RBL cells as models for in vitro studies of mast cells and basophils

Since their establishment in 1981, RBL-2H3 cells have been widely used as a mast cell (MC) model. Their ability to be easily grown in culture in large amounts, their responsiveness to FcεRI-mediated triggers and the fact that they can be genetically manipulated, have provided advantages over primary MCs, in particular for molecular studies relying on genetic screening. Furthermore, the ability to generate clones that stably express proteins of interest, for example, a human receptor, have marked the RBL cells as an attractive MC model for drug screening. Indeed, 3 RBL reporter cell lines (RS-ATL8, NFAT-DsRed, and NPY-mRFP) have been generated providing useful models for drug and allergen screening. Similarly, RBL cells stably expressing the human MrgprX2 receptor provide a unique paradigm for analyzing ligand interactions and signaling pathways of the unique human receptor. Finally, transient co-transfections of RBL cells allow functional genomic analyses of MC secretion by combining library screening with simultaneous expression of a reporter for exocytosis. RBL cells thus comprise powerful tools for the study of intracellular membrane trafficking and exocytosis and the detection of allergens, vaccine safety studies and diagnosis of allergic sensitization. Their recent uses as an investigative tool are reviewed here.     

Impedimetric immunosensor for dengue diagnosis using graphite screen-printed electrodes coated with poly(4-aminophenylacetic acid)

Dengue is an infectious viral disease transmitted by the Aedes aegypti mosquito, the control of which is complex. In addition, the clinical diagnosis is difficult to perform since it resembles other febrile infections; thus, the development of more effective methods to detect dengue virus (DV) has drawn increasing attention. The present study aimed to develop an impedimetric immunosensor for dengue diagnosis using a screen-printed electrode (SPE) functionalized with polymer films derived from 4-aminophenylacetic acid (4-APA). Data obtained from scanning electron microscopy (SEM) showed the deposition of a uniformly distributed material over the electrode surface. The immunosensor was based on the specific interaction between dengue antigen, NS1 protein, and anti-NS1 antibodies, IgG and IgM. In a characterization study using cyclic voltammetry (CV), the polymer film showed two oxidation peaks at +0.17 and?+?0.35 V in 0.50 M sulfuric acid solution, indicating its adsorption and electroactivity at the SPE surface. Electrochemical impedance spectroscopy (EIS) measurements showed a higher charge transfer resistance (R_ct) to the polymer film-modified SPE as compared with the bare SPE, corroborating a previous study. The best rNS1 concentration for immobilization was 1.00 ng/mL, and the immunoreaction time between the antigen (Ag) and the antibody (Ab) was 20 min. Dilutions of positive and negative clinical serum samples were evaluated by EIE, from which it was possible to elucidate, for the positive serum, that the more diluted the serum the greater the R_ct. Negative serum also showed an analytical signal, probably due to the presence of non-specific antibodies; however, the generated signal presented values closer to the rNS1 signal, indicating good selectivity of the proposed platform. The experiments were repeated using bare SPE to verify the importance of the polymer film in biosensor construction. No significant difference was observed between these results.

Open image in new window

Graphical abstract Proposed schematic for the genosensor development

     

Multifocal nivolumab immune-related adverse effects during asymptomatic SARS-CoV-2 infection: causality or casuality?

Neurological Sciences -     

Photodynamic therapy for squamous cell carcinoma of the head and neck: narrative review focusing on photosensitizers

Lasers in Medical Science - This narrative review aimed to evaluate the effectiveness of PDT in early or advanced squamous cell carcinoma of the head and neck (SCCHN). Scopus, MEDLINE/PubMed, and...     

Proficiency-based training of medical students using virtual simulators for laparoscopy and robot-assisted surgery: results of a pilot study

Proficiency-based training has become essential in the training of surgeons such that on completion they can execute complex operations with novel surgical approaches including direct manual laparoscopic surgery (DMLS) and robotically assisted laparoscopic surgery (RALS). To this effect, several virtual reality (VR) simulators have been developed. The objective of the present study was to assess and establish proficiency gain curves for medical students on VR simulators for DMLS and RALS. Five medical students participated in training course consisting of didactic teaching and practical hands-on training with VR simulators for DMLS and RALS. Evaluation of didactic component was by questionnaire completed by participating students, who also were required to undertake selected exercises to reach proficiency at each VR simulator: (1) 12 tasks on LapSim VR (Surgical Science, Gothenburg, Sweden) for DMLS, and (2) six selected exercises on the dV-Trainer Mimic (Seattle, WA, United States). The five medical students reached the 60% threshold on the questionnaire-based didactic component. During selected hands-on simulation on VR simulators, students with previous experience with simulators (n?=?3) outperformed those without (n?=?2) in ten out of twelve LapSim tasks and all six at dV-Trainer, by requiring fewer attempts to reach proficiency although the difference was not significant (p?<?0.05). In this work, we developed a proficiency-based training program for medical undergraduates based on surgical simulation for DMLS and RALS.z. Larger studies are needed to evaluate the benefit of this program in stimulating interest for surgical career amongst medical students after the qualify.     

Navigated robotic assistance results in improved screw accuracy and positive clinical outcomes: an evaluation of the first 54 cases

Computer-aided navigation and robotic guidance systems have become widespread in their utilization for spine surgery. A recent innovation combines these tw     

Leishmaniasis in cat shelters: A serological,molecular and entomological study

An epidemiological Leishmania spp. and entomological Phlebotomine sandflies survey was performed in cat shelters at leishmaniasis endemic area of Brazil. Blood and conjunctival swab (CS) samples were collected from 94 cats in two animal protection shelters. These samples were subjected to serological tests using the indirect immunofluorescence antibody test (IFAT) and indirect enzyme‐linked immunosorbent assay (ELISA) and to molecular test by polymerase chain reaction (PCR). In addition, a Phlebotomine sandflies survey was performed in the same shelters. The analyses revealed a positivity of 31.91% (30/94) through ELISA and 29.79% (28/94) through IFAT. The two serological tests showed a positive association with perfect agreement (k = 0.925). None of the cats were positive by Leishmania spp. DNA. One Lutzomyia (Lutzomyia) longipalpis male was found in one of the cat shelters. The results and the implications of our findings are discussed below.     

Serum proteome of dogs at subclinical and clinical onset of canine leishmaniosis

The objective of this study was to identify changes in serum proteome in dogs that may occur after an experimental infection at subclinical and clinical stages of canine leishmaniosis (CanL). For this purpose, canine pre‐ and post‐infection with Leishmania infantum serum proteomes in the same dogs were analysed by a high‐throughput label‐based quantitative LC‐MS/MS proteomic approach. A total of 169 proteins were identified, and 74 of them including complement C8 alpha chain, adiponectin, transferrin, sphingomyelin phosphodiesterase acid‐like 3A and immunoglobulins showed different modulation between the different stages of CanL. These proteins could be considered as potential serum biomarkers of early diagnostic or disease progression in CanL. Additionally, biological pathways modulated during CanL such as blood coagulation or gonadotropin‐releasing hormone receptor were revealed, which could help to understand the pathological mechanisms of the disease.