Mechanism of resistance to tyrosine kinase inhibitors in philadelphia-positive acute lymphblastic leukaemia (all): from genetic alterations to impaired RNA editing

The Ph chromosome is the most frequent cytogenetic aberration associated with adult ALL and it represents the single most significant adverse prognostic marker. Despite imatinib has led to significant improvements in the treatment of patients with Ph+ ALL, in the majority of cases resistance developed quickly and disease progressed. Some mechanisms of resistance have been widely described but the full knowledge of contributing factors, driving both the disease and resistance, remains to be defined. The observation of rapid development of lymphoblastic leukemia in mice expressing altered Ikaros (Ik) isoforms represented the background of this study. Ikaros is a zinc finger transcription factor required for normal hemopoietic differentiation and proliferation, particularly in the lymphoid lineages. By means of alternative splicing, Ikaros encodes several proteins that differ in their abilities to bind to a consensus DNA-binding site. Shorter, DNA nonbinding isoforms exert a dominant negative effect, inhibiting the ability of longer heterodimer partners to bind DNA. The differential expression pattern of Ik isoforms in Ph+ ALL patients was analyzed in order to determine if molecular abnormalities involving the Ik gene could associate with resistance to imatinib and dasatinib. Bone marrow and peripheral blood samples from 46 adult patients (median age 55 yrs, 18-76) with Ph+ ALL at diagnosis and during treatment with imatinib (16 pts) or dasatinib (30 pts) were collected. We set up a fast, high-throughput method based on capillary electrophoresis technology to detect and quantify splice variants. 41% Ph+ ALL patients expressed high levels of the non DNA-binding dominant negative Ik6 isoform lacking critical N-terminal zinc-fingers which display abnormal subcellular compartmentalization pattern. Nuclear extracts from patients expressed Ik6 failed to bind DNA in mobility shift assay using a DNA probe containing an Ikaros-specific DNA binding sequence. In 59% Ph+ ALL patients there was the coexistence in the same PCR sample and at the same time of many splice variants corresponded to Ik1, Ik2, Ik4, Ik4A, Ik5A, Ik6, Ik6 and Ik8 isoforms. In these patients aberrant full-length Ikaros isoforms in Ph+ ALL characterized by a 60-bp insertion immediately downstream of exon 3 and a recurring 30-bp in-frame deletion at the end of exon 7 involving most frequently the Ik2, Ik4 isoforms were also identified. Both the insertion and deletion were due to the selection of alternative splice donor and acceptor sites. The molecular monitoring of minimal residual disease showed for the first time in vivo that the Ik6 expression strongly correlated with the BCR-ABL transcript levels suggesting that this alteration could depend on the Bcr-Abl activity. Patient-derived leukaemia cells expressed dominant-negative Ik6 at diagnosis and at the time of relapse, but never during remission. In order to mechanistically demonstrated whether in vitro the overexpression of Ik6 impairs the response to tyrosine kinase inhibitors (TKIs) and contributes to resistance, an imatinib-sensitive Ik6-negative Ph+ ALL cell line (SUP-B15) was transfected with the complete Ik6 DNA coding sequence. The expression of Ik6 strongly increased proliferation and inhibited apoptosis in TKI sensitive cells establishing a previously unknown link between specific molecular defects that involve the Ikaros gene and the resistance to TKIs in Ph+ ALL patients. Amplification and genomic sequence analysis of the exon splice junction regions showed the presence of 2 single nucleotide polymorphisms (SNPs): rs10251980 [A/G] in the exon2/3 splice junction and of rs10262731 [A/G] in the exon 7/8 splice junction in 50% and 36% of patients, respectively. A variant of the rs11329346 [-/C], in 16% of patients was also found. Other two different single nucleotide substitutions not recognized as SNP were observed. Some mutations were predicted by computational analyses (RESCUE approach) to alter cis-splicing elements. In conclusion, these findings demonstrated that the post-transcriptional regulation of alternative splicing of Ikaros gene is defective in the majority of Ph+ ALL patients treated with TKIs. The overexpression of Ik6 blocking B-cell differentiation could contribute to resistance opening a time frame, during which leukaemia cells acquire secondary transforming events that confer definitive resistance to imatinib and dasatinib.

Crowdsensing and proximity services for impaired mobility

La tesi si occupa della creazione di una piattaforma virtuale, composta da un sito web e da una applicazione Android, a supporto di persone con handicap motori. La piattaforma e composta da una mappa interattiva che permette agli utenti di inserire nuovi locali o di commentarne esistenti, e di fare lo stesso per le barriere architettoniche. Per questi motivi il progetto e dettato da una continua comunicazione tra client e server, rendendo la piattaforma aggiornata e dinamica, anche alla vista degli utenti. La parte web viene implementata attraverso Spring MVC, utilizzando delle View .jsp ed AJAX per la comunicazione remota con il server. La parte mobile e stata implementata basandosi principalmente sulle classi di geolocalizzazione di Android, oltre alle librerie osmdroid ed osmbonuspack, fornendo compatitiblita con OSM. Questa fornisce anche un servizio di calcolo del percorso, cercando di evitare il numero maggiore di ostacoli. L'applicazione Android appoggia le proprie comunicazioni sulla libreria Robospice. La parte di persistenza e stata implementata adottando un approccio ad alto livello, grazie ad Hibernate e JPA.

Detrusor activity is impaired during thoracic epidural analgesia after open renal surgery

There are no data on lower urinary tract function during postoperative thoracic epidural analgesia (TEA). Because selected segmental blockade can be achieved with epidural analgesia, we hypothesized that lower urinary tract function remains unchanged during TEA within segments T4-T11 after open renal surgery.

MRI morphometry, cartilage damage and impaired function in the follow-up after slipped capital femoral epiphysis

To assess rotation deficits, asphericity of the femoral head and localisation of cartilage damage in the follow-up after slipped capital femoral epiphysis (SCFE).

Association between chronic caregiving stress and impaired endothelial function in the elderly

We examined the relationship between chronic caregiving stress and endothelial function.

Development of an auditory implant manipulator for minimally invasive surgical insertion of implantable hearing devices

To present the auditory implant manipulator, a navigation-controlled mechanical and electronic system which enables minimally invasive ('keyhole') transmastoid access to the tympanic cavity.

Design of a semi-implantable hearing device for direct acoustic cochlear stimulation

A new hearing therapy based on direct acoustic cochlear stimulation was developed for the treatment of severe to profound mixed hearing loss. The device efficacy was validated in an initial clinical trial with four patients. This semi-implantable investigational device consists of an externally worn audio processor, a percutaneous connector, and an implantable microactuator. The actuator is placed in the mastoid bone, right behind the external auditory canal. It generates vibrations that are directly coupled to the inner ear fluids and that, therefore, bypass the external and the middle ear. The system is able to provide an equivalent sound pressure level of 125 dB over the frequency range between 125 and 8000 Hz. The hermetically sealed actuator is designed to provide maximal output power by keeping its dimensions small enough to enable implantation. A network model is used to simulate the dynamic characteristics of the actuator to adjust its transfer function to the characteristics of the middle ear. The geometry of the different actuator components is optimized using finite-element modeling.

Non-organic hearing loss: new and confirmed findings

Although non-organic hearing losses are relatively rare, it is important to identify suspicious findings early to be able to administer specific tests, such as objective measurements and specific counseling. In this retrospective study, we searched for findings that were specific ti or typical for non-organic hearing losses. Patient records from a 6 year period (2003-2008) from the University ENT Department of Bern, Switzerland, were reviewed. In this period, 40 subjects were diagnosed with a non-organic hearing loss (22 children, ages 7-16, mean 10.6 years; 18 adults, ages 19-57, mean 39.7 years; 25 females and 15 males). Pure tone audiograms in children and adults showed predominantly sensorineural and frequency-independent hearing losses, mostly in the range of 40-60 dB. In all cases, objective measurements (otoacoustic emissions and/or auditory-evoked potentials) indicated normal or substantially better hearing thresholds than those found in pure tone audiometry. In nine subjects (22.5%; 2 children, 7 adults), hearing aids had been fitted before the first presentation at our center. Six children (27%) had a history of middle ear problems with a transient hearing loss and 11 (50%) knew a person with a hearing loss. Two new and hitherto unreported findings emerged from the analysis: it was observed that a small air-bone gap of 5-20 dB was typical for non-organic hearing losses and that speech audiometry might show considerably poorer results than expected from pure tone audiometry.

Audiological results with Baha in conductive and mixed hearing loss

The level of improvement in the audiological results of Baha(®) users mainly depends on the patient's preoperative hearing thresholds and the type of Baha sound processor used. This investigation shows correlations between the preoperative hearing threshold and postoperative aided thresholds and audiological results in speech understanding in quiet of 84 Baha users with unilateral conductive hearing loss, bilateral conductive hearing loss and bilateral mixed hearing loss. Secondly, speech understanding in noise of 26 Baha users with different Baha sound processors (Compact, Divino, and BP100) is investigated. Linear regression between aided sound field thresholds and bone conduction (BC) thresholds of the better ear shows highest correlation coefficients and the steepest slope. Differences between better BC thresholds and aided sound field thresholds are smallest for mid-frequencies (1 and 2 kHz) and become larger at 0.5 and 4 kHz. For Baha users, the gain in speech recognition in quiet can be expected to lie in the order of magnitude of the gain in their hearing threshold. Compared to its predecessor sound processors Baha(®) Compact and Baha(®) Divino, Baha(®) BP100 improves speech understanding in noise significantly by +0.9 to +4.6 dB signal-to-noise ratio, depending on the setting and the use of directional microphone. For Baha users with unilateral and bilateral conductive hearing loss and bilateral mixed hearing loss, audiological results in aided sound field thresholds can be estimated with the better BC hearing threshold. The benefit in speech understanding in quiet can be expected to be similar to the gain in their sound field hearing threshold. The most recent technology of Baha sound processor improves speech understanding in noise by an order of magnitude that is well perceived by users and which can be very useful in everyday life.

Petrous bone cholesteatoma removal with hearing preservation

Clinical and radiologic outcome analysis after petrous bone cholesteatoma (PBC) removal with simultaneous functional reconstruction.

Loss of the C terminus of melanocortin receptor 2 (MC2R) results in impaired cell surface expression and ACTH insensitivity

Mutations in melanocortin receptor 2 (MC2R) and its related melanocortin receptor accessory protein (MRAP) cause familial glucocorticoid deficiency. We identified a novel MC2R mutation, K289fs. This unique mutation in the C terminus of MC2R is located in the intracellular part of the protein for which the exact function is unknown.

Impaired performance on the rapid visual information processing task (RVIP) could be an endophenotype of schizophrenia

The aim of the present study was to investigate whether healthy first-degree relatives of schizophrenia patients show reduced sensitivity performance, higher intra-individual variability (IIV) in reaction time (RT), and a steeper decline in sensitivity over time in a sustained attention task. Healthy first-degree relatives of schizophrenia patients (n=23) and healthy control subjects (n=46) without a family history of schizophrenia performed a demanding version of the Rapid Visual Information Processing task (RVIP). RTs, hits, false alarms, and the sensitivity index A' were assessed. The relatives were significantly less sensitive, tended to have higher IIV in RT, but sustained the impaired level of sensitivity over time. Impaired performance on the RVIP is a possible endophenotype for schizophrenia. Higher IIV in RT, apparently caused by impaired context representations, might result in fluctuations in control and lead to more frequent attentional lapses.