Renal involvement in mitochondrial cytopathies

Mitochondrial cytopathies constitute a group of rare diseases that are characterized by their frequent multisystemic involvement, extreme variability of phenotype and complex genetics. In children, renal involvement is frequent and probably underestimated. The most frequent renal symptom is a tubular defect that, in most severe forms, corresponds to a complete De Toni-Debré-Fanconi syndrome. Incomplete proximal tubular defects and other tubular diseases have also been reported. In rare cases, patients present with chronic tubulo-interstitial nephritis or cystic renal diseases. Finally, a group of patients develop primarily a glomerular disease. These patients correspond to sporadic case reports or can be classified into two major defects, namely 3243 A>G tRNALEU mutations and coenzyme Q10 biosynthesis defects. The latter group is particularly important because it represents the only treatable renal mitochondrial defect. In this Educational Review, the principal characteristics of these diseases and the main diagnostic approaches are summarized

Panniculite lipoatrophiante de l’adulte : traitement par hydroxychloroquine

International audienceBACKGROUND: Lipoatrophic panniculitis is generally considered to be a rare disease affecting children. We report a case involving this condition in an adult patient presenting with striking clinical features and responding to hydroxychloroquine therapy. We discuss the nosological relationship between lipoatrophic panniculitis and connective tissue panniculitis.PATIENTS AND METHODS: A 62-year-old woman was referred to our institution with a six-month history of painful erythematous nodules and plaques on the calves, thighs, buttocks, breasts, abdomen and arms. With each outbreak of new lesions, she felt unwell and experienced fever, chills and sweating. After a few weeks, the lesions progressed circumferentially and led to large areas of subcutaneous atrophy showing a central depression covered with a yellowish, supple skin and surrounded by an annular, infiltrated, erythematous and tender inflammatory margin. Deep subcutaneous biopsy specimens showed typical features of lobular and septal lipophagic panniculitis, with a dense inflammatory infiltrate composed of large histiocytes, multinucleated giant cells and few neutrophils, without vasculitis. The patient was started on hydroxychloroquine 400 mg daily. Three weeks later, her pain and tenderness had completely resolved and the inflammatory margin of the lesions had clearly regressed.DISCUSSION: This unique condition, with distinctive clinical and histological features, is similar to cases described under the term "lipophagic panniculitis", seen mostly in children, but also "connective tissue panniculitis". Their clinical resemblance and response to hydroxychloroquine therapy leads us to think that these two entities, previously subsumed under the eponym of Weber-Christian disease or Rothman-Makai syndrome, are closely related.CONCLUSION: Dermatologists and dermatopathologists should be made aware of this unusual entity, and of the fact that it can arise in adult patients, so that they may make an early diagnosis and thus prevent the unsightly consequences of lipoatrophy.</p

Hybrid quantum systems with high-T c_c c superconducting resonators

Abstract Superconducting microwave resonators are crucial elements of microwave circuits, offering a wide range of potential applications in modern science and technology. While conventional low-T $$_c$$ c superconductors are mainly employed, high-T $$_c$$ c cuprates could offer enhanced temperature and magnetic field operating ranges. Here, we report the realization of $$\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_{7-\delta }$$ YBa 2 Cu 3 O 7 - δ superconducting coplanar waveguide resonators, and demonstrate a continuous evolution from a lossy undercoupled regime, to a lossless overcoupled regime by adjusting the device geometry, in good agreement with circuit model theory. A high-quality factor resonator was then used to perform electron spin resonance measurements on a molecular spin ensemble across a temperature range spanning two decades. We observe spin-cavity hybridization indicating coherent coupling between the microwave field and the spins in a highly cooperative regime. The temperature dependence of the Rabi splitting and the spin relaxation time point toward an antiferromagnetic coupling of the spins below 2 K. Our findings indicate that high-Tc superconducting resonators hold great promise for the development of functional circuits. Additionally, they suggest novel approaches for achieving hybrid quantum systems based on high-T $$_c$$ c superconductors and for conducting electron spin resonance measurements over a wide range of magnetic fields and temperatures