Search

Controversy still exists about the pro- or antithrombotic side effects of contrast media used in daily medical practice. Recent reports have shown that various contrast media, including ionic compounds, have deleterious prothrombotic actions. A new evaluation of these adverse side effects is reported here, with the study of the dose–effect relationship. Two ionic (ioxaglate and diatrizoate) and two non-ionic contrast media (iopamidol and iohexol) were studied. Experiments were done on 22 groups of 5 Wistar male rats each, using a Laser Argon-induced thrombosis model in mesenteric microvessels. Three parameters were studied: the number of laser beams needed to induce platelet thrombus formation, the number of emboli, and the duration of embolization. Platelet count and platelet aggregation also were determined. Iopamidol and iohexol induced a significant rise in both the number of emboli and the duration of embolization in mesenteric microvessels at doses up to 1 mL/kg. Ioxaglate and diatrizoate also significantly increased these parameters at doses up to 2 mL/kg. All the products tested decreased platelet count, inducing a −17 to −30% variation from control values. Diatrizoate and ioxaglate inhibited platelet aggregation, while iopamidol and Iohexol behaved as activators. All non-ionic, and to a lesser extent, all ionic contrast media demonstrated prothrombotic properties.

Objective: The aim is to search for a pattern of muscle involvement in patients with nemaline myopathy due to mutations in the NEB gene and to correlate MRI findings with clinical severity. Methods: The series consisted of seven patients followed in two different French centers and for whom whole body MRI (WBMRI) was done. T1-TSE sequences in axial and frontal views were performed. Results: the clinical phenotype was determined by the severity of motor and respiratory involvement. Two patients had severe phenotype: wheelchair bound and total dependence on mechanical ventilation. Two cases had moderate phenotype: able to walk but limitation of activity outside due to fatigue, severe restrictive lung disease. Three patients have mild phenotype: complete autonomy, proximal weakness after prolonged activity, and no need for ventilator support. WBMRI showed in all patients marked involvement of tongue and tibialis anterior muscles. Other muscles also altered were lateral pterygoid, soleus and extensor digitorum (severe cases); temporal, abdominal belt and soleus muscles (moderate); extensor digitorum (mild). Discussion: NEB-mutated patients present a wide spectrum of severity. A positive correlation between the clinical severity and the degree of muscle abnormalities is observed. Although there is variability in the distribution of the abnormalities in trunk and proximal limbs, a cranial and distal limb involvement is identified. Conclusion: Selective involvement of the tongue and tibialis anterior muscles in NEB mutated patients makes WBMRI a useful tool for diagnosis of nemaline myopathy.

Megaconial myopathies are known as rare and severe autosomal recessive, early-onset pediatric diseases caused by mutations in the CHKB gene, characterized on muscle biopsy by the presence of giant mitochondria. We present here a 50-year old male, stemming from a Jewish consanguineous Lebanese family, who developed progressive muscle wasting and weakness form age 5 years on. The course was slowly progressive; the patient remained ambulant until age 37 years. He displayed episodes of regressive paroxysmal supraventricular tachyarrhythmia at age 46 and 47 years, and a severe restrictive respiratory insufficiency from his early thirties. The patient underwent three muscle biopsies, at age 28, 39 and 49 years. Diagnosis was suspected on the last biopsy, showing an uneven distribution of the intermyofibrillary network associating peripheral giant mitochondria with central areas devoid of organelles. Electron microscopy confirmed the presence of numerous giant mitochondria spanning up to two or more sarcomeres and reaching 1.2–1.8 μm in length and 0.6–0.8 μm in width. Retrospective analysis of the two first biopsies found some similar abnormalities. The patient harbours a homozygous c.499A > T (p.Ile167Phe) substitution in exon 4 of the mutation of the CHKB gene. A whole-body MRI was performed at the age of 42. A diffuse and severe fatty replacement (Mercuri 4) of muscles was detectable. Masticatory muscles and tongue as well as forearms, rectus femoris at thighs and anterior compartment of the legs were totally or partially preserved. This case, resembling a congenital myopathy, differs from the usual pattern of megaconial myopathies and expands the clinical spectrum of this disorder.