Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Glycobiology ; 34(5)2024 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-38376259

RESUMEN

In various organisms, α1,3/α1,4-fucosyltransferases (CAZy GT10 family enzymes) mediate the assembly of type I (Galß1,3GlcNAc) and/or type II (Galß1,4GlcNAc)-based Lewis structures that are widely distributed in glycoconjugates. Unlike enzymes of other species, plant orthologues show little fucosyltransferase activity for type II-based glycans and predominantly catalyze the assembly of the Lewis A structure [Galß1,3(Fucα1,4)GlcNAc] on the type I disaccharide unit of their substrates. However, the structural basis underlying this unique substrate selectivity remains elusive. In this study, we investigated the structure-function relationship of MiFUT13A, a mango α1,3/α1,4-fucosyltransferase. The prepared MiFUT13A displayed distinct α1,4-fucosyltransferase activity. Consistent with the enzymatic properties of this molecule, X-ray crystallography revealed that this enzyme has a typical GT-B fold-type structure containing a set of residues that are responsible for its SN2-like catalysis. Site-directed mutagenesis and molecular docking analyses proposed a rational binding mechanism for type I oligosaccharides. Within the catalytic cleft, the pocket surrounding Trp121 serves as a binding site, anchoring the non-reducing terminal ß1,3-galactose that belongs to the type I disaccharide unit. Furthermore, Glu177 was postulated to function as a general base catalyst through its interaction with the 4-hydroxy group of the acceptor N-acetylglucosamine residue. Adjacent residues, specifically Thr120, Thr157 and Asp175 were speculated to assist in binding of the reducing terminal residues. Intriguingly, these structural elements were not fully conserved in mammalian orthologue which also shows predominant α1,4-fucosyltransferase activity. In conclusion, we have proposed that MiFUT13A generates the Lewis A structure on type I glycans through a distinct mechanism, divergent from that of mammalian enzymes.


Asunto(s)
Mangifera , Animales , Mangifera/metabolismo , Simulación del Acoplamiento Molecular , Fucosiltransferasas/metabolismo , Oligosacáridos/química , Disacáridos , Especificidad por Sustrato , Mamíferos/metabolismo
2.
Digestion ; 103(3): 205-216, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35081535

RESUMEN

INTRODUCTION: Preoperative endoscopic biliary drainage (PEBD) for malignant hilar biliary obstruction (MHBO) is widely accepted. Recent PEBD consists of endoscopic nasobiliary drainage (ENBD), conventional endoscopic biliary stenting (CEBS) with plastic stents across the papilla, and endoscopic biliary inside stenting (EBIS) with plastic stents above the papilla, while ENBD is the primary procedure in Asian countries. Thus, we aimed to compare the efficacy of ENBD with those of CEBS and EBIS as a means of PEBD for MHBO. METHODS: We retrospectively identified patients with MHBO who underwent upfront surgery between January 2011 and December 2018 in a multicenter setting. The outcome measures were cumulative dysfunction of PEBD, risk factors for PEBD dysfunction, and adverse events. RESULTS: We analyzed a total of 219 patients, comprising 163 males (74.4%); mean age, 69.7 (±7.6) years; Bismuth-Corlette (BC) classification I, II, IIIa, IIIb, and IV in 68, 49, 43, 30, and 29 patients, respectively; and diagnosis of hilar cholangiocarcinoma and gallbladder cancer in 188 and 31 patients, respectively. PEBD procedures were performed in 160 patients with ENBD, 31 patients with CEBS, and 28 patients with EBIS. PEBD dysfunction occurred in 58 patients (26.5%), and the cumulative dysfunction rates were not significantly different among PEBD methods (p = 0.60). Multivariate analysis showed that BC-IV was significantly associated with the occurrence of PEBD dysfunction (hazard ratio = 2.10, p = 0.02). The adverse event rates were not significantly different among PEBD groups (p = 0.70). CONCLUSION: ENBD as a means of PEBD for MHBO is comparable with CEBS and EBIS in rates of dysfunction and adverse events.


Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Colestasis , Anciano , Neoplasias de los Conductos Biliares/complicaciones , Neoplasias de los Conductos Biliares/cirugía , Conductos Biliares Intrahepáticos/cirugía , Colangiocarcinoma/etiología , Colangiocarcinoma/cirugía , Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Colestasis/etiología , Colestasis/cirugía , Drenaje/efectos adversos , Drenaje/métodos , Femenino , Humanos , Masculino , Plásticos , Estudios Retrospectivos , Stents/efectos adversos , Resultado del Tratamiento
3.
BMC Cancer ; 21(1): 946, 2021 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-34425774

RESUMEN

BACKGROUND: In patients with average risk of bleeding, second-look endoscopy does not reportedly reduce bleeding after gastric endoscopic submucosal dissection. However, effectiveness of second-look endoscopy for patients with a high risk of bleeding, such as those who are taking antithrombotic agents, is unclear. Hence, this study aims to clarify the effectiveness of second-look endoscopy for patients with antithrombotic therapy. METHODS: We studied 142 consecutive patients with 173 gastric epithelial neoplasms who were routinely taking antithrombotic agents and were treated by endoscopic submucosal dissection at Tonan Hospital between November 2013 and December 2019. They were classified into two groups: those with second-look endoscopy (SLE group, 69 patients with 85 lesions) and those without second-look endoscopy (non-SLE group, 73 patients with 88 lesions). The incidence of post-endoscopic submucosal dissection bleeding was compared between the SLE and non-SLE groups. RESULTS: There were no statistical differences in the rate of patients undergoing single antiplatelet therapy, single anticoagulant therapy, and multiple therapy between the SLE and non-SLE groups (SLE group vs. non-SLE group; 32 [46.4%], 16 [23.2%], and 21 [30.4%] patients vs. 37 [50.7%], 20 [27.4%], and 16 [21.9%] patients, respectively; p = 0.50). Post-endoscopic submucosal dissection bleeding incidence was 21.7% (15/69) and 21.9% (16/73) in the SLE and non-SLE groups, respectively, and did not significantly differ between the two groups (p = 0.98). CONCLUSIONS: For patients taking antithrombotic agents, the incidence of post-endoscopic submucosal dissection bleeding was not reduced by second-look endoscopy.


Asunto(s)
Resección Endoscópica de la Mucosa/efectos adversos , Fibrinolíticos/efectos adversos , Gastroscopía/efectos adversos , Neoplasias Glandulares y Epiteliales/terapia , Hemorragia Posoperatoria/prevención & control , Segunda Cirugía/métodos , Neoplasias Gástricas/terapia , Anciano , Estudios de Casos y Controles , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Masculino , Neoplasias Glandulares y Epiteliales/patología , Hemorragia Posoperatoria/diagnóstico , Hemorragia Posoperatoria/etiología , Pronóstico , Neoplasias Gástricas/patología
4.
BMC Cancer ; 21(1): 235, 2021 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-33676442

RESUMEN

BACKGROUND: Recent studies have shown that mixed predominantly differentiated-type (MD) early gastric cancer (EGC) might have more malignant potential than pure differentiated-type (PD) EGC. However, no study has analyzed all differentiated-type EGC cases treated endoscopically and surgically. This study aimed to compare the differences in clinicopathological features and long-term prognosis between MD- and PD-EGC. METHODS: We evaluated all patients with differentiated-type EGCs who were treated endoscopically and surgically in our hospital between January 2010 and October 2014. The clinicopathological features and long-term prognosis of MD-EGC were compared with those of PD-EGC. RESULTS: A total of 459 patients with 459 lesions were evaluated in this study; of them, 409 (89.1%) and 50 (10.9%) were classified into the PD and MD groups, respectively. Submucosal invasion was found in 96 (23.5%) patients of the PD group and in 33 (66.0%) patients of the MD group (p < 0.01). The rates of positive lymphatic and vascular invasion and ulceration were significantly higher in the MD group than in the PD group (p < 0.01). The proportion of patients with lymph node metastasis was also significantly higher in the MD group than in the PD group (5 (10%) vs 6 (1.5%), p < 0.01). The 5-year overall and EGC-specific survival rates in the PD group were 88.3 and 99.5%, respectively, while they were 94.0 and 98.0% in the MD group, respectively. CONCLUSIONS: MD-EGC has more malignant potential than PD-EGC. However, the long-term prognosis of MD-EGC is good and is not significantly different from that of PD-EGC when treated appropriately.


Asunto(s)
Gastrectomía , Mucosa Gástrica/patología , Recurrencia Local de Neoplasia/epidemiología , Neoplasias Gástricas/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Diferenciación Celular , Resección Endoscópica de la Mucosa , Femenino , Estudios de Seguimiento , Mucosa Gástrica/diagnóstico por imagen , Mucosa Gástrica/cirugía , Gastroscopía , Humanos , Estimación de Kaplan-Meier , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Invasividad Neoplásica/patología , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/patología , Neoplasias Gástricas/cirugía , Tasa de Supervivencia , Factores de Tiempo , Resultado del Tratamiento
5.
Scand J Gastroenterol ; 55(4): 503-508, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32275454

RESUMEN

Background: The incidence of post-ERCP pancreatitis (PEP) has been reported to be significantly higher in patients without main pancreatic duct (MPD) obstruction who undergo transpapillary biliary metal stent (MS) placement than in those with ordinary ERCP setting.Objective: To evaluate the benefit of endoscopic sphincterotomy (ES) prior to MS placement in preventing PEP in patients with distal malignant biliary obstruction (MBO) without MPD obstruction.Materials and methods: In total, 160 patients who underwent initial MS placement for MBO were enrolled. Eighty-two patients underwent ES immediately prior to MS placement, whereas 78 underwent MS placement without ES. An inverse probability of treatment weighting method was adopted to adjust the differences of the patients' characteristics. The primary outcome was the incidence of PEP. The secondary outcomes included the incidence of other adverse events (bleeding, cholangitis, perforation and stent dislocation) and time to recurrent biliary obstruction.Results: The incidence of PEP was 26.8% in the ES and 23.1% in the non-ES (unadjusted odds ratio [OR] [95%CI]: 1.22, [0.60-2.51], adjusted OR [95%CI]: 1.23, [0.53-2.81], p = .63). Logistic-regression analysis revealed no factors that could be attributed to the occurrence of PEP. The incidence of other adverse events was not different between the groups. The median time to recurrent biliary obstruction was 131 (2-465) days and 200 (4-864) days in the ES and non-ES, respectively (p = .215).Conclusions: ES prior to MS placement for patients with distal MBO without MPD obstruction does not reduce the incidence of PEP.


Asunto(s)
Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Pancreatitis/prevención & control , Esfinterotomía Endoscópica , Stents , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Japón , Modelos Logísticos , Masculino , Metales , Persona de Mediana Edad , Conductos Pancreáticos , Pancreatitis/etiología , Estudios Retrospectivos
6.
Dig Endosc ; 32(5): 801-811, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31876309

RESUMEN

BACKGROUND AND AIMS: Needle tract seeding after preoperative endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for pancreatic body and tail cancer has been reported. This study aimed to investigate the long-term outcomes, including the needle tract seeding ratio, of patients undergoing distal pancreatectomy for pancreatic body and tail cancer diagnosed preoperatively by EUS-FNA. METHODS: This retrospective, observational cohort study assessed patients from three university hospitals and 11 tertiary referral centers. All patients who underwent distal pancreatectomy for invasive cancer of the pancreatic body and tail between January 2006 and December 2015 were identified and reviewed. Needle tract seeding rate, recurrence-free survival (RFS), and overall survival (OS) were evaluated. RESULTS: Of the 301 total patients analyzed, 176 underwent preoperative EUS-FNA (EUS-FNA group) and 125 did not (non-EUS-FNA group). The median follow-up periods of the EUS-FNA group and non-EUS-FNA group were 32.8 and 30.1 months. Six patients (3.4%) in the EUS-FNA group were diagnosed as having needle tract seeding. The 5-year cumulative needle tract seeding rate estimated using Fine and Gray's method was 3.8% (95% CI 1.6-7.8%). The median RFS or OS was not significantly different between the EUS-FNA group and the non-EUS-FNA group (23.7 vs 16.9 months: P = 0.205; 48.0 vs 43.9 months: P = 0.392). CONCLUSION: Although preoperative EUS-FNA for pancreatic body and tail cancer has no negative effect on RFS or OS, needle tract seeding after EUS-FNA was observed to have a non-negligible rate. (UMIN000030719).


Asunto(s)
Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico , Neoplasias Pancreáticas , Estudios de Cohortes , Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/efectos adversos , Humanos , Pancreatectomía/efectos adversos , Neoplasias Pancreáticas/cirugía , Estudios Retrospectivos
9.
Gastric Cancer ; 20(3): 489-495, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27541379

RESUMEN

BACKGROUND: Only a few studies have reported long-term outcomes for endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) in elderly patients. The aim of this study was to evaluate the efficacy of ESD for EGC in elderly patients ≥75 years with respect to both short- and long-term outcomes. METHODS: We reviewed the clinical data of elderly patients ≥75 years who had undergone ESD for EGC at Tonan Hospital from January 2003 to May 2010. RESULTS: A total of 177 consecutive patients, including 145 with curative resection (CR) and 32 with noncurative resection (non-CR), were examined. Of the 32 patients with non-CR, 15 underwent additional surgery, and lymph node metastases were found in 3 patients. The remaining 17 patients were followed without additional surgery because of advanced age or poor general condition. Procedure-related complications, such as post-ESD bleeding, perforation and pneumonia, were within the acceptable range. The 5-year survival rates of patients with CR, those with additional surgery after non-CR, and those without additional surgery after non-CR were 84.6, 73.3, and 58.8 %, respectively. No deaths were attributable to the original gastric cancer; patients succumbed to other illnesses, including malignancy and respiratory disease. CONCLUSIONS: In elderly patients, ESD is an acceptable treatment for EGC in terms of both short- and long-term outcomes. Careful clinical assessment of elderly patients is necessary before ESD. After ESD, medical follow-up is important so that other malignancies and diseases that affect the elderly are not overlooked.


Asunto(s)
Resección Endoscópica de la Mucosa , Neoplasias Gástricas/mortalidad , Neoplasias Gástricas/cirugía , Anciano , Anciano de 80 o más Años , Resección Endoscópica de la Mucosa/efectos adversos , Resección Endoscópica de la Mucosa/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Neoplasias Gástricas/patología , Tasa de Supervivencia , Resultado del Tratamiento
10.
Gastric Cancer ; 20(4): 690-698, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27905029

RESUMEN

BACKGROUND: Only a few studies have reported treatment options for stenosis after endoscopic submucosal dissection (ESD) for gastric neoplasms. This study aimed to identify the risk factors for and evaluate the management of stenosis after ESD for gastric epithelial neoplasms in the cardia and antrum. METHODS: We retrospectively reviewed 1218 patients (1447 gastric epithelial neoplasms) who underwent ESD at Tonan Hospital from June 2004 to November 2015. Post-ESD stenosis was defined when a standard endoscope could not be passed through the site. RESULTS: Post-ESD stenosis occurred in 10 (21.3%) of the 47 cardia cases and 14 (3.2%) of the 432 antrum cases. A wide resection of more than three fourths of the circumferential extent was the sole significant risk factor related to post-ESD stenosis in both cardia and antrum. Prophylactic endoscopic balloon dilation (EBD) was performed in 3 of 10 patients with cardiac stenosis and 4 of 14 with antral stenosis. Post-EBD bleeding occurred in one cardia (10%) and one antrum (7.1%) case each and was endoscopically treated. Perforation during EBD occurred in two (14.3%) antrum cases, both of which required emergency open surgery. All complications were observed in patients with conventional EBD, and no complications were associated with prophylactic EBD. CONCLUSIONS: A wide resection of more than three fourths of the circumferential extent was the significant risk factor for post-ESD stenosis in both cardia and antrum, and prophylactic EBD could be a promising procedure for the management of post-ESD stenosis.


Asunto(s)
Resección Endoscópica de la Mucosa/efectos adversos , Gastropatías/epidemiología , Gastropatías/etiología , Gastropatías/cirugía , Neoplasias Gástricas/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Constricción Patológica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
11.
Endoscopy ; 48(4): 350-7, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26760604

RESUMEN

BACKGROUND AND STUDY AIMS: Endoscopic bile duct stone (BDS) removal is a well-established treatment; however, the preference for basket or balloon catheters for extraction is operator-dependent. We therefore conducted a multicenter prospective randomized trial to compare catheter performance. PATIENTS AND METHODS: We enrolled patients with a BDS diameter ≤ 10 mm and common bile duct diameter ≤ 15 mm. Participants were randomly assigned to groups that were treated with basket or balloon catheters between October 2013 and September 2014. The primary endpoint was the rate of complete clearance of the duct; the secondary endpoints were the rate and time to complete clearance in one endoscopic session. RESULTS: We initially enrolled 172 consecutive patients; 14 were excluded after randomization. The complete clearance rates were 92.3 % (72/78) in the balloon group and 80.0 % (64 /80) in the basket group. The difference in the rates between the two groups was 12.3 percentage points, indicating non-inferiority of the balloon method (non-inferiority limit -10 %; P < 0.001 for non-inferiority). Moreover, the balloon was superior to the basket (P = 0.037). The rate of complete clearance in one endoscopic session was 97.4 % using the balloon and 97.5 % using the basket (P = 1.00). The median times to complete clearance in one endoscopic session were 6.0 minutes (1 - 30) and 7.8 minutes (1 - 37) in the balloon and basket groups, respectively (P = 0.15). CONCLUSIONS: For extraction of BDSs ≤ 10 mm, complete endoscopic treatment with a single catheter is more likely when choosing a balloon catheter over a basket catheter.University Hospital Medical Information Network Trials Registry: UMIN000011887.


Asunto(s)
Catéteres , Conducto Colédoco/cirugía , Cálculos Biliares/cirugía , Esfinterotomía Endoscópica/instrumentación , Anciano , Colangiopancreatografia Retrógrada Endoscópica/métodos , Conducto Colédoco/diagnóstico por imagen , Diseño de Equipo , Femenino , Estudios de Seguimiento , Cálculos Biliares/diagnóstico , Humanos , Masculino , Estudios Prospectivos , Factores de Tiempo , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
12.
J Immunol ; 190(1): 195-204, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-23203928

RESUMEN

LPS is recognized by TLR4 and radioprotective 105 kDa in B cells. Susceptibility to LPS in murine B cells is most closely linked to the locus containing the TLR4 gene. However, the molecular mechanism underlying genetic control of LPS sensitivity by this locus has not been fully elucidated. In this study, we revealed that C57BL/6 (B6) B cells respond to mAb-induced, TLR4-specific signals stronger than BALB/c (BALB) B cells, as assessed by proliferation and upregulation of CD69 and CD86. In contrast, BALB B cells were not hyporesponsive to agonistic anti-radioprotective 105 kDa mAb or the TLR9 agonist CpG. Although the level of TLR4 mRNA in BALB B cells was comparable with that in B6 B cells, surface TLR4 expression in BALB B cells was lower than that in B6 B cells. This lower surface expression of BALB TLR4 was also observed when HEK293 and Ba/F3 cells were transfected with a BALB TLR4 expression construct. We identified a V254I mutation as the responsible single nucleotide polymorphism for lower surface expression of BALB TLR4. Furthermore, cotransfection of myeloid differentiation factor-2 increased BALB TLR4 expression, although it was still lower than B6 TLR4 expression. In concordance with reduced expression, Ba/F3 cells transfected with BALB TLR4 and myeloid differentiation factor-2 were hyporesponsive compared with those with B6 TLR4, as assessed by LPS-induced NF-κB activation. In conclusion, we revealed that LPS sensitivity is genetically controlled by the level of surface TLR4 expression on B cells. A V254I mutation accounts for the LPS hyporesponsive phenotype of BALB B cells.


Asunto(s)
Subgrupos de Linfocitos B/inmunología , Lipopolisacáridos/genética , Mutación Puntual/inmunología , Receptor Toll-Like 4/antagonistas & inhibidores , Receptor Toll-Like 4/biosíntesis , Animales , Subgrupos de Linfocitos B/metabolismo , Línea Celular Tumoral , Membrana Celular/genética , Membrana Celular/inmunología , Células Cultivadas , Células HEK293 , Humanos , Inmunofenotipificación , Lipopolisacáridos/biosíntesis , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Ratas , Ratas Wistar , Receptor Toll-Like 4/deficiencia
13.
Gan To Kagaku Ryoho ; 42(13): 2497-500, 2015 Dec.
Artículo en Japonés | MEDLINE | ID: mdl-26809313

RESUMEN

A 74-year-old woman with advanced gastric cancer was admitted to our hospital. A central venous (CV) port catheter was implanted into the right subclavian vein for preoperative chemotherapy and parenteral nutritional management. On the 35th day after implantation, she complained of diarrhea, fever and dyspnea. The chest radiograph showed a right-sided massive pleural effusion. As the patient progressively fell into severe respiratory distress, endotracheal intubation was performed for management of respiration by mechanical ventilation. Initially, given the patient's symptoms, she was diagnosed with septic shock. Therefore, after placement of a CV catheter through the right femoral vein, in consideration of the possibility of a port infection, she was treated with thoracentesis and infusion of antibiotics. The patient gradually recovered, and again received parenteral nutrition through the CV port catheter. After the infusion was administered, she complained of dyspnea. A CT scan of the chest revealed a right pleural effusion and displacement of the tip of the CV port catheter out of the wall of the superior vena cava. We diagnosed delayed vascular injury (DVI), and the CV port catheter was removed. She soon recovered with conservative treatment. We speculated that the initial respiratory symptoms such as the pleural effusion were caused by DVI. DVI should therefore be recognized as a complication related to implanted CV port catheters.


Asunto(s)
Infecciones por Bacillaceae/microbiología , Bacillus cereus , Catéteres de Permanencia/efectos adversos , Catéteres Venosos Centrales/efectos adversos , Neoplasias Gástricas , Lesiones del Sistema Vascular/microbiología , Anciano , Femenino , Humanos , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/cirugía
14.
Biochim Biophys Acta ; 1830(10): 4482-90, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23688399

RESUMEN

BACKGROUND: The synthesis of eukaryotic N-glycans and the rhizobia Nod factor both involve α1,6-fucosylation. These fucosylations are catalyzed by eukaryotic α1,6-fucosyltransferase, FUT8, and rhizobial enzyme, NodZ. The two enzymes have similar enzymatic properties and structures but display different acceptor specificities: FUT8 and NodZ prefer N-glycan and chitooligosaccharide, respectively. This study was conducted to examine the fucosylation of chitooligosaccharides by FUT8 and NodZ and to characterize the resulting difucosylated chitooligosaccharides in terms of their resistance to hydrolysis by glycosidases. METHODS: The issue of whether FUT8 or NodZ catalyzes the further fucosylation of chitooligosaccharides that had first been monofucosylated by the other. The oligosaccharide products from the successive reactions were analyzed by normal-phase high performance liquid chromatography, mass spectrometry and nuclear magnetic resonance. The effect of difucosylation on sensitivity to glycosidase digestion was also investigated. RESULTS: Both FUT8 and NodZ are able to further fucosylate the monofucosylated chitooligosaccharides. Structural analyses of the resulting oligosaccharides showed that the reducing terminal GlcNAc residue and the third GlcNAc residue from the non-reducing end are fucosylated via α1,6-linkages. The difucosylation protected the oligosaccharides from extensive degradation to GlcNAc by hexosamidase and lysozyme, and also even from defucosylation by fucosidase. CONCLUSIONS: The sequential actions of FUT8 and NodZ on common substrates effectively produce site-specific-difucosylated chitooligosaccharides. This modification confers protection to the oligosaccharides against various glycosidases. GENERAL SIGNIFICANCE: The action of a combination of eukaryotic and bacterial α1,6-fucosyltransferases on chitooligosaccharides results in the formation of difucosylated products, which serves to stabilize chitooligosaccharides against the action of glycosidases.


Asunto(s)
Quitina/metabolismo , Fucosa/metabolismo , Fucosiltransferasas/metabolismo , Oligosacáridos/metabolismo , Secuencia de Bases , Secuencia de Carbohidratos , Cartilla de ADN , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Datos de Secuencia Molecular , Oligosacáridos/química
15.
Biochem Biophys Res Commun ; 450(2): 953-60, 2014 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-24973708

RESUMEN

Although core α1,6-fucosylation is commonly observed in N-glycans of both vertebrates and invertebrates, the responsible enzyme, α1,6-fucosyltransferase, has been much less characterized in invertebrates compared to vertebrates. To investigate the functions of α1,6-fucosyltransferase in insects, we cloned the cDNA for the α1,6-fucosyltransferase from Bombyx mori (Bmα1,6FucT) and characterized the recombinant enzyme prepared using insect cell lines. The coding region of Bmα1,6FucT consists of 1737bp that code for 578 amino acids of the deduced amino acid sequence, showing significant similarity to other α1,6-fucosyltransferases. Enzyme activity assays demonstrated that Bmα1,6FucT is enzymatically active in spite of being less active compared to the human enzyme. The findings also indicate that Bmα1,6FucT, unlike human enzyme, is N-glycosylated and forms a disulfide-bonded homodimer. These findings contribute to a better understanding of roles of α1,6-fucosylation in invertebrates and also to the development of the more efficient engineering of N-glycosylation of recombinant glycoproteins in insect cells.


Asunto(s)
Bombyx/enzimología , Fucosiltransferasas/química , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , Fucosiltransferasas/genética , Fucosiltransferasas/metabolismo , Glicosilación , Humanos , Datos de Secuencia Molecular , Multimerización de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Alineación de Secuencia
16.
J Dig Dis ; 25(5): 310-317, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38973135

RESUMEN

OBJECTIVES: Unresectable ampullary cancer (AC) is a rare disease entity. The risk factors for recurrent biliary obstruction (RBO) following endoscopic biliary stenting (EBS) for unresectable AC remain unknown. In this study we aimed to evaluate the cumulative RBO rate and to identify risk factors for RBO following palliative EBS in patients with unresectable AC. METHODS: This multicenter retrospective observational study enrolled consecutive patients with unresectable AC who had undergone palliative EBS between April 2011 and December 2021. The cumulative rate of and risk factors for RBO following palliative EBS were evaluated via multivariate analysis. RESULTS: The study analysis comprised 107 patients with a median age of 84 years (interquartile range 79-88 years). Plastic stents (PSs) and self-expandable metal stents (SEMSs) were placed in 53 and 54 patients, respectively. Functional success was accomplished in 104 (97.2%) patients. Of these, RBO occurred in 62 (59.6%) patients, with obstruction and complete/partial migration occurring in 47 and 15 patients, respectively. The median time to RBO was 190 days. Multivariate analysis showed that PS was associated with a higher rate of RBO compared to SEMS (hazard ratio [HR] 2.48; P < 0.01) and that the presence of common bile duct stones/sludge immediately after EBS was an independent risk factor for RBO (HR 1.99; P = 0.04). CONCLUSIONS: The use of SEMS compared to PS during EBS reduced the time to RBO in patients with unresectable AC. Common bile duct stones/sludge immediately after EBS was a risk factor for RBO.


Asunto(s)
Ampolla Hepatopancreática , Colestasis , Neoplasias del Conducto Colédoco , Cuidados Paliativos , Recurrencia , Stents , Humanos , Masculino , Femenino , Anciano de 80 o más Años , Estudios Retrospectivos , Anciano , Ampolla Hepatopancreática/cirugía , Factores de Riesgo , Colestasis/etiología , Colestasis/cirugía , Stents/efectos adversos , Neoplasias del Conducto Colédoco/cirugía , Neoplasias del Conducto Colédoco/complicaciones , Cuidados Paliativos/métodos , Stents Metálicos Autoexpandibles/efectos adversos , Colangiopancreatografia Retrógrada Endoscópica/efectos adversos
17.
Biochem Biophys Res Commun ; 440(1): 31-6, 2013 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-24021278

RESUMEN

MD-2 is essential for lipopolysaccharide (LPS) recognition of Toll-like receptor 4 (TLR4) but not for cell surface expression. The TLR4/MD-2 complex is formed intracellularly through co-expression. Extracellular complex formation remains a matter for debate because of the aggregative nature of secreted MD-2 in the absence of TLR4 co-expression. We demonstrated extracellular complex formation using three independent monoclonal antibodies (mAbs), all of which are specific for complexed TLR4 but unreactive with free TLR4 and MD-2. These mAbs bound to TLR4-expressing Ba/F3 cells only when co-cultured with MD-2-secreting Chinese hamster ovary cells or incubated with conditioned medium from these cells. All three mAbs bound the extracellularly formed complex indistinguishably from the intracellularly formed complex in titration studies. In addition, we demonstrated that two mAbs lost their affinity for TLR4/MD-2 on LPS stimulation, suggesting that these mAbs bound to conformation-sensitive epitopes. This was also found when the extracellularly formed complex was stimulated with LPS. Additionally, we showed that cell surface TLR4 and extrinsically secreted MD-2 are capable of forming the functional complex extracellularly, indicating an additional or alternative pathway for the complex formation.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Antígeno 96 de los Linfocitos/metabolismo , Receptor Toll-Like 4/metabolismo , Animales , Afinidad de Anticuerpos , Células CHO , Línea Celular , Cricetinae , Cricetulus , Humanos , Receptores de Lipopolisacáridos/inmunología , Lipopolisacáridos/inmunología , Antígeno 96 de los Linfocitos/química , Antígeno 96 de los Linfocitos/inmunología , Conformación Proteica , Receptor Toll-Like 4/química , Receptor Toll-Like 4/inmunología
18.
Int Immunol ; 24(8): 495-506, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22499954

RESUMEN

Recognition of LPS by the toll-like receptor 4 (TLR4)/MD-2 complex is a trigger of innate immune defense against bacterial invasion. However, excessive immune activation by this receptor complex causes septic shock and autoimmunity. Manipulation of TLR4 signaling represents a potential therapy that would avoid the detrimental consequences of unnecessary immune responses. In this study, we established two novel mAbs that inhibit LPS-induced human TLR4 activation. HT52 and HT4 mAbs inhibited LPS-induced nuclear factor-κB activation in TLR4/MD-2-expressing Ba/F3-transfected cells and cytokine production and up-regulation of CD86 in the human cell line U373 and PBMCs. These inhibitory activities were stronger than that of HTA125 mAb, which we previously reported. Immunofluorescent and biochemical studies using TLR4 deletion mutants revealed that HT52 and HT4 recognized spatially distinct regions on TLR4 irrespective of MD-2 association. The HT52 and HTA125 epitopes were localized within aa 50-190, while the HT4 epitope was formed only by the full length of TLR4. In addition, we demonstrated that HT52 and HT4 failed to compete with LPS for binding to TLR4/MD-2 but inhibited LPS-induced TLR4 internalization. Inhibitory activities were not due to the interaction with the Fcγ receptor CD32. Our finding that binding of mAbs to at least two distinct regions on TLR4 inhibits LPS-dependent activation provides a novel method for manipulating TLR4 activation and also a rationale for designing drugs targeted to TLR4.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Inmunidad Innata/inmunología , Receptor Toll-Like 4/inmunología , Animales , Anticuerpos Monoclonales/farmacología , Western Blotting , Línea Celular , Activación Enzimática/efectos de los fármacos , Activación Enzimática/inmunología , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Humanos , Inmunoprecipitación , Lipopolisacáridos/inmunología , Antígeno 96 de los Linfocitos/efectos de los fármacos , Antígeno 96 de los Linfocitos/inmunología , Antígeno 96 de los Linfocitos/metabolismo , Ratones , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Receptor Toll-Like 4/efectos de los fármacos , Receptor Toll-Like 4/metabolismo , Transfección
19.
Nihon Shokakibyo Gakkai Zasshi ; 110(5): 846-51, 2013 May.
Artículo en Japonés | MEDLINE | ID: mdl-23648541

RESUMEN

A 38-year-old man was given a diagnosis of as sigmoid colon cancer and underwent sigmoid colectomy. Post-operative pathological staging was stage IIIb. He then underwent adjuvant chemotherapy. One year and 4 months after the surgery, CT scans revealed multiple liver and lung metastases. He was given mFOLFOX6+bevacizumab, which was changed later to FOLFIRI+bevacizumab. After these chemotherapies, he was admitted to the hospital due to sudden abdominal pain and high grade fever. Obstructive jaundice was initially diagnosed, but detailed study of initial CT revealed intragastric wall abscess. After the drainage of the abscess, his conditions improved. We speculated that the abscess formation was caused by mucosal damage due to bevacizumab.


Asunto(s)
Absceso/inducido químicamente , Inhibidores de la Angiogénesis/administración & dosificación , Inhibidores de la Angiogénesis/efectos adversos , Anticuerpos Monoclonales Humanizados/efectos adversos , Gastropatías/inducido químicamente , Adulto , Anticuerpos Monoclonales Humanizados/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Bevacizumab , Quimioterapia Adyuvante/efectos adversos , Mucosa Gástrica/efectos de los fármacos , Humanos , Masculino , Neoplasias del Colon Sigmoide/terapia
20.
Sci Total Environ ; 896: 165265, 2023 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-37400029

RESUMEN

The Angkor monuments have been registered on the World Cultural Heritage List of UNESCO, while the buildings built mostly of sandstone are suffering from serious deterioration and damage. Microorganisms are one of the leading causes for the sandstone deterioration. Identification of the mechanisms underlying the biodeterioration is of significance because it reveals the biochemical reaction involved so that effective conservation and restoration of cultural properties can be achieved. In this study, the fungal colonization and biodeterioration of sandstone in simulation experiments were examined using confocal reflection microscopy (CRM) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Aspergillus sp. strain AW1 and Paecilomyces sp. strain BY8 isolated from the deteriorated sandstone of Angkor Wat and Bayon of Angkor Thom, respectively, were inoculated and incubated with the sandstone used for construction of Angkor Wat. With CRM, we could visualize that strain AW1 tightly attached to and broke in the sandstone with extension of the hyphae. Quantitative imaging analyses showed that the sandstone surface roughness increased and the cavities formed under the fungal hyphae deepened during the incubation of strains AW1 and BY8. These highlighted that the massive growth of fungi even under the culture conditions was associated with the cavity formation of the sandstone and its expansion. Furthermore, SEM-EDS indicated the flat and Si-rich materials, presumably quartz and feldspar, were found frequently at the intact sandstone surface. But the flatness was lost during the incubation, possibly due to the detachment of the Si-rich mineral particles by the fungal deterioration. Consequently, this study proposed a biodeterioration model of the sandstone in that the hyphae of fungi elongated on the surface of the sandstone to penetrate into the soft and porous sandstone matrix, damaging the matrix and gradually destabilize the hard and Si-rich minerals, such as quartz and feldspar, to the collapse and cavities.


Asunto(s)
Silicatos de Aluminio , Cuarzo , Compuestos de Potasio , Minerales , Hongos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA