Massimo Russo

The Efficacy of Valproate‐Lamotrigine Comedication in Refractory Complex Partial Seizures: Evidence for a Pharmacodynamic Interaction

Summary: Purpose: To assess the comparative therapeutic value of valproate (VPA), lamotrigine (LTG), and their combination in patients with complex partial seizures resistant to other established antiepileptic drugs (AEDs).

MRI of Cardiac Involvement in Transthyretin Familial Amyloid Polyneuropathy

OBJECTIVE The purpose of this study was to evaluate cardiac MRI features in a group of patients with transthyretin familial amyloid polyneuropathy (FAP). SUBJECTS AND METHODS Sixteen patients with transthyretin FAP underwent 2D echocardiography with Doppler examination, cardiac MRI, and (99m)Tc-diphosphonate (DPD) scintigraphy. Four patients had peripheral polyneuropathy, three had carpal tunnel syndrome, one patient had symptoms and signs of heart failure, and eight patients had no symptoms but had a family history of FAP. At MRI, cardiac function parameters and delayed contrast enhancement findings were evaluated. RESULTS Six patients had cardiac radiotracer uptake at scintigraphy (FAP cardiac group), and 10 patients had no cardiac uptake (FAP noncardiac group). The FAP cardiac group included the four patients with peripheral neuropathy, one patient with carpal tunnel syndrome, and the only patient with heart failure. At MRI, abnormal contrast enhancement was found in all patients with positive scintigraphic findings and in no patient with negative scintigraphic findings. All patients had involvement of the left ventricle and other chambers or structures (atria, right ventricle, tricuspid valve leaflets). Left ventricular contrast enhancement was focal in four patients, subendocardial circumferential in one patient, and diffuse in one patient. The only patient with signs of heart failure had circumferential subendocardial enhancement. CONCLUSION Cardiac contrast-enhanced MRI can be used to identify cardiac amyloidosis in patients with FAP who do not have clinical signs of heart involvement. In these patients, the typical subendocardial circumferential pattern of contrast enhancement is rare. We observed unusual enhancement patterns as focal or diffuse left ventricular enhancement accompanied by enhancement of the atria, tricuspid valve, or right ventricle.

Flavocoxid counteracts muscle necrosis and improves functional properties in mdx mice: a comparison study with methylprednisolone.

Muscle degeneration in dystrophic muscle is exacerbated by the endogenous inflammatory response and increased oxidative stress. A key role is played by nuclear factor(NF)-kappaB. We showed that NF-kappaB inhibition through compounds with also antioxidant properties has beneficial effects in mdx mice, the murine model of Duchenne muscular dystrophy (DMD), but these drugs are not available for clinical studies. We evaluated whether flavocoxid, a mixed flavonoid extract with anti-inflammatory, antioxidant and NF-kappaB inhibiting properties, has beneficial effects in mdx mice in comparison with methylprednisolone, the gold standard treatment for DMD patients. Five-week-old mdx mice were treated for 5 weeks with flavocoxid, methylprednisolone or vehicle. The evaluation of in vivo and ex vivo functional properties and morphological parameters was performed. Serum samples were assayed for oxidative stress markers, creatine-kinase (CK) and leukotriene B-4. Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), tumor necrosis factor-alpha, p-38, JNK1 expression was evaluated in muscle by western blot analysis. NF-kappaB binding activity was investigated by electrophoresis mobility shift assay. The administration of flavocoxid: (1) ameliorated functional properties in vivo and ex vivo; (2) reduced CK; (3) reduced the expression of oxidative stress markers and of inflammatory mediators; (4) inhibited NF-kappaB and mitogen-activated protein kinases (MAPKs) signal pathways; (5) reduced muscle necrosis and enhanced regeneration. Our results highlight the detrimental effects of oxidative stress and NF-kappaB, MAPKs and COX/5-LOX pathways in the dystrophic process and show that flavocoxid is more effective in mdx mice than methylprednisolone.

Variable phenotypes are associated with PMP22 missense mutations

Charcot-Marie-Tooth disease (CMT) is the commonest hereditary neuropathy encompassing a large group of clinically and genetically heterogeneous disorders. The commonest form of CMT, CMT1A, is usually caused by a 1.4 megabase duplication of chromosome 17 containing the PMP22 gene. Mutations of PMP22 are a less common cause of CMT. We describe clinical, electrophysiological and molecular findings of 10 patients carrying PMP22 missense mutations. The phenotype varied from mild hereditary neuropathy with liability to pressure palsies (HNPP) to severe CMT1. We identified six different point mutations, including two novel mutations. Three families were also found to harbour a Thr118Met mutation. Although PMP22 point mutations are not common, our findings highlight the importance of sequencing the PMP22 gene in patients with variable CMT phenotypes and also confirm that the PMP22 Thr118Met mutation is associated with a neuropathy albeit with reduced penetrance.

Comparison Between 99mTc-Diphosphonate Imaging and MRI With Late Gadolinium Enhancement in Evaluating Cardiac Involvement in Patients With Transthyretin Familial Amyloid Polyneuropathy

OBJECTIVE Cardiac involvement is not rare in systemic amyloidosis and is associated with poor prognosis. Both (99m)Tc-diphosphonate imaging and cardiac MRI with late gadolinium enhancement are considered valuable tools in revealing amyloid deposition in the myocardium; however, to our knowledge, no comparative study between the two techniques exists. We compared findings of these two techniques in patients with transthyretin-familial amyloid polyneuropathy (FAP). SUBJECTS AND METHODS Eighteen patients with transthyretin-FAP underwent (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement. Images were visually evaluated by independent readers to determine the presence of radiotracer accumulation or late gadolinium enhancement-positive areas at the level of cardiac chambers. RESULTS Interobserver agreement ranged from moderate to very good for (99m)Tc-diphosphonate imaging findings and was very good for findings of MRI with late gadolinium enhancement. Left ventricle (LV) radiotracer uptake was found in 10 of 18 patients, whereas LV late gadolinium enhancement-positive areas were found in eight of 18 patients (χ(2) = 0.9; p = 0.343). One hundred fifty-nine LV segments showed (99m)Tc-diphosphonate accumulation, and 57 LV segments were late gadolinium enhancement positive (p < 0.0001). Radiotracer uptake was found in the right ventricle (RV) in eight patients and in both atria in five patients, whereas MRI showed that RV was involved in three patients and both atria in six patients; the differences were not statistically significant (RV, p = 0.07; atria, p = 1). Intermodality agreement between (99m)Tc-diphosphonate imaging and MRI ranged from fair to good. CONCLUSION Our study shows that, although (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement have similar capabilities to identify patients with myocardial amyloid deposition, cardiac amyloid infiltration burden can be significantly underestimated by visual analysis of MRI with late gadolinium enhancement compared with (99m)Tc-diphosphonate imaging.

Interaction of carbamazepine-10.11-epoxide, an active metabolite of carbamazepine, with valproate : a pharmacokinetic study

Summary: The mechanism responsible for the valproate (VPA)‐induced elevation of serum carbamazepine‐10,11‐epoxide (CBZ‐E) levels was investigated in 6 normal subjects who received single oral doses of CBZ‐E (100 mg) in a control session and during concurrent treatment with sodium VPA [500 mg twice daily (b.i.d.)]. VPA caused a significant prolongation of CBZ‐E terminal half‐life (t± from 6.3 ± 1.2 to 9.0 ± 2.0 h, mean values ± SD) and decreased CBZ‐E clearance (from 90.6 ± 18.8 to 63.2 ± 16.1 ml h ‐1 kg‐1, mean values ± SD) without affecting CBZ‐E apparent volume of distribution (from 0.82 ± 0.19 to 0.81 ± 0.241 kg‐1, mean values ± SD). These findings indicate that VPA impairs the elimination of CBZ‐E, presumably by inhibiting its metabolism.

Carbamazepine-viloxazine interaction in patients with epilepsy.

In six depressed epileptic patients stabilised on carbamazepine therapy, addition of the antidepressant agent viloxazine (300 mg/day for three weeks) induced a marked (average 55%) increase in steady-state plasma carbamazepine concentration. The concentration of the active metabolite carbamazepine-10,11-epoxide also increased during viloxazine therapy, but to a lesser extent (16%). In three patients, these effects were associated with symptoms of carbamazepine intoxication, which regressed rapidly when plasma carbamazepine and carbamazepine-10,11-epoxide levels returned to baseline values after discontinuation of viloxazine. In a seventh patient, viloxazine had to be discontinued after only two weeks because of severe side effects associated with a striking elevation of carbamazepine and carbamazepine 10,11-epoxide levels (by 197% and 137% respectively). Although viloxazine appears to be one of the few antidepressants which can be used safely in patients with epilepsy these results indicate that the drug should be prescribed with great caution in subjects treated with carbamazepine. The mechanism of the interaction probably involves inhibition of the metabolism of both carbamazepine and its active epoxide metabolite.

Transthyretin‐related familial amyloidotic polyneuropathy: description of a cohort of patients with Leu64 mutation and late onset

Transthyretin‐related familial amyloidotic polyneuropathy (TTR‐FAP) usually presents itself as a progressive sensorimotor polyneuropathy with severe autonomic dysfunction and cardiomyopathy. Eighteen patients carrying the Leu64 mutation underwent a series of regular follow‐ups, including: neurological examination, electroneurography, electromyography, electrocardiography and echocardiography, blood analysis, a questionnaire on autonomic symptoms, cardiovascular autonomic tests and a 99mTc‐DPD examination study. A late onset of a slowly progressive disease which reached its terminal stage after about 10  years was observed. The onset was mainly a length‐dependent sensory neuropathy, although a focal onset with carpal tunnel syndrome was detected in three patients. At the onset of the disease, autonomic dysfunction was present in a small number of patients, but, within a few years, this had manifested in all members of the sample group. The only extra‐neurological manifestations were cardiac related. It is reasonable to consider Southern Italy as an endemic focus of TTR‐FAP. An underestimation of disease prevalence could be caused by a late onset of FAP, which can manifest in patients up to their late 70s. Follow‐up of asymptomatic individuals may permit the early detection of symptoms and signs, allowing a detailed record of the natural history of the disease from the beginning and facilitating prompt treatment.

Subcutaneous immunoglobulin in CIDP and MMN: a different long-term clinical response?

Subcutaneous immunoglobulin (SCIg) has been recently proposed as an effective alternative to intravenous immunoglobulin (IVIg) for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN) treatment. The non-inferiority of SCIg over IVIg has been recently confirmed by a 4-month multicentre Italian observational study,1 where a similar efficacy was observed between the two therapies, with the SCIg showing possible advantages of stable plasmatic concentration2 and independence from hospital care. Here we report the 2-year experience of six Italian Neurological Centres, describing the long-term clinical outcomes of 66 patients (45 CIDP and 21 MMN) who were shifted from IVIg to SCIg. All the CIDP and MMN patients treated with SCIg between 2009 and 2014 were considered, including patients with a previous documented response to IVIg (at least 6 months), and a wear-off effect between each IVIg infusion documented by a worsening of at least 1 point at the Overall Neuropathy Limitation Scale (ONLS). Adherence to therapy was the primary outcome measure, while quality of life and clinical predictors of long-term disability were analysed as secondary outcomes. The clinical assessments were regularly performed by means of the ONLS, the Medical Research Council (MRC) scale in eight-muscle group bilaterally, and Life Quality Index (LQI). Clinical worsening was defined as increase of ≥1 ONLS point, requiring augmentation of SCIg dose, SCIg/IVIg combination therapy, or a return to IVIg for stabilising the clinical conditions. SCIg was administered at the patients home, as previously described,1 converting the IVIg dose to an equivalent SCIg dose (20% solution of immunoglobulin ready-to-use) delivered via a programmable infusion pump. All patients signed a written informed consent, and ethical committee approval was obtained (CEI—629 Prot. n 0010675, 25 January 2013). Statistical analyses were carried out utilising the Wilcoxon, Mann-Whitney and Friedman non-parametric tests, Cox proportional hazard regression …

Elevation of plasma phenytoin by viloxazine in epileptic patients: a clinically significant drug interaction.

The effect of viloxazine (150-300 mg daily for 21 days) on plasma phenytoin levels at steady state was examined in 10 epileptic patients stabilised on a fixed phenytoin dosage. After starting viloxazine treatment, plasma phenytoin concentrations increased by 37% on average (range 7-94%) from a mean value of 18.8 micrograms/ml at baseline to a mean value of 25.7 micrograms/ml during the last week of combined therapy. In four patients the rise in plasma phenytoin was associated with the development of signs of phenytoin toxicity. Discontinuation of viloxazine resulted in return of plasma phenytoin towards baseline values and disappearance of the clinical symptoms. The mechanism of interaction probably involves inhibition of phenytoin metabolism by viloxazine. Careful monitoring of plasma phenytoin levels is recommended in patients treated with phenytoin who need to be started on viloxazine therapy.