The cholinomimetic agent carbachol induces headache in healthy subjects

The parasympathetic nervous system is likely to be involved in migraine pathogenesis. We hypothesized that the cholinomimetic agonist carbachol would induce headache and vasodilation of cephalic and radial arteries. Carbachol (3 µg/kg) or placebo was randomly infused into 12 healthy subjects in a double-blind crossover study. Headache was scored on a verbal rating scale from 0–10. Velocity in the middle cerebral artery (V_MCA) and diameter of the superficial temporal artery (STA) and radial artery (RA) were recorded. Nine participants developed headache after carbachol compared with three after placebo. The area under the curve for headache was increased after carbachol compared with placebo both during infusion (0–30 min) ( P  = 0.042) and in the postinfusion period (30–90 min) ( P  = 0.027). Carbachol infusion caused a drop in V_MCA ( P  = 0.003) and an increase in STA diameter ( P  = 0.006), but no increase in the RA diameter ( P  = 0.200). In conclusion, the study demonstrated that carbachol caused headache and dilation of cephalic arteries in healthy subjects.     

The use of mitoxantrone (Novantrone) for the treatment of multiple sclerosis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

Mitoxantrone is the first drug approved for the treatment of secondary progressive multiple sclerosis (SPMS) in the United States. This assessment considers use of mitoxantrone in the treatment of MS. Mitoxantrone probably reduces the clinical attack rate and reduces attack-related MRI outcomes in patients with relapsing MS (Type B recommendation). Also, mitoxantrone may have a beneficial effect on disease progression in patients with MS whose clinical condition is worsening (Type B recommendation). The potential for serious toxicity of mitoxantrone, however, must be taken into account when considering this therapy in individual patients. Moreover, because the potential clinical benefits on disease progression appear to be only modest, the results of the single phase III trial should be replicated in another (and hopefully much larger) clinical study before this agent is widely recommended for the treatment of patients with MS.     

Randomized controlled trial of interferon-beta-1a in secondary progressive MS: MRI results

OBJECTIVE: To examine MRI changes resulting from treatment of secondary progressive MS (SPMS) with two doses of interferon-beta-1a (Rebif). BACKGROUND: Interferon-beta (IFN-beta) reduces relapses and delays progression in relapsing-remitting MS, but there are conflicting results on its clinical benefit in SPMS. METHODS: In a double-blind, randomized, multicenter, placebo-controlled study (SPECTRIMS), 618 patients received IFN-beta-1a 22 microg, 44 microg, or placebo subcutaneously three times weekly for 3 years. T2 activity and burden of disease (BOD) were measured in 617 patients by using semiannual proton density/T2-weighted (PD/T2) MRI scans. A cohort of 283 patients also had 11 monthly PD/T2 and T1-weighted gadolinium-enhanced (T1-Gd) scans at study start. RESULTS: Treatment reduced median numbers of active lesions per patient per scan (semiannual T2 activity: 0.17, 0.20 and 0.67 for the high dose, low dose, and placebo, p < 0.0001; monthly combined unique activity [T1+T2]: 0.11, 0.22, and 1.00, p < 0.0001) and accumulation of BOD (percent change from baseline to month 36: -1.3, -0.5, and 10.0 for the high dose, low dose, and placebo, respectively; p = 0.0001). MRI benefit was most evident in the subgroup of patients who reported relapses in the 2 years before the study. Neutralizing antibody development was associated with reduction in treatment effect: antibody-positive patients did not show significant differences from placebo at either dose. CONCLUSIONS: Interferon-beta-1a used in SPMS showed significant effects on all MRI measures, particularly in patients with relapses in the 2 years before the study.     

Guidelines for using quantitative measures of brain magnetic resonance imaging abnormalities in monitoring the treatment of multiple sclerosis

The change of brain lesion load, measured on T₂-weighted magnetic resonance imaging (MRI) using computer-assisted techniques, is a widely used secondary endpoint for phase III clinical trials in multiple sclerosis (MS). Collections, transfer, and analysis of the electronic data across multiple centers have all proved challenging and give rise to potential errors. However, many new acquisition schemes and postprocessing techniques have been developed; these may reduce scan times and result in better lesion conspicuity or lessen the human interaction needed for data analysis. This review considers many aspects of the use of MRI in clinical trials for MS and provides international consensus guidelines, derived from a task force of the European Magnetic Resonance Networks in Multiple Sclerosis (MAGNIMS) together with a group of North American experts. The main points considered are the organization of correctly powered trials and selection of participating sites; the appropriate choice of pulse sequences and image acquisition protocol given the current state of technology; quality assurance for data acquisition and analysis; accuracy and reproducibility of lesion load assessments; and the potential for the application of quantitative methods to other MRI-derived measures of disease burden.     

Spin-spin relaxation in experimental allergic Encephalomyelitis. Analysis of CPMG data using a non-linear least squares method and linear inverse theory

We have used the CPMG pulse sequence to measure proton T₂ values and water content in spinal cord and brain samples from Hartley guinea pigs inoculated to produce experimental allergic encephalomyelitis (EAE). Relaxation data were fitted using minuit, a non-linear curve fitting routine. Three exponentials provided the best fit to spinal cord data (10 ms (13%), 76 ms (57%), 215 ms (30%)) and two exponentials for brain tissue (10 ms (4%), 92 ms (96%)). Least squares algorithms were also used to analyse the spinal cord data in terms of discrete and smooth distributions of relaxation times. The discrete least squares solutions consisted of three to five isolated spikes between 0.010 and 0.300 s. This type of solution was difficult to interpret in terms of water reservoirs. Smooth solutions consisted of two broad peaks, a small peak with a T₂ near 0.010 s and a larger peak near 0.100 s. The integral ratio of the larger to the smaller peak was 7.092 ± 1.782 for normal tissue, and increased to a maximum of 16 with increasing parenchymal cellular infiltration and demyelination. The short T₂ peak has been assigned to water in the hydration layers of the myelin sheath. The width of the longer T₂ peak was sensitive to tissue heterogeneity. The least squares and smooth distribution analysis models could be used to distinguish samples with extensive parenchymal infiltration from normal tissue, even though only a maximum of 60% of the tissue was affected. The short T₂ component could provide a direct method of measuring intact myelin, which would have a profound effect on the understanding of the evolution of pathology in multiple sclerosis.     

Linoleic acid in multiple sclerosis: Failure to show any therapeutic benefit

We have studied the effect of a dietary supplement with linoleic acid (LA) in 76 patients with MS. We could detect no effect of this supplement on the progression of neurological findings, the relapse rate, or the severity of relapses. We were also able to show that oral supplementation with a linoleic acid preparation would raise the blood level of LA in these patients. We were unable to show that there was any reduction in the linoleic acid blood levels associated with acute relapses of MS during this study.     

CSF electrophoresis: an adaptation using cellulose acetate for the identification of oligoclonal banding.

An adaptation of cellulose acetate electrophoresis for studying concentrated cerebrospinal fluid is described. Two hundred and twenty-one patients have been studied, and the specificity for multiple sclerosis and sub-acute sclerosing panencephalitis is discussed. This has been positive for oligoclonal banding (OB) in 79% of patients with clinically definite multiple sclerosis.