PubMed Health⌕ Search

Biomedical subjects

W J Triggs

Publications and source records attributed to W J Triggs.

46 records · Page 3Linked to original sources
PubMed1992

A congenital myasthenic syndrome refractory to acetylcholinesterase inhibitors.

We studied 4 siblings (3 men and 1 woman), ages 22 to 43 years, with congenital ptosis, external ophthalmoplegia, proximal muscle weakness and fatigability unresponsive to acetylcholinesterase (AChE) inhibitors. Repetitive nerve stimulation showed a significant compound muscle action potential (CMAP) area decrement at 2 or 3 Hz. Nerve conduction studies and concentric needle electromyography were normal, and repetitive CMAPs to single nerve stimulation were not observed. Voluntary single fiber electromyography (SFEMG) showed increased jitter and blocking. Assessment of individual end-plates using SFEMG with intramuscular axonal microstimulation showed no uniform relationship between jitter and the rate of stimulation, consistent with a postsynaptic defect of neuromuscular transmission. Edrophonium eliminated the decremental response to repetitive nerve stimulation, but caused no significant clinical improvement, suggesting an additional mechanism for weakness in these patients.

Adult↗
PubMed1992

Sensory abnormalities and dysaesthesias in the anterior spinal artery syndrome.

We present three patients with a nontraumatic cervical anterior spinal artery syndrome, two of whom developed painful burning dysaesthesias below the level of spinal cord lesion, refractory to opiate, anticonvulsant and tricyclic antidepressant therapy. Quantitative sensory testing and neurophysiological assessment showed absence of pain and temperature sensation below the level of the lesion, with preservation of light touch, vibratory and position sensibilities and cortical somatosensory evoked potentials in all three patients. Dysaesthesias in both affected patients were exacerbated by somatosensory input attributed to intact posterior column function. Posterior column electrical stimulation worsened the dysaesthesias in one affected patient, and was ineffective in the other. Both patients affected with dysaesthesias showed significant improvement in motor function and developed clinical spasticity, while the third patient developed neither dysaesthesias nor spasticity, but remained flaccid without motor improvement, suggesting a more complete lesion of anterolateral spinal pathways. These cases illustrate that lesions of the anterolateral spinal cord may lead to the development of dysaesthesias, perhaps related in part to selective neospinothalamic deafferentation and preservation of the posterior columns.

Adult↗
PubMed1992

Motor nerve inexcitability in Guillain-Barré syndrome. The spectrum of distal conduction block and axonal degeneration.

We studied 34 patients with the Guillain-Barré syndrome (GBS) to clarify the clinical significance of inexcitable motor nerves and of low amplitude compound muscle action potentials (CMAPs). The patients were subdivided into two groups. Group 1 included eight patients who had electrically inexcitable motor nerves within 2 wks of the first symptom. (Two patients without extensive conduction studies had only one inexcitable motor nerve.) The outcome in this group at 1 yr varied from complete recovery (five patients) to severe motor sequelae (three patients). Group 2 included 26 patients who had two electrophysiological assessments, and in whom the serial changes in CMAP amplitudes were analysed and correlated to outcome. Fourteen of these 26 sets of serial studies were performed within 1 mth. Twelve of 26 patients in Group 2 showed decrease in the amplitude of CMAPs between serial studies; only six of these had a good outcome at 1 yr. Nine of 26 patients showed increase in CMAP amplitude between serial studies, of these eight had a good clinical outcome. Low-amplitude CMAPs or inexcitable motor nerves in the initial stages of GBS are due to distal pathology of the motor axons, either distal conduction block or axonal degeneration. The nature of these changes cannot be predicted by the results of the initial electrophysiological evaluation, including the presence or absence of active denervation. However, improvement of CMAP amplitude on sequential studies suggests a good outcome at 1 yr. We believe that, in the absence of a biological marker for GBS, individualization of an 'axonal variant' of the syndrome is not warranted at the present time.

Action Potentials↗
PubMed1992

Neuropsychiatric manifestations of defect in mitochondrial beta oxidation response to riboflavin.

A 29 year old woman is described with severe hyperemesis gravidarum, atypical migraine, numerous admissions to hospital for psychiatric illness, non-epileptic seizures, and valproate-induced coma. Metabolic studies and measurement of [9,10(n)-3H]palmitate oxidation by cultured fibroblasts suggested a multiple acyl-CoA dehydrogenation disorder. Treatment with riboflavin abolished headaches and abnormal behaviour and normalised the plasma free carnitine level. Subtle defects in mitochondrial beta oxidation may be a treatable cause of disordered behaviour in adults.

Acids↗
PubMed1991

Iron-induced lipid peroxidation and brain injury responses.

Head trauma with cerebral contusion causes extravasation of red blood cells, followed by hemolysis and deposition of iron-containing blood products within the neuropil. Liberation of heme compounds is associated with deposition of hemosiderin, and with gliosis, neuronal loss and occasionally the development of seizures. In this experiment we injected components of red blood cell contents into rat amygdala, and then measured the rate of appearance of products of lipid peroxidation. Injection of microliter volumes of hemin and hemoglobin, with hematoprotoporphyrin and rodent plasma injection and contralateral uninjected tissue as controls, showed that the presence of the iron moiety within the protoporphyrin ring was required to initiate and propagate peroxidation. Free radical reactions initiated by iron or heme deposited within the neuropil may be a fundamental reaction associated with brain injury responses, and possibly with posttraumatic epileptogenesis.

Amygdala↗
PubMed1990

Valproate-induced coma with ketosis and carnitine insufficiency.

We observed two patients who developed coma following administration of valproate in dosages of 32 to 40 mg/kg per day. Valproate levels were within the therapeutic range, and results of liver function studies were normal. Both patients had ketosis and adipic aciduria. Plasma free carnitine levels were decreased during coma and after recovery. One patient excreted ethylmalonic acid, butyrylcarnitine, and glutarylcarnitine during and after resolution of coma, suggesting a multiple acyl coenzyme A dehydrogenation defect. Low serum carnitine levels may predispose patients to development of altered consciousness when treated with valproate.

Acids↗
PubMed1986

The role of iron-induced hippocampal peroxidation in acute epileptogenesis.

Intracortical injection of iron salts causes lipid peroxidation, focal edema, necrosis, gliosis, and the development of behavioral and electrographic seizures. Tocopherol pretreatment prevents the histopathologic perturbations associated with iron injection, and appears to accelerate the resolution of focal accumulation of peroxidation products. In this experiment, rats were pretreated with 500 mg/kg DL-alpha-tocopherol acetate prior to the injection of 3 microliter of 100 mM FeCl2 into the dorsal hippocampus, or induction of convulsive seizures by s.c. injection of 0.8 mg/100 g bicucullin. Tocopherol pretreatment prevented the occurrence of convulsive seizures in a significant number of iron-salts injected animals. Lipid peroxidation measured in the dissected hippocampus was significantly increased in untreated rats developing iron-induced seizures and in rats treated with tocopherol, but developing convulsive seizures. Tocopherol failed to prevent bicucullin-induced seizures. Further, convulsive seizures induced by bicucullin failed to alter hippocampal fluorescence levels. Hence, we concluded that the epileptogenic effects of hippocampal injection of iron salts appear to be related to the induction of peroxidation of neural lipids within the injection site.

Animals↗
PubMed1984

In vivo lipid peroxidation in rat brain following intracortical Fe2+ injection.

Cerebral contusion, cortical laceration, intracerebral hematoma formation, and hemorrhagic cortical infarction cause extravasation of red blood cells, followed by hemolysis, decompartmentalization of iron, formation and deposition of hemosiderin, and an increased incidence of epilepsy. In this experiment, 10 microliter of an aqueous solution containing 100 mmol/L FeCl2, 100 mmol/L CoCl2, or 0.9% (wt/vol) NaCl were injected at a depth of 1.8 mm into rat isocortex. The rate of formation of fluorescent compounds was measured in chloroform-methanol extracts of isocortical homogenates. Significant increases in the quantity of fluorescent products of lipid peroxidation were found 120 min after the injection of 100 mmol/L FeCl2. Cobaltous chloride and saline injection had no effect on the levels of fluorescent products found in the cortical homogenates. Although the intracortical deposition of aqueous solutions containing CoCl2 or FeCl2 in rodent cortex causes acute epileptiform discharges, the epileptogenic effect of CoCl2 is transient, while the injection of iron salts causes persistent seizures. Since CoCl2 injection failed to cause formation of lipid peroxidation products while the isocortical injection of iron caused significant increase in fluorescence within the injected hemisphere, we suggest that the occurrence of iron-induced lipid peroxidation may be of importance in initiation of recurrent seizures in the rat.

Animals↗
PubMed1984

Effect of phenytoin and corticosteroids on seizures and lipid peroxidation in experimental posttraumatic epilepsy.

Head trauma, intracerebral hematoma formation, and hemorrhagic cerebral infarction cause extravasation of the intravascular contents, red blood cell (RBC) hemolysis, hemosiderin deposition within the neuropil, and an increased incidence of epilepsy. Reports conflict regarding the efficacy of the administration of prophylactic anticonvulsant drugs to head-injured patients to prevent the development of posttraumatic epilepsy. In this study, rats received a 10-microliter injection of 100 mM FeCl2 at a depth of 1.8 mm into the isocortex, or an equal volume of saline. Rats were then treated with 30 mg/kg methylprednisolone (MPS), 90 mg/kg MPS, 100 mg/kg phenytoin, or with an equal volume of propylene glycol. Behavioral or electroencephalographic (EEG) seizures occurred in all control-treated iron-injected rats within 93 +/- 6 minutes of injection. Brain injury responses as measured by the occurrence of fluorescent product formation from iron-induced lipid peroxidation showed 6.6 +/- 0.8 units/gm in the saline-injected animals, and 16.7 +/- 2.5 units/gm in the control-treated iron-injected rats. Of the 90-mg/kg MPS-treated rats, 8% had seizures; fluorescence in those animals was 5.7 +/- 0.5 units/gm. Phenytoin treatment prevented the occurrence of convulsive and EEG seizures; however, lipid peroxidation was unaffected (16.5 +/- 4.1 units/gm). If posttraumatic epilepsy develops because of RBC extravasation, hemolysis, parenchymal deposition of heme compounds, and initiation of lipid peroxidation, then treatments designed to prevent peroxidation may be more effective for epilepsy prophylaxis than administration of anticonvulsant drugs that mask convulsive seizures while biochemical brain injury continues.

Animals↗