Polymer nano-particles (PNPs) with a near-infrared (NIR) light absorption were prepared by the nano-emulsion method to develop contrast agents for photo-acoustic (PA) imaging. The PNP containing silicon naphthalocyanine showed a high absorption coefficient up to 10(10) M(-1) cm(-1). This is comparable to plasmonic gold nano-particles, which have been studied as PA contrast agents. For the PNP larger than 100 nm, the enhancement of the PA signal was observed compared to the gold nano-particle with a similar absorption coefficient and size. In the case of the PNP, the heat by the light absorption is confined in the particle due to the low thermal diffusivity of polymer materials. We showed that the strong thermal confinement effect of PNP results in the enhancement of the efficiency of the PA signal generation and that the PA intensity can be enhanced by the increase of the Grüneisen parameter of the matrix polymer of PNP. The PA signal from the PNP of poly(methyl methacrylate) was 9-fold larger than that of gold nano-particles with the same absorption coefficient. We demonstrated that in the in vivo PA imaging the detection limit of PNP was of the order of 10(-13) M. The NIR absorbing PNP will be a promising candidate of a sensitive contrast agent for PA imaging.
The eradication rate of
Helicobacter pylori
(
H. pylori
) with proton pump inhibitors, amoxicillin, and clarithromycin has reportedly decreased. Some studies have found probiotics to be useful in eradicating
H. pylori
, but these effects have not been sufficiently investigated. We aimed to elucidate the role of probiotics in eradicating
H. pylori
infection. Patients in our hospital with
H. pylori
infection that received standard treatment from January 2015 to December 2016 were retrospectively evaluated (
n
= 468). They were divided into three groups based on their treatment regime, being either proton pump inhibitors, amoxicillin, or clarithromycin (PPI group), vonoprazan, amoxicillin, or clarithromycin (VPZ group), and proton pump inhibitors, amoxicillin, or clarithromycin/probiotics (Miya-BM
®
) (PPI + MBM group). We retrospectively evaluated the
H. pylori
eradication rate and reported side effects. According to intention-to-treat analyses, the eradication rate of
H. pylori
was significantly higher in the PPI + MBM group (87.1%) than in the PPI group (70.1%). There was no difference in side effects between any of the three groups. In conclusion, Miya-BM
®
may have an additive effect when included with eradication therapies for
H. pylori
.
Besides the preventive effect of aspirin on cerebrocardiovascular diseases, aspirin has adverse effects, especially on the gastrointestinal system and kidneys. Especially, a recent advancement in endoscopy revealed that aspirin-induced small intestinal mucosal injury is considerably higher than previously believed. However, the mechanism of this phenomenon is not clear yet. Moreover, effective prophylaxis does not exist. First, we investigated the cytotoxic effect of aspirin on the intestinal epithelial cell line in rats at a high concentration, and found that aspirin significantly decreased heat shock protein 70 expression, increased reactive oxygen species production, and increased epithelial cell apoptosis. These phenomena were prevented by the increment of heat shock protein 70 expression. Next, we investigated the effect of a lower concentration of aspirin on epithelial cell permeability, and found that aspirin significantly increased reactive oxygen species production, decreased tight junction protein expression, and increased epithelial permeability. These phenomena were suppressed by an antioxidant. Finally, we investigated the role of intestinal mucus on aspirin-induced mucosal damage using an in vivo model, and found that mucus prevented a high concentration of aspirin-induced mucosal damage. The investigation of chronic users of aspirin revealed that mucus-increasing therapy might be useful for preventing aspirin-induced small intestinal mucosal injury.
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