Evaluation and application of a new scintillator-based heat-resistant back-scattered electron detector during heat treatment in the scanning electron microscope.

A new high-temperature detector dedicated to the collection of backscattered electrons is used in combination with heating stages up to 1050°C, in high-vacuum and low-vacuum modes in order to evaluate its possibilities through signal-to-noise ration measurements and different applications. Four examples of material transformations occurring at high temperature are herein reported: grain growth during annealing of a rolled platinum foil, recrystallisation of a multiphased alloy, oxidation of a Ni-based alloy and complex phase transformations occurring during the annealing of an Al-Si coated boron steel. The detector could be potentially adapted to any type of SEM and it offers good opportunities to perform high-temperature experiments in various atmospheres.

Optimizing the effective spot size and the dosimetric leaf gap of the AcurosXB algorithm for VMAT treatment planning.

PURPOSE: The aim of this study is to provide and test a new methodology to adjust the AcurosXB beam model for VMAT treatment plans. METHOD: The effective target spot size of the AcurosXB v15 algorithm was adjusted in order to minimize the difference between calculated and measured penumbras. The dosimetric leaf gap (DLG) was adjusted using the asynchronous oscillating sweeping gap tests defined in the literature and the MLC transmission was measured. The impact of the four parameters on the small field output factors was assessed using a design of experiment methodology. Patient quality controls were performed for the three beam models investigated including two energies and two MLC models. RESULTS: Effective target spot sizes differed from the manufacturer recommendations and strongly depended on the MLC model considered. DLG values ranged from 0.7 to 2.3 mm and were found to be larger than the ones based on the sweeping gap tests. All parameters were found to significantly influence the calculated output factors, especially for the 0.5 cm × 0.5 cm field size. Interactions were also identified for fields smaller than 2 cm × 2 cm, suggesting that adjusting the parameters on the small field output factors should be done with caution. All patient quality controls passed the universal action limit of 90%. CONCLUSION: The methodology provided is simple to implement in clinical practice. It was validated for three beam models covering a large variety of treatment types and localizations.

Chronic active Epstein-Barr virus infection with cutaneous and sinus lymphoproliferation in a white female patient with 25 years' follow-up: an original case report.

Chronic active Epstein-Barr virus infection (CAEBV) is characterized by chronic infectious mononucleosis-like symptoms associated with very high viral load, as assessed by quantitative polymerase chain reaction. We present an unusual case in a French woman who was followed up over 25 years with cutaneous and sinus lymphoproliferation. This white woman presented with a long history of recurrent cutaneous necrotic papules of the skin, which started during childhood and healed spontaneously with depressed scars. The lesions spread to the left maxillary sinus and were associated with hepatomegaly and splenomegaly with no other visceral locations. Pathological examination of the skin and sinus revealed a dermal monoclonal T-cell lymphoproliferative disorder, CD7(+) and CD20(-) , with no epidermotropism. T-cell receptor rearrangement was positive, showing the monoclonality from the first biopsy. This T-cell proliferation was positive for EBV-encoded small RNA and was associated with a high EBV viral load. Since then, the patient has been in good health, despite a permanently high EBV viral load. Hydroa vacciniforme (HV)-like lymphoma and natural killer/T-cell lymphoma were discussed, but none really fit our case. Natural killer cell lymphoma was ruled out because of the indolent course, but sinus lesions do not exist in HV-like lymphoma. A therapeutic approach is difficult because of the coexistence of viral infection and monoclonal T-cell proliferation. Chemotherapy is not efficient and induces immunosuppression, which may worsen the prognosis. Although rituximab may have an immunomodulatory function, it was not effective in our case.

[Acanthosis nigricans in children and Crouzon syndrome]. / Acanthosis nigricans chez l'enfant et syndrome de Crouzon.

BACKGROUND: Crouzon syndrome with acanthosis nigricans is a rare form of Crouzon syndrome in which craniosynostosis and facial dysmorphism are associated with acanthosis nigricans. PATIENTS AND METHODS: Cutaneous examination of a 9-year-old child presenting bicoronal craniosynostosis revealed acanthosis nigricans of the cervical, axillar, inguinal and popliteal regions which appeared at the age of two. He had a dysmorphic face including a large forehead, hypertelorism, mid-face hypoplasia, prognathism and low-set ears. These clinical anomalies suggested a case of Crouzon syndrome with acanthosis nigricans, which was later confirmed by the finding of a mutation in the FGFR3 gene. DISCUSSION: Acanthosis nigricans in children is often a cutaneous marker of insulin resistance. However, it may also form part of diverse diseases, notably those of genetic origin. The association of craniosynostosis and acanthosis nigricans allows incrimination of the FGFR3 gene from the outset and diagnosis of Crouzon syndrome with acanthosis nigricans. In the present case, dermatological examination allowed an aetiology of craniosynostosis to be determined.

[Infantile bullous pemphigoid]. / Pemphigoïde bulleuse du nourrisson.

BACKGROUND: Bullous pemphigoid (BP) is a form of autoimmune bullous disease commonly seen in adults but rare amongst children. Only a few cases have been described in children after vaccination. This article reports a new case of BP that occurred in an infant after a first vaccination. PATIENTS AND METHODS: A 3-month-old girl presented a bullous eruption 2 weeks after a first injection of Infanrix Quinta(®) and Prevenar(®). The eruption began on her palms and soles. It was associated with urticaria-like lesions on her thighs, chest and abdomen. A histological skin examination and direct immunofluorescence showed dermal-epidermal cleavage and IgG and C3 deposits in the epidermal basement membrane zone, which are typical features of BP. No antibodies against basement membrane were seen. Clinical remission was observed after 5 weeks of treatment with dermal-corticosteroids. Resumption of the vaccination schedule did not induce any recurrence of the disease. DISCUSSION: The clinical presentation of BP amongst children differs from that seen in adults, notably in terms of the predominance of palmoplantar lesions in children aged less than 1 year. In addition, lesions on mucous membrane are more frequently reported amongst older children. Histological findings are similar in all age groups. The outbreak of BP due to a vaccinal antigen appears hypothetical. However, continuation of the vaccination schedule did not induce any recurrence. Moreover, it is a rare disease amongst children despite the frequency of vaccinations in this population. CONCLUSION: Childhood BP is a diagnosis that should be considered in any case of bullous eruption, in particular if the palms and soles are affected. It is a benign disease that resolves in less than a year under treatment. The current data do not incriminate vaccines in the outbreak of childhood BP and suggest that continuation of vaccination is not contraindicated.

Comparison of five dose calculation algorithms in a heterogeneous media using design of experiment.

PURPOSE: Design of experiments (DoE) provides a methodology to reveal the influence of input values on the measured output with a limited number of trials. The purpose of this study was to describe how DoE can be used to evaluate the performances of several dose calculation systems in heterogeneous media, including algorithms like Pencil Beam (PB), Anisotropic Analytical Algorithm (AAA), Acuros XB (AXB), Monte Carlo (MC) and Collapsed Cone Volume (CCV). METHOD: This study was carried out using a CIRS Model 002LFC IMRT Thorax Phantom customized with a water-equivalent heterogeneity inside the lung. The calculated dose distributions were compared to Gafchromic® EBT3 film measurements. The beam configurations were selected using DoE to study the influence of five parameters simultaneously (energy, collimator angulation, gantry angulation, X and Y jaws) and to optimize the number of experiments. An analysis of variance was performed over the entire irradiation field and over various regions of interest (tumour, shadow of tumour and lungs). RESULTS: DoE enabled to quantify and determine the statistically significant factors, leading to an evaluation of the dose calculation systems in the lung case. The resulting scoring could be as follow (from best to worst): AXB_Dm, CCV, AXB_Dw, XVMC_Dm, XVMC_Dw, AAA and last PB. Differences between the algorithms were specially observed in the tumour and the shadow regions. CONCLUSION: DoE is a robust statistical method to compare several dose calculation systems. The various analyses lead to the conclusion that AXB handled more accurately most of the situations investigated in heterogeneous media.

[Cutaneous infantile hemangiomas]. / Hémangiomes infantiles cutanés.

Superficial vascular anomalies are a heterogeneous group of diseases, developed from various types of vessels and differentiated by their clinical presentation, progression, and prognosis. Their classification was first published by Mulliken and Glowacki in 1982, then endorsed by the International society of the study of vascular anomalies (ISSVA) in 1996 and updated in 2014. It separates vascular anomalies into two categories: vascular tumors characterized by cellular proliferation and vascular anomalies that are structural anomalies of blood vessels. Infantile hemangiomas (IHs) are the most frequent childhood vascular tumor. In most cases, IHs are small, involute progressively with or without a few sequelae, and do not require any treatment. However, in particular localizations or in complicated hemangiomas, treatment is essential to limit tumor growth and accelerate their involution. Propranolol is now the first-line treatment. Its efficacy and safety have been clearly demonstrated.

Riluzole series. Synthesis and in vivo "antiglutamate" activity of 6-substituted-2-benzothiazolamines and 3-substituted-2-imino-benzothiazolines.

Two series of analogues of riluzole, a blocker of excitatory amino acid mediated neurotransmission, have been synthesized: monosubstituted 2-benzothiazolamines and 3-substituted derivatives. Of all the compounds prepared in the first series, only 2-benzothiazolamines bearing alkyl, polyfluoroalkyl, or polyfluoroalkoxy substituents in the 6-position showed potent anticonvulsant activity against administration of glutamic acid in rats. The most active compounds displaying in vivo "antiglutamate" activity were the 6-OCF(3) (riluzole), 6-OCF(2)CF(3), 6-CF(3), and 6-CF(2)CF(3) substituted derivatives with ED(50) values between 2.5 and 3.2 mg/kg i.p. Among the second series of variously substituted benzothiazolines, compounds as active as riluzole or up to 3 times more potent were identified in two series: benzothiazolines bearing a beta-dialkylaminoethyl moiety and compounds with an alkylthioalkyl chain and their corresponding sulfoxides and sulfones. The most potent derivatives were 2-imino-3-(2-methylthio)- and 2-imino-3-(2-methylsulfinyl)-ethyl-6-trifluoromethoxybenzothiazolines (61 and 64, ED(50) = 1.0 and 1.1 mg/kg i.p., respectively). In addition, intraperitoneal administration of some of the best benzothiazolines protected mice from mortality produced by hypobaric hypoxia.

Synthesis and biological evaluation of O-alkylated tropolones and related alpha-ketohydroxy derivatives as ribonucleotide reductase inhibitors.

A series of O-alkylated tropolones and related alpha-ketohydroxy compounds were evaluated for their biological activities and were shown to present an expected ribonucleotide reductase inhibition and cytotoxicity against some cancer cell lines but no antitubulin activity. Pharmacomodulation studies were realised to understand and enhance the observed activities. These original benzylic, heterocyclic and allylic compounds have been synthesised by a phase-transfer catalysed O-alkylation developed in our laboratories.

Asymmetrically substituted ethylenediamine platinum(II) complexes as antitumor agents: synthesis and structure-activity relationships.

A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one carbon atom of the ethylenediamine ligand, with or without a functional group on the side chain, have been prepared and investigated for antitumor activity against L1210 leukemia. They were tested both in vitro, with cisplatin-sensitive and resistant cell lines, and in vivo, with cisplatin-sensitive and resistant tumors grafted i.p. in B6D2F1 mice. The rationale for this study was to test how charge, polarity and shape of the R side chain influence antitumor activity. Complexes carrying one or more ammonium groups on the side chain were all inactive. Derivatives with a carbamate function attached by the nitrogen atom, via a methylene group, to the ethylenediamine moiety ('N-bound' carbamate) were highly active in vitro and in vivo. The best results were obtained with these carbamates bearing hydrophobic substituents of intermediate size. Replacement of N-bound by O-bound carbamate or by urea groups led to decreased in vivo activity. Sulfonamide derivatives were all inactive. Good to excellent activities were also recorded for complexes bearing bulky bicycloalkyl substituents, without any functional group, attached to one ethylenediamine carbon atom. Thus, it is the steric features of the side chain rather than its polarity that appear to favor the antitumor activity of the complex. Compared to cisplatin and oxaliplatin, the present complexes do not exhibit advantages in terms of experimental antitumor activities in solid tumor models.