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BackgroundSurface modification of flow-diverting stents has been explored to reduce thrombus-related complications that may arise under clinical use. This study investigated the thromboresistant properties of the flow redirection endoluminal device (FRED) X, a flow diverter treated with a copolymer of poly(2-methoxyethyl acrylate) (PMEA; X Technology).MethodsThe performance of FRED, FRED X, and Pipeline Flex with Shield Technology (sPED) was evaluated in an in vitro blood loop model. Blood activation level was assessed by the concentration of thrombin-antithrombin complex (TAT), β-thromboglobulin (β-TG), and platelet count, and qualitatively by scanning electron microscopy (SEM). Cellular adhesion characteristics were measured using human aortic endothelial cells that were seeded on flat sheets mimicking the surface of FRED, FRED X, and sPED, and evaluated with fluorescence microscopy. Statistical comparisons were conducted using one-way analysis of variance (ANOVA) with Tukey post hoc tests.ResultsFRED X, sPED, and control blood loops showed significantly reduced blood activation levels (TAT and β-TG) compared with FRED (pConclusionThe X Technology surface modification of FRED X demonstrated superior thromboresistant properties over untreated FRED while maintaining comparable cellular adhesion. Taken together, these properties may help mitigate material-related thromboembolic complications.

Pigment-dispersing factor PDF is an 18-amino acid insect neuropeptide that mediates a circadian rhythmicity in locomotor activity. PDF is coded in a precursor protein together with another neuropeptide named PDF-associated peptide, PAP. PDF is highly conserved among insects, whereas the homology of PAPs is very low with considerably varied amino acid sequences. Since such dissimilarity has suggested that the function of PAP peptide is not associated with that of PDF, we have attempted to analyze the sequences of PDF precursor proteins among a series of species of insects and hypothesized that PDF precursors are classified into at least three different classes: Drosophila-Musca, Meimuna-Romalea, and Gryllus. In order to exemplify this hypothesis, we here describe the molecular cloning of the pdf-gene of the black blowfly Phormia regina and an in silico screening for the pdf-gene in the genome databank of the mosquito Anopheles gambie, both species belonging to the Diptera. It was found that deduced amino acid sequences of PDF peptides are almost completely conserved among all Dipterans and also the amino acid sequences of PAPs are considerably highly preserved (55–82 similarity) among the species of Diptera. The results confirmed the validity of grouping the PDF precursor proteins. In situ hybridization was carried out in fly brains to identify the precise locations of pdf-expressing cells and to examine any daily cycling of pdf mRNA. Intense signals for pdf mRNA were identified in the medulla, but not in the pars lateralis where PDF neurons were strongly immunostained by the antibody raised against PDF peptide. Hybridization was also performed for the brain samples at two hour intervals throughout the day. Although very intense hybridization signals were observed at ZT8 even in some neurites, no prominent rhythmicity of pdf mRNA expression was observed.

Pigment-dispersing factor PDF is an 18-amino acid insect neuropeptide that mediates a circadian rhythmicity in locomotor activity. PDF is coded in a precursor protein together with another neuropeptide named PDF-associated peptide, PAP. PDF is highly conserved among insects, whereas the homology of PAPs is very low with considerably varied amino acid sequences. Since such dissimilarity has suggested that the function of PAP peptide is not associated with that of PDF, we have attempted to analyze the sequences of PDF precursor proteins among a series of species of insects and hypothesized that PDF precursors are classified into at least three different classes: Drosophila-Musca, Meimuna-Romalea, and Gryllus. In order to exemplify this hypothesis, we here describe the molecular cloning of the pdf-gene of the black blowfly Phormia regina and an in silico screening for the pdf-gene in the genome databank of the mosquito Anopheles gambie, both species belonging to the Diptera. It was found that deduced amino acid sequences of PDF peptides are almost completely conserved among all Dipterans and also the amino acid sequences of PAPs are considerably highly preserved (55–82 similarity) among the species of Diptera. The results confirmed the validity of grouping the PDF precursor proteins. In situ hybridization was carried out in fly brains to identify the precise locations of pdf-expressing cells and to examine any daily cycling of pdf mRNA. Intense signals for pdf mRNA were identified in the medulla, but not in the pars lateralis where PDF neurons were strongly immunostained by the antibody raised against PDF peptide. Hybridization was also performed for the brain samples at two hour intervals throughout the day. Although very intense hybridization signals were observed at ZT8 even in some neurites, no prominent rhythmicity of pdf mRNA expression was observed.

The molecular basis of the circadian clock is an autoregulatory feedback loop in which the PAS domain-containing protein PERIOD periodically inhibits its own transcription. In the present study on PERIOD of the silk moth Bombyx mori, we have cloned two distinct period mRNA homologues with different PAS domain sequences either with or without the pentapeptide GTQEK. A period cDNA fragment first amplified by PCR exhibited a 15 bp-deleted nucleotide sequence in the PAS domain, compared with the database sequence. A possible alternative splicing mechanism was examined by PCR analyses, and a 15 bp-inserted clone was also amplified. The entire sequences of these period alpha and period beta isoforms were then determined by the 3' and 5' RACE methods. Isoform period alpha consists of a 3,324 bp oligonucleotide encoding 1,108 amino acid residues, whereas isoform period beta comprises 3,309 bp corresponding to 1,103 amino acids. Isoforms period alpha and period beta were found to be exactly identical except for the 15 bp deletion/insertion site. Such a pair of isoforms with a deletion/insertion sequence, namely two splice variants, has previously been reported only for the PERIOD proteins of the two honeybees, Apis mellifera and A. cerana. The occurrence of an alternative splicing mechanism in the B. mori period gene was hypothesized based on the genome structure recently clarified. Bombyx mori PERIOD alpha and beta proteins are the isomers that reveal firstly the different PAS domain sequences.