Novel perfusion system using continuous liquid-suction catheter attachment in colorectal endoscopic submucosal dissection with water pressure method (with video).

Water pressure method (WPM) is useful for colorectal endoscopic submucosal dissection (ESD), characterized not only by underwater conditions but also by active water pressure via the waterjet function. However, the extension of the colorectum by injecting excess water and contaminating the operative field by stool and bleeding have been issues. This study aimed to evaluate the feasibility of a novel perfusion system using a continuous liquid-suction catheter attachment (CLCA) in colorectal ESD with WPM. We retrospectively reviewed cases in which the perfusion system was used in colorectal ESD with WPM between August 2022 and September 2023. We evaluated clinical characteristics, treatment outcomes, volume of injection by the waterjet function, volume of suction by the endoscope and CLCA, and concentration of floating matter in the operative field over time. Thirty-one cases were enrolled. The median lesion size was 30 (range, 15-100) mm. In all cases, en bloc resection was achieved without perforation. The median injection volume was 2312 (range, 1234-13,866) g. The median suction volumes by the endoscope and CLCA were 918 (range, 141-3162) and 1147 (range, 254-11,222) g, respectively. The median concentration of floating matter in the operative field (measured in 15 cases) was 15.3 (range, 7.3-112) mg/mL when the endoscope arrived at the lesion and 8.0 (range, 3.2-16) mg/mL after endoscopically washing at the beginning of the ESD. It ranged from 7.6 to 13.4 mg/dL every 20 min during ESD. This perfusion system could prevent the extension of the lumen and maintain a good field of view in colorectal ESD with WPM.

Video capsule endoscopy in overt and occult obscure gastrointestinal bleeding: Insights from a single-center, observational study in Japan.

Objective: This study aimed to evaluate the use of video capsule endoscopy (VCE) in patients with obscure gastrointestinal bleeding (OGIB), compare cases of overt and occult OGIB, assess the rates of balloon-assisted enteroscopy (BAE) interventions and rebleeding, and identify predictive markers of positive VCE findings. Methods: Medical records of 430 patients who underwent VCE for OGIB between 2004 and 2022 were analyzed. Occult OGIB was defined as IDA or positive fecal occult blood, whereas overt OGIB was defined as clinically imperceptible bleeding. We retrospectively analyzed demographics, VCE findings based on Saurin classification (P0, P1, and P2), outcome of BAE interventions, and rebleeding rates. Results: A total of 253 patients with overt OGIB and 177 with occult OGIB were included. P1 findings were predominant in both groups, with a similar distribution. The percentage of patients receiving conservative therapy was higher in P1 than in P2 for both overt and occult OGIB. BAE was more frequently performed in P2 than in P1 VCE (83.0% vs. 35.3% in overt OGIB, 84.4% vs. 24.4% in occult OGIB). The percentage of positive findings and intervention in total BAE performed patients were comparable in P1 and P2 of overt OGIB, whereas these percentages in P2 were more than P1 of occult OGIB. Conclusion: VCE effectively identified OGIB lesions requiring intervention, particularly occult OGIB lesions, potentially reducing unnecessary BAE. Rebleeding rates varied according to the VCE findings, emphasizing the importance of follow-up in high-risk patients.

Production of two recombinant insulin-like growth factor binding protein-1 subtypes specific to salmonids.

Salmonids have four subtypes of insulin-like growth factor binding protein (IGFBP)-1, termed -1a1, -1a2, -1b1 and 1b2, owing to teleost- and a lineage-specific whole-genome duplications. We have previously produced recombinant proteins of masu salmon IGFBP-1a1 and -1b2 and conducted functional analysis. To further characterize salmonid-specific IGFBP-1s, we cloned cDNAs encoding mature proteins of IGFBP-1a2 and -1b1 from the liver of masu salmon (Oncorhynchus masou). IGFBP-1a2 and -1b1 shared a 56% amino acid sequence homology whereas their homologies with their counterparts (i.e. -1a1 and -1b2) were 77% and 82%, respectively. We next expressed recombinant masu salmon (rs) IGFBP-1a2 and -1b1 with fusion partners thioredoxin (Trx) and a His-tag using the pET-32a(+) vector system in Escherichia coli. Trx.His.rsIGFBP-1s were detected in the insoluble faction, solubilized in a buffer containing urea, and isolated by Ni-affinity chromatography. They were refolded by dialysis and cleaved from the fusion partners by enterokinase. rsIGFBP-1a2 and -1b1 were purified by reversed-phase high performance liquid chromatography. Purified rsIGFBP-1a2 and -1b1 had the ability to bind digoxigenin-labeled human IGF-I on ligand blotting. We then examined the effects of rsIGFBP-1a1, -1a2, -1b1 and -1b2 in combination with human IGF-I on growth hormone (GH) release from cultured pituitary cells of masu salmon. IGF-I alone reduced GH release while the addition of rsIGFBP-1a1, -1b1 or -1b2, but not rsIGFBP-1a2, diminished the suppressive effect of IGF-I. Addition of rsIGFBP-1s without IGF-I had no effect on GH release. These results show that rsIGFBP-1b1, along with rsIGFBP-1a1 and -1b2, inhibits IGF-I action on the pituitary in masu salmon. The lack of the effect by rsIGFBP-1a2 suggests that salmon IGFBP-1 subtypes underwent subfunction partitioning and have different degrees of IGF-inhibitory action.

Optogenetic manipulation of intracellular calcium by BACCS promotes differentiation of MC3T3-E1 cells.

Bone remodeling is maintained through the balance between bone formation by osteoblasts and bone resorption by osteoclasts. Previous studies suggested that intracellular Ca2+ signaling plays an important role in the differentiation of osteoblasts; however, the molecular mechanism of Ca2+ signaling in the differentiation of osteoblasts remains unclear. To elucidate the effect of Ca2+ signaling in osteoblasts, we employed an optogenetic tool, blue light-activated Ca2+ channel switch (BACCS). BACCS was used to spatiotemporally control intracellular Ca2+ with blue light stimulation. MC3T3-E1 cells, which have been used as a model of differentiation from preosteoblast to osteoblast, were promoted to differentiate by BACCS expression and rhythmical blue light stimulation. The results indicated that intracellular Ca2+ change from the outside of the cells can regulate signaling for differentiation of MC3T3-E1 cells. Our findings provide evidence that Ca2+ could cause osteoblast differentiation.

An ascending visual pathway to the dorsal telencephalon through the optic tectum and nucleus prethalamicus in the yellowfin goby Acanthogobius flavimanus (Temminck & Schlegel, 1845).

Dual visual pathways reaching the telencephalon appear to be an ancient vertebrate trait, but some teleost fish seem to possess only one pathway via the optic tectum. We undertook the present study to determine if and when this loss occurred during evolution. Tracer injection experiments to the optic nerve, the optic tectum, and the dorsal telencephalon were performed in the present study, to investigate ascending visual pathways to the dorsal telencephalon in an acanthopterygian teleost, the yellowfin goby Acanthogobius flavimanus (Temminck & Schlegel, 1845). We confirmed the presence of a nucleus prethalamicus (PTh) in the goby, which has been convincingly identified only in holocentrids, suggesting that this nucleus is present in other acanthopterygians. We found that the optic tectum projects to the PTh bilaterally. The PTh projects in turn to the dorsal telencephalon, ipsilaterally. These results suggest that the yellowfin goby possesses only an extrageniculate-like pathway, while a geniculate-like pathway could not be identified. This situation is common with that of holocentrids and may be a character common in acanthopterygians. It is possible that a geniculate-like system was lost in the common ancestor of acanthopterygians, although the scenario for the evolution of ascending visual systems in actinopterygians remains uncertain due to the lack of precise knowledge in a number of actinopterygian taxons.