Comparison of semi-quantitative and visual assessment of early MRI signal evolution in acute ischaemic stroke

Background

The evaluation of DWI/FLAIR mismatch in ischaemic stroke patients with unknown, time from onset can determine the treatment strategy. This approach is based on, visual assessment and may be subject to insufficient inter-rater agreement.

Objective

To compare the inter-rater agreement of visual evaluation of FLAIR MRI and proposed region of interest (ROI) semiquantitative method in large vessel occlusion (LVO) strokes.

Methods

Five readers have analysed MRIs of 104 patients obtained within six hours of the onset of stroke symptoms resulting from LVO visually and semi-quantitatively. For the semiquantitative analysis, a ROI method was used to obtain relative signal intensity compared to the unaffected side. Cut-off values of 1.15 and 1.10 were tested. The analysis yielded FLAIR-positive (abnormal) and negative (normal) findings. Percentage agreement and Fleiss kappa coefficients were calculated.

Results

The visual agreement of 5/5 readers and ≥ 4/5 readers occurred in 31% and 59% of cases respectively. Semi-quantitative evaluation using a cut-off value of 1.15 increased the agreements to 67% and 88% respectively. The agreement of visual evaluation was fair. The semi-quantitative method utilising the cut-off of 1.15 had moderate agreement although it increased the number of FLAIR-negative results compared to the visual evaluation. A low cut-off value of 1.10 didn't improve the agreement significantly.

Conclusion

The inter-rater agreement of visual evaluation of FLAIR in patients with short-duration large vessel occlusion stroke was fair. The high cut-off value of semiquantitative evaluation increased the agreement although it changed the proportion of FLAIR positive and negative results.

Blastic plasmacytoid dendritic cell neoplasm: First retrospective study in the Czech Republic

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with aggressive behavior and poor prognosis. We present the first retrospective analysis mapping its incidence and therapeutic outcomes in patients diagnosed and treated from 2000 to 2017 in the Czech Republic. The cohort comprised 14 patients (10 males, 4 females) with a median age at diagnosis of 39 years (range, 5-68 years). Initially, skin involvement was noted in 10 (71%) patients and bone marrow infiltration was present in 9 (64%). The first complete remission was achieved in 6/14 (43%) patients after acute lymphoblastic leukemia/lymphoma induction therapy and in 3/14 (21%) patients after acute myeloid leukemia regimen. Nine patients underwent allogeneic hematopoietic cell transplantation, with two patients achieving the first complete remission only after allogeneic transplantation. Patients undergoing allogeneic hematopoietic cell transplantation had longer overall survival than those treated without transplantation (the median survival over the period 16.4 vs. 8.1 months). Relapse of the disease was a significant predictor of mortality (p=0.05). Over the study period, patients' survival ranged from 3.3 to 44.2 months, with a median overall survival of 13 months. Our results revealed an effectivity of allogeneic hematopoietic cell transplantation on complete remission achievement in refractory/relapsed disease. The study aimed to present the actual data from the Czech Republic and thus contribute to a global understanding of BPDCN.

Quantitation and biospecific identification of virus-like particles of human papillomavirus by capillary electrophoresis

Capillary electrophoresis (CE) for HPV-VLP quantitation is a very interesting alternative technique compared to those currently used in viral analysis, such as SDS-PAGE, Western blot or protein assay that are destructive and semi-quantitative or non specific. In this study, the quantitative performance of the CE method was evaluated. A main issue in virus quantitation is the absence of reference material. Therefore, the concentration of a HPV16-VLP sample produced in the laboratory was determined using ELISA with Gardasil^®, after adjuvant dissolution, as reference material and conformational H16.V5 antibody. HPV16-VLP concentration was found to influence particles electrophoretic mobility until a plateau was reached for concentrations ≤ 50µgml^-1. As zeta potential is directly proportional to the electrophoretic mobility, it was measured at different HPV-VLP concentrations and the results were in complete accordance with the measured electrophoretic mobilities. The concentration dependence of the electrophoretic mobility could be explained by an overlap of the electrical double layers of adjacent particles. The HPV16-VLP peak identity was demonstrated unequivocally by the study of HPV16-VLP/H16.V5 antibody complex formation using affinity CE. Finally, the CE method was successfully validated following the ICH Q2R1 guidelines. To overcome the sample heterogeneity issue, a well-designed sample preparation was used. Considering sample complexity, validation results were satisfactory with maximum repeatability and intermediate precision RSD of 12.2% and a maximum relative bias of 1.4%.

Promoting Vaginal Distribution of E7 and MCL-1 siRNA-Silencing Nanoparticles for Cervical Cancer Treatment

There is an urgent need to develop a less aggressive and more effective treatment against cervical lesions induced by different high-risk human papillomavirus (HR-HPV). We investigated the potential of a cocktail of small interfering RNA (siRNA) directed against the oncoprotein E6 (E6), the oncoprotein E7 (E7), or the antiapoptotic protein MCL-1 (MCL-1). The combination of siRNA anti-E7 and anti-MCL-1 demonstrated high efficacy on multiple HPV16 and HPV18 cell lines and no effects on healthy keratinocytes. This gene therapy has been considered for a vaginal administration since this route of application holds high potential for the treatment of diseases in the female reproductive tracts. Therefore, PEGylated lipoplexes have been designed and characterized to protect siRNA and to diffuse in the mucosal environment before they reach the cervico/vaginal epithelium. This new nanovector complexed to the combination of active siRNA induced an efficient mRNA knockdown since biological effects were obtained in vitro. This work also provided evidence that the PEGylated lipoplexes had appropriate physicochemical properties to diffuse into a mucin network according to size measurement experiments in artificial mucus. After demonstrating the distribution and the efficacy of siRNA into a 3D-cervical model lesion and through porcine vaginal mucosa, in vivo experiments in mouse have been performed under physiological conditions. This study revealed a complete and sustained coverage of the mucosal epithelium following an unique vaginal administration of fluorescent PEGylated lipoplexes. Overall, our results showed the potential of the PEGylated lipoplexes for the prolonged delivery of active siRNA to treat HPV-induced lesions.

PEGylation of lipoplexes: The right balance between cytotoxicity and siRNA effectiveness

The delivery of small interfering RNA (siRNA) is an attractive therapeutic approach to treat several pathologies, such as viral infections or cancers. However, the stability and the efficacy of these biotherapies are still a major obstacle to their use. Cationic liposomes (DOTAP/Chol/DOPE 1/0.75/0.5M ratio) have been complexed to siRNA (lipoplexes) in order to be administrated by the vaginal route, in the context of HPV16 induced cervical preneoplastic lesions. To overcome the constraint of the cervico-vaginal mucus, PEGylation is required to allow the diffusion of lipoplexes through it. Thereby, PEGylated lipoplexes coated with three types of polyethylene glycol (PEG) as DSPE-PEG2000, DSPE-PEG750 or C8-PEG2000-Ceramide (Ceramide-PEG2000) at different densities have been developed and characterized. PEGylated lipoplexes were successfully prepared and showed a hydrodynamic diameter around 200nm, appropriate for vaginal application. In vitro assays on HPV16 positive cell lines revealed that a positive charge of PEGylated lipoplexes allows a higher mRNA knockdown by siRNA. However, the cationic property is also associated to cytotoxicity. The addition of a high percentage of PEG prevented this toxicity but seemed also to reduce siRNA endosomal escape, probably by steric hindrance. The decreasing of PEG density of Ceramide-PEG2000 to 20% allows the release of siRNA and in consequence, biological activities, contrarily to DSPE-PEG. These results suggest that Ceramide-PEG is more appropriate for siRNA delivery compared to DSPE-PEG. In conclusion, the right balance between cytotoxicity and siRNA effectiveness has been found with the transfection of lipoplexes coated with 20% of Ceramide-PEG2000. This new nanovector could have a high potential against multiple mucosal diseases, such as human papillomavirus-induced genital lesions.

Capillary electrophoresis method to determine siRNA complexation with cationic liposomes

Small interfering RNA (siRNA) inducing gene silencing has great potential to treat many human diseases. To ensure effective siRNA delivery, it must be complexed with an appropriate vector, generally nanoparticles. The nanoparticulate complex requires an optimal physiochemical characterization and the complexation efficiency has to be precisely determined. The methods usually used to measure complexation in gel electrophoresis and RiboGreen^® fluorescence-based assay. However, those approaches are not automated and present some drawbacks such as the low throughput and the use of carcinogenic reagents. The aim of this study is to develop a new simple and fast method to accurately quantify the complexation efficiency. In this study, capillary electrophoresis (CE) was used to determine the siRNA complexation with cationic liposomes. The short-end injection mode applied enabled siRNA detection in less than 5 min. Moreover, the CE technique offers many advantages compared with the other classical methods. It is automated, does not require sample preparation and expensive reagents. Moreover, no mutagenic risk is associated with the CE approach since no carcinogenic product is used. Finally, this methodology can also be extended for the characterization of other types of nanoparticles encapsulating siRNA, such as cationic polymeric nanoparticles.

Freeze-dried mucoadhesive polymeric system containing pegylated lipoplexes: Towards a vaginal sustained released system for siRNA

Topical vaginal sustained delivery of siRNA presents a significant challenge due to the short residence time of formulations. Therefore, a drug delivery system capable to adhere to the vaginal mucosa is desirable, as it could allow a prolonged delivery and increase the effectiveness of the therapy. The aim of this project is to develop a polymeric solid mucoadhesive system, loaded with lipoplexes, able to be progressively rehydrated by the vaginal fluids to form a hydrogel and to deliver siRNA to vaginal tissues. To minimize adhesive interactions with vaginal mucus components, lipoplexes were coated with different derivatives of polyethylene glycol: DPSE-PEG2000, DPSE-PEG750 and ceramide-PEG2000. Based on stability and diffusion properties in simulated vaginal fluids, lipoplexes containing DSPE-PEG2000 were selected and incorporated in hydroxyethyl cellulose (HEC) hydrogels. Solid systems, called sponges, were then obtained by freeze-drying. Sponges meet acceptable mechanical characteristics and their hardness, deformability and mucoadhesive properties are not influenced by the presence of lipoplexes. Finally, mobility and stability of lipoplexes inside sponges rehydrated with vaginal mucus, mimicking in situ conditions, were evaluated by advanced fluorescence microscopy. The release rate was found to be influenced by the HEC concentration and consequently by the viscosity after rehydration. This study demonstrates the feasibility of entrapping pegylated lipoplexes into a solid matrix system for a prolonged delivery of siRNA into the vagina.

Development of anti-E6 pegylated lipoplexes for mucosal application in the context of cervical preneoplastic lesions

Cervical cancer induced by human papillomavirus (HPV) is the fourth highest mortality causing cancer in women despite the use of prophylactic vaccines. E6 targeting represents an attractive strategy to treat this cancer. Indeed, oncoprotein E6 is produced by keratinocytes infected by HPV and is partially responsible for carcinogenesis. E6 interferes with the apoptosis process in stressed cells by degradation of p53 tumor suppressor gene. Our strategy consists in using E6 siRNA complexed with pegylated lipoplexes. The addition of hydrophilic polymer around the nanoparticles is crucial to use them by vaginal application on account of cervicovaginal mucus. Physicochemical characteristics were evaluated and in vitro assays were performed to evaluate transfection potential, E6 mRNA extinction and p53 re-expression. Cationic liposomes DOTAP/Cholesterol/DOPE 1/0.75/0.5 (N/P 2.5) with or without 50% DSPE-PEG2000 and associated with siE6 have demonstrated good physicochemical characteristics in terms of complexation, size, surface charge and stability. Both lipoplexes have been tested on CaSki cell line (HPV 16+) with 50 nM and 100 nM of siE6. Lipoplexes formulations induce 30-40% of E6 mRNA extinction and induce the re-expression of p53. In conclusion, pegylated anti-E6 lipoplexes have demonstrated their efficiency to cross the cellular membrane and to release siRNA into the cytoplasm confirmed by final p53 protein production.

Mucoadhesive cellulosic derivative sponges as drug delivery system for vaginal application

Vaginal delivery of active drugs has been largely studied for local and systemic applications. It is well known that vagina is a complex route, due to physiological and non-physiological changes. Therefore, in order to achieve a prolonged local effect, these variations have to be considered. The aim of this study was to formulate and to characterize a solid system, called sponges, obtained by lyophilization of cellulosic derivative (HEC 250M) hydrogels. These sponges have to meet particular criteria to be adapted for vaginal application: they have to adhere to the vaginal cavity and to be rehydrated by the small amount of vaginal fluids. Moreover, they have to be easily manipulated and to be stable. Three freezing temperatures have been tested to prepare sponges (-15°C, -25°C, -35°C). By SEM analyzes, it was observed that the pores into the sponges were smaller and numerous as the freezing temperature decreases. However, this temperature did not have any influence on the rehydration speed that was rather influenced by the HEC concentration. Viscosity and mucoadhesive strength of hydrogels and corresponding sponges were also measured. It appeared that these parameters are mainly dependent on the HEC concentration. These mucoadhesive sponges can be considered as potential drug delivery systems intended for vaginal application.

Food choice: a conceptual model of the process

Interviews examining the food choice process were conducted with 29 adults, primarily individuals making grocery store food choice decisions, who were sampled for their diversity. These people were asked about how they chose foods when shopping and in other settings, and what influenced their choices. Verbatim transcripts of the interviews were analysed using qualitative methods that included constant comparison, concept mapping, and case summaries, and a conceptual food choice process model was developed. Data from the interviews are presented to illustrate the structure of this conceptual model. People's life course experiences affected major influences on food choice that included ideals, personal factors, resources, social contexts and the food context. These influences informed the development of personal systems for making food choices that incorporated value negotiations and behavioral strategies. Value negotiations weighed sensory perceptions, monetary considerations, health and nutrition beliefs and concerns, convenience, social relationships and quality of food choice decisions. Strategies employed to simplify the food choice process developed over time. The conceptual food choice process model represents the rich and complex bases of food practices, and provides a theoretical framework for research and practice in nutrition.