INSERT: A Novel Clinical Scanner for Simultaneous SPECT/MRI Brain Studies

A clinical SPECT insert for a commercial MRI scanner has been developed within the INSERT project, allowing simultaneous SPECT/MRI studies of the human brain. Here we present preliminary experimental results. The reconstructed resolution was 6-11 mm and the sensitivity 280-440 s-1/MBq. The INSERT is the first clinical SPECT prototype for simultaneous SPECT/MRI

Evaluation of a Partial Genome Screening of Two Asthma Susceptibility Regions Using Bayesian Network Based Bayesian Multilevel Analysis of Relevance

Genetic studies indicate high number of potential factors related to asthma. Based on earlier linkage analyses we selected the 11q13 and 14q22 asthma susceptibility regions, for which we designed a partial genome screening study using 145 SNPs in 1201 individuals (436 asthmatic children and 765 controls). The results were evaluated with traditional frequentist methods and we applied a new statistical method, called Bayesian network based Bayesian multilevel analysis of relevance (BN-BMLA). This method uses Bayesian network representation to provide detailed characterization of the relevance of factors, such as joint significance, the type of dependency, and multi-target aspects. We estimated posteriors for these relations within the Bayesian statistical framework, in order to estimate the posteriors whether a variable is directly relevant or its association is only mediated. With frequentist methods one SNP (rs3751464 in the FRMD6 gene) provided evidence for an association with asthma (OR = 1.43(1.2–1.8); p = 3×10−4). The possible role of the FRMD6 gene in asthma was also confirmed in an animal model and human asthmatics. In the BN-BMLA analysis altogether 5 SNPs in 4 genes were found relevant in connection with asthma phenotype: PRPF19 on chromosome 11, and FRMD6, PTGER2 and PTGDR on chromosome 14. In a subsequent step a partial dataset containing rhinitis and further clinical parameters was used, which allowed the analysis of relevance of SNPs for asthma and multiple targets. These analyses suggested that SNPs in the AHNAK and MS4A2 genes were indirectly associated with asthma. This paper indicates that BN-BMLA explores the relevant factors more comprehensively than traditional statistical methods and extends the scope of strong relevance based methods to include partial relevance, global characterization of relevance and multi-target relevance

Influence of pH and chain length on the phase transition of phosphatidic acid

Phosphatidic acids (PA) are normally minor components in natural membranes but there is increasing evidence that these components play a key role in aggregation, fusion and transport processes in cellular membranes. The aim of this research was to investigate the influences of pH on the transition temperatures and enthalpies of various aqueous PA dispersions. The phase transition temperatures (Tt) and enthalpies (Ht) were measured using differential scanning calorimetry. The Tt vs pH diagrams of the four phosphatidic acids are quite similar, the transition temperatures decrease with increasing pH from 4 to 10. The Ht vs pH diagrams have similar shape. Our experimental data are compared with measurements of different authors. The chain length dependence of Tt and Ht at different pH values were established too. The diagrams are compared to that of phosphatidylcholines and phosphatidylethanolamines

A study on the phosphatidic acid phase transition parameters

Chain length dependence of phosphatidic acid phase transition parameters. There is increasing evidence that phosphatidic acids (PA) play a key role in aggregation, fusion and transport processes in cellular membranes although these molecules are normally minor components in natural membranes. Since some intrinsic membrane proteins preferentially bind acid phospholipids, it is reasonable to assume that the membrane protein conformation is influenced by this microenvironment rather than by the properties of bulk lipid. Aim of this work was to determine the chain length dependence of Tt (transition temperature) for PA bilayers by means of DSC (differential scanning calorimetry) measurements

pH dependence of phosphatidic acid transition temperatures

Phosphatidic acids (PA) are normally minor components in natural membranes but there is increasing evidence that these components play a key role in aggregation, fusion and transport processes in cellular membranes. The aim of this research was to investigate the influences of pH on the transition temperatures and hentalpies of aqueous PA dispersions. The phase transition temperatures (Tt) of aqueous phosphatidic acid dispersions at different degrees of dissociation were measured using differential scanning calorimetry. The Tt vs pH diagrams of the four phosphatidic acids are quite similar and of a characteristic shape. Our experimental data are compared with measurements of different authors. A decrease of the transition temperatures was observed increasing pH and decreasing the chain lenght

pH and chain length dependence of phosphatidic acid phase transition parameters

A growing interest can be observed in the literature in the behaviour of phosphatidic acids. The aim of this work was to investigate the influence of pH on the transition temperatures and enthalpies of aqueous PA dispersions. In addition, the chain length dependence of Tt was established and the cooperative unit sizes were calculated for different pH values. Experimental results are compared to the data available in the literature of which a critical review is given

INSERT: A Novel Clinical Scanner for Simultaneous SPECT/MRI Brain Studies

A clinical SPECT insert for a commercial MRI scanner has been developed within the INSERT project, allowing simultaneous SPECT/MRI studies of the human brain. Here we present preliminary experimental results. The reconstructed resolution was 6-11 mm and the sensitivity 280-440 s^-1/MBq. The INSERT is the first clinical SPECT prototype for simultaneous SPECT/MRI