Functionalisation of TiO2 nanoparticles with a fluorescent organosilane: A synergy enabling their visualisation in biological cells and an enhanced photocatalytic activity.

Nanoparticles, such as TiO2 particles, have a great potential for biomedical applications due to their ultra-small size and large specific surface area. However, their detection within cells is to date more than challenging. Thus, implementing fluorescence properties to nanoparticles via their controlled functionalisation with an organic chromophore is an original and efficient strategy to enable their visualization. In this work, a silylated coupling agent bearing a luminescent rhodamine B group was synthesised and grafted on the surface of anatase nanoparticles. The successful functionalisation was demonstrated via zeta potential, dynamic light scattering and diffuse reflectance infrared Fourier transform analyses. Remarkably, the obtained luminescent TiO2 particles showed an improved photocatalytic activity compared to the pristine nanoparticles. Both, as-synthesised and functionalised TiO2 nanoparticles samples appear to be non-toxic towards malignant and non-malignant cells. Moreover, the detection of the functionalised particles within cultured cells was proven to be easy and efficient via confocal fluorescence microscopy.

Mode structure and ray dynamics of a parabolic dome microcavity

We consider the wave and ray dynamics of an electromagnetic field in a parabolic dome microcavity. The structure of the fundamental s wave involves a main lobe in which the electromagnetic field is confined around the focal point in an effective volume of the order of a cubic wavelength, while modes with finite angular momentum have a structure that avoids the focal area and have correspondingly larger effective volumes. The ray dynamics indicate that the fundamental s wave is robust with respect to small geometrical deformations of the cavity, while the higher order modes are unstable, giving rise to optical chaos. We discuss the incidence of these results on the modification of the spontaneous emission dynamics of an emitter placed in such a parabolic dome microcavity.

[Liver transplantation and the major histocompatibility complex]. / Transplantation hépatique et complexe majeur d'histocompatibilité.

We have carried out a retrospective study over 308 liver transplant patients (31 of them have had a retransplantation) in Professor Bismuth's Department at Paul Brousse Hospital. The purpose of the study was a search for the possible effect of donor/recipient major histocompatibility complex on the evolution of the transplantation. We chose to study four parameters: early acute rejection; chronic rejection; retransplantation cases and death frequency; graft survival. We observed the following: for HLA A locus: in cases of total or partial compatibility there are more moderate early acute rejections than in the case of incompatibility (p less than 0.02); for HLA B locus: in the case of total compatibility there are more chronic rejections than in cases of partial or total incompatibility (p less than 0.03); for joint A and B locus: the results are similar to those of A locus (p less than 0.03); for HLA class I: we observed no effect either on graft survival or on retransplantation cases or on death frequency; for HLA DR: we did not find any effect on the studied parameters. Considering the low statistical significance of these results and in order to confirm our analysis, we have started a prospective study in collaboration with two other European Transplantation Centers.

[Subcutaneous analgesic administration]. / L'administration sous-cutanée d'analgésique.

In March 1989, Saint Luke's Hospital in Montréal piloted the use of continuous and intermittent subcutaneous injection of analgesics. This practice involved patients whose pain could not be relieved by traditional methods of analgesic administration. The article describes the positive results of the project, and clearly identifies suitable patients. It also outlines the advantages, limiting factors and risks involved with each type of infusion. Procedures for set-up and monitoring are briefly explained. The authors conclude that family members of patients can be easily taught to perform the procedure at home.

[Inhibition of tumoral graft growth by pretreatment with normal or heat-modified tumoral cells]. / Inhibition de la croissance d'une greffe tumorale par injections préalables de cellules tumorales intactes ou modifiées par la chaleur.

The intravenous injection of Ehrlich tumour cells (TC) into Swiss mice, or BP8-fibrosarcoma cells into C3H mice, caused no intra-organ dissemination of the tumour but resulted in increasing resistance of animals to these two tumours. The percentage of mice protected against a regularly lethal dose of TC given intraperitoneally (i.p.) increased with the dose and the number of immunizing injections to the i.p. challenge. However, after high or repeated doses a cancerous nodule sometimes developed at the site of intravenous injections (penis vein), which caused death of the animal, not by extension of the tumour but by urethral occlusion. Moderate heating (46, 49.5 or 52 degrees C) of the TC did not impair their immunogenicity but prevented their multiplication in normal mice. It was thus possible, by intradermal injections of heated TC, to protect mice against a dose of intact TC. The efficiency of prophylaxis depended on the temperature to which the cells were exposed (optimal temperature depending on the type of tumour), on the number of injections and on the medium in which the cells were suspended. When Freund's complete adjuvant was used, all mice were protected against tumour ascites following challenge.

[Antitumoral immunity induced by the administration of homologous and isologous tumoral cells treated by moderate heating]. / Immunité antitumorale induite par l'administration de cellules tumorales homologues et isologues traitées par un chauffage ménagé

Treatment of tumour cells with heat ranging between 46 and 52 degrees C attenuates strongly their virulence and renders the tumour cells immunogenic to the host. By repeated administration of heat treated tumour cells suspended in Freund's complete adjuvant, the animals acquire a state of immunity which makes them tolerant to tumour inocula 100% lethal in the controls. The immunity so conferred is cell-mediated and can be adoptively transferred to isogenic recipients with donor peritoneal exudate and, to a lesser degree, splenic cells.