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1.
Clin Gastroenterol Hepatol ; 22(2): 271-282.e3, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-37743040

RESUMO

BACKGROUND & AIMS: Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin. METHODS: We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated. RESULTS: The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively. CONCLUSIONS: Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin.


Assuntos
Fibrilação Atrial , Neoplasias Colorretais , Ressecção Endoscópica de Mucosa , Humanos , Varfarina , Rivaroxabana/efeitos adversos , Dabigatrana/efeitos adversos , Japão , Ressecção Endoscópica de Mucosa/efeitos adversos , Estudos Retrospectivos , Hemorragia/induzido quimicamente , Anticoagulantes , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/complicações , Administração Oral , Fibrilação Atrial/complicações
2.
RSC Adv ; 12(47): 30696-30703, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36337942

RESUMO

NASICON-type LiZr2(PO4)3 (LZP) has attracted significant attention as a solid oxide electrolyte for all-solid-state Li-ion or Li-metal batteries owing to its high Li-ion conductivity, usability in all-solid-state batteries, and electrochemical stability against Li metal. In this study, we aim to improve the Li-ion conductivity of Li-rich NASICON-type LZPs doped with CaO and SiO2, i.e., Li1+x+2y Ca y Zr2-y Si x P3-x O12(0 ≤ x ≤ 0.3, 0 ≤ y ≤ 0.3) (LCZSP). Herein, a total of 49 compositions were synthesised, and their crystal structures, relative densities, and Li-ion conductivities were characterised experimentally. We confirmed the improvement in Li-ion conductivity by simultaneous replacement of Zr and P sites with Ca and Si ions, respectively. However, the intuition-derived determination of the composition exhibiting the highest Li-ion conductivity is technically difficult because the compositional dependence of the relative density and the crystalline phase of the sample is very complex. Bayesian optimisation (BO) was performed to efficiently discover the optimal composition that exhibited the highest Li-ion conductivity among the samples evaluated experimentally. We also optimised the composition of the LCZSP using multi-task Gaussian process regression after transferring prior knowledge of 47 compositions of Li1+x+2y Y x Ca y Zr2-x-y P3O12 (0 ≤ x ≤ 0.376, 0 ≤ y ≤ 0.376) (LYCZP), i.e., BO with transfer learning. The present study successfully demonstrated that BO with transfer learning can search for optimal compositions two times as rapid as the conventional BO approach. This approach can be widely applicable for the optimisation of various functional materials as well as ionic conductors.

3.
Sci Rep ; 11(1): 16260, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376800

RESUMO

Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic intestinal diseases of unknown etiology that present with variable disease extents and outcomes. The use of biomarkers for the diagnosis and management of IBDs is considered beneficial. Palmitoleic acid (PO) is an adipose tissue-derived mono-unsaturated free fatty acid that potentially serves as a lipokine in metabolic and inflammatory diseases. The aim of this study was to investigate the significance of PO levels in the serum of patients with UC and CD. The study included patients with UC (n = 22), patients with CD (n = 35), and controls (n = 22). The levels of serum PO were analyzed using gas chromatography. The association of serum PO levels with the clinical features and disease outcomes in IBD was examined. Serum PO levels were significantly higher in patients with CD than in controls, whereas no difference in these levels was observed between patients with UC and controls. Serum PO levels were significantly associated with the CD activity index. Additionally, high serum PO levels were associated with an increased risk of surgical intervention requirement during follow-up. In a pilot study with a few patients, high PO levels were observed in the mesenteric tissue in the active disease site of patients with CD (n = 7) compared with those with colon cancer (n = 6). Elevated serum PO levels might serve as a marker for local inflammation and prognosis in patients with CD.


Assuntos
Biomarcadores/sangue , Colite Ulcerativa/diagnóstico , Neoplasias do Colo/diagnóstico , Doença de Crohn/diagnóstico , Ácidos Graxos Monoinsaturados/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Colite Ulcerativa/sangue , Neoplasias do Colo/sangue , Doença de Crohn/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Prognóstico , Estudos Retrospectivos , Índice de Gravidade de Doença , Adulto Jovem
4.
Wounds ; 33(1): E10-E13, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33914697

RESUMO

INTRODUCTION: Rectovaginal fistulas (RVFs) are abnormal connections between the rectum and vagina. CASE REPORT: A 61-year-old female patient was admitted to the authors' hospital with swelling, extending from the left thigh to the left lower abdomen and crepitus. An axial computed tomography scan showed air in the soft tissue of the left thigh, left buttock, perineal region, and left lower abdomen. Gas gangrene was suspected. Accordingly, the patient was administered meropenem, clindamycin, and vancomycin and underwent emergency debridement. An intraoperative examination revealed necrotizing fasciitis in the left buttock but no inflammatory signs in the thigh. On postoperative day 8, fecal matter was discharged from the patient's vagina, and an RVF was detected by colon fiberscopy. The patient underwent resurfacing surgery with a free skin graft, and a colon stoma was fashioned 15 days after the primary surgery. The patient was discharged on day 14 following surgery with wound healing. CONCLUSION: The existence of free air in subcutaneous tissue combined with an infection, particularly in the extremities, is generally suggestive of gas gangrene. In the present case, subcutaneous gas was not caused by gas gangrene but rather by air inflow from an RVF. Appropriate treatment of the RVF was necessary to avoid the exacerbation of Fournier's gangrene and prevent necrosis spreading to the thigh.


Assuntos
Gangrena de Fournier , Gangrena Gasosa , Enfisema Subcutâneo , Feminino , Gangrena de Fournier/cirurgia , Gangrena Gasosa/terapia , Humanos , Pessoa de Meia-Idade , Fístula Retovaginal , Enfisema Subcutâneo/diagnóstico por imagem , Enfisema Subcutâneo/etiologia , Coxa da Perna
6.
Regen Ther ; 14: 87-94, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31988998

RESUMO

INTRODUCTION: Cultured stratified epithelial cell sheets have been clinically utilized as transplantable grafts for the regeneration of epithelial tissues, such as the esophagus, cornea, skin, and intraoral cavity. These cell sheets are expected to gain widespread use as regenerative medicine products and save many patients. For this purpose, establishing and disseminating the stale protocol of fabricating the cell sheet is crucial. The fabrication of cultured stratified epithelial cell sheets consists of many important steps, and since the patients' epithelial cell conditions vary widely and are sometimes unstable, the qualities of the epithelial cell grafts are likewise potentially unstable. Therefore, in this paper, we report the stable protocol for fabrication of the transplantable cell sheet particularly from patient-derived oral mucosal tissues. METHODS: Serum extracted from blood and buccal mucosal tissue were collected in Nagasaki University and transported to Tokyo Women's Medical University. Oral mucosal epithelial cells were collected by minimum trypsin method, and this treatment was studied whether to be a critical procedure. After 14 days cultivation, cultured cells were examined whether to be transplantable as cell sheets. RESULTS: We successfully transported buccal mucosal tissue and serum without damage and contamination. Oral mucosal epithelial cells were collected with high viability by minimum trypsin method. Finally, we succeeded to stably fabricate oral mucosal epithelial cell sheets in all 10 patients. CONCLUSIONS: We established a stable protocol for the fabrication of human oral mucosal epithelial cell sheets and their transportation in clinical settings in this study. These methodologies could also be basis for transplantation therapy using cultured cell sheets of various types other than oral mucosal epithelial cell and will contribute largely to the future development of regenerative medicine.

7.
Digestion ; 101(4): 450-457, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31129673

RESUMO

BACKGROUND/AIMS: The present study was performed to compare the safety of sedation with propofol during endoscopic submucosal dissection (ESD) for gastric tumors under sedation in the endoscopy room by an endoscopist versus sedation in the operation room by an anesthesiologist. METHODS: In total, 638 patients with gastric tumors who underwent ESD from January 2011 to August 2017 at Ureshino Medical Center and Saga Medical Center Koseikan were retrospectively reviewed. The patients were divided into 2 groups: those who underwent ESD in the endoscopy room (Group E, n = 532) and those who underwent ESD in the operation room (Group O, n = 106). Propensity score matching was applied for evaluation. The treatment outcome of ESD and the adverse events of sedation during ESD (desaturation, hypotension, bradycardia, and arrhythmia) were compared between the 2 groups to consider the safety of ESD. RESULTS: The propensity score-matching analysis created 82 matched pairs. Adjusted comparisons between Groups E and O showed similar treatment outcomes of ESD for gastric tumors. There were no significant differences in the treatment outcomes, anesthesia time, and mean propofol dose between the 2 groups. With respect to adverse events, desaturation occurred more often in Group E than Group O (18.3 vs. 3.7%, respectively; p = 0.005). There were no significant differences in other adverse events (hypotension, bradycardia, and arrhythmia) between the 2 groups. CONCLUSION: Sedation with propofol in the operation room might be required to ensure safer application of ESD for gastric tumors. However, a decrease in the desaturation rate was the only disadvantage of sedation in the endoscopy room.


Assuntos
Anestesiologistas/estatística & dados numéricos , Ressecção Endoscópica de Mucosa/métodos , Gastroenterologistas/estatística & dados numéricos , Hipnóticos e Sedativos/administração & dosagem , Propofol/administração & dosagem , Neoplasias Gástricas/cirurgia , Idoso , Feminino , Mucosa Gástrica/cirurgia , Humanos , Masculino , Salas Cirúrgicas , Pontuação de Propensão , Estudos Retrospectivos , Resultado do Tratamento
8.
BMC Gastroenterol ; 19(1): 192, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31744465

RESUMO

BACKGROUND: Endoscopic mucosal resection (EMR) to remove colon polyps is increasingly common in patients taking antithrombotic agents. The safety of EMR with submucosal saline injection has not been clearly demonstrated in this population. AIMS: The present study aimed to evaluate the efficacy and safety of submucosal injection of saline-epinephrine versus hypertonic saline in colorectal EMR of patients taking antithrombotic agents. METHODS: This study enrolled 204 patients taking antithrombotic agents among 995 consecutive patients who underwent colonic EMR from April 2012 to March 2018 at Ureshino Medical Center. Patients were divided into two groups according to the injected solution: saline-epinephrine or hypertonic (10%) saline (n = 102 in each group). Treatment outcomes and adverse events were evaluated in each group and risk factors for immediate and post-EMR bleeding were investigated. RESULTS: There were no differences between groups in patient or polyp characteristics. The main antithrombotic agents were low-dose aspirin, warfarin, and clopidogrel. Propensity-score matching created 80 matched pairs. Adjusted comparisons between groups showed similar en bloc resection rates (95.1% with saline-epinephrine vs. 98.0% with hypertonic saline). There were no significant differences in adverse events (immediate EMR bleeding, post-EMR bleeding, perforation, or mortality) between groups. Multivariate analyses revealed that polyp size over 10 mm was associated with an increased risk of immediate EMR bleeding (odds ratio 12.1, 95% confidence interval 2.0-74.0; P = 0.001). CONCLUSIONS: Two tested solutions in colorectal EMR were considered to be both safe and effective in patients taking antithrombotic agents.


Assuntos
Pólipos do Colo/cirurgia , Ressecção Endoscópica de Mucosa/efeitos adversos , Epinefrina/administração & dosagem , Fibrinolíticos/uso terapêutico , Hemostáticos/administração & dosagem , Hemorragia Pós-Operatória/prevenção & controle , Solução Salina Hipertônica/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Humanos , Injeções , Mucosa Intestinal , Pontuação de Propensão , Estudos Retrospectivos , Fatores de Risco , Vasoconstritores/administração & dosagem
9.
PLoS One ; 13(11): e0207099, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30462677

RESUMO

BACKGROUND: Small bowel obstruction (SBO) is usually caused by postoperative adhesions and malignant disease, and decompression is effective for SBO. Our previous case report suggested that a new transnasal ileus tube insertion method, the anterior balloon method (ABM), could achieve decompression for adhesive SBO. AIMS: The study aimed to investigate the effectiveness of a new method for inserting transnasal ileus tubes in patients with SBO. METHODS: Altogether, 134 patients with small bowel obstruction treated from January 2011 to December 2017 were reviewed. The patients were categorized into two groups: those with the new method that inserts an anterior balloon (ABM group: 52 patients, 2014-2017) versus those with the ordinary insertion method (OIM group: 82 patients, 2011-2014). RESULTS: The patients' characteristics and symptoms on admission were similar in the ABM and OIM groups. Adhesions were the main cause of ileus in the two groups. The insertion time duration was significantly shorter in the ABM group than in OIM group (28.4 ± 9.1 vs. 33.5 ± 13.0 min; p = 0.01). The ABM group also had significantly longer tubes than OIM group (222.4 ± 32.2 vs. 157.4 ± 31.7 cm; p < 0.001), which resulted in a significantly shorter time until clinical symptoms were relieved in ABM group. There were no significant differences in adverse events between the two groups. CONCLUSIONS: The ABM group had shorter insertion duration and longer tubes than those of OIM group. The ABM might become a preferred therapeutic choice to achieve decompression in patients with SBO.


Assuntos
Descompressão Cirúrgica/instrumentação , Descompressão Cirúrgica/métodos , Obstrução Intestinal/cirurgia , Intestino Delgado/cirurgia , Cirurgia Endoscópica por Orifício Natural/métodos , Idoso , Descompressão Cirúrgica/economia , Feminino , Humanos , Obstrução Intestinal/diagnóstico por imagem , Obstrução Intestinal/etiologia , Intestino Delgado/diagnóstico por imagem , Masculino , Cavidade Nasal , Cirurgia Endoscópica por Orifício Natural/economia , Cirurgia Endoscópica por Orifício Natural/instrumentação , Estudos Retrospectivos , Aderências Teciduais/complicações , Aderências Teciduais/diagnóstico por imagem , Aderências Teciduais/cirurgia , Resultado do Tratamento
10.
Sci Rep ; 7(1): 17460, 2017 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-29234120

RESUMO

Endoscopic submucosal dissection (ESD) permits en bloc removal of superficial oesophageal squamous cell carcinoma (ESCC). However, post-procedure stricture is common after ESD for widespread tumours, and multiple endoscopic balloon dilation (EBD) procedures are required. We aimed to evaluate the safety and effectiveness of endoscopic transplantation of tissue-engineered autologous oral mucosal epithelial cell sheets that had been transported by air over a distance of 1200 km in controlling postprocedural oesophageal stricture. Ten patients who underwent complete circular or semicircular ESD for ESCC were transplanted with cell sheets. The safety of the entire process including cell sheet preparation, transport, ESD and cell sheet transplantation was assessed. The incidence of oesophageal stricture, number of EBD sessions, and time until epithelialization were investigated. Each ESD was successfully performed, with subsequent cell sheet engrafting carried out safely. Following cell sheet transplantation, the luminal stenosis rate was 40%, while the median number of EBD sessions was 0. The median post-ESD ulcer healing period was rather short at 36 days. There were no significant complications at any stage of the process. Cell sheet transplantation and preparation at distant sites and transportation by air could be a safe and promising regenerative medicine technology.


Assuntos
Carcinoma de Células Escamosas/cirurgia , Ressecção Endoscópica de Mucosa , Células Epiteliais/transplante , Neoplasias Esofágicas/cirurgia , Mucosa Bucal/transplante , Engenharia Tecidual/métodos , Idoso , Aeronaves , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Células Cultivadas , Endoscopia do Sistema Digestório , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/metabolismo , Mucosa Bucal/patologia , Complicações Pós-Operatórias , Transplante Autólogo/métodos , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/metabolismo
11.
Gastroenterol Res Pract ; 2016: 1457357, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27022390

RESUMO

Background and Study Aims. When performing endoscopic submucosal dissection (ESD) for patients on antithrombotic agents, the frequency of delayed bleeding is expected to increase. The endoscopic polyglycolic acid (PGA) felt and fibrin glue sealing method could be a new method for prevention of delayed bleeding. Patients and Methods. The safety and efficacy of the endoscopic tissue sealing method with PGA sheets and fibrin glue for the prevention of post-ESD bleeding were examined in 104 patients taking antithrombotic agents. During the study period, 70 patients taking antithrombotic agents did not undergo the sealing method, 36 patients discontinued antithrombotic agents, and 724 patients had not received antithrombotic therapy. Results. Delayed bleeding rates were 3.8% (4/104) in the sealing group, 12.9% (9/70) in the nonsealing group, 8.3% (3/36) in the discontinuation group, and 4.6% (33/724) in the nonantithrombotic therapy group. Thus, the delayed bleeding rate was significantly lower in the sealing group than in the nonsealing group and comparable to that in the nonantithrombotic therapy group. Conclusions. This PGA felt and fibrin glue sealing method might become a promising post-ESD bleeding prevention method in patients taking antithrombotic agents (UMIN000013990, UMIN000013993).

12.
Photodiagnosis Photodyn Ther ; 12(2): 201-8, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25840141

RESUMO

OBJECTIVE: Photodynamic diagnosis (PDD) is an imaging technology that is based on the fundamental biological features of cancer cells. Five-aminolevulinic acid (ALA), a precursor of photosensitizing protoporphyrin IX (PpIX) has been applied. In fact, ALA-mediated PDD provides good visualization for certain tumors. However, there have been few studies on clinical application of PDD for gastrointestinal (GI) cancers. This study was aimed to investigate the feasibility of ALA-mediated PDD for navigation of upper GI tumors. MATERIALS AND METHODS: Using a newly developed endoscope equipped with a blue laser light excitation, ALA-mediated PDD was conducted in 27 lesions from 23 patients with upper GI tumors including 2 Barrett's intramucosal cancers. ALA solution was given orally 3h before PDD. All the adenocarcinomas came under clinical stage I, and the tumors were resected endoscopic submucosal dissection and/or laparoscopic surgery. Red fluorescence signal and intensity was assessed as for clinicopathological features of the cases. RESULTS: The laser-based endoscopy could detect upper GI tumors as red fluorescent navigation (PDD-positive) in 23 of the 27 lesions. All but one intestinal typed tumors in histopathology were significantly PDD-positive, whereas each signet ring cell carcinoma was PDD-negative. There was a significant difference in tumor size between the PDD-positive and -negative tumors. The elevated lesions emitted significantly more intense fluorescence. CONCLUSIONS: Fluorescence navigation by ALA-mediated PDD provided sufficient detection of upper GI tumors in particular for the intestinal typed tumors. Thus, ALA-PDD using the blue laser-equipped endoscope offers a promising diagnostic tool.


Assuntos
Adenocarcinoma/diagnóstico , Ácido Aminolevulínico/uso terapêutico , Neoplasias Gastrointestinais/diagnóstico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Gravação de Videoteipe , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células em Anel de Sinete/diagnóstico , Carcinoma de Células em Anel de Sinete/patologia , Endoscopia Gastrointestinal , Feminino , Fluorescência , Neoplasias Gastrointestinais/patologia , Neoplasias Gastrointestinais/cirurgia , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
13.
Dig Dis Sci ; 59(2): 315-21, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24166663

RESUMO

BACKGROUND: Adipocytokines are associated with energy homeostasis and mediate various immune responses and inflammatory processes. Vaspin is a novel adipocytokine that is thought to exhibit anti-inflammatory effects. AIM: We aimed to evaluate serum vaspin levels in inflammatory bowel disease (IBD) and determine its possible associations with the course and to clarify its intestinal localization. METHODS: Serum samples were obtained from patients with Crohn's disease (CD; n = 30) and ulcerative colitis (UC; n = 33) and from healthy volunteers (controls; n = 26). Enzyme-linked immunosorbent assays were performed for all patients. Vaspin immunohistochemical staining was performed for intestines affected with IBD. RESULTS: Serum vaspin concentrations were significantly higher in patients with UC than in patients with CD and controls (422.9 ± 361.9 vs. 163.4 ± 116.2 vs. 147.5 ± 89.4 pg/mL, respectively; P < 0.01). There was no difference in the serum vaspin concentrations between the patients with CD and controls. There was also no difference in the serum vaspin concentrations between the patients with active IBD and those with inactive IBD. However, the serum vaspin concentrations of most patients with UC increased after remission induction. Vaspin was expressed in the adipocytes of the mesenteric adipose tissues but not in the epithelial or inflammatory cells of large intestines of the patients with IBD. CONCLUSIONS: Serum vaspin concentrations are elevated in patients with UC and increase further after remission induction, suggesting that vaspin may aid the auxiliary diagnosis of UC and may be useful for assessing disease activity in patients.


Assuntos
Colite Ulcerativa/sangue , Colo/química , Serpinas/sangue , Tecido Adiposo/química , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Doença de Crohn/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Regulação para Cima , Adulto Jovem
14.
J Chromatogr A ; 1059(1-2): 225-31, 2004 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-15628146

RESUMO

6-Methoxy-4-quinolone (6-MOQ, 1), an oxidation product derived from 5-methoxyindole-3-acetic acid, is a novel fluorophore, which has several useful characteristics for biomedical analysis. Compound 1 has strong fluorescence with a large Stokes' shift in aqueous media, and the maximum fluorescence excitation and emission wavelengths are 243 nm and 374 nm, respectively. The molar absorptivity at the maximum excitation wavelength and fluorescence quantum yield in aqueous 10% (v/v) methanol are 32 600 L mol(-1) cm(-1) and 0.38, respectively. The fluorescence intensity of 1 is scarcely affected by changing the medium pH, showing strong fluorescence from pH 2.0 to 11.0. In addition, 1 is highly stable against light and heat, and no degradation was observed at 60 degrees C for 3 days with exposure to daylight. As a fluorescent labeling reagent, [(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl)methyl]amine (6-MOQ-NH2, 2) was synthesized, and determination of carboxylic acids was demonstrated; 50 pmol of standard propionic acid and isobutyric acid were derivatized, and the obtained S/N ratios for 10 fmol (injection amount) of these two acids were 206 and 164, respectively.


Assuntos
Corantes Fluorescentes/química , Concentração de Íons de Hidrogênio , Quinolonas/química , Cromatografia Líquida de Alta Pressão , Fluorescência , Espectroscopia de Ressonância Magnética , Água/química
15.
Anal Biochem ; 316(2): 154-61, 2003 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-12711335

RESUMO

The amount of endogenous melatonin in the individual pineal glands of inbred mice has been determined using reversed-phase micro-high-performance liquid chromatography after precolumn oxidation of melatonin to a compound having strong fluorescence. The fluorescent compound was identified as N-[(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl)methyl]acetamide. The excitation and emission wavelengths of this compound are 245 and 380 nm, respectively, and the fluorescence intensity is 6.8 times greater than that of melatonin. Molar absorptivity and fluorescence quantum yield of this compound are 46,300[L mol(-1)cm(-1)] and 0.31 (245 nm), respectively. The lower quantification limit of melatonin in biological samples using this precolumn oxidation method is 200 amol, and the calibration curve of spiked melatonin is linear from 200 amol to 50 fmol (r>0.999). The sensitivity of the present method is almost 10 times higher than that of the previous method. The values of endogenous melatonin obtained for ICR, C57BL, BALB/c, and AKR mice are 4.7, 6.1, 7.4, and 18.8 fmol/pineal gland, respectively. The amounts of endogenous pineal melatonin of these strains had not been clearly reported due to the poor enzymatic activities for melatonin biosynthesis; this is the first report that clearly demonstrates the existence of endogenous melatonin in these inbred mice.


Assuntos
Iodoacetamida/análogos & derivados , Melatonina/análise , Glândula Pineal/metabolismo , Animais , Cromatografia Líquida de Alta Pressão/métodos , Fluorescência , Iodoacetamida/normas , Espectroscopia de Ressonância Magnética , Melatonina/análogos & derivados , Camundongos , Camundongos Endogâmicos , Microquímica/métodos , Estrutura Molecular , Oxirredução , Glândula Pineal/química , Padrões de Referência
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