A model of mandibular irradiation in the rabbit: preliminary results

Radiotherapy is widely used in the treatment of head and neck cancers. Its major adverse effect is osteoradionecrosis, which can occur during the whole life of the patient, involving the vital prognosis. The aim of the study was to develop a model for irradiation of the rabbit mandible in order to have a better knowledge of radiotherapy-induced bone alterations and thus a better prevention and treatment of osteoradionecrosis. The control group consisted in 7 rabbits and was used to assess anatomical and histological parameters of the rabbit’s mandible. A first group of 14 rabbits was weekly irradiated at doses of 5.5 Gy during 5 weeks, at a total dose of 46.8Gy. Sacrifices were done at 1 week, 4 weeks, 12 weeks and 24 weeks. As histological analysis did not reveal statistical differences with the control group, a second group (3 rabbits) was weekly irradiated at 8.0, 8.5 and 9 Gy during 5 weeks. The first histological results seem to show vascular alterations, bone cells decrease and alterations of bone architecture. The role of intra alveolar collagen sponges, PRF®, ultrasounds and stem cells in bone regeneration after radiotherapy will be further studied. La radiothérapie est une modalité thérapeutique utilisée quasi systématiquement dans le traitement des cancers des voies aérodigestives supérieures. Son principal effet secondaire est l’ostéoradionécrose, qui peut survenir tout au long de la vie du patient et compromettre le pronostic vital. Le but de ce travail est de mettre au point un modèle d’irradiation des maxillaires chez le lapin afin de mieux connaître la pathogénie de l’ostéoradionécrose et proposer une prévention et des traitements plus efficaces. Un groupe contrôle de 7 lapins a permis de connaître l’anatomie et l’histologie de la mandibule de lapin. Un premier groupe de 14 lapins a été irradié à raison d’une séance hebdomadaire de 5.5 Gy pendant 5 semaines, soit un équivalent de dose de 46.8 Gy. Ils ont été sacrifiés à 1, 4, 12 et 24 semaines. L’analyse statistique n’ayant pas montré de différences significatives avec le groupe contrôle, un second groupe de 3 lapins a été irradié à une séance hebdomadaire de 8.0, 8.5 et 98.0 Gy respectivement pendant 5 semaines. Les premiers résultats histologiques montrent une altération vasculaire, la diminution du nombre de cellules osseuses et des modifications de l’architecture osseuse. Le rôle des éponges collagéniques intra alvéolaires, du PRF®, des ultrasons et des cellules souches sera étudié ultérieurement

Stochastic Eulerian Lagrangian Methods for Fluid-Structure Interactions with Thermal Fluctuations

We present approaches for the study of fluid-structure interactions subject to thermal fluctuations. A mixed mechanical description is utilized combining Eulerian and Lagrangian reference frames. We establish general conditions for operators coupling these descriptions. Stochastic driving fields for the formalism are derived using principles from statistical mechanics. The stochastic differential equations of the formalism are found to exhibit significant stiffness in some physical regimes. To cope with this issue, we derive reduced stochastic differential equations for several physical regimes. We also present stochastic numerical methods for each regime to approximate the fluid-structure dynamics and to generate efficiently the required stochastic driving fields. To validate the methodology in each regime, we perform analysis of the invariant probability distribution of the stochastic dynamics of the fluid-structure formalism. We compare this analysis with results from statistical mechanics. To further demonstrate the applicability of the methodology, we perform computational studies for spherical particles having translational and rotational degrees of freedom. We compare these studies with results from fluid mechanics. The presented approach provides for fluid-structure systems a set of rather general computational methods for treating consistently structure mechanics, hydrodynamic coupling, and thermal fluctuations.Comment: 24 pages, 3 figure

Glial Fibrillary Acidic Protein Autoimmunity: A French Cohort Study

Background and ObjectivesTo report the clinical, biological, and imaging features and clinical course of a French cohort of patients with glial fibrillary acidic protein (GFAP) autoantibodies.MethodsWe retrospectively included all patients who tested positive for GFAP antibodies in the CSF by immunohistochemistry and confirmed by cell-based assay using cells expressing human GFAPα since 2017 from 2 French referral centers.ResultsWe identified 46 patients with GFAP antibodies. Median age at onset was 43 years, and 65% were men. Infectious prodromal symptoms were found in 82%. Other autoimmune diseases were found in 22% of patients, and coexisting neural autoantibodies in 11%. Tumors were present in 24%, and T-cell dysfunction in 23%. The most frequent presentation was subacute meningoencephalitis (85%), with cerebellar dysfunction in 57% of cases. Other clinical presentations included myelitis (30%) and visual (35%) and peripheral nervous system involvement (24%). MRI showed perivascular radial enhancement in 32%, periventricular T2 hyperintensity in 41%, brainstem involvement in 31%, leptomeningeal enhancement in 26%, and reversible splenial lesions in 4 cases. A total of 33 of 40 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89%), despite a severe clinical presentation. Adult and pediatric features are similar. Thirty-two patients were treated with immunotherapy. A total of 11/22 patients showed negative conversion of GFAP antibodies.DiscussionGFAP autoimmunity is mainly associated with acute/subacute meningoencephalomyelitis with prodromal symptoms, for which tumors and T-cell dysfunction are frequent triggers. The majority of patients followed a monophasic course with a good outcome

Preface

This is the final version. Available from CEUR Workshop Proceedings via the URL in this record.

A reassessment of the Hypoglossum group (Delesseriaceae, Rhodophyta), with a critique of its genera

A reassessment of the Hypoglossum group (Delesseriaceae, Rhodophyta), with a critique of its genera. Eight genera are assigned to the Hypoglossum Kützing, Phitymophora J. Agardh, Pseudobranchioglossum Bodard, and Zellera Martens. The circumscription of the group is emended to include forms with network-forming ( Zellera ) an dspirally twisted ( Duckerella ) thalli. The definition of the group is lalso modified to include members (e.g. some species of Hypoglossum ) in which tetrasporangia are produced by primary cells as in the Caloglossa group. Exogenous branching, a distinguishing feature of the closely related Caloglossa group, never occurs in the Hypoglossum group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47938/1/10152_2006_Article_BF02365624.pd