Single and combined impacts of irradiation and surgery on lymphatic vasculature and fibrosis associated to secondary lymphedema.

Lymphedema (LD) refers to a condition of lymphatic dysfunction associated with excessive fluid accumulation, fibroadipose tissue deposition and swelling. In industrialized countries, LD development mainly results from a local disruption of the lymphatic network by an infection or cancer-related surgery (secondary LD). In the absence of efficient therapy, animal models are needed to decipher the cellular and molecular mechanisms underlying LD and test putative drugs. In this study, we optimized and characterized a murine model of LD that combines an irradiation of the mice hind limb and a radical surgery (lymph node resection associated to lymphatic vessel ligation). We investigated the respective roles of irradiation and surgery in LD formation by comparing their impacts, alone or in combination (with different intervention sequences), on eight different features of the pathology: swelling (paw thickness), indocyanine green (ICG) clearance, lymphatic vasculature remodeling, epidermal and dermal thickening, adipocyte accumulation, inflammatory cell infiltration and collagen deposition. This study supports the importance of radiation prior to surgery to experimentally induce a rapid, severe and sustained tissue remodeling harboring the different hallmarks of LD. We provide the first experimental evidence for an excessive deposition of periostin (POSTN) and tenascin-C (TNC) in LD. Through a computerized method of digital image quantification, we established the spatial map of lymphatic expansion, as well as collagen, POSTN and TNC deposition in papillary and reticular dermis of lymphedematous skins. This mouse model is available to study the patho-physiology of LD and test potential therapeutic targets.

Role of surface microgeometries on electron escape probability and secondary electron yield of metal surfaces.

The influence of microgeometries on the Secondary Electron Yield (SEY) of surfaces is investigated. Laser written structures of different aspect ratio (height to width) on a copper surface tuned the SEY of the surface and reduced its value to less than unity. The aspect ratio of microstructures was methodically controlled by varying the laser parameters. The results obtained corroborate a recent theoretical model of SEY reduction as a function of the aspect ratio of microstructures. Nanostructures - which are formed inside the microstructures during the interaction with the laser beam - provided further reduction in SEY comparable to that obtained in the simulation of structures which were coated with an absorptive layer suppressing secondary electron emission.

[Coronary diseases in the black African. Apropos of a 2d group of 50 patients. Diagnostic and epidemiological aspects]. / Coronaropathies chez l'africain noir. A propos dun deuxième groupe de 50 malades suspects. Aspects diagnostiques et épidémiologiques

1. Study of a group of 50 patients suspected to have coronary artery disease. This is a complement to a previous study concerning "definite" coronary patients. 2. The method followed consisted in cross-examination of the files by three observers in order to separate the subjects who seemed really affected by coronary artery disease. This treble examination led to a rather restrictive selection. To facilitate the study, the patients were subdivided into 4 groups: patients with arterial hypertension, with diabetes mellitus, with cardiac failure, with a heart disease and miscellaneous patients. 3. The study of the 20 files which were discarded was peculiarly interesting as it provided the opportunity to underline the differential diagnosis either with common diseases (left ventricular overload, heart block, brain vascular accident), or with more specific diseases for Black Africa (endomyocardial fibrosis, aneurysm of the left ventricle, cardiomyopathy). In that respect, it is underlined that, in the absence of any anatomical or functional disease, the electrocardiogram of the healthy Black is identical to that of the White. 4. Study of the 30 patients considered as coronary made it possible to underline aetiological and epidemiological factors, although some are still lacking. However the facts observed could be compared with those reported in a previous work concerning 45 "definite" coronary patients. The overall documents thus gathered in 75 patients suggest that the African candidate to coronary artery diseases resembles his Occidental homologue, but that he might have kept a traditional diet.