accumulates in the cell nucleus in a ligand-dependent manner and inhibits transcription by interfering with transcriptional factors and coactivators. Heat-shock proteins (HSPs) are stress-induced chaperones that facilitate the refolding and, thus, the degradation of abnormal proteins. Geranylgeranylacetone (GGA), a nontoxic antiulcer drug, has been shown to potently induce HSP expression in various tissues, including the central nervous system. In a cell model of SBMA, GGA increased the levels of Hsp70, Hsp90, and Hsp105 and inhibited cell death and the accumulation of pathogenic AR. Oral administration of GGA also up-regulated the expression of HSPs in the central nervous system of SBMA-transgenic mice and suppressed nuclear accumulation of the pathogenic AR protein, resulting in amelioration of polyglutamine-dependent neuromuscular phenotypes. These observations suggest that, although a high dose appears to be needed for clinical effects, oral GGA administration is a safe and promising therapeutic candidate for polyglutamine-mediated neurodegenerative diseases, including SBMA.

Motor neuron disease and optic neuropathy after acute exposure to a methanol-containing solvent mixture

A 34-years-old floor-layer developed optic neuropathy and motor neuron disease after being accidentally exposed to a solvent mixture containing methanol and other substances. Optic neuropathy is a complication of methanol poisoning, but the onset of a motor neuron disorder resembling amyotrophic lateral sclerosis after the exposure to these substances has not been previously described. The temporal onset of the clinical symptoms, biological plausibility, young age of the patient and absence of neurological disorders in the family history raises suspicion of a possible causative relationship.

Protective effect of amifostine against cisplatin-induced motor neuropathy in rat

Cisplatin (CDDP) is a potent anticancer drug. Neurotoxicity is one of the most important dose-limiting toxicity of CDDP. We investigated the role of amifostine in the protection against CDDP-induced neurotoxicity especially on the motor nerves. All experiments were conducted on female Wistar albino rats. Animals were randomly assigned to two groups, each including six rats. Group A received CDDP plus amifostine and Group B received CDDP only. Electroneurography (ENG) was carried out in the beginning and at the end of 7 wk; then, the rats were sacrificed and the sciatic nerve was removed for histopathological examination. The mean initial latency was 2.4667 msn for group A and 2.44833 msn for group B. After 7 wk of treatment, the latency was 2.9167 for group A and 2.6333 for group B. The difference in latencies was not statistically significant. The amplitude was 11.7853 mV and 13.533 mV for groups A and B, respectively. After 7 wk of treatment, the amplitude was 9.400 mV and 9.000 mV, respectively. The decrease of amplitude in compound muscle action potential (CMAP) was 20% in the amifostine group and the decrease was 33% in the untreated group. The mean area of the CMAP in group A was 9.400 mVsn initially and 9.666 mVsn at the end of the treatment; there was a 0.3% increase despite CDDP treatment. In group B, the mean area of the CMAP was 13.816 mVsn initially and 11.857 mVsn at the end of the treatment; this corresponded to a statistically significant 14% decrease as a result of CDDP treatment. The ENG and histopathological studies showed that at the given dose and schedule CDDP-induced motor neuropathy and amifostine reduced this neuropathy both by protection of the amplitude and area of the CMAP in ENG studies and by sparing a larger number of nerve fibers.

Motor neuron involvement in a patient with long-term corticosteroid administration

An asthmatic patient with corticosteroid treatment for 45 years presented with slowly progressive limb muscle atrophy. His muscle symptoms were involved in four limbs and tongue, and deep tendon reflexes were exaggerated. Biopsied muscle pathology indicated the presence of neurogenic muscular atrophy in combination with corticosteroid myopathy. Furthermore, 8-hydroxy-deoxyguanosine (8-OH-dG) was prominently increased in mitochondrial and nuclear DNA. An aerobic exercise test demonstrated remarkable serum lactate elevation, which was attenuated by the administration of coenzyme Q10. These findings are consistent with the assumption that long-term corticosteroid administration potentially induces not only myopathy but also motor neuron involvement as in mitochondrial diseases.

A hypothetical mathematical construct explaining the mechanism of biological amplification in an experimental model utilizing picoTesla (PT) electromagnetic fields

We seek to answer the conundrum: What is the fundamental mechanism by which very weak, low frequency Electromagnetic fields influence biosystems? In considering the hydrophobicity of intramembranous protein (IMP) H-bonds which cross the phospholipid bilayer of plasma membranes, and the necessity for photonic recycling in cell surface interactions after dissipation of energetic states, present models lack structure and thermodynamic properties to maintain (DeltaE) sufficient energy sources necessary for amplifications by factors of 10(12). Even though one accepts that the ligand-receptor association alters the conformation of extracellular, extruding portions of IMP's at the cell surface, and that this change can be transmitted to the cytoplasm by the transmembranous helical segments by nonlinear vibrations of proteins with generation of soliton waves, one is still unable to account for repair and balanced function. Indeed, responses of critical molecules to certain magnetic field signals may include enhanced vibrational amplitudes, increased quanta of thermal energies and order inducing interactions. We may accept that microtrabecular reticulum-receptor is associated with actin filaments and ATP molecules which contribute to the activation of the cyclase enzyme system through piezoelectricity. Magnetic fields will pass through the membrane which sharply attenuates the electric field component of an EM field, due to its high impedance. Furthermore, EM oscillations are converted to mechanical vibrations; i.e., photon-phonon transduction, to induce molecular vibrations of frequencies specifically responsible for bioamplifications of weak triggers at the membrane surface, as well as GAP junctions. The hydrogen bonds of considerable importance are those in proteins (10(12)Hz) and DNA (10(11)Hz) and may be viewed as centers of EM radiation emission in the range from the mm microwaves to the far IR. However, classical electrodynamical theory does not yield a model for biomolecular resonant responses which are integrated over time and account for the connection between the phonon field and photons. Jacobson Resonance does supply an initial physical mechanism, as equivalencies in energy to that of Zeeman Resonance (i.e., zero-order magnetic resonance) and cyclotron resonance may be derived from the DeBroglie wave particle equation. For the first time, we view the introduction of Relativity Theory to biology in the expression, mc(2)=BvLq, where m is the mass of a particle in the 'box' or 'string' (molecule in a biosystem), c is the velocity of electromagnetic field in space, independent of its inertial frame of reference, B is the magnetic flux density,v is the velocity of the carrier or 'string' (a one or two dimensional 'box') in which the particle exists, L is its dimension (length) and q represents a unit charge q=1C, by defining electromotive force as energy per unit charge. Equivalencies suggest that qvBL is one of the fundamental expressions of energy of a charged wave-particle in magnetic fields, just as Zeeman and cyclotron resonance energy expressions, gbetaB and qhB/2pim, and is applicable to all charged particles (molecules in biological systems). There may exist spontaneous, independent and incessant interactions of magnetic vector B and particles in biosystems which exert Lorentz forces. Lorentz forces may be transmitted from EM field to gravitational field as a gravity wave which return to the phonon field as microgravitational fluctuations to therein produce quantum vibrational states that increase quanta of thermal energies integrated over time. This may account for the differential of 10(12) between photonic energy of ELF waves and the Boltzman energy kT. Recent data from in vivo controlled studies are included as empirical support for the various hypotheses presented.

Temocapril prevents motor neuron damage and upregulation of cyclooxygenase-II in glutamate-induced neurotoxicity

To examine the possible neuroprotective effect of temocapril, one kind of angiotensin-converting enzyme inhibitor, against glutamate-induced neurotoxicity, we analyzed the pharmacologic utility of temocapril in a post-natal organotypic culture model of motor neuron degeneration. Treatment with 10(-5) M of glutamate resulted in a motor neuron loss and decreased activity of choline acetyltransferase (ChAT). Cotreatment of 10(-5) M of glutamate and temocapril revealed protective effect on motor neuron death and decreased activity of ChAT. Next we performed reverse transcription-PCR analysis for cyclooxygenase-II (COX-II). COD-II mRNA was upregulated in glutamate-treated culture. Cotreatment with temocapril and glutamate inhibited upregulation of COX-II. Taken together, temocapril may have therapeutic potential for diseases which associate with upregulation of COX-II, in addition to its role in glutamate excitotoxicity.

Persistent konzo and cyanogen toxicity from cassava in northern Mozambique

We aimed to detect new cases of konzo and monitor cyanogen exposure from cassava flour in communities previously affected by konzo epidemics in Nampula Province, northern Mozambique. Other objectives were to detect subclinical upper motor neuron damage in schoolchildren and test a new kit to measure urinary thiocyanate concentration. In 1999 and 2000, we carried out active and passive case detection for konzo in Memba and Mogincual Districts. In July and October, 1999, we collected cassava flour from 30 houses in three communities and measured cyanogen concentrations with a picrate kit. In October 1999, we examined all schoolchildren in three communities for ankle clonus and measured urinary thiocyanate concentration in thirty schoolchildren in each of five communities with a picrate kit. We found 27 new cases of konzo in Mogincual District. Mean total cyanogen concentrations in cassava flour varied between both seasons and years, but were always high, ranging from 26 to 186 ppm. Very high mean levels at three sites in November 1998 and July 1999 were probably due to low rainfall in the 1997-1998 season. The proportion of schoolchildren with ankle clonus varied from 8 to 17%. The new picrate kit for urinary thiocyanate worked well; mean concentrations in schoolchildren ranged from 225 to 384 micromol x l(-1). Konzo and sub-clinical upper motor neuron damage persist in poor rural communities in northern Mozambique, associated with high cyanogen concentrations in cassava flour and high urinary thiocyanate concentrations in schoolchildren.

Onset of grip- and pinch-strength impairment after acute poisonings with organophosphate insecticides

The course of organophosphate-induced delayed polyneuropathy (OPIDP) in humans has not been quantitatively measured in epidemiologic studies. This study evaluated the association of acute OP poisonings with motor neurologic impairment. Hand grip and pinch strength were evaluated among 62 Nicaraguan men hospitalized for acute OP poisoning between 1992 and 1996; 39 cattle ranchers and fishermen who had never experienced pesticide poisoning were controls. Exposure categories were moderate and severe poisonings with neuropathic and non-neuropathic OPs. Strength was measured at hospital discharge and seven weeks after poisoning. Grip and pinch strength were impaired among all OP-poisoned subjects at both examinations, more noticeably among those poisoned with OPs with suspected neuropathic effects, methamidophos and chlorpyrifos. In those with severe poisonings with neuropathic OPs, impairments were more marked among intentional than among occupational poisonings. The performances of suicidal subjects worsened at the second examination, consistent with OPIDP. Early motor impairment at the time of hospital discharge is consistent with cholinergic depolarization blockade after acute poisoning. The persistence of deficits in motor strength in all severely poisoned patients regardless of pesticide type was unexpected, and may reflect persistent cholinergic blockade or intermediate syndrome, neuropathy, or a combination of these.

Long-lasting aberrant tubulovesicular membrane inclusions accumulate in developing motoneurons after a sublethal excitotoxic insult: a possible model for neuronal pathology in neurodegenerative disease

We have previously shown that chronic treatment of chick embryos [from embryonic day 5 (E5) to E9] with NMDA rescues spinal cord motoneurons (MNs) from programmed cell death. In this situation, MNs exhibit a reduced vulnerability to acute excitotoxic lesions and downregulate NMDA and AMPA-kainate receptors. Here, we report that this treatment results in long-lasting sublethal structural changes in MNs. In Nissl-stained sections from the spinal cord of NMDA-treated embryos, MNs display an area adjacent to an eccentrically positioned nucleus in which basophilia is excluded. Ultrastructurally, MNs accumulate tubulovesicular structures surrounded by Golgi stacks. Thiamine pyrophosphatase but not acid phosphatase was detected inside the tubulovesicular structures, which are resistant to disruption by brefeldin A or monensin. Immunocytochemistry reveals changes in the content and distribution of calcitonin gene-related peptide, the KDEL receptor, the early endosomal marker EEA1, and the recycling endosome marker Rab11, indicating that a dysfunction in membrane trafficking and protein sorting occurs in these MNs. FM1-43, a marker of the endocytic pathway, strongly accumulates in MNs from isolated spinal cords after chronic NMDA treatment. Changes in the distribution of cystatin C and presenilin-1 and an accumulation of amyloid precursor protein and beta-amyloid product were also observed in NMDA-treated MNs. None of these alterations involve an interruption of MN-target (muscle) connections, as detected by the retrograde tracing of MNs with cholera toxin B subunit. These results demonstrate that chronic NMDA treatment induces severe changes in the motoneuronal endomembrane system that may be related to some neuropathological alterations described in human MN disease.

Vecuronium-associated axonal motor neuropathy: a variant of critical illness polyneuropathy?

Neuromuscular blocking agents are routinely used as an adjunct therapy for critically ill patients. Unlike many neuromuscular blocking agents, vecuronium does not cause significant histamine release, which may lead to bronchoconstriction. Due to a short duration of action and limited accumulation, vecuronium has been widely used. Prolonged ventilatory dependence due to persistent neuromuscular blockade has been reported in patients treated with vecuronium. We report a case of an 8-year-old girl who had a primarily motor axonopathy presenting with weakness after extended vecuronium administration with prolonged course of recovery. This primarily motor neuropathy with axonal features may be a variant of critical illness polyneuropathy, a rarely reported condition in pediatric patients.

Possible role of enhanced microtubule phosphorylation in dichlorvos induced delayed neurotoxicity in rat

The effect of a single subcutaneous dose of 200 mg/kg body weight dichlorvos on neuronal microtubule phosphorylation has been studied in rat following the development of organophosphate induced delayed neurotoxicity (OPIDN). Microtubule associated Ca2+/calmodulin dependent as well as cAMP dependent protein kinases were assayed. Dichlorvos administration led to a consistent increase in the activity of both the kinases at all post exposure intervals (7th, 15th and 21st day) as compared to that of controls. After in vitro phosphorylation using [gamma-32P]ATP, various proteins were resolved on one-dimensional 8% SDS-PAGE, stained with Coomassie Blue and autoradiographed. The amount of 32P incorporated was quantified by microdensitometry. Dichlorvos enhanced the phosphorylation of 55- and 280-kDa proteins. These two proteins were identified as tubulin and microtubule associated protein-2 (MAP-2) by immunoblotting. This study showed that dichlorvos induced hyperphosphorylation of tubulin and MAP-2 which in turn destabilizes microtubule assembly, and may ultimately result in axonal degeneration leading to dichlorvos induced delayed neurotoxicity.

Motor nervous pathway function is impaired after treatment of childhood acute lymphoblastic leukemia: a study with motor evoked potentials

BACKGROUND

The objective was to evaluate whether motor nervous pathways are affected when patients are treated for childhood acute lymphoblastic leukemia (ALL).

PROCEDURE

Thirty-two children with ALL were studied at the end of treatment by means of motor evoked potentials (MEPs) elicited by magnetic stimulation (MS) transcranially and peripherally and underwent a detailed neurological examination. Thirty-two healthy children matched with them for age, sex, and height served as a control group.

RESULTS

The latencies of the MEPs were significantly prolonged along the entire motor nervous pathway in the patients with ALL compared with the healthy controls, indicating demyelination in the thick motor fibres. The MEP amplitudes of the distal extremities elicited by stimulation at the brachial plexus and LV spinal level were significantly lowered in the patients treated for ALL, also indicating anatomical or functional loss of descending motor fibres and/or muscle fibres. The MEP amplitudes elicited by cortical MS showed wider variation and no clear abnormalities were found. Neurological signs and symptoms were common after treatment: 41% of the patients had depressed deep tendon reflexes, 31% had fine motor difficulties and 63% gross motor difficulties, and 34% had dysdiadochokinesia. The conduction delay within the peripheral nerve was related to the post-therapeutic interval after administration of vincristine and the lesions within the CNS to the number of injections of intrathecal methotrexate.

CONCLUSIONS

The present results show adverse effects of the ALL treatment on the entire motor nervous pathways. In our experience, the measurement of MEPs by MS provides an objective, painless, and practical tool for assessing the treatment-related neurotoxicity in both the CNS and the peripheral nerves. These disturbances in the motor nervous pathways at the end of treatment raise the question of the long-term effects of ALL treatment on the motor nerve tracts, and have led us to employ MEPs to study these effects in long-term survivors of ALL.

Glutamate enhances DNA fragmentation in cultured spinal motor neurons of rat

The role of glutamate in the mechanism of spinal motor neuron death is not fully understood. With addition of glutamate to primary culture of 11-day-old rat spinal cord, terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) positive nuclei were found in spinal large motor neurons from 24 h, and the number of TUNEL positive large motor neurons greatly increased at 48 h. In contrast, only a small number of large motor neurons became TUNEL positive at 48 h with addition of vehicle to the primary spinal cord culture. The present results show that excessive amount of glutamate enhances DNA fragmentation in developing large motor neuron of cultured spinal cord by involving in apoptotic process of the neurons.

Peripheral neuropathy in a turkey vulture with lead toxicosis

Clinical, electromyographic, and pathologic findings characteristic of lead toxicosis were detected in a turkey vulture (Cathartes aura). The bird had generalized lower motor neuron dysfunction that progressed over 5 days. Electromyography revealed diffuse denervation potentials and a presumed decrement in the sciatic-tibial nerve conduction velocity. Histologic examination of peripheral nerves obtained at necropsy revealed changes that could be compatible with lead-induced neuropathy. Lead toxicosis was confirmed by determination of blood lead concentrations. Lead toxicosis causing neurologic disorders in birds has been described. However, this report emphasizes the effects of lead on the peripheral nervous system and demonstrates the use of electromyography for diagnosis of peripheral neuropathy in birds.

Motor neuron degeneration due to aluminium deposition in the spinal cord: a light microscopical study

For a long time, aluminium has been considered as an indifferent element from a toxicological point of view. In recent years, it became clear that aluminium is a potential toxic agent in humans and has been implicated in the pathogenesis of several clinical disorders, such as dementia, respiratory tract disorders and allergic reactions. Chronic exposure to aluminium fumes, inhalation of aluminium and aluminium-oxide powder increase the risk to develop serious central nervous system pathology, in particular Alzheimer's disease and amyotrophic lateral sclerosis (ALS). In the present study, 3 experimental and 1 control group of rats were used to study the effects of aluminium on the central nervous system. Aluminium was injected intracisternally as a single dose (50 micrograms for group I, 100 micrograms for group II and 300 micrograms for group III) to the experimental groups (n = 5 in each group). The same dose was given at 3 months after the first injection to all groups. The control group (n = 5) was intracisternally given a physiological salt solution. Electromyography (EMG) was applied to the rats of the experimental groups. Rats were decapitated at 3 months after the second injections. Spinal cord samples from lumbar and cervical regions were removed and histological examination was performed. Light microscopical investigations revealed severe degeneration in motor neurons of the rats treated with 300 micrograms. Neurofibrillary tangle formation, chromatolysis and abnormal localization of the nuclei were found in swollen perikarya. Extreme loss of motor neurons with "ghost cell" appearance was found in that group. Sections of spinal cords of rats treated with lower doses of aluminium showed a moderate degree of motor neuron damage. EMGs of rats treated with the high dose of aluminium revealed severe acute denervation whereas treatment with lower doses resulted in moderate denervation. We conclude that aluminium may cause severe motor neuron damage in rat spinal cord resembling ALS.

[Motor neuropathy, putamen necrosis and optic nerve atrophy after acute methanol poisoning]

Optic neuropathy and putaminal necrosis are the most common sequellae of methanol poisoning. We report a case in a patient with a chronic motor neuro(no)pathy in addition to these neurological complications. Peripheral nerve and spinal cord disorders, related to methanol poisoning, are uncommon and probably underestimated.

Leukaemia inhibitory factor (LIF) production in a mouse model of spinal trauma

A model of spinal trauma was developed where spinal neurones of adult mice were exposed to the excitotoxic glutamate analogue beta-N-oxylamino-L-alanine (L-BOAA). After 24 h, the injured neurones received a single dose of [125I]-LIF at the same site of the spinal cord, and 2 h later, tissues were removed to assess the distribution of leukaemia inhibitory factor (LIF). There was a significant increase in LIF binding to the injured region of the spinal cord over saline controls, and this corresponded with a significant increase in LIF mRNA expression in the same region of the cord. There was a change in the expression of ciliary neurotrophic factor, but the expression of cardiotrophin-1 (CT-1) and the common receptor subunit LIF receptor beta (LIFRbeta) did not change after neurotoxin treatment. The results add to the evidence that LIF plays a significant role in the response of adult neuronal tissue to injury.

Selective involvement of large motor neurons in the spinal cord of rats treated with methylmercury

Mercury is thought to be a possible epidemiological factor for the pathogenesis of motor neuron disease, since it has been reported that metallic, inorganic and organic mercury causes a syndrome clinically resembling amyotrophic lateral sclerosis. We administered 10 mg/kg/day methylmercury chloride to adult rats for 10 consecutive days. The hind-limbs became flaccid and atrophic, and 14 out of the 34 rats had died by the 18th day after methylmercury treatment began. Light microscopical examination of the large motor neurons in the spinal anterior horn revealed cytoplasmic vacuolation and loss of Nissl substance on the 14th day, and neuronophagia appeared on the 16th day. On the 18th day, the loss of large motor neurons was almost complete, whereas small to medium-sized neurons were preserved. Silver acetate autometallography to detect mercury revealed the selective accumulation of mercury in the large motor neurons. These findings suggest that although a high dose is required, organic mercury can cause the definite loss of large spinal motor neurons in rats.

Development of degenerative muscle weakness by chronic administration of beta,beta'-iminodipropionitrile in the drinking water to rats: a model for motorneuropathy

Progressive muscle weakness accompanied by progressive muscle atrophy was investigated in rats administered beta,beta'-iminodipropionitrile (IDPN) chronically in the drinking water. Spontaneous running wheel activity declined slowly and reached a constant low level before postural muscle weakness was apparent. The rats being offered IDPN in the drinking water showed definite postural muscle weakness about 25 weeks after first being given IDPN, and muscle strength declined gradually throughout the remainder of the experiment (to 66 weeks). Flaccid paralysis became apparent in the hind limbs in the later stages of the experiment. Neurogenic muscle atrophy, measured by group atrophy of the muscle fibers, also progressed slowly, almost in parallel with the loss of muscle strength. At the end of the experiment, muscle weight of the gastrocnemius had decreased to about 20% that of control [F(2, 12) = 40.4, p < 0.05]. Plasma creatinine in the rats given IDPN in the drinking water for 66 weeks was significantly elevated over that of controls [F(2, 12) = 20.1, p < 0.05]. On the other hand, in rats given IDPN intraperitoneally, postural muscle weakness and muscle atrophy were less apparent, and plasma creatinine was normal. However, in these animals, abnormal behaviors, such as hyperexcitement, circling, and choreic movement (ECC syndrome), were apparent. These results suggest that the present model, which administers IDPN chronically in the drinking water ad lib and does not show involuntary movements and ECC syndrome, is of potential importance for investigation of chronic diseases of progressive muscle weakness with progressive muscle atrophy, and for assessing the efficacy of drugs and therapies for treating chronic neuromuscular diseases.

Effect of dietary supplementation with branched-chain amino acids on spontaneous motor activity and muscle function in beta,beta'-iminodipropionitrile-treated rats: a model for motorneuropathy

Beta,beta'-iminodipropionitrile (IDPN)-induced muscle weakness in rats is a model for motorneuropathy diseases. The effects of oral administration of branched-chain amino acids on the progression of muscle weakness and muscle atrophy induced by the administration of IDPN in the drinking water, were investigated in this study. The spontaneous motor activity of the animals, as measured with a running wheel, slowly declined after IDPN administration, reaching a steady and low level at approximately week 15. Progressive muscle weakness and muscle atrophy were observed beginning at approximately 15 weeks after the initiation of administration of IDPN. Administration of branched-chain amino acids (BCAA) as a dietary supplement did not improve the lowered spontaneous motor activity seen in IDPN animals, but it did significantly improve measures of postural weakness and muscle strength [range of F values (2, 24) = 4.1-9.5, p < 0.05]. Plasma creatinine of the IDPN-treated rats was markedly elevated, and BCAA administration also significantly suppressed this elevation [F(2, 24) = 41.2, p < 0.05]. Moreover, although BCAA in plasma were elevated in the rats administered BCAA [range of F values (2, 21) = 25.7-29.7, p < 0.05], skeletal muscle showed no differences (at the p < 0.05 level) in the amounts of BCAA, whether or not BCAA were administered. These data suggest that the BCAA taken up in the skeletal muscle were utilized in the muscle of motorneuropathic rats and improved muscle function, such as energy metabolism, and that the BCAA treatment is one important therapeutic approach for retarding the progression of muscle weakness seen in certain neuromuscular disorders.

An unusual axonal polyneuropathy induced by low-dose interferon alfa-2a

OBJECTIVES

To describe a patient who developed an unusual polyneuropathy after treatment with interferon alfa-2a for hepatitis C and to discuss issues related to diagnosis and pathogenesis.

DESIGN

Case report.

SETTING

Tertiary care center.

CASE

A 46-year-old man with chronic hepatitis C had acute onset of an axonal polyneuropathy with prominent small-fiber involvement shortly after completing a standard 6-month course of therapy with low-dose interferon alfa-2a.

MAIN OUTCOME AND RESULTS

Further interferon treatment for hepatitis C was discontinued.

CONCLUSION

Standard, low-dose interferon alfa-2a treatment can produce a persistent predominantly small-fiber polyneuropathy.

Sensorimotor neurotoxicity associated with high-dose deferoxamine treatment

PURPOSE

We report a reversible sensorimotor neurotixicity that developed in two beta-thalassemic patients treated with high-dose deferoxamine (DFO) for iron overload.

METHODS

Two patients were treated with high-dose (120 mg/kg/day) intravenous DFO for iron overload.

RESULTS

Sensorimotor toxicity developed after 5 and 6 months of treatment, respectively. The development of the neurotoxicity did not correlate with the serum ferritin or the ratio of DFO dose to serum ferritin. Symptoms resolved in both patients with discontinuation of DFO treatment. In 1 patient, symptoms recurred with resumption of DFO treatment.

CONCLUSIONS

These cases demonstrate that a reversible sensorimotor neurotoxicity, a previously unreported toxicity, may complicate DFO therapy, this complements the previously reported auditory and visual neurotoxicity associated with DFO therapy. Discontinuation of therapy at the time of onset of neurotoxicity is recommended, with possible resumption at lower doses.

Tau in aluminum-induced neurofibrillary tangles

Aluminum is a neurotoxin and in susceptible species induces a neurofibrillary pathology characterized by argentophilic masses in neuronal perikarya and in axonal spheroids. These inclusions are known to contain neurofilament proteins. Using immunocytochemistry and immunoblotting, we demonstrate that tau is a component of these aluminum-induced neurofibrillary tangles (Al-NFTs) in rabbits. Double-label immunocytochemistry experiments reveal co-localization of phosphorylated neurofilaments (using SMI31) and tau (using tau-1, tau-5, AT8, and PHF-1) in the perikaryal Al-NFTs. Non-phosphorylated tau (detected using tau-1) occupies a smaller area of the Al-NFT than the total pool of tau proteins (detected using tau-5). The area of total tau and non-phosphorylated tau immunolabeling in the Al-NFT increases as the size of the Al-NFT (i.e., the proportion of cell area occupied by the Al-NFT) increases. The proportion of cell area (outside of the Al-NFT) occupied by tau (as indicated by tau-5) decreases as the area of tau in the Al-NFT increases and as the size of the Al-NFT in the cell increases. Immunoblotting experiments demonstrate 1) the specificity of the tau antibody labeling and verify a lack of cross-reactivity of the tau-5 antibody to neurofilament proteins in rabbit tissue; and 2) no alterations in the levels of tau resulting from aluminum-treatment. These data suggest that as the size of the Al-NFT in a cell increases there is less tau in the neuronal perikarya. Therefore, there may be less tau in the perikarya available to perform normal functions such as microtubule polymerization and stabilization. Tau and neurofilament proteins are perturbed in a number of neurodegenerative disorders such as Alzheimer's disease, diffuse Lewy body disease, and Parkinson's disease. Aluminum-induced neurofibrillary pathology may provide a model to study perturbation in tau and neurofilaments, their phosphorylation and deposition into pathological inclusions.

Evaluation of neuropathy in patients on suramin treatment

Suramin, a promising chemotherapeutic agent, causes a dose-limiting sensorimotor polyneuropathy. We undertook a phase 1 study of suramin that included serial neurologic and electrophysiologic examinations as part of the safety evaluation. We found that 6 of 41 (15%) patients developed suramin-induced demyelinating neuropathy which resembled Guillain-Barre syndrome clinically. There was 1 asymptomatic patient with electrophysiologic abnormalities suggestive of a demyelinating neuropathy. In addition, 1 patient with mild axonal neuropathy at baseline had deterioration of his symptoms during suramin treatment. Four asymptomatic patients developed electrophysiologic findings suggestive of a mild axonal neuropathy. We conclude that: (1) serial electrophysiologic monitoring is helpful for early detection of suramin-induced neuropathy; and (2) fixed dosing schedule of suramin without adaptive control does not lead to an increased incidence of demyelinating neuropathy when compared to adaptively controlled dosing schedules.