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M J Strong

Publications and source records attributed to M J Strong.

At least 19 recordsLinked to original sources
PubMed2006

Tau protein hyperphosphorylation in sporadic ALS with cognitive impairment.

The authors have characterized frontal cortical tau protein in cognitively intact (4) and cognitively impaired (ALSci, 4) ALS patients and compared it with control (2) or Alzheimer disease (AD, 1)- derived tau. The authors observed expression of both 3R and 4R tau isoforms; increased insoluble tau protein; phosphatase resistance; and hyperphosphorylation at T175, S208, and S210. Soluble tau from both AD and ALSci was also phosphorylated at S237. Tau hyperphosphorylation is associated with ALS.

Aged↗
PubMed2003

Percutaneous endoscopic gastrostomy (PEG) in patients with ALS and bulbar dysfunction.

OBJECTIVE: To compare characteristics of ALS patients with and without percutaneous endoscopic gastrostomy (PEG). METHODS: Using the ALS Patient Care Database, data from patients with and without PEG with ALS Functional Rating Scale-bulbar subscale (ALSFRSb) scores < or = 5 were analyzed; follow-up data were also collected. RESULTS: PEG use was markedly increased with declining ALSFRSb scores. Demographics did not differ, but ALSFRS composite scores and bulbar and arm subscale scores were lower (P<0.0001). PEG patients used significantly more assistive devices, multidisciplinary care, home care nurses and aides, had more frequent physician and emergency department visits and hospital admissions (P<0.0001), and had lower health status based on the mini-SIP scale (P=0.0047). PEG use varied greatly between ALS centers. In the follow-up study, positive impact of PEG was noted in 79 % of PEG patients but in only 37.5% of patients who received PEG later, based on a small number of patients. PEG use showed no survival benefit. CONCLUSION: Patients did not receive PEG until bulbar function was severely reduced and overall ALS had markedly progressed. PEG may have been performed too late to demonstrate survival benefits. Aggressive proactive nutritional management appears essential in patients with ALS. To determine whether PEG provides benefits, it must be performed at earlier stages of the disease and prospectively studied.

Amyotrophic Lateral Sclerosis↗
PubMed2001

Cognitive impairment in sporadic ALS: a pathologic continuum underlying a multisystem disorder.

BACKGROUND: Traditionally considered a motor neuron-selective disorder, the clinical manifestations of ALS can include a frontotemporal dementia. Although the pathologic substrate of cognitive impairment remains to be defined, the presence of ubiquitin-immunoreactive (Ub+) intraneuronal inclusions in cortical regions has been suggested to constitute a pathologic marker of this process. METHODS: The authors compared the neuropathological features of four cognitively impaired patients with ALS, four cognitively intact patients with ALS, and four neurologically normal patients. The extent and load of Ub+ neuronal inclusions, Ub+ dystrophic neurites, and superficial linear spongiosis (SLS) was determined among a number of cortical, hippocampal, and subcortical regions. RESULTS: Although Ub+, alpha-synuclein-negative, and tau-negative neuronal inclusions were observed in both cognitively impaired and cognitively intact patients with ALS, their density and extent was greater among the former, with the difference greatest in the cingulate gyrus. Ub+ neurites were observed in a similar distribution. Only the presence of SLS, affecting the first and second cortical layers, reliably distinguished between the cognitively impaired and cognitively intact ALS subpopulations. In three of four cognitively impaired patients with ALS, SLS was associated with transcortical microglial activation, in the absence of detectable differences in astrocytosis, density of calbindin or parvalbumin neurons, or optical density of synaptophysin and SNAP-25. CONCLUSIONS: Although intraneuronal Ub+ inclusions and dystrophic neurites are observed in both ALS subpopulations, the presence of cognitive impairment was associated with a greater distribution and load of both neuropathologic features, suggesting a disease continuum. Moreover, cognitive impairment was uniformly associated with superficial linear spongiosis, a pathologic feature common to several forms of frontotemporal dementia.

Adult↗
PubMed2001

Progress in clinical neurosciences: the evidence for ALS as a multisystems disorder of limited phenotypic expression.

Traditionally, amyotrophic lateral sclerosis (ALS) is considered to be a unique neurodegeneration disorder in which motor neurons are selectively vulnerable to a single disease process. Our current understanding of ALS, however, suggests that this is far too limited an approach. While motor neuron degeneration remains the central component to this process, there is considerable phenotypic variability including broad ranges in survivorship and the presence or absence of cognitive impairment. The number of familial variants of ALS for which unique genetic linkage has been identified is increasing, attesting further to the biological heterogeneity of the disorder. At the cellular level, derangements in cytoskeletal protein and glutamate metabolism, mitochondrial function, and in glial interactions are clearly evident. When considered in this fashion, ALS can be justifiably considered a disorder of multiple biological processes sharing in common the degeneration of motor neurons.

Amyotrophic Lateral Sclerosis↗
PubMed2001

Phosphorylation state of the native high-molecular-weight neurofilament subunit protein from cervical spinal cord in sporadic amyotrophic lateral sclerosis.

The intraneuronal aggregation of phosphorylated high-molecular-weight neurofilament protein (NFH) in spinal cord motor neurons is considered to be a key pathological marker of amyotrophic lateral sclerosis (ALS). In order to determine whether this observation is due to the aberrant or hyper-phosphorylation of NFH, we have purified and characterized NFH from the cervical spinal cords of ALS patients and controls. We observed no differences between ALS and normal controls in the physicochemical properties of NFH in Triton X-100 insoluble protein fractions, with respect to migration patterns on 2D-iso electrofocusing (IEF) gels, the rate of Escherichia coli alkaline phosphatase mediated dephosphorylation, or the rate of calpain-mediated proteolysis. The rate of calpain-mediated proteolysis was unaffected by either exhaustive NFH dephosphorylation or by the addition of calmodulin to the reaction. Phosphopeptides and the phosphorylated motifs characterized by liquid chromatography tandem mass spectroscopy (LC/MS/MS) analysis demonstrated that all the phosphorylated residues found in ALS NFH were also found to be phosphorylated in normal human NFH samples. Hence, we have observed no difference in the physicochemical properties of normal and ALS NFH extracted from cervical spinal cords, suggesting that the perikaryal aggregation of highly phosphorylated NF in ALS neurons reflects the aberrant somatotopic localization of normally phosphorylated NFH.

Amino Acid Sequence↗
PubMed2001

Deposition of 7-aminoflunitrazepam and flunitrazepam in hair after a single dose of Rohypnol.

In recent years, there has been a notable increase in the number of reports on drug-facilitated sexual assault. Benzodiazepines are the most common so-called "date-rape" drugs, with flunitrazepam (Rohypnol) being one of the most frequently mentioned. The aim of this study was to determine whether flunitrazepam and its major metabolite 7-aminoflunitrazepam could be detected in hair collected from ten healthy volunteers after receiving a single 2 mg dose of Rohypnol using solid phase extraction and NCI-GC-MS. Such data would be of great importance to law enforcement agencies trying to determine the best time interval for hair collection from a victim of drug-facilitated sexual assault in order to reveal drug use. Ten healthy volunteers (eight women and two men, 21 to 49 years old) participated in the study. The following hair samples were collected from each volunteer: one before flunitrazepam administration, and 1, 3, 5, 14, 21, and 28 days after. In five volunteers, 7-aminoflunitrazepam was detected 24 h after flunitrazepam administration and remained in hair throughout the entire 28-day study period (0.6-8.0 pg/mg). In two cases, 7-aminoflunitrazepam appeared in hair 21 days after drug intake (0.5-2.7 pg/mg), and in two subjects 14 days later (0.5-5.4 pg/mg). In one volunteer, 7-aminoflunitrazepam was detected on day 14 and 21 but concentrations were below the quantitation limit. Flunitrazepam was detected in some samples but all concentrations were below the quantitation limit (0.5-2.3 pg/mg).

Adult↗
PubMed2000

A morphological analysis of the motor neuron degeneration and microglial reaction in acute and chronic in vivo aluminum chloride neurotoxicity.

The monthly intracisternal inoculation of aluminum chloride (AlCl3) to young adult New Zealand white rabbits induces motor neuron degeneration marked by intraneuronal neurofilamentous aggregates similar to that observed in amyotrophic lateral sclerosis (ALS). However, in contrast to ALS, this process occurs in the experimental paradigm in the absence of a glial response. In addition, whereas ALS is a fatal disorder, the cessation of aluminum exposure leads to both clinical and neuropathological recovery. Because microglia can influence neuronal regeneration, we have examined the effect of both acute and chronic aluminum exposure on microglial activation in vivo. We have studied microglial morphology in young adult New Zealand white rabbits receiving either single (1000 microg) or repeated sublethal (100 microg monthly) intracisternal inoculums of AlCl3. In addition, rabbits receiving 1000 microg AlCl3 inoculums were studied following an unilateral sciatic axotomy 48 h prior to the AlCl3 exposure. Our studies demonstrate that microglial activation in vivo is inhibited by AlCl3 exposure, and that a correlation exists between the extent of microglia suppression and the potential for recovery. This suggests that microglial activation is an important determinant of neuronal injury.

Aluminum Chloride↗
PubMed2000

Motor neuronal death in sporadic amyotrophic lateral sclerosis (ALS) is not apoptotic. A comparative study of ALS and chronic aluminium chloride neurotoxicity in New Zealand white rabbits.

Whether diseased motor neurones in sporadic amyotrophic lateral sclerosis (ALS) die via apoptosis is unknown. Because this relates primarily to difficulties in utilizing post-mortem tissue from end-stage disease, motor neurone degeneration in ALS spinal cord was compared with that of a model of a chronic motor neurone degeneration. Degenerating motor neurones in ALS, identified by ubiquitin immunoreactivity, did not demonstrate the morphological characteristics of apoptosis and were not c-Jun immunoreactive or TUNEL positive. A temporal analysis of spinal motor neurone death in the chronic AlCl3 neurotoxicity model of motor neurone degeneration was also undertaken. AlCl3 was administered intracisternally every 4 weeks and, at intervals of 51, 107, 156 and 267 days, evidence of apoptosis was sought by morphology, TUNEL hybridization or DNA laddering. Double-labelling immunostudies were also performed with antibodies to either c-Jun, ubiquitin or high molecular weight neurofilament (NFH) with TUNEL hybridization. Although significant neurone loss was evident, apoptosis was not found. These studies demonstrate a lack of apoptosis in ALS spinal motor neurones and suggest that this observation does not relate to the utilization of post-mortem tissue in which apoptotic neurones may have been lost.

Adult↗
PubMed2000

Quantitation of clonazepam and its major metabolite 7-aminoclonazepam in hair.

Clonazepam (CLO) is an anticonvulsant benzodiazepine approved by the Food and Drug Administration for use in the treatment of seizures. It produces pharmacological effects (depression, amnesia) similar to other compounds from the same therapeutic class, and in combination with alcohol, its CNS-depressant action can be significantly potentiated. As with some other benzodiazepines, CLO is a drug possibly used in "date-rape" situations. A method using solid-phase extraction followed by a highly sensitive negative chemical ionization gas chromatography-mass spectrometry for the simultaneous quantitation of CLO and its major metabolite 7-aminoclonazepam (7-ACLO) in hair was developed and validated. The method has potential application to alleged drug-facilitated rape cases. To determine the feasibility of detecting 7-ACLO and CLO in hair, specimens were collected from 10 psychiatric patients treated with CLO, divided into 2-cm segments, and analyzed. Standard curves for 7-ACLO (1-1000 pg/mg) and CLO (10-400 pg/mg) had correlation coefficients of 0.998. All precision and accuracy values were within acceptable limits. 7-ACLO was present in measurable quantities (1.37-1267 pg/mg) in 9 out of 10 patient samples. CLO concentrations in hair were much lower (10.7-180 pg/mg). In 4 out of 10 cases, CLO was not detected in hair. Two patients who had never been treated with CLO before received a single 2-mg dose of the drug. Approximately three weeks later, hair samples were collected, and measurable quantities of 7-ACLO (4.8 pg/mg) were detected in the first segment (proximal) of one of those samples, and traces of the drug were present in the other sample. We concluded that the 7-ACLO is being deposited in hair in much higher quantities than the parent drug and remains there for extended periods of time. Our study also indicates that it is possible to detect 7-ACLO after a single dose of CLO as in the typical date-rape scenarios.

Adult↗
PubMed2000

Characterization of neuronal intermediate filament protein expression in cervical spinal motor neurons in sporadic amyotrophic lateral sclerosis (ALS).

Because transgenic mice expressing an altered stoichiometry of neurofilament proteins develop a motor neuron degeneration associated with neurofilamentous aggregate formation similar to that found in amyotrophic lateral sclerosis (ALS), we studied the expression of intermediate filament proteins in sporadic ALS. Archival cervical spinal cord paraffin-embedded sections from 11 disease and 11 control cases were studied by either in situ hybridization using 35S-labeled riboprobes or immunohistochemically using specific antibodies for the individual neurofilament subunit proteins, alpha-internexin, nestin, peripherin, vimentin, beta-actin, or Talpha1-tubulin. Median NFL, alpha-internexin, and peripherin steady-state mRNA levels were significantly reduced in the lateral motor neuron cell column (p < 0.05) of ALS cases, while neither NFM nor NFH mRNA levels were altered. ALS cases demonstrated an elevation of beta-actin mRNA levels (p < 0.01) with no increase in Talpha1-tubulin mRNA levels. No motor neuronal expression of nestin or vimentin was observed. Ubiquitin-immunoreactive perikaryal aggregates were immunoreactive for NFH or beta-actin, but not for peripherin, alpha-internexin, vimentin, or nestin. In contrast, neuroaxonal spheroids were strongly immunoreactive for NFH and peripherin, but not for beta-actin, alpha-internexin, vimentin, or nestin. These findings suggest that the stoichiometry of cytoskeletal protein expression in ALS spinal motor neurons is significantly altered in a pattern conducive to the formation of neurofilamentous aggregates.

Adolescent↗
PubMed1999

A prospective study of cognitive impairment in ALS.

OBJECTIVE: To characterize prospectively the cognitive profile in ALS. METHODS: Clinically definite ALS patients (11 men, 2 women), age 39.9 to 74.0 years (mean age, 54.2 +/- 9.6 years; mean disease duration, 21.1 +/- 10.5 months) underwent neuropsychologic, language, and speech testing followed by MR 1H spectroscopy (4 T). Five spousal control subjects completed an identical protocol. Eight ALS patients participated in follow-up studies at a 6-month interval. RESULTS: Relative to control subjects, ALS patients showed mild impairment in word generation, recognition memory (faces), and motor-free visual perception. Bulbar-onset patients showed greater impairment in a number of measures (working memory, problem solving/cognitive flexibility, visual perception, and recognition memory for words and faces), and cognitive impairment appeared more progressive over time. ALS patients demonstrated anomia on a confrontation naming test, with no significant problems following commands or repeating. Speech motor performance scores and intelligibility scores were not significantly different. No significant declines in forced vital capacity, forced expiratory volume, or peak expiratory flow rates were observed. Although normal at initial testing (T1), MR 1H spectroscopy demonstrated a reduction of the N-acetylaspartate/creatine (NAA/Cr) ratio in the nondominant precentral motor strip across the two testing intervals. In contrast, the NAA/Cr ratio obtained from the anterior cingulate gyrus at T1 was already reduced in bulbar-onset patients (p < 0.001), whereas no deficits were observed in limb-onset individuals in the same region. CONCLUSIONS: Bulbar-onset ALS patients with cognitive impairments and neuronal loss in the anterior cingulate gyrus subsequently developed more profound neuropsychological dysfunction whereas both language and speech capabilities remained relatively preserved. Of note, the absence of bulbar signs did not predict an absence of cognitive decline.

Adult↗
PubMed1999

Percutaneous gastrojejunostomy in amyotrophic lateral sclerosis.

We have performed a retrospective review of the use of a percutaneous gastrojejunostomy in patients with amyotrophic lateral sclerosis (ALS). Forty-one patients with initial bulbar manifestations of ALS and 32 patients with initial limb manifestations underwent a percutaneous gastrojejunostomy under fluoroscopic control using the Rankin gastrojejunostomy tube. Survival characteristics were compared with 86 bulbar onsetting and 207 limb onsetting ALS patients who did not require nutritional support. The 30-day mortality rate was 9.6% (respiratory death in three bulbar onsetting patients and four limb onsetting patients) and the 30 day morbidity rate was 4.1% (one operative site infection and intraperitoneal leakage in two patients). The most frequent long-term complication was the requirement for tube changing (blockage in six; dislodgment in two). Gastric reflux was not described amongst the treated patients. Overall survivorship (symptom onset to death) was less in the bulbar onsetting patients receiving a gastrojejunostomy tube than in the control population (median survival 22.0 vs. 33.7 months, respectively, P=0.005). As a group, the median survivorship for limb onsetting patients was not different for those receiving a gastrojejunostomy than for those who did not. However, a significant reduction in survival was observed in limb onsetting patients receiving a gastrojejunostomy early in the course of their disease (P=0.001) compared to those with a longer duration prior to the procedure. This was not observed in the bulbar onsetting patients. In both patient populations, no relationship was observed between survival post-gastrojejunostomy and the severity of pulmonary involvement at the time of the intervention, serum chloride, or age at onset. These studies demonstrate that a percutaneous gastrojejunostomy is a well-tolerated and safe alternative technique for enteral nutritional support in ALS patients. It also offers the advantage of not requiring either a general anaesthetic at the time of the procedure or instrumentation through the oropharynx. We have also observed that limb onsetting patients requiring a gastrojejunostomy early in the course of their illness are in a distinctive, less favorable, prognostic group.

Adult↗
PubMed1999

Neurofilament metabolism in sporadic amyotrophic lateral sclerosis.

Although the role of intraneuronal neurofilamentous aggregates in the pathogenesis of ALS is unknown, their presence forms a key neuropathological hallmark of the disease process. Conversely, the experimental induction of neurofilamentous aggregates in either neurotoxic or transgenic mice gives rise to motor system degeneration. To determine whether alterations in the physiochemical properties of NF are present in sporadic ALS, we purified NF subunit proteins from cervical spinal cord of ALS and age-matched control patients. The cytoskeleton-enriched, Triton X-100 insoluble fraction was further separated into individual NF subunits using hydroxyapatite HPLC. We observed no differences between control and ALS in the characteristics of NFH, including migration patterns on 2D-IEF, sensitivity to E. coli, alkaline phosphatase mediated dephosphorylation, peptide mapping, or proteolysis (calpain, calpain/calmodulin mediated, phosphorylated or dephosphorylated NFH). NFL showed no differences in 2D-IEF migration patterns, peptide mapping, or the extent of NFL nitrotyrosine immunoreactivity in either the Triton soluble or insoluble fractions. The latter observation demonstrated that NFL nitration is a ubiquitous occurrence in neurons and suggests that NFL might function as a sink for free reactive nitrating species. In contrast to the lack of differences in the post-translational processing of NF in ALS, we did observe a selective suppression of NFL steady state mRNA levels in the limb innervating lateral motor neuron column of ALS. This occurred in the absence of modifications in NFH, NFM or neuronal nitric oxide synthase (Type I NOS; nNOS) steady state mRNA levels. Coupled with previous observations of nNOS immunoreactivity co-localizing with NF aggregates in ALS motor neurons, this suggests activation of the nNOS enzyme complex in ALS, which would be predicted to contribute directly to the generation of reactive nitrating species. Given this, the isolated suppression of NFL steady state mRNA levels in ALS may indicate that ALS motor neurons are at an intrinsic deficit in the ability to buffer free reactive nitrating species.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Simplifying the approach: what can we do?

Although it is desirable to simplify the diagnosis of amyotrophic lateral sclerosis (ALS), it is not obvious how to achieve this. Although a simplified electrophysiologic approach can be easily performed, interpretation of the results in a complex differential diagnosis is far from simple. Genetic screening may potentially be useful but is still in its infancy, even in familial ALS. Spasticity scales are most informative when greater degrees of spasticity are present, but usually these cases can also be identified clinically. It is difficult to envisage simplifying the scales because bedside rating scales are inherently not good at the mild end of the spectrum. Although MRI may prove to be useful in simplifying the diagnostic procedure, at present the numbers of patients studied are too small and the findings not sufficiently specific. Among the major issues that must be decided are whether any of the newer diagnostic techniques are sufficiently reliable, sensitive, and specific to allow any further simplification, and whether paraclinical tests are acceptable surrogates for clinical phenomena. The diagnostic approach of moving a possible diagnosis of ALS into the category of probable ALS earlier by giving more weight to electrophysiologic findings appears to be the only option, together with a more rigorous approach to excluding disorders known to mimic ALS. The problem lies less in the specialist reaching a correct diagnosis than at the level of initial evaluation, where the suspicion of ALS may be raised in only 27-40% of cases.

Adult↗
PubMed1998

Nitration of the low molecular weight neurofilament is equivalent in sporadic amyotrophic lateral sclerosis and control cervical spinal cord.

To determine the extent to which enhanced nitration of the low molecular weight neurofilament subunit protein (NFL) is of pathogenic significance in sporadic ALS, we isolated the neurofilament (NF) from the cervical spinal cord of 15 cases of sporadic ALS and 11 age-matched control cases. Of the three NF subunits, only NFL demonstrated consistent nitrotyrosine immunoreactivity on immunoblots against mouse monoclonal anti-nitrotyrosine antibodies. Regardless of whether the NFL was isolated from the Triton X-100 soluble or insoluble cytoskeletal fractions, the extent of NFL nitration did not differ between ALS and control tissue. Similarly, no differences were observed on either two dimensional isoelectric focusing or NFL peptide maps. These findings suggest that NFL is particularly susceptible to peroxynitrite-mediated nitration in vivo, but reveal no significant qualitative or quantitative modifications in the nitration of NFL isolated from sporadic ALS cervical spinal cord tissue as compared to non-ALS controls.

Adolescent↗
PubMed1998

Diagnostic difficulties in myasthenia gravis.

Four patients with myasthenia gravis presented with severe, largely isolated, bulbar and respiratory muscles weakness. Tensilon tests were positive and antiacetylcholine receptor (anti-AChR) antibody titers were negative in all patients. Only 1 patient had a greater than 10% decremental response during the period of respiratory failure. Although routine nerve conduction studies were normal, all had very low-amplitude diaphragmatic compound muscle action potentials. Three patients had abundant fibrillation potentials and positive sharp waves largely restricted to respiratory muscles. Clinical and electrophysiological findings improved with corticosteroids, and surprisingly, decremental responses became positive in all patients. The assessment of patients with largely isolated bulbar and respiratory muscle weakness due to myasthenia gravis may be difficult and misleading, as anti-AChR antibody titers may be negative, decremental responses may be absent, and electrophysiological assessment atypical. Due consideration of clinical symptomatology, a Tensilon test, and a trial of immunosuppression may be necessary to establish the diagnosis.

Adult↗