Toward the Establishment of a Harmonized Physicochemical Profiling Platform for Therapeutic Oligonucleotides: A Case Study for Aptamers Where the Higher-Order Structure Influences Physical Properties.

Oligonucleotides are short nucleic acids that serve as one of the most promising classes of drug modality. However, attempts to establish a physicochemical evaluation platform of oligonucleotides for acquiring a comprehensive view of their properties have been limited. As the chemical stability and the efficacy as well as the solution properties at a high concentration should be related to their higher-order structure and intra-/intermolecular interactions, their detailed understanding enables effective formulation development. Here, the higher-order structure and the thermodynamic stability of the thrombin-binding aptamer (TBA) and four modified TBAs, which have similar sequences but were expected to have different higher-order structures, were evaluated using ultraviolet spectroscopy (UV), circular dichroism (CD), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). Then, the relationship between the higher-order structure and the solution properties including solubility, viscosity, and stability was investigated. The impact of the higher-order structure on the antithrombin activity was also confirmed. The higher-order structure and intra-/intermolecular interactions of the oligonucleotides were affected by types of buffers because of different potassium concentrations, which are crucial for the formation of the G-quadruplex structure. Consequently, solution properties, such as solubility and viscosity, chemical stability, and antithrombin activity, were also influenced. Each instrumental analysis had a complemental role in investigating the higher-order structure of TBA and modified TBAs. The utility of each physicochemical characterization method during the preclinical developmental stages is also discussed.

A case of colonic fecal impaction caused by excessive dietary fiber intake that was endoscopically treated with intra-fecal injection of a bowel-cleansing agent.

Background and Aim: A 75-year-old man who had eaten half a head of chopped raw cabbage (approximately 600 g) daily was suffering from the left lower pain, abdominal fullness, and constipation. He was diagnosed with colonic ileus and obstructive colitis due to a fecal impaction in the sigmoid-descending junction. During colonoscopy, a tapered catheter was repeatedly inserted into the impacted feces to inject a bowel-cleansing agent. Finally, the feces were broken to be fragmented enough to path the endoscope through. After the procedure, his symptoms were immediately relieved. Relevance for Patients: Excessive dietary fiber intake can induce fecal ileus. Endoscopic treatment with intra-fecal injection of a bowel-cleansing agent is useful and worth attempting for disimpaction of feces.

Influence of the crystallization tendencies of pharmaceutical glasses on the applicability of the Adam-Gibbs-Vogel and Vogel-Tammann-Fulcher equations in the prediction of their long-term physical stability.

Amorphization is a powerful approach for improving the aqueous solubility and bioavailability of poorly water-soluble compounds. However, it can cause chemical and physical instability, the latter of which can lead to crystallization during storage, diminishing the solubility advantage of the amorphous state. As there is no standard method for predicting the physical stability of amorphous materials, a long-term stability study is needed in drug development. This study investigated the correlation between the physical stability of amorphous compounds and molecular mobility based on the assumption that physical stability is governed by the diffusional motion of a molecule. Model compounds were evaluated for crystallization onset time, structural relaxation time, fragility, and fictive temperature. The crystallization onset time of acetaminophen glass correlated with its relaxation time calculated from the Adam-Gibbs-Vogel equation; however, that of felodipine glass correlated with the relaxation time calculated from the Vogel-Tammann-Fulcher equation. The different crystallization tendencies of these compounds can be explained by the differences in the rate limiting steps in their crystallization processes, indicating the importance of distinguishing the critical process associated with crystallization. These findings will be useful for more accurate prediction of long-term physical stability of amorphous materials.

Palliative Radiotherapy for Bleeding from Unresectable Gastric Cancer Using Three-Dimensional Conformal Technique.

Optimal regimens using recent radiotherapy (RT) equipment for bleeding gastric cancer (GC) have not been fully investigated yet. We retrospectively reviewed the clinical data of 20 patients who received RT for bleeding GC in our institution between 2016 and 2021. Three-dimensional conformal RT was performed. The effectiveness of RT was evaluated by the mean serum hemoglobin (Hb) level and the number of transfused red blood cell (RBC) units 1 month before and after RT. The median first radiation dose was a BED of 39.9 Gy. The treatment success rate was 95% and the rebleeding rate was 10.5%. There was a significant increase in the mean Hb level (8.0 ± 1.1 vs. 9.8 ± 1.3 g/dL, p = 0.01), and a significant decrease in the mean number of transfused RBC units (6.8 ± 3.3 vs. 0.6 ± 1.5 units, p < 0.01). Severe toxicity was observed in two patients (anorexia [n = 1] and gastrointestinal [GI] perforation [n = 1]). Reirradiation was attempted in three patients (for hemostasis [n = 2] and for mass reduction [n = 1]). The retreatment success rate for rebleeding was 100%. GI perforation occurred in two patients who had received hemostatic reirradiation. Palliative RT for bleeding GC using recent technology had excellent efficacy. However, it may be associated with a risk of GI perforation.

A Rare Case of COVID-19 Pneumonia Concomitant with Bleeding from Acute Gastric Mucosal Lesions.

A 70-year-old man was diagnosed with coronavirus disease 2019 (COVID-19) pneumonia. Twenty-six days after admission, he experienced hematemesis despite improvement in his respiratory symptoms. Contrast-enhanced computed tomography revealed edematous stomach wall thickening with neither ischemic findings in the gastric wall nor obstruction of the gastric artery. Emergent esophagogastroduodenoscopy showed diffuse dark-red mucosa accompanied by multiple easy-bleeding, irregularly shaped ulcers throughout almost the whole stomach without active bleeding or visible vessels. The clinical course, including the endoscopic findings, progressed favorably with conservative treatment. COVID-19 pneumonia can present with acute gastric mucosal lesion, which may be induced by microvascular thrombosis due to COVID-19-related coagulopathy.

Endoscopic ultrasonography for pre-operative local assessment and endoscopic ultrasonography-guided marking before gastrojejunostomy for duodenal obstruction using magnetic compression anastomosis.

BACKGROUND AND AIM: A 93-year-old woman who was bedridden with severe dementia was referred to our department with a 3-day history of repeated vomiting after meals. Computed tomography revealed significant dilatation of the duodenum up to the level of the third portion, which was compressed by a large, low-density mass. Upper gastrointestinal endoscopy showed narrowing of the third portion of the duodenum with edematous mucosa covered with multiple white spots, where the endoscope was able to pass through with mild resistance. B-cell lymphoma was histopathologically suspected from biopsy specimens of the mucosa. We performed gastrojejunostomy through the magnetic compression anastomosis (MCA) technique. We prepared two neodymium magnets: Flat plate shaped (15 × 3 mm) with a small hole 3 mm in diameter; a nylon thread was passed through each hole. We then confirmed the absence of no non-target tissue, including large vessels and intestine adjacent to the anastomosis where the magnets were to be placed using endoscopic ultrasonography (EUS) from the stomach. EUS-guided marking using biopsy forceps by biting the mucosa and placing a hemoclip was performed at the anastomosis site in the stomach. The magnet was pushed and delivered to the duodeno-jejuno junction, and another magnet was delivered to the marking point in the stomach. The magnets were attracted toward each other transmurally. The magnets fell into the colon by 11 days after starting the compression, and the completion of gastrojejunostomy was confirmed. RELEVANCE FOR PATIENTS: Endoscopic gastrojejunostomy using MCA is useful as a minimally invasive alternative treatment for duodenal obstruction. EUS for the pre-operative local assessment and EUS-guided marking can ensure the safety of the MCA procedure.

[Endoscopic closure of an esophago-pleural fistula resulting from a perforated esophageal ulcer due to systemic sclerosis:filling and shielding using polyglycolic acid sheets and fibrin glue].

A woman in her 70s with systemic sclerosis experienced dyspnea, and consequently, she was diagnosed with an esophago-pleural fistula, which was caused by a perforated esophageal ulcer. We administered conservative treatments including continuous pleural drainage and total parenteral nutrition. The fistula was closed but recurred, at which point we attempted to close the fistula by filling and shielding using polyglycolic acid (PGA) sheets and fibrin glue (FG). We were able to safely and smoothly fill and shield the fistula using the PGA sheets with a guidewire. We show that endoscopic closure of an esophago-pleural fistula using this technique is an effective, low-invasive treatment for gastrointestinal perforation and refractory fistulas.

Filling of Polyglycolic Acid Sheets for Closure of Gastrointestinal Fistulas With an Easily Deliverable Technique Using a Guidewire.

BACKGROUND: This retrospective study aimed to investigate the suitable indications, methodology and long-term effect of the closure of gastrointestinal (GI) fistulas using polyglycolic acid (PGA) sheets and fibrin glue (FG) and to evaluate the usefulness of a delivery technique using a guidewire. METHODS: It involved 10 applications in six patients (median age 73 (range 53 - 78) years old, three men) with GI fistulas. A guidewire was introduced endoscopically or percutaneously into the fistula beyond the opposite orifice of the fistula with radiologic control. A tapered catheter was inserted over the guidewire, and the fistula was cleaned with an adequate quantity of saline. Subsequently, a small piece of PGA sheet was skewered onto the guidewire at the center and then pushed using the tapered catheter over the guidewire and delivered into the fistula. In cases of endoscopic procedure, the mucosa around the fistula was ablated, and the orifice of the fistula along with the surrounding mucosa was shielded with a piece of PGA sheet fixed with hemoclips and FG. RESULTS: Technical success of fistula closure was achieved in all applications, and no complications were observed after the procedure. The long-term occlusion of the fistula was ultimately achieved in four of six patients at 202 - 654 days (median duration, 244 days) after the last procedure with one or two applications. CONCLUSIONS: The closure of GI fistulas using PGA sheets and FG demonstrated long-term efficacy for upper GI fistula of a certain length, and the filling technique using a guidewire ensured a safe smooth procedure.

IgG4-related Autoimmune Hepatitis with a Suspected Drug-induced Etiology.

A 69-year-old man was referred to our department with acute hepatitis. He had been newly treated with benidipine hydrochloride for two months. His blood test results were as follows: aspartate aminotransferase, 1,614 IU/L; alanine aminotransferase, 1,091 IU/L and anti-smooth muscle antibody, ×80. Needle liver biopsy specimen showed interface hepatitis with mainly lymphocytic infiltration and bridging fibrosis in the periportal area. Immunohistochemistry revealed lymphocytic infiltration positive for IgG4. We diagnosed him with IgG4-related AIH with an etiology that was suspected of being drug-induced. Oral prednisolone was started and then tapered after achieving biochemical remission. Hepatitis recurred after the cessation of steroids; however, remission was achieved with ursodeoxycholic acid.

A box-shaped shielding device for reducing the risk of COVID-19 droplet infection during gastrointestinal endoscopic procedures.

BACKGROUND AND AIMS: Endoscopists and endoscopic assistants are easily exposed to germs, including COVID-19, during aerosol-generating procedures such as gastrointestinal endoscopy. This retrospective study investigated the utility of a box-shaped shielding device for reducing the risk of COVID-19 droplet infection during endoscopic procedures. METHODS: We created a cuboid box (500 × 650 × 450 mm) with four sides were covered with a transparent, vinyl-chloride sheet having two windows for endoscopic passage and assistance. The shielding box was then placed over a patient's head and shoulders and covered with another transparent vinyl sheet. We assessed its utility and safety using the medical data concerning the procedure time and vital signs and a questionnaire for the endoscopic staff and patients. RESULTS: We performed endoscopic retrograde cholangiopancreatography-related procedures using this device for two patients suspected of having COVID-19-associated pneumonia. Both patients were smoothly and successfully treated without any complications. No difficulties were noted with either endoscopic operation or in assisting the procedure, and the transparency was good enough to observe the patients' faces and movements. CONCLUSIONS: This box-shaped shielding device can be used to reduce the risk of COVID-19 droplet infection during endoscopic procedures in the clinical setting. RELEVANCE FOR PATIENTS: The COVID-19 outbreak has reminded healthcare personnel working in endoscopy units of the importance of infection prevention during endoscopy. The box-shaped shielding device can help endoscopic staff avoid hospital-setting COVID-19 infection.

A rare case of Goodpasture syndrome concomitant with bleeding jejunal Dieulafoy's lesion.

An 81-year-old man was diagnosed with Goodpasture syndrome (GS) because he met the criteria of positive anti-GBM antibodies, rapid progressive glomerulonephritis and pulmonary hemorrhage. After starting plasmapheresis and steroid pulse therapy, he experienced tarry stool and contrast-enhanced CT revealed an aneurysmal finding in the jejunum. Paroral enteroscopy showed a jejunal Dieulafoy's lesion (DL) with gush-out hemorrhage. Hemostasis was successfully achieved by hemoclipping, and he then experienced no re-bleeding events. GS can present as a jejunal DL, and contrast-enhanced CT is useful for investigating the etiology and site of small intestinal bleeding, which can lead to smooth, effective endoscopic hemostasis.

Endoscopic Gastrojejunostomy for Superior Mesenteric Artery Syndrome Using Magnetic Compression Anastomosis.

An 89-year-old woman who was bedridden suffered repeated vomiting due to superior mesenteric artery syndrome (SMAS). We performed gastrojejunostomy via the magnetic compression anastomosis (MCA) technique because her situation was not improved by conservative therapy and because the operative risk was high. We prepared two neodymium magnets: a flat plate-shaped magnet (15 × 3 mm) and a ring-shaped magnet of the same size. The ring-shaped magnet which passed through a guidewire was pushed to the duodenum by an endoscope over the guidewire. The duodenal stricture was balloon-dilated in front of the magnet, and the magnet was pushed all together beyond the stricture and placed at the duodenojejunal junction. Subsequently, the flat plate-shaped magnet was delivered endoscopically to the stomach using a biopsy forceps. The magnets were attracted towards each other transmurally after one more flat plate-shaped magnet was added to the gastric-side magnet. Completion of gastrojejunostomy was confirmed while retrieving the magnets 10 days after starting compression. She has been asymptomatic for 1 month since anastomosis. Endoscopic gastrojejunostomy using MCA was an effective, low-invasive treatment for SMAS.

Experience of Endoscopic Jejunojejunostomy for Anastomotic Obstruction After Subtotal Gastrectomy Using Magnetic Compression Anastomosis.

Magnetic compression anastomosis (MCA) was developed as a low-invasive treatment for gastro-enteric or entero-enteric obstruction. A 72-year-old man underwent subtotal gastrectomy with Billroth II reconstruction for early gastric cancer. After the operation, he suffered from repeated aspiration pneumonia due to anastomotic obstruction caused by jejunal kinking at the efferent loop of anastomosis. We therefore performed jejunojejunostomy via the MCA technique, as his situation was not improved despite conservative therapy and he had a high reoperative risk. We prepared two flat plate-shaped neodymium magnets (15 × 3 mm) each with a small hole, and a nylon thread was passed through each hole. Each magnet was then delivered endoscopically to the anal side of the jejunal kinking, subsequently to the anastomosis, using biopsy forceps. The two magnets immediately became attracted towards each other transmurally. Oozing hemorrhage with clot at the mated magnets was observed 10 days after starting the compression. After retrieving the magnets, we confirmed the completion of jejunojejunostomy and then successfully achieved hemostasis of the anastomotic hemorrhage using argon plasma coagulation. The widely patent anastomosis was confirmed endoscopically 1 month after canalization; and he has been asymptomatic and able to eat a normal diet ever since. Endoscopic MCA is an effective, low-invasive treatment for anastomotic obstruction after subtotal gastrectomy. A standardized, safer procedure should be established for general use in the clinical setting.

Prophylactic Biliary Stenting Before Cholecystectomy in Patients With Gallstones and Common Bile Duct Stones.

BACKGROUND: The usefulness of prophylactic biliary stenting for patients with common bile duct stones (CBDS) and gallstones (GS) to prevent recurrent biliary events after endoscopic sphincterotomy (EST) and CBDS extraction before elective cholecystectomy remains controversial. The aim of this study was to evaluate the risk of recurrent CBDS around the perioperative period and clarify its risk factors. METHODS: The clinical data of all patients who received prophylactic biliary stenting after EST for CBDS and later underwent cholecystectomy for GS followed by stent extraction in our institution were retrospectively reviewed. The numbers of residual CBDS at the end first and second endoscopic retrograde cholangiography (ERC) studies were compared. Univariate and multivariate analyses were performed using a logistic regression model to determine risk factors for recurrent CBDS in the perioperative period. RESULTS: Forty-two consecutive patients received prophylactic biliary stenting and subsequent cholecystectomy for GS. Three of these patients were excluded from this study because the number of residual stones was not confirmed. The median maximum CBDS diameter at second ERC was 0 mm (range, 0 - 10 mm); six patients had multiple CBDS (≥ 5). The number of CBDS at second ERC was increased in comparison to that at the first ERC in 15 patients (38.4%), and was unchanged or decreased in 24 patients. The median minimum cystic duct diameter was 4 mm (range, 1 - 8 mm). The median interval between first ERC and operation was 26 days (range, 2 - 131 days). The median interval between operation and second ERC was 41 days (range, 26 - 96 days). Laparoscopic cholecystectomy (LC) was performed in 38 patients, one of whom was converted from LC to open cholecystectomy. Postoperative complications (transient bacteremia) occurred in one patient. The cystic duct diameter was an independent risk factor for an increased number of CBDS at second ERC in the multivariate analysis (odds ratio 0.611 (95% confidence interval (0.398 - 0.939)), P = 0.03). CONCLUSION: Recurrent CBDS around the perioperative period of cholecystectomy is not a rare complication after EST and the removal of CBDS with concomitant GS. Prophylactic biliary stenting is considered useful for preventing CBDS-associated complications, especially for patients in whom the cystic duct diameter is larger (≥ 5 mm).

A Rare Case of Local Recurrence Following Curative Endoscopic Submucosal Dissection of Intramucosal Differentiated-Type Gastric Cancer.

A 78-year-old man underwent endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) (type 0-IIa) in the anterior wall of the antrum. En bloc resection was achieved. The histopathological examination revealed very well-differentiated tubular adenocarcinoma (tub1) of 30 × 22 mm in size, confined to the mucosa. No lymphovascular invasion or ulceration was observed, and there was no undifferentiated-type component and the margins were tumor-free. Therefore, this lesion fulfilled the eCuraA criteria. Two years after ESD, esophagogastroduodenoscopy revealed an irregular, slightly-depressed lesion within the post-ESD scar. Tubular adenocarcinoma was suspected based on histopathological examination of a biopsy specimen. The tumor was resected by ESD. A histopathological examination revealed well-differentiated tubular adenocarcinoma (tub1) of 6 × 4 mm in size, confined to the mucosa. No lymphovascular invasion was detected and the margins were tumor-free. These findings indicated a curative resection. Recurrence following a curative ESD of an intramucosal differentiated-type EGC which fulfilled the eCuraA criteria is rare. Careful endoscopic observation using magnifying narrow band imaging (NBI) is needed after ESD, even when curative resection is achieved.

Experience of Manual Compression Hemostasis Under Endoscopic Observation for Acute Hemorrhagic Rectal Ulcer.

We experienced two cases in which manual compression hemostasis under endoscopic observation was used in patients with acute hemorrhagic rectal ulcer (AHRU). The patients experienced an episode of massive fresh hematochezia, requiring the blood transfusion. Emergent sigmoidoscopy revealed multiple ulcers with a large protuberant visible vessel or with gush-out hemorrhage on the lower rectum. Endoscopic hemostasis by hemoclips and hypertonic saline-epinephrine injection was attempted; however, mechanical mucosal injury induced by hemoclips and needles caused another gush-out hemorrhage. Thus, the site of bleeding was manually compressed by a forefinger under endoscopic observation. After 5 min, compression hemostasis was achieved, and the postoperative course was uneventful. Manual compression hemostasis under endoscopic observation is useful and worth attempting for AHRU.

[A case of cholangiolocellular carcinoma found to be hepatic hemangioma at 16-month follow up].

We report a rare case of hepatic cholangiolocellular carcinoma (CoCC) with long-term observation. A 73-year-old woman was found to have a solitary hepatic tumor with a diameter of 10mm on dynamic computed tomography (CT), which showed peripheral enhancement in the arterial phase and enhancement retention in the delayed phase. Although it was initially diagnosed as hepatic hemangioma, the follow up examination conducted 16 months later revealed that the tumor had grown to 18mm. Doubling time of the tumor was calculated to be 177 days. Because magnetic resonance imaging results were not typical for hepatic hemangioma, hepatocellular carcinoma was suspected and partial hepatectomy was performed. Histologically, the tumor was comprised dense proliferation of small irregular tubules with fibrous stroma. Immunohistochemistry revealed that the carcinoma cells were positive for cytokeratin (CK) 7, CK19, and neurnal cell adhesion molecule. Cells were negative for hepatocyte paraffin 1. Periodic acid-Schiff and Alcian blue staining showed an absence of mucin in the tumor cells, and epithelial membrane antigen was strongly positive on the luminal surface of tubules. These findings were typical of CoCC;therefore, CoCC should be ruled out when dynamic CT images suggest hepatic hemangioma.

Polyamines stimulate the CHSY1 synthesis through the unfolding of the RNA G-quadruplex at the 5'-untraslated region.

Glycosaminoglycans (GAGs), a group of structurally related acidic polysaccharides, are primarily found as glycan moieties of proteoglycans (PGs). Among these, chondroitin sulfate (CS) and dermatan sulfate, side chains of PGs, are widely distributed in animal kingdom and show structural variations, such as sulfation patterns and degree of epimerization, which are responsible for their physiological functions through interactions with growth factors, chemokines and adhesion molecules. However, structural changes in CS, particularly the ratio of 4-O-sulfation to 6-O-sulfation (4S/6S) and CS chain length that occur during the aging process, are not fully understood. We found that 4S/6S ratio and molecular weight of CS were decreased in polyamine-depleted cells. In addition, decreased levels of chondroitin synthase 1 (CHSY1) and chondroitin 4-O-sulfotransferase 2 proteins were also observed on polyamine depletion. Interestingly, the translation initiation of CHSY1 was suppressed by a highly structured sequence (positions -202 to -117 relative to the initiation codon) containing RNA G-quadruplex (G4) structures in 5'-untranslated region. The formation of the G4s was influenced by the neighboring sequences to the G4s and polyamine stimulation of CHSY1 synthesis disappeared when the formation of the G4s was inhibited by site-directed mutagenesis. These results suggest that the destabilization of G4 structures by polyamines stimulates CHSY1 synthesis and, at least in part, contribute to the maturation of CS chains.

[A case of a gas-forming liver abscess caused by Clostridium perfringens after transcatheter arterial chemoembolization].

An 80-year-old man had a medical history of chronic hepatitis C and pancreatoduodenectomy. We detected recurrence of hepatocellular carcinoma, and performed transcatheter arterial chemoembolization, instead of radiofrequency ablation or surgery, because of the patient's medical history of bile duct reconstruction and liver dysfunction. On the second day, he was diagnosed with a gas-forming liver abscess and underwent liver abscess drainage. Clostridium perfringens and sordellii were detected by aspiration and the blood culture. Meropenem and Clindamycin were administered intravenously. He was treated shortly after the occurrence before the involvement of severe hemolysis and recovered from the acute phase.

Polyamines release the let-7b-mediated suppression of initiation codon recognition during the protein synthesis of EXT2.

Proteoglycans (PGs), a family of glycosaminoglycan (GAG)-protein glycoconjugates, contribute to animal physiology through interactions between their glycan chains and growth factors, chemokines and adhesion molecules. However, it remains unclear how GAG structures are changed during the aging process. Here, we found that polyamine levels are correlated with the expression level of heparan sulfate (HS) in human skin. In cultured cell lines, the EXT1 and EXT2 enzymes, initiating HS biosynthesis, were stimulated at the translational level by polyamines. Interestingly, the initiation codon recognition by 43S preinitiation complex during EXT2 translation is suppressed by let-7b, a member of the let-7 microRNA family, through binding at the N-terminal amino acid coding sequence in EXT2 mRNA. Let-7b-mediated suppression of initiation codon depends on the length of 5'-UTR of EXT2 mRNA and its suppression is inhibited in the presence of polyamines. These findings provide new insights into the HS biosynthesis related to miRNA and polyamines.