Idiopathic gastroparesis is associated with specific transcriptional changes in the gastric muscularis externa.

BACKGROUND: The molecular changes that occur in the stomach that are associated with idiopathic gastroparesis are poorly described. The aim of this study was to use quantitative analysis of mRNA expression to identify changes in mRNAs encoding proteins required for the normal motility functions of the stomach. METHODS: Full-thickness stomach biopsy samples were collected from non-diabetic control subjects who exhibited no symptoms of gastroparesis and from patients with idiopathic gastroparesis. mRNA was isolated from the muscularis externa and mRNA expression levels were determined by quantitative reverse transcriptase (RT)-PCR. KEY RESULTS: Smooth muscle tissue from idiopathic gastroparesis patients had decreased expression of mRNAs encoding several contractile proteins, such as MYH11 and MYLK1. Conversely, there was no significant change in mRNAs characteristic of interstitial cells of Cajal (ICCs) such as KIT or ANO1. There was also a significant decrease in mRNA-encoding platelet-derived growth factor receptor α (PDGFRα) and its ligand PDGFB and in Heme oxygenase 1 in idiopathic gastroparesis subjects. In contrast, there was a small increase in mRNA characteristic of neurons. Although there was not an overall change in KIT expression in gastroparesis patients, KIT expression showed a significant correlation with gastric emptying whereas changes in MYLK1, ANO1 and PDGFRα showed weak correlations to the fullness/satiety subscore of patient assessment of upper gastrointestinal disorder-symptom severity index scores. CONCLUSIONS AND INFERENCES: Our findings suggest that idiopathic gastroparesis is associated with altered smooth muscle cell contractile protein expression and loss of PDGFRα+ cells without a significant change in ICCs.

Slewing Mirror Telescope optics for the early observation of UV/optical photons from Gamma-Ray Bursts.

We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT can deliver the images of GRB optical counterparts to the intensified CCD detector within 1.5~1.8 s over ± 35 degrees in the slewing field of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides a 17 × 17 arcmin² instantaneous field of view. Technical details of design, construction, the laboratory performance tests in space environments for this unique SMT are described in conjunction with the plan for in-orbit operation onboard the Lomonosov satellite in 2013.

The loop B domain is physically separable from the loop A domain in the hairpin ribozyme.

In order to understand the catalysis mechanism of the hairpin ribozyme, mutant ribozymes were constructed. The distance between the loop A domain and the loop B domain was extended by inserting various lengths of nucleotide linkers at the hinge region in cis mutants, or the domains were separated physically in a trans mutant. All the mutant ribozymes, including the trans mutant, could cleave substrate RNA at the predicted site. A cis mutant with a single nucleotide insertion exhibited cleavage activity about twice as high as that of the wild-type (wt) ribozyme. The insertion of 2-5 nucleotides (nt) gradually reduced the activity to the level of the wt ribozyme. Insertion of a longer linker, up to 11 nt, resulted in the reduction of activity to one half of that of the wt ribozyme. The ribozyme with a single nucleotide insertion at the hinge region seems to form a more suitable conformation for catalysis by three-dimensional fold-back of the loop B to loop A containing the cleavage site. The trans mutant, in which the A and B domains were physically separated, maintained a significant level of activity, suggesting that both domains are necessary for catalysis, but separable. These results demonstrate that interaction between the A and B domains results in catalysis.