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1.
Chemistry ; : e202401343, 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38676431

RESUMEN

A chiral shape-persistent macrocyclic compound (Si-[3]), designed by the C/Si substitution in the spiro-atom of spirobifluorene in the cyclic trimer (C-[3]), has been successfully synthesized in this study. The C/Si substitution made the spiro-conjugation and energy levels of HOMO and LUMO decrease. Due to the silicon substitution, the macrocyclic compound Si-[3] was able to be degraded by fluoride ions, but its reaction rate was slower than that of the unsubstituted spirosilabifluorene, showing the chemical stability of Si-[3]. Furthermore, the chiroptical properties of Si-[3] with D3-symmetric macrocyclic structure were investigated, and (P,P,P)-Si-[3] showed a high emission quantum yield (Φf=80 %) and moderate dissymmetry factor of circularly polarized luminescence (CPL) (glum,exp=-1.2×10-3). According to the time-dependent density-functional theory (TD-DFT) calculations using polarizable continuum model (PCM), the bright CPL from Si-[3] was explained by a planarization of one bisilafluorenyl moiety at the excited state, which is responsible for the almost fully-allowed radiative transition with a short emission lifetime of τf=1.89 ns.

2.
Dig Dis ; : 1-8, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38749404

RESUMEN

INTRODUCTION: Superficial non-ampullary duodenal epithelial tumors (SNADETs) include low-grade adenoma (LGA) and high-grade adenoma or carcinoma (HGA/Ca) and are classified into two different epithelial subtypes, gastric-type (G-type) and intestinal-type (I-type). We attempted to distinguish them by endoscopic characteristics including magnifying endoscopy with narrow-band imaging (M-NBI). METHODS: Various endoscopic and M-NBI findings of 286 SNADETs were retrospectively reviewed and compared between G- and I-types and histological grades. M-NBI findings were divided into four patterns based on the following vascular patterns; absent, network, intrastructural vascular (ISV), and unclassified. Lesions displaying a single pattern were classified as mono-pattern and those displaying multiple patterns as mixed-pattern. Lesions showing CDX2 positivity were categorized as I-types and those showing MUC5AC or MUC6 positivity were categorized as G-types based on immunohistochemistry. RESULTS: Among 286 lesions, 23 (8%) were G-type and 243 (85%) were I-type. More G-type lesions were located oral to papilla (91.3 vs. 45.6%, p < 0.001), and had protruding morphology compared to those of I-types (65.2 vs. 14.4%, p < 0.001). The major M-NBI pattern was ISV in G-type (78.2 vs. 26.3%, p < 0.001), and absent for I-type (0 vs. 34.5%, p = 0.003). Three endoscopic characteristics; location oral to papilla, protruding morphology, and major M-NBI pattern (ISV) were independent predictors for G-type. Mixed-pattern was more common in HGA/Ca than LGA for I-type (77.0 vs. 58.8%, p = 0.01); however, there was no difference for those in G-type. CONCLUSION: Endoscopic findings including M-NBI are useful to differentiate epithelial subtypes.

3.
J Gastroenterol Hepatol ; 39(4): 725-732, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38229468

RESUMEN

BACKGROUND AND AIM: Prophylactic closure with the over-the-scope clip (OTSC) after endoscopic submucosal dissection (ESD) of superficial non-ampullary duodenal epithelial tumors (SNADETs) has been reported to reduce postoperative adverse events (AEs). However, there are few evidences regarding AEs-associated factors and long-term outcomes of OTSCs. METHODS: From January 2011 to December 2020, 139 consecutive patients with SNADETs who underwent ESD followed by OTSC closure in five institutions were extracted in this retrospective study. The primary endpoint was the rate of postoperative AEs after prophylactic OTSC closure. The secondary endpoints were the complete closure rate, residual rate, and long-term AEs associated with residual OTSCs. RESULTS: The rate of complete closure of the mucosal defect was 97.3% (142) in 146 SNADETs, which were completely resected by ESD. Postoperative AEs, including delayed bleeding, delayed perforation, and localized peritonitis, occurred in 6.2%, 3.4%, and 2.1% of patients, respectively; however, all of the cases improved without surgical treatment. In the multivariate logistic regression analysis, the use of two or more OTSCs was a significant independent risk factor for postoperative AEs (odds ratio, 2.94; 95% confidence interval, 1.02-8.46; P = 0.046). The residual OTSC rate was 46.4% at 1 year postoperatively, and long-term AEs included duodenal erosions and ulcers associated with residual OTSCs. CONCLUSIONS: Prophylactic closure with OTSCs after duodenal ESD can provide acceptable short-and long-term outcomes for preventing postoperative AEs. However, multiple OTSCs were the independent risk factors of postoperative AEs due to the gaps between and near the OTSCs.


Asunto(s)
Neoplasias Duodenales , Resección Endoscópica de la Mucosa , Humanos , Resección Endoscópica de la Mucosa/efectos adversos , Estudios Retrospectivos , Resultado del Tratamiento , Neoplasias Duodenales/cirugía , Neoplasias Duodenales/patología , Instrumentos Quirúrgicos
4.
Digestion ; : 1, 2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38857583

RESUMEN

INTRODUCTION: Crohn's disease (CD) induces persistent inflammation throughout the gastrointestinal (GI) tract, potentially resulting in complications such as intestinal stenosis and fistulas, particularly in the small bowel. Small bowel capsule endoscopy (SBCE) is recommended for monitoring CD, especially when GI tract patency is maintained. This study aimed to retrospectively assess patients with CD who underwent SBCE to determine the timing of clinical changes and address the current lack of evidence regarding GI tract patency loss during CD treatment. METHODS: Of the 166 consecutive patients who underwent SBCE at our institution, 120 were followed up and included in this study. Forty-six patients were excluded due to colitis type or immediate treatment changes post-SBCE. This study focused on the primary and secondary endpoints, including the cumulative stricture-free rate of the GI tract, emergency hospitalization post-SBCE, and post-SBCE treatment strategies, at the discretion of the attending physicians. RESULTS: Demographic data revealed that the mean age of the study population was 43 years and that there was a male predominance (75%). The median disease duration was 12 years and the mean Crohn's Disease Activity Index was 98. During a 1,486-day observation period, 37% of patients experienced treatment changes. A Lewis score of >264 and perianal lesions were identified as independent risk factors for additional treatment needs. Emergency hospitalization occurred in 6% of patients and GI patency failure in 11%. Female sex and Lewis score>264 were associated with higher risks. GI patency rate declined 2 years after SBCE. CONCLUSIONS: For patients who experienced no treatment changes based on SBCE results, it is recommended to undergo SBCE monitoring at intervals of no longer than 2 years.

5.
Dig Dis Sci ; 69(7): 2573-2585, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38713271

RESUMEN

BACKGROUND: Numerous biological interventions and small molecules are used to treat Crohn's disease; however, the effectiveness of these treatments varies largely. Non-responsiveness to biological therapies is associated with interleukin (IL)-18 gene polymorphisms and high IL-18 expression has been implicated in the pathogenesis of Crohn's disease. AIMS: The aim of this study was to elucidate the expression of precursor and mature IL-18 in patients with Crohn's disease who exhibited varied responses to cytokine-targeted treatments and determine whether selective inhibition of mature IL-18 offers a novel therapeutic avenue. METHODS: We generated a monoclonal antibody that specifically recognizes the neoepitope of caspase-cleaved mature IL-18. Expression of precursor and mature IL-18 was analyzed in patients with Crohn's disease. Anti-mature IL-18 monoclonal antibodies were intraperitoneally administered in an acute colitis mouse model, and the disease activity index, body weight loss, tissue pathology, proinflammatory cytokine expression, goblet cell function, and microbiota composition were assessed. RESULTS: Precursor and mature IL-18 expression was upregulated and goblet cell function was impaired in patients with Crohn's disease who were unresponsive to biological therapies. Administration of anti-mature IL-18 antibodies ameliorated induced colitis by repairing goblet cell function and restoring the mucus layer. CONCLUSIONS: The newly developed monoclonal antibody holds promise as a therapeutic alternative for Crohn's disease.


Asunto(s)
Anticuerpos Monoclonales , Enfermedad de Crohn , Células Caliciformes , Interleucina-18 , Interleucina-18/metabolismo , Interleucina-18/inmunología , Animales , Células Caliciformes/inmunología , Células Caliciformes/patología , Células Caliciformes/efectos de los fármacos , Humanos , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Ratones , Enfermedad de Crohn/inmunología , Enfermedad de Crohn/tratamiento farmacológico , Femenino , Masculino , Modelos Animales de Enfermedad , Colitis/inmunología , Colitis/tratamiento farmacológico , Adulto , Ratones Endogámicos C57BL
6.
Rev Esp Enferm Dig ; 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38450507

RESUMEN

Ectopic pancreas (EP) is defined as pancreatic tissue that lacks anatomical or vascular connections to the normal pancreas. EP is generally asymptomatic and is detected incidentally during endoscopy. However, due to pseudocyst formation, inflammation, or malignant transformation, it may cause non-specific gastrointestinal symptoms, such as abdominal pain, abdominal discomfort, nausea, vomiting, and bleeding. Pseudocyst formation in EP may result from the retention of exocrine secretions in the absence of connections between the glandular epithelium and gastric lumen. We herein report a case of EP with a pseudocyst associated with epigastric pain. EP with a pseudocyst, although rare, needs to be considered in a differential diagnosis of cystic lesions of the stomach.

7.
Chemistry ; 29(47): e202301161, 2023 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-37264730

RESUMEN

Despite several small molecules being encapsulated inside cage-opened fullerene derivatives, such species have not considerably affected the structures and properties of the outer carbon cages. Herein, we achieved an effective inner-space modification for an open-cage C60 derivative by insertion of a neutral CH3 CN molecule into the cavity. The CH3 CN@open-C60 thus obtained showed an enhanced polarity, thus affording an easy separation from a mixture containing the empty cage by column chromatography on silica gel, without the preparative HPLC that was needed for previous cases. The less negative reduction potentials with respect to those of empty cage reflect the decreased energy level of the LUMO, which is supported by the DFT calculations. NMR spectroscopy, single-crystal X-ray analysis, and theoretical calculations revealed that both the presence of the encapsulated CH3 CN and cage deformation caused by the CH3 CN play an essential role in the change of the electronic properties. Furthermore, the favored binding affinity of deuterated acetonitrile CD3 CN with internal C60 surface is discussed.

8.
Dig Dis ; 41(1): 80-88, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-35108704

RESUMEN

INTRODUCTION: Endoscopic submucosal dissection for duodenal neoplasms (D-ESD) is considered a technically demanding procedure regarding the high risk of delayed adverse events. Data regarding optimal managements of ulcers after D-ESD are lacking. METHODS: A retrospective analysis was performed on consecutive 145 cases of D-ESD for superficial nonampullary duodenal epithelial tumors at a single referral center. Factors related to delayed adverse events and the healing process of ulcers after D-ESD were analyzed. RESULTS: Complete ulcer suture after D-ESD was performed in 128 cases (88%). Two delayed perforation occurred among cases with incomplete suture. Delayed bleeding occurred in 8 cases (6%) within 3 weeks. The ulcer closure rate at second-look endoscopy (SLE) was significantly low among cases with delayed bleeding (12.5% vs. 75%, p = 0.001). The bleeding rate before SLE was significantly high among patients who did not have complete ulcer closure after D-ESD (0.8% vs. 12%, p = 0.036). The ratio of lesions located in the second oral-Vater was significantly low among ulcers re-opened at SLE (38% vs. 14%, p = 0.044). Proton-pump inhibitors (PPIs) were administered for a median of 7 weeks (range 1-8 weeks). At 3 weeks, active ulcer stages were observed in a few cases, and healing or scarring was observed in most cases. CONCLUSIONS: Complete ulcer suture was related to decreased risk of delayed adverse events after D-ESD. From the bleeding period and healing process of D-ESD ulcers, the minimum required length of PPI may be 3 weeks after D-ESD.


Asunto(s)
Resección Endoscópica de la Mucosa , Neoplasias Gástricas , Úlcera Gástrica , Humanos , Duodeno/patología , Resección Endoscópica de la Mucosa/efectos adversos , Endoscopía Gastrointestinal/efectos adversos , Inhibidores de la Bomba de Protones/efectos adversos , Estudios Retrospectivos , Neoplasias Gástricas/patología , Úlcera Gástrica/patología , Úlcera/inducido químicamente
9.
Jpn J Clin Oncol ; 53(10): 877-884, 2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37394910

RESUMEN

With the recent increase in the frequency of duodenal tumor detection, significant progress has been made in endoscopic diagnosis and treatment. Although the first guidelines were issued in Japan, patient treatment varies widely among institutions. There is a need for improving the quality of endoscopic diagnosis and more curative and safer treatments. Biopsy is the standard diagnostic method; however, the diagnostic accuracy of endoscopic biopsy is not so high. Therefore, the differentiation of superficial non-ampullary duodenal epithelial tumors from non-neoplastic lesions is being developed. The incidence of lymph node and distant metastases of duodenal epithelial tumors is extremely rare in intramucosal carcinomas, and they are considered good candidates for endoscopic treatment if the technical difficulties can be resolved. Adverse events associated with endoscopic treatment are greatly reduced at advanced facilities through novel resection and closure methods, and further improvements are expected in the future. Clarifying the risk of metastatic recurrence may lead to the development of more appropriate treatments and curative resection criteria.

10.
Rev Esp Enferm Dig ; 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-38095173

RESUMEN

When performing endoscopic submucosal dissection (ESD) beyond stenoses, there have only been two choices: balloon dilation until a conventional therapeutic endoscope passes through or the use of an ultrathin endoscope. However, balloon dilation has a risk of perforation and an ultrathin endoscope limits the devices that may be used. The novel thin-therapeutic endoscope has an outer diameter of 7.9 mm and instrument channel diameter of 3.2 mm; therefore, there are no restrictions on the ESD device that may be used, and the procedure may be performed in the same manner as regular ESD. We herein report a case in which the thin-therapeutic endoscope was useful for esophageal ESD beyond a stenosis.

11.
Rev Esp Enferm Dig ; 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-38095259

RESUMEN

Suturing of a mucosal defect after gastric endoscopic submucosal dissection (ESD) reduces the incidence of adverse events and shortens hospitalization. However, post-ESD mucosal defects are circular, large, and with a thick mucosal layer, which are difficult to suture using conventional clips alone. The MANTIS Clip (Boston Scientific Japan, Tokyo, Japan) is a reopenable, rotatable through-the-scope clip designed for large defect closure. It uses anchor prongs to securely grasp wound edges. The initial use of the MANTIS Clip significantly reduces mucosal defects, which then allows for easy suturing with conventional clips. We herein report a case in which the MANTIS Clip was useful for suturing a mucosal defect after gastric ESD.

12.
Esophagus ; 20(2): 325-332, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36253658

RESUMEN

BACKGROUND AND AIMS: Multiple biopsies are recommended for the diagnosis of eosinophilic esophagitis (EoE) because inflammatory changes are frequently patchy. Reports on EoE using endocytoscopy (ECS) are limited. This present study aimed to assess if diagnostic yield improves by adding ECS on conventional white light imaging (WLI) in patients with esophageal eosinophilia (EE). METHODS: A total of 284 biopsy specimens from 71 patients with a known diagnosis of EE were enrolled and divided into the WLI group (156 specimens) or the ECS group (128 specimens). Four biopsies from 5 and 10 cm proximal to the esophagogastric junction were taken from each patient. In the ECS group, the biopsy was performed where bilobed nuclei were observed. The biopsy sensitivity for EE, eosinophil count of a single specimen and the biopsy sensitivity of each endoscopic finding were evaluated between both groups. RESULTS: The sensitivity of a single biopsy specimen was higher in the ECS group than that of the WLI group (62.5 vs. 41.7%, P < 0.001). In addition, the median eosinophil count in the ECS group was significantly higher [19 vs. 6.5/high-power field (HPF), P < 0.001]. For each endoscopic finding, ECS-based biopsy had higher sensitivity than that of WLI in the diagnosis of edema (33.1 vs. 11.3%, P = 0.007) and linear furrows (75.8 vs. 52%, P = 0.005). CONCLUSION: This study showed that adding ECS to WLI improved the biopsy sensitivity and eosinophil detection in patients with EE.


Asunto(s)
Esofagitis Eosinofílica , Esofagoscopía , Humanos , Esofagoscopía/métodos , Biopsia/métodos , Esofagitis Eosinofílica/diagnóstico
13.
Chemistry ; 28(2): e202103836, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34850990

RESUMEN

An H2 O2 molecule was isolated inside hydroxylated open-cage fullerene derivatives by mixing an H2 O2 solution with a precursor molecule followed by reduction of one of carbonyl groups on its orifice. Depending on the reduction site, two structural isomers for H2 O2 @open-fullerenes were obtained. A high encapsulation ratio of 81 % was attained at low temperature. The structures of the peroxosolvate complexes thus obtained were studied by 1 H NMR spectroscopy, X-ray analysis, and DFT calculations, showing strong hydrogen bonding between the encapsulated H2 O2 and the hydroxy group located at the center of the orifice. This OH group was found to act as a kinetic stopper, and the formation of the hydrogen bonding caused thermodynamic stabilization of the H2 O2 molecule, both of which prevent its escape from the cage. One of the peroxosolvates was isolated by HPLC, affording H2 O2 @open-fullerene with 100 % encapsulation ratio, likely due to the intramolecular hydrogen-bonding interaction.

14.
Digestion ; 103(4): 319-328, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35649343

RESUMEN

BACKGROUND: The utility of endoscopic ultrasonography (EUS) in predicting tumor depth among superficial nonampullary duodenal epithelial tumors (SNADETs) is unclear. The aim was to compare EUS with conventional endoscopy (CE) for the evaluation of tumor invasion of SNADETs. METHODS: A retrospective analysis was performed on consecutive 174 lesions/169 patients with duodenal dysplasia or adenocarcinoma with invasion up to submucosa who underwent both CE and EUS before endoscopic (n = 133) or surgical (n = 41) treatment. Endoscopic staging by CE was performed based on the characteristic endoscopic criteria of submucosal invasion (irregular surface, submucosal tumor [SMT]-like marginal elevation, and fusion of converging folds). The diagnostic performance of each test was compared with the final histology. RESULTS: The sensitivity and accuracy of estimating the depth were higher for CE compared to that of EUS (99.4% vs. 89.4%, p < 0.01 and 97.7% vs. 87.9%, p < 0.01, respectively). Univariate analysis of endoscopic factors revealed that tumor diameter, red color, SMT-like appearance, and hypoechogenicity were factors related to advanced histology. Multivariate analysis revealed that the presence of SMT-like appearance based on CE was an independent factor to predict submucosal invasion (p = 0.025). Gross morphology of the combined type was associated to incorrect diagnosis of EUS (p = 0.007). Among 3 cases in which EUS overestimated the tumor depth, carcinoma extension in submucosal Brunner's gland or nontumorous submucosal cystic dilation was observed. CONCLUSION: EUS may not be necessary, and CE may be sufficient for determining the optimal therapeutic strategy for SNADETs.


Asunto(s)
Adenocarcinoma , Neoplasias Duodenales , Neoplasias Gástricas , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Neoplasias Duodenales/diagnóstico por imagen , Neoplasias Duodenales/patología , Neoplasias Duodenales/cirugía , Endoscopía Gastrointestinal , Endosonografía , Mucosa Gástrica/patología , Humanos , Invasividad Neoplásica/patología , Estudios Retrospectivos , Neoplasias Gástricas/patología
15.
Int J Clin Oncol ; 27(5): 940-947, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35194703

RESUMEN

BACKGROUND AND AIM: Esophageal stenosis is a serious complication after endoscopic submucosal dissection (ESD) for thoracic esophageal cancer (TEC), and steroid has been applied for stenosis prevention. However, the rate of stenosis and effect of steroid for ESD of cervical esophageal cancer (CEC) remain unknown. The aim was to clarify the rate and managements of post-ESD stenosis for CEC. METHODS: A total of 325 lesions with 272 patients who underwent ESD for esophageal cancers were enrolled and were divided to the CEC group (43 lesions) or the TEC group (282 lesions). Patient characteristics, clinicopathological features, procedure-related outcomes of esophageal ESD, stenosis rate and clinical outcome of steroid use cases were evaluated. RESULTS: More patients in the CEC group received preventive steroid treatment compared to the TEC group (37.2% vs 14.5%, P = 0.001). The rate of post-ESD stenosis tended to be higher in the CEC group (11.6%) than in the TEC group (6.7%). For cases of 3/4 ≤ of circumference, local injection with oral steroid had lower stenosis rate than local injection only in both groups (CEC 40% vs 100%, TEC 30.7% vs 56.3%). More sessions and longer duration of dilation were needed to release the stenosis in the CEC group (20 times vs. 5 times, P = 0.015; 196 days vs. 55 days, P = 0.043). CONCLUSION: The post-ESD stenosis rate of CEC tended to be higher than that of TEC. More intensive preventive measures for post-ESD stenosis may be needed for CEC than TEC.


Asunto(s)
Resección Endoscópica de la Mucosa , Neoplasias Esofágicas , Neoplasias del Cuello Uterino , Constricción Patológica/etiología , Resección Endoscópica de la Mucosa/efectos adversos , Neoplasias Esofágicas/complicaciones , Femenino , Humanos , Estudios Retrospectivos , Esteroides/uso terapéutico
16.
Dig Endosc ; 34(3): 526-534, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34185924

RESUMEN

OBJECTIVES: Endoscopic submucosal dissection (ESD) in the duodenum is challenging. The water pressure method (WP-ESD) has been developed with a decreased rate of perforation. However, details of perioperative adverse events of WP-ESD are unknown. The purpose of this study was to clarify the frequency and related factors of fecal incontinence and oral regurgitation during WP-ESD. METHODS: A chart-based retrospective analysis was performed on 43 patients who underwent duodenal WP-ESD. The saline volume given into the body was calculated in all cases. All adverse events during WP-ESD until 6 weeks were extracted, and factors related to intraoperative fecal incontinence or oral regurgitation were analyzed. The frequency of fecal incontinence and oral regurgitation was also compared to those of 83 conventional ESD cases. RESULTS: In WP-ESD, intraoperative fecal incontinence occurred in 12 (28%), oral regurgitation in six (14%), and aspiration pneumonia in one patient. For fecal incontinence, the infusion speed (saline volume divided by resection time) around 17 mL/min was a significant factor in multivariable analysis. For oral regurgitation, only tumor size was a significant factor in univariate analysis (P = 0.027). Significant difference was observed in the frequency of fecal incontinence between WP-ESD and conventional ESD (28% vs. 0%, P < 0.001), but no difference was observed in oral regurgitation or aspiration pneumonia. CONCLUSIONS: Intraoperative fecal incontinence is a unique adverse event of WP-ESD related to the infusion speed. WP-ESD did not pose a risk for oral regurgitation, but we should be aware of the risk in large tumor cases.


Asunto(s)
Resección Endoscópica de la Mucosa , Incontinencia Fecal , Duodeno , Resección Endoscópica de la Mucosa/efectos adversos , Resección Endoscópica de la Mucosa/métodos , Incontinencia Fecal/epidemiología , Incontinencia Fecal/etiología , Humanos , Estudios Retrospectivos , Resultado del Tratamiento , Agua
17.
J Am Chem Soc ; 143(15): 5845-5854, 2021 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-33755463

RESUMEN

Helical folding of randomly coiled linear polymers is an essential organization process not only for biological polypeptides but also for synthetic functional polymers. Realization of this dynamic process in supramolecular polymers (SPs) is, however, a formidable challenge because of their inherent lability of main chains upon changing an external environment that can drive the folding process (e.g., solvent, concentration, and temperature). We herein report a photoinduced reversible folding/unfolding of rosette-based SPs driven by photoisomerization of a diarylethene (DAE). Temperature-controlled supramolecular polymerization of a barbiturate-functionalized DAE (open isomer) in nonpolar solvent results in the formation of intrinsically curved, but randomly coiled, SPs due to the presence of defects. Irradiation of the randomly coiled SPs with UV light causes efficient ring-closure reaction of the DAE moieties, which induces helical folding of the randomly coiled structures into helicoidal ones, as evidenced by atomic force microscopy and small-angle X-ray scattering. The helical folding is driven by internal structure ordering of the SP fiber that repairs the defects and interloop interaction occurring only for the resulting helicoidal structure. In contrast, direct supramolecular polymerization of the ring-closed DAE monomers by temperature control affords linearly extended ribbon-like SPs lacking intrinsic curvature that are thermodynamically less stable compared to the helicoidal SPs. The finding represents an important concept applicable to other SP systems; that is, postpolymerization (photo)reaction of preorganized kinetic structures can lead to more thermodynamically stable structures that are inaccessible directly through temperature-controlled protocols.


Asunto(s)
Etilenos/química , Polímeros/química , Rayos Ultravioleta , Barbitúricos/química , Isomerismo , Sustancias Macromoleculares/química , Microscopía de Fuerza Atómica , Polimerizacion , Temperatura , Termodinámica
18.
J Org Chem ; 86(1): 770-781, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33275444

RESUMEN

π-Conjugated molecules with small highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps (ΔEH-L) have been extensively studied because of their unique optoelectronic properties. Although the expansion of π-conjugation is one of the well-known approaches for designing molecules with small ΔEH-L values, such an approach inevitably gives large π-conjugated molecules sometimes suffering from synthetic difficulty and low solubility toward organic solvents. To develop relatively small donor-acceptor molecules with small ΔEH-L values, we have designed and synthesized π-conjugated zwitterions composed of electron-donating anions, such as phenoxide and anthroxide, and electron-accepting cations, such as pyridinium and acridinium. The energy difference between the HOMO of the anion and the LUMO of the cation (ΔED-A) and the interplanar angle between them (φDA) have a crucial effect on ΔEH-L, and hence, on the electronic structures and optoelectronic properties of these zwitterions. The zwitterions with small ΔED-A and large φDA have a small ΔEH-L of ca. 1 eV and show amphoteric redox properties and near-infrared (NIR) electronic absorption exceeding λ = 1000 nm. The NIR absorption responds to solvent polarity, temperature, and acid addition. This molecular design will generate small π-conjugated donor-acceptor molecules with small ΔEH-L values.

19.
Digestion ; 102(6): 895-902, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34098561

RESUMEN

INTRODUCTION: Endoscopic criteria for the diagnosis of superficial nonampullary duodenal epithelial tumors (SNADETs) are lacking. The aim of this study was to explore the usefulness of endocytoscopy (ECS) in the duodenum. METHODS: A total of 77 ECS images stained by methylene blue and 58 images with double staining of methylene blue and crystal violet were obtained from 20 patients. Images were classified into 3 grades based on nuclear and villi atypia: EC A, B, and C. Diagnostic performance of ECS classification to predict histology and interobserver agreement was evaluated. The performance was compared between staining methods and ×520 or ×936 zoom. RESULTS: With methylene blue staining, high rates of accuracy, sensitivity, specificity, and positive predictive value (PPV) over 90% were achieved for tumor and nontumor diagnosis as assessed by EC A versus EC B. High rates of accuracy, sensitivity, PPV, and negative predictive value over 90% were achieved for the differentiation between the diagnosis of the Vienna category 3 and 4/5 as assessed by EC B versus C. The accuracy rate of interpreting ECS images with ×936 zoom among 10 endoscopists was 82%, and the interobserver agreement rate was 0.803 (Kendall's coefficient of concordance). In the ×936 zoom group, methylene blue staining was significantly associated with higher accuracy rate (odds ratio 1.76 [1.06-2.92], p value 0.0297). No benefit was observed by double staining. CONCLUSIONS: ECS diagnosis with methylene blue provides a high accuracy rate and good interobserver agreement to predict histology of SNADETs.


Asunto(s)
Neoplasias Duodenales , Neoplasias Glandulares y Epiteliales , Neoplasias Duodenales/diagnóstico por imagen , Duodeno/diagnóstico por imagen , Violeta de Genciana , Humanos , Azul de Metileno
20.
Nature ; 500(7462): 354-8, 2013 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-23851392

RESUMEN

During animal development, the proper regulation of apoptosis requires the precise spatial and temporal execution of cell-death programs, which can include both caspase-dependent and caspase-independent pathways. Although the mechanisms of caspase-dependent and -independent cell killing have been examined extensively, how these pathways are coordinated within a single cell that is fated to die is unknown. Here we show that the Caenorhabditis elegans Sp1 transcription factor SPTF-3 specifies the programmed cell deaths of at least two cells-the sisters of the pharyngeal M4 motor neuron and the AQR sensory neuron-by transcriptionally activating both caspase-dependent and -independent apoptotic pathways. SPTF-3 directly drives the transcription of the gene egl-1, which encodes a BH3-only protein that promotes apoptosis through the activation of the CED-3 caspase. In addition, SPTF-3 directly drives the transcription of the AMP-activated protein kinase-related gene pig-1, which encodes a protein kinase and functions in apoptosis of the M4 sister and AQR sister independently of the pathway that activates CED-3 (refs 4, 5). Thus, a single transcription factor controls two distinct cell-killing programs that act in parallel to drive apoptosis. Our findings reveal a bivalent regulatory node for caspase-dependent and -independent pathways in the regulation of cell-type-specific apoptosis. We propose that such nodes might act as features of a general mechanism for regulating cell-type-specific apoptosis and could be therapeutic targets for diseases involving the dysregulation of apoptosis through multiple cell-killing mechanisms.


Asunto(s)
Apoptosis/genética , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Caspasas/metabolismo , Factor de Transcripción Sp1/genética , Factor de Transcripción Sp1/metabolismo , Animales , Secuencia de Bases , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Regulación del Desarrollo de la Expresión Génica , Datos de Secuencia Molecular , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Alineación de Secuencia
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