Biphasic positive airway pressure minimizes biological impact on lung tissue in mild acute lung injury independent of etiology

Abstract Introduction Biphasic positive airway pressure (BIVENT) is a partial support mode that employs pressure-controlled, time-cycled ventilation set at two levels of continuous positive airway pressure with unrestricted spontaneous breathing. BIVENT can modulate inspiratory effort by modifying the frequency of controlled breaths. Nevertheless, the optimal amount of inspiratory effort to improve respiratory function while minimizing ventilator-associated lung injury during partial ventilatory assistance has not been determined. Furthermore, it is unclear whether the effects of partial ventilatory support depend on acute lung injury (ALI) etiology. This study aimed to investigate the impact of spontaneous and time-cycled control breaths during BIVENT on the lung and diaphragm in experimental pulmonary (p) and extrapulmonary (exp) ALI. Methods This was a prospective, randomized, controlled experimental study of 60 adult male Wistar rats. Mild ALI was induced by Escherichia coli lipopolysaccharide either intratracheally (ALIp) or intraperitoneally (ALIexp). After 24 hours, animals were anesthetized and further randomized as follows: (1) pressure-controlled ventilation (PCV) with tidal volume (Vt) = 6 ml/kg, respiratory rate = 100 breaths/min, PEEP = 5 cmH2O, and inspiratory-to-expiratory ratio (I:E) = 1:2; or (2) BIVENT with three spontaneous and time-cycled control breath modes (100, 75, and 50 breaths/min). BIVENT was set with two levels of CPAP (Phigh = 10 cmH2O and Plow = 5 cmH2O). Inspiratory time was kept constant (Thigh = 0.3 s). Results BIVENT was associated with reduced markers of inflammation, apoptosis, fibrogenesis, and epithelial and endothelial cell damage in lung tissue in both ALI models when compared to PCV. The inspiratory effort during spontaneous breaths increased during BIVENT-50 in both ALI models. In ALIp, alveolar collapse was higher in BIVENT-100 than PCV, but decreased during BIVENT-50, and diaphragmatic injury was lower during BIVENT-50 compared to PCV and BIVENT-100. In ALIexp, alveolar collapse during BIVENT-100 and BIVENT-75 was comparable to PCV, while decreasing with BIVENT-50, and diaphragmatic injury increased during BIVENT-50. Conclusions In mild ALI, BIVENT had a lower biological impact on lung tissue compared to PCV. In contrast, the response of atelectasis and diaphragmatic injury to BIVENT differed according to the rate of spontaneous/controlled breaths and ALI etiology.

Differentiability of bizonal positive definite kernels on complex spheres

We prove that any continuous function with domain {z ∈ C: |z| ≤ 1} that generates a bizonal positive definite kernel on the unit sphere in 'C POT.Q' , q ⩾ 3, is continuously differentiable in {z ∈ C: |z| < 1} up to order q − 2, with respect to both z and 'Z BARRA'. In particular, the partial derivatives of the function with respect to x = Re z and y = Im z exist and are continuous in {z ∈ C: |z| < 1} up to the same order.

Canine heartworm disease in Porto Velho: first record, distribution map and occurrence of positive mosquitoes

The aim of this study was to make the first report on canine heartworm disease in the state of Rondônia and confirm its transmission in this state. Blood samples were randomly collected from 727 dogs in the city of Porto Velho. The samples were analyzed to search for microfilariae and circulating antigens, using three different techniques: optical microscopy on thick blood smears stained with Giemsa; immunochromatography; and PCR. Mosquitoes were collected inside and outside the homes of all the cases of positive dogs and were tested using PCR to search for DNA of Dirofilaria immitis. Ninety-three blood samples out of 727 (12.8%) were positive according to the immunoassay technique and none according to the thick smear method. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No difference in the frequency of infection was observed between dogs raised indoors and in the yard. PCR on the mosquitoes resulted in only one positive pool. This result shows that the transmission of canine heartworm disease is occurring in the city of Porto Velho and that there is moderate prevalence among the dogs. The techniques of immunochromatography and PCR were more effective for detecting canine heartworm than thick blood smears. The confirmation of canine heartworm disease transmission in Porto Velho places this disease in the ranking for differential diagnosis of pulmonary nodules in humans in Rondônia.

Matrix-vector multiplication and triangular linear solver using GPGPU for symmetric positive definite matrices derived from elliptic equations

The modern GPUs are well suited for intensive computational tasks and massive parallel computation. Sparse matrix multiplication and linear triangular solver are the most important and heavily used kernels in scientific computation, and several challenges in developing a high performance kernel with the two modules is investigated. The main interest it to solve linear systems derived from the elliptic equations with triangular elements. The resulting linear system has a symmetric positive definite matrix. The sparse matrix is stored in the compressed sparse row (CSR) format. It is proposed a CUDA algorithm to execute the matrix vector multiplication using directly the CSR format. A dependence tree algorithm is used to determine which variables the linear triangular solver can determine in parallel. To increase the number of the parallel threads, a coloring graph algorithm is implemented to reorder the mesh numbering in a pre-processing phase. The proposed method is compared with parallel and serial available libraries. The results show that the proposed method improves the computation cost of the matrix vector multiplication. The pre-processing associated with the triangular solver needs to be executed just once in the proposed method. The conjugate gradient method was implemented and showed similar convergence rate for all the compared methods. The proposed method showed significant smaller execution time.

On existence and uniqueness of positive solutions to a class of fractional boundary value problems

[EN] The purpose of this paper is to investigate the existence and uniqueness of positive solutions for the following fractional boundary value problem D 0 + α u ( t ) + f ( t , u ( t ) ) = 0 , 0 < t < 1 , u ( 0 ) = u ( 1 ) = u ′ ( 0 ) = 0 , where 2 < α ≤ 3 and D 0 + α is the Riemann-Liouville fractional derivative. Our analysis relies on a fixed-point theorem in partially ordered metric spaces. The autonomous case of this problem was studied in the paper [Zhao et al., Abs. Appl. Anal., to appear], but in Zhao et al. (to appear), the question of uniqueness of the solution is not treated. We also present some examples where we compare our results with the ones obtained in Zhao et al. (to appear). 2010 Mathematics Subject Classification: 34B15

Existence and uniqueness of positive and nondecreasing solutions for a class of singular fractional boundary value problems

[EN] We establish the existence and uniqueness of a positive and nondecreasing solution to a singular boundary value problem of a class of nonlinear fractional differential equation. Our analysis relies on a fixed point theorem in partially ordered sets.

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.

Depicting the role of CDKN2A/ARF alterations in adult BCR-ABL1-positive acute lymphoblastic leukemia patients: from genomic deletions to prognostic impact

This 9p21 locus, encode for important proteins involved in cell cycle regulation and apoptosis containing the p16/CDKN2A (cyclin-dependent kinase inhibitor 2a) tumor suppressor gene and two other related genes, p14/ARF and p15/CDKN2B. This locus, is a major target of inactivation in the pathogenesis of a number of human tumors, both solid and haematologic, and is a frequent site of loss or deletion also in acute lymphoblastic leukemia (ALL) ranging from 18% to 45% 1. In order to explore, at high resolution, the frequency and size of alterations affecting this locus in adult BCR-ABL1-positive ALL and to investigate their prognostic value, 112 patients (101 de novo and 11 relapse cases) were analyzed by genome-wide single nucleotide polymorphisms arrays and gene candidate deep exon sequencing. Paired diagnosis-relapse samples were further available and analyzed for 19 (19%) cases. CDKN2A/ARF and CDKN2B genomic alterations were identified in 29% and 25% of newly diagnosed patients, respectively. Deletions were monoallelic in 72% of cases and in 43% the minimal overlapping region of the lost area spanned only the CDKN2A/2B gene locus. The analysis at the time of relapse showed an almost significant increase in the detection rate of CDKN2A/ARF loss (47%) compared to diagnosis (p = 0.06). Point mutations within the 9p21 locus were found at very low level with only a non-synonymous substition in the exon 2 of CDKN2A. Finally, correlation with clinical outcome showed that deletions of CDKN2A/B are significantly associated with poor outcome in terms of overall survival (p = 0.0206), disease free-survival (p = 0.0010) and cumulative incidence of relapse (p = 0.0014). The inactivation of 9p21 locus by genomic deletions is a frequent event in BCR-ABL1-positive ALL. Deletions are frequently acquired at the leukemia progression and work as a poor prognostic marker.

Heteroatom containing polycyclic aromatic hydrocarbons with positive charge - synthesis and characterization

The synthesis and characterization of various heteroatom containing PAHs with positive charge were investigated in this work: 1. A series of 2-phenyl-benzo[8,9]quinolizino[4,5,6,7-fed]phenanthridinylium (PQP) salts with different alkyl chains and anions were synthesized. The synthesis of the extended derivates of PQP salts with two fused benzene rings, 2-phenyl-naphthacene[1,2]quinolizino[3,4,5,6-def]benzo[i]phenanthridinium (DBPQP) tetrafluoroborate was also developed. The self-assembly behavior of these amphiphilic PAHs was investigated in methanolic solution as well as in the bulk. Various aggregates with different morphologies such as fibers, tubes and vesicals were obtained from their solution. All of these morphology changes could be ascribed to the changes in intermolecular interactions which resulting from the difference in the molecular structures such as aromatic cores, alkyl chains and counterions. 2. The synthetic strategy of oxygen containing positively charged PAHs, benzo[5,6]naphthaceno[1,12,11,10-jklmna]xanthylium (BNAX) salts and its dibenzo derivates, DBNAX salts were developed. With a similar method, sulfur containing benzo[5,6]naphthaceno[1,12,11,10-jklmna]thioxanthylium (BNATX) salts were also synthesized. Various BNAX salts with different alkyl chains could be obtained and their supramolecular behavior were investigated. A discotic liquid crystalline behavior was observed for di- (3-25) and tridodecyl (3-27) substituted BNAX salts and both compounds exhibited large unit cell in their 2D-WAXS patterns which could be attributed to the formation of dimer structures. By drop casting their methanolic solution on silicon wafers, similar nanoscaled fibers from monododecyl substituted BNAX bromide 3-24 and DBNAX bromide 3-35 could be observed. 3. A novel synthetic method toward nitrogen containing 14-phenyl-dibenzo[jk,mn]naphtho[2,1,8-fgh]thebenidinium (DBNT) salts was also developed. In this method, the undehydrogenated precursor of DBNT, dibenzoacridinium salt could be produced directly from the reaction between dibenzoxanthenylium derivates and amine/aniline in reasonable yields. Various DBNT salts with different alkyl and alkylphenyl chains on their nitrogen atom were synthesized in this two-step method. The self-assembly behavior of two alkylated DBNT salts, 4-15a and 4-18b was also studied in this work. Compound 4-15a formed nanoscaled fibers and helical aggregates were obtained from 4-18b in their methanolic solutions. 4. Various ionic complexes were derived by complexing PQP and DBPQP cations with different sulfate/sulfonate group containing anionic surfactants. The ionic complexes resulting from the ionic self-assembly (ISA) method exhibited self-assembly behavior which was controllable by the species and shape of cations and anions. Various aggregates such as nanofibers and spherical aggregates could be produced from their methanolic solution in a defined manner conveniently.

Targeting the p53–MDM2 interaction by the small-molecule MDM2 antagonist Nutlin-3a: a new challenged target therapy in adult Philadelphia positive acute lymphoblastic leukemia patients

The human p53 tumor suppressor, known as the “guardian of the genome”, is one of the most important molecules in human cancers. One mechanism for suppressing p53 uses its negative regulator, MDM2, which modulates p53 by binding directly to and decreasing p53 stability. In testing novel therapeutic approaches activating p53, we investigated the preclinical activity of the MDM2 antagonist, Nutlin-3a, in Philadelphia positive (Ph+) and negative (Ph-) leukemic cell line models, and primary B-Acute lymphoblastic leukemia (ALL) patient samples. In this study we demonstrated that treatment with Nutlin-3a induced grow arrest and apoptosis mediated by p53 pathway in ALL cells with wild-type p53, in time and dose-dependent manner. Consequently, MDM2 inhibitor caused an increase of pro-apoptotic proteins and key regulators of cell cycle arrest. The dose-dependent reduction in cell viability was confirmed in primary blast cells from Ph+ ALL patients with the T315I Bcr-Abl kinase domain mutation. In order to better elucidate the implications of p53 activation and to identify biomarkers of clinical activity, gene expression profiling analysis in sensitive cell lines was performed. A total of 621 genes were differentially expressed (p < 0.05). We found a strong down-regulation of GAS41 (growth-arrest specific 1 gene) and BMI1 (a polycomb ring-finger oncogene) (fold-change -1.35 and -1.11, respectively; p-value 0.02 and 0.03, respectively) after in vitro treatment as compared to control cells. Both genes are repressors of INK4/ARF and p21. Given the importance of BMI in the control of apoptosis, we investigated its pattern in treated and untreated cells, confirming a marked decrease after exposure to MDM2 inhibitor in ALL cells. Noteworthy, the BMI-1 levels remained constant in resistant cells. Therefore, BMI-1 may be used as a biomarker of response. Our findings provide a strong rational for further clinical investigation of Nutlin-3a in Ph+ and Ph-ALL.

Next-Generation Sequencing-Based Mutations Scanning Strategy of the BCR-ABL Kinase Domain in Patients with PhiladelPhia-Chromosome Positive Leukemias Treated with Tyrosine Kinase Inhibitors

In chronic myeloid leukemia and Philadelphia-positive acute lymphoblastic leukemia patients resistant to tyrosine kinase inhibitors (TKIs), BCR-ABL kinase domain mutation status is an essential component of the therapeutic decision algorithm. The recent development of Ultra-Deep Sequencing approach (UDS) has opened the way to a more accurate characterization of the mutant clones surviving TKIs conjugating assay sensitivity and throughput. We decided to set-up and validated an UDS-based for BCR-ABL KD mutation screening in order to i) resolve qualitatively and quantitatively the complexity and the clonal structure of mutated populations surviving TKIs, ii) study the dynamic of expansion of mutated clones in relation to TKIs therapy, iii) assess whether UDS may allow more sensitive detection of emerging clones, harboring critical 2GTKIs-resistant mutations predicting for an impending relapse, earlier than SS. UDS was performed on a Roche GS Junior instrument, according to an amplicon sequencing design and protocol set up and validated in the framework of the IRON-II (Interlaboratory Robustness of Next-Generation Sequencing) International consortium.Samples from CML and Ph+ ALL patients who had developed resistance to one or multiple TKIs and collected at regular time-points during treatment were selected for this study. Our results indicate the technical feasibility, accuracy and robustness of our UDS-based BCR-ABL KD mutation screening approach. UDS was found to provide a more accurate picture of BCR-ABL KD mutation status, both in terms of presence/absence of mutations and in terms of clonal complexity and showed that BCR-ABL KD mutations detected by SS are only the “tip of iceberg”. In addition UDS may reliably pick 2GTKIs-resistant mutations earlier than SS in a significantly greater proportion of patients.The enhanced sensitivity as well as the possibility to identify low level mutations point the UDS-based approach as an ideal alternative to conventional sequencing for BCR-ABL KD mutation screening in TKIs-resistant Ph+ leukemia patients