RESUMEN
BACKGROUND: The pathological conditions of UC and CD involved in inflammatory bowel disease-unclassified (IBD-U), UC with primary sclerosing cholangitis (PSC-UC), and UC with autoimmune pancreatitis type 2 (AIP-UC) remain unclear. Therefore, it is difficult to decide the appropriate treatments for these subtypes of UC. Our aim was to examine whether the discriminant equation using the mucosally expressed mediators designed as our previous study for IBD, could characterize IBD-U, PSC-UC, or AIP-UC. METHODS: A total of 56 patients including UC (n = 24), CD (n = 15), IBD-U (n = 10), PSC-UC (n = 4), and AIP-UC (n = 3), along with 9 control patients were enrolled in this study. Mucosally expressed inflammatory mediators related to Th1, Th2, Th17, and Treg were measured using quantitative PCR in endoscopic biopsies from the inflamed intestines of the patients. The IBD-U, PSC-UC or AIP-UC were characterized using discriminant analysis and principle component analysis. RESULTS: Through discriminant analyses, combinations of 3 to 7 inflammatory mediators were used to discriminate between UC and CD. Moreover, the identified 3 markers could diagnose patients with IBD-U as UC or CD with high accuracy. The distribution graph of inflammatory mediators using the principal component analysis revealed that PSC-UC and AIP-UC exhibited CD-like and UC-like features, respectively. CONCLUSIONS: The discriminant equation using mucosally expressed mediators of IL-13, IL-21 and T-bet can be used as a universal diagnostic tool not only for IBD-U but also to assess pathological conditions in PSC-UC and AIP-UC.
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Colitis Ulcerosa , Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Colitis Ulcerosa/diagnóstico , Citocinas , Humanos , Enfermedades Inflamatorias del Intestino/diagnóstico , Factores de TranscripciónRESUMEN
Ulcerative colitis (UC) has been considered a Th2- and Th17-related disease. However, anti-IL-12/23 p40 antibody, which blocks Th1 and Th17 cell induction and maintenance, has shown efficacy in treating UC, suggesting that UC might not be a prototypical Th2 and Th17 cell-mediated autoimmune disease. To verify how the immune responses in UC patients interact with each other, we analyzed the cytokine expression and transcription factors involved in the Th1, Th2, and Th17 responses. The mucosal expression of 19 cytokines and transcription factors related to Th1, Th2, and Th17 cells, as well as Tregs, were measured by quantitative polymerase chain reaction using endoscopic biopsy specimens from inflamed colons of UC patients. A correlation analysis between the cytokines and transcription factors was conducted. The characteristic cytokine profile in UC patients has two immune response clusters: Th17-related responses and Th1-/Th2-related responses. IL-23 showed a weaker association with Th17 cell-related cytokines and transcription factor RORC and a much stronger correlation with T-bet and GATA3. In the high-IL-23-expression group, the rate of chronic continuous type was higher and the remission rate lower than in the low-IL-23-expression group. IL-23 may be a very important cytokine for evaluating the UC disease condition, as the expression of IL-23 is associated with certain clinical characteristics of UC patients. A unique association between IL-23 and T-bet/GATA3 might play a key role in the pathogenesis of UC.
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Colitis Ulcerosa/inmunología , Factor de Transcripción GATA3/inmunología , Interleucina-23/inmunología , Proteínas de Dominio T Box/inmunología , Células TH1/inmunología , Células Th17/inmunología , Células Th2/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Análisis por Conglomerados , Colitis Ulcerosa/diagnóstico , Colitis Ulcerosa/metabolismo , Colon/inmunología , Citocinas/inmunología , Citocinas/metabolismo , Femenino , Factor de Transcripción GATA3/metabolismo , Humanos , Interleucina-23/metabolismo , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa , Estudios Retrospectivos , Proteínas de Dominio T Box/metabolismo , Células TH1/metabolismo , Células Th17/metabolismo , Células Th2/metabolismo , Adulto JovenRESUMEN
BACKGROUND/AIM: Currently, there are no established biomarkers to differentiate between glucocorticoid (GC)-resistant and GC-sensitive ulcerative colitis (UC); however, interleukin (IL)-1ß could be one such candidate biomarker. The aim of this study was to investigate whether mucosally expressed IL-1ß could predict the response to GC in patients with UC. METHODS: A total of 27 mucosal tissue samples from 10 patients with GC-resistant UC (GC-resistant group), 9 patients with GC-sensitive UC (GC-sensitive group), and 8 control patients (control group) were analyzed by qRT-PCR for the expression of IL-1ß, GC receptor α (GRα), GRß, and other inflammatory mediators. Rachmilewitz endoscopic index (REI) between the GC-resistant and GC-sensitive groups was matched to avoid any potential influence of inflammation. RESULTS: The REI did not significantly differ between the GC-resistant and GC-sensitive groups. Mucosally expressed IL-1ß levels in the GC-resistant group were significantly higher than those in the GC-sensitive group. However, there were no significant differences in the expression levels of GRα, GRß, and other inflammatory mediators between the 2 groups. We could distinguish between the GC-resistant and GC-sensitive groups with a sensitivity of 90.0% and specificity of 77.8% based on mucosally expressed IL-1ß. CONCLUSIONS: Mucosally expressed IL-1ß can be used as a predictor of GC response in patients with UC.
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Colitis Ulcerosa , Glucocorticoides , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/genética , Glucocorticoides/uso terapéutico , Humanos , Interleucina-1 , Mucosa Intestinal , Receptores de Glucocorticoides/genéticaRESUMEN
BACKGROUND/AIMS: Although gastric atrophy is primarily caused by Helicobacter pylori infection, it is unclear why patients serologically diagnosed with gastric atrophy without H. pylori infection exhibit greater atrophy. We investigated histopathological features in serologically diagnosed gastric atrophy without H. pylori infection. METHODS: Thirty-four patients with positive serum pepsinogen and negative serum H. pylori antibody tests underwent gastric biopsy and histological evaluation. The presence of enterochromaffin-like cells (ECL) was also evaluated. Gastric cancer risks for each histological feature according to the Operative Link on Gastritis Assessment (OLGA) and Operative Link on Gastric Intestinal Metaplasia (OLGIM) were assessed. RESULTS: Twenty-five (74%) patients had histological gastric atrophy. Among those, the following histological subgroups were identified: eight had H. pylori but no ECL, 13 had neither H. pylori nor ECL, and 4 had ECL without H. pylori. Nine patients without histological atrophy had neither H. pylori nor ECL. Patients with H. pylori on histological diagnosis had significantly higher scores on OLGA and OLGIM. CONCLUSIONS: Various histological features, with significant differences in gastric cancer risk, were identified in the gastric mucosa serologically diagnosed with atrophy without H. pylori infection. Therefore, serological screening for gastric cancer risk tests has several limitations, and additional evaluations should be considered.
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Células Similares a las Enterocromafines/metabolismo , Mucosa Gástrica/patología , Gastritis Atrófica/patología , Lesiones Precancerosas/patología , Neoplasias Gástricas/diagnóstico , Adulto , Anciano , Biopsia , Detección Precoz del Cáncer , Femenino , Gastritis Atrófica/diagnóstico , Humanos , Masculino , Metaplasia , Persona de Mediana Edad , Lesiones Precancerosas/diagnóstico , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Neoplasias Gástricas/patologíaRESUMEN
A 37-year-old man developed abdominal pain and the frequency of severe abdominal pain steadily increased to once a month. He was therefore admitted to our hospital. Abdominal CT showed bowel obstruction. It revealed transient stenosis in the small intestine. There were no symptoms such as fever or weight loss, it seemed unlikely that the patient had inflammatory bowel disease. Considering the history of recurrent abdominal pain, Familial Mediterranean Fever (FMF) was considered. As a result, a genetic analysis revealed mutations in exons 3 and 8 of the MEFV gene. We herein report the first known case of FMF with transient small bowel stenosis in Japan.
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Fiebre Mediterránea Familiar/diagnóstico , Fiebre Mediterránea Familiar/genética , Pirina/genética , Dolor Abdominal/etiología , Adulto , Constricción Patológica , Análisis Mutacional de ADN , Fiebre Mediterránea Familiar/complicaciones , Fiebre/genética , Humanos , Obstrucción Intestinal , Intestino Delgado , Japón , Masculino , MutaciónRESUMEN
BACKGROUND: Chemotherapy is a standard strategy for stage IV gastric cancer patients. However, some cases cannot undergo conversion surgery because of their frailty, even if the patients had response to chemotherapy. For these patients, local tumor progression is a problem. We report here the case of a patient whose residual gastric cancer was resected through endoscopic submucosal dissection (ESD) after concomitant chemotherapy for metastatic gastric cancer. CASE SUMMARY: An 85-year-old male complained of difficulty swallowing, and examination revealed gastric cancer with multiple liver metastases. Although he received concomitant chemotherapy, a residual tumor was observed in the primary lesion while the metastatic lesions disappeared completely. Conversion surgery was considered optional treatment; however, he could not undergo that because of advanced age and comorbidities. Thus, we performed ESD to treat the residual tumor. As a result, we resected the residual lesion completely. The patient has been alive for 29 mo since ESD, without recurrence. CONCLUSION: We achieved local control using ESD, and these findings may provide therapeutic improvements both in local control and patient survival outcomes.
RESUMEN
In many countries, methimazole (MMI) therapy is the first-line treatment in children with Graves' disease (GD). The rate of side effects of antithyroid drugs (ATDs) in children has been reported to range between 6% and 35%. Of these side effects, polyarthritis is uncommon but serious, and can also develop as a part of the antineutrophil cytoplasmic antibody-associated vasculitis that is induced by ATDs. Here, we describe two GD girl patients aged 15 years and 11 years who developed polyarthritis. The onset of polyarthritis in these patients was 24 days and 28 days after the initiation of MMI therapy, respectively. MMI was suspected of causing the polyarthritis in the two patients and was withdrawn. The symptoms of polyarthritis disappeared rapidly following cessation of treatment. Subsequently, one patient was treated with 131I therapy and the other patient was subjected to thyroidectomy. Although it rarely occurs in pediatric GD patients, severe polyarthritis is a serious side effect of MMI and is an indication for prompt cessation of treatment.
Asunto(s)
Antitiroideos/efectos adversos , Artritis/inducido químicamente , Enfermedad de Graves/tratamiento farmacológico , Metimazol/efectos adversos , Adolescente , Niño , Femenino , HumanosRESUMEN
A convenient method for the synthesis of 3-methylthioindoles has been established which does not use smelly compounds such as thiol derivatives. The method, which introduces an alkyl- or arylthio-group into the C(3)-position of the indole skeleton, was extended to the direct introduction of a methylthio or bromo group at the C(2)-position using 3-methylthioindoles. No dimerization occurred, and the reaction mechanism was confirmed. The products have the partial structure of potent anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) bromomethylthioindoles (MC 5-8) isolated from marine algae. Furthermore, this reaction could be applied to the synthesis of 3,3-diindolyl thioether which is a core structure of Echinosulfone A.
Asunto(s)
Antibacterianos/química , Antibacterianos/síntesis química , Indoles/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Compuestos de Sulfhidrilo/química , Antibacterianos/farmacología , DimerizaciónRESUMEN
Several new amyloid-ß (Aß) aggregation inhibitors were synthesized according to our theory that a hydrophilic moiety could be attached to the Aß-recognition unit for the purpose of preventing amyloid plaque formation. A distyrylbenzene-derivative, DSB(EEX)(3), which consider the Aß recognition unit (DSB, 1,4-distyrylbenzene) and expected to bind to amyloid fibrils (ß-sheet structure), was combined with the hydrophilic aggregation disrupting element (EEX) (E, Glu; X, 2-(2-(2-aminoethoxy)ethoxy)acetic acid). This DSB(EEX)(3) compound, compared to several others synthesized similarly, was found to be the most active for reducing Aß toxicity toward IMR-32 human neuroblastoma cells. Moreover, its inhibition of Aß-aggregation or fibril formation was directly confirmed by transmission electron microscopy and atomic force microscopy. These results suggest that the Aß aggregation inhibitor DSB(EEX)(3) disrupts clumps of Aß protein and is a likely candidate for drug development to treat Alzheimer's disease.
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Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/antagonistas & inhibidores , Amiloide/antagonistas & inhibidores , Estirenos/química , Estirenos/farmacología , Enfermedad de Alzheimer/metabolismo , Amiloide/metabolismo , Amiloide/ultraestructura , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/ultraestructura , Línea Celular Tumoral , HumanosRESUMEN
Although liposomes are considered to be one of the most promising carriers for drug delivery systems (DDS), they have drawbacks such as insufficient drug-entrapment efficiency and long-term stability. The objectives of this study are to improve the trapping efficiency by addition of lipopeptides (LPs), and using a supercritical CO(2) reverse-phase evaporation (SCRPE) process, along with incorporation of PEG-modified phospholipids to improve long-term stability. In this study, bovine serum albumin (BSA) was used as a model drug substance for entrapment by liposomes. Improvements in the entrapment efficiency and stability of liposomes were achieved by modification with LPs and use of a SCRPE preparation process. The BSA-entrapment efficiency of liposomes modified with cationic LPs with arginine residues, as a result of their ionic interactions, was six times that of liposomes prepared by the Bangham method. Use of a SCRPE method along with LP modification further enhanced entrapment and enabled spontaneous formation of unilamellar liposomes with long-term stability. Liposomes consisting of DPPC/Chol/C(16)-Arg2/DSPE-PEG2000 (60/30/5/5), with up to 70% entrapment efficiency for BSA and a stability level of 90% for over 40 h, were obtained. DSC and SAXS analyses indicated that certain amounts of LP in the DPPC induced phase-transitional and structural changes in the lamellar membrane, and these changes improved the DDS carrier properties.The SCRPE method provides organic-solvent-free liposomes, and the LPs for the liposome modification are derivatives of amino acids and fatty acids, which are sustainable and biocompatible materials. This study therefore suggests that there are opportunities for the development of novel DDS carriers with excellent performance and which address environmental concerns.
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Dióxido de Carbono/química , Lipopéptidos/química , Liposomas/síntesis química , Animales , Bovinos , Química Farmacéutica , Liposomas/química , Estructura Molecular , Tamaño de la Partícula , Albúmina Sérica Bovina/química , Propiedades de SuperficieRESUMEN
Taxanes, which are widely used in treatment of numerous cancer types, are well-known to induce hypersensitivity reactions (HSR), especially in the case of paclitaxel. Although the cause of the HSR is commonly thought to be a non-immunological direct effect of the diluent which is used to dissolve paclitaxel, some reports suggest the possibility of the presence of an immunological reaction to the common taxane structure. The aim of this study was to establish a method to determine the presence of anti-taxane antibodies in body fluids of patients who have previously received paclitaxel, in order to estimate the risk of the occurrence of HSR to other taxane compounds, such as docetaxel. To prepare an enzyme-linked immunosorbent assay (ELISA) plate for determining taxanes, 10-deacetylbaccatin III (DAB) was first succinylated by use of dimethylaminopyridine and succinic anhydride in dried pyridine. After the succinylation reaction, three different products were obtained, and these were confirmed as 7-succinoyl DAB (7-DAB), 10-succinoyl DAB (10-DAB), and 7,10-disuccinoyl DAB (7,10-DAB) by (1)H-NMR analysis. Each of these three products was conjugated with bovine serum albumin (BSA), and adsorbed on an ELISA plate. By using a commercially available anti-taxane monoclonal antibody as a model antibody, the detection limit of the anti-taxane antibodies on the 7-DAB-BSA-, 10-DAB-BSA-, and 7,10-DAB-BSA-conjugated ELISA plate was estimated as 0.3, 1 and 10 ng/ml, respectively. The ELISA system established in this study may therefore be useful for estimating the risk of HSR to taxanes in a patient prior to the use of these drugs.
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Anticuerpos/metabolismo , Antineoplásicos Fitogénicos/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Hipersensibilidad/inmunología , Fitoterapia/efectos adversos , Taxoides/inmunología , Animales , Anticuerpos Monoclonales/metabolismo , Antineoplásicos Fitogénicos/efectos adversos , Antineoplásicos Fitogénicos/uso terapéutico , Bovinos , Hongos/química , Hongos/inmunología , Humanos , Hipersensibilidad/etiología , Ratones , Neoplasias/tratamiento farmacológico , Paclitaxel/efectos adversos , Paclitaxel/inmunología , Paclitaxel/uso terapéutico , Factores de Riesgo , Taxoides/efectos adversos , Taxoides/uso terapéutico , Taxus/química , Taxus/inmunología , Taxus/microbiologíaRESUMEN
We present a rare case report of a patient who presented with posterior interosseous nerve palsy caused by synovial chondromatosis. Synovial chondromatosis arising in the annular periradial recesses of the elbow joint was detected, and the mass developed two major portions constricted with the annular ligament. After surgical resection, posterior interosseous nerve palsy fully recovered and there was no recurrence of the lesion of synovial chondromatosis.
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Condromatosis Sinovial/complicaciones , Articulación del Codo/inervación , Parálisis/etiología , Neuropatía Radial/etiología , Condromatosis Sinovial/diagnóstico , Condromatosis Sinovial/cirugía , Descompresión Quirúrgica , Articulación del Codo/diagnóstico por imagen , Articulación del Codo/cirugía , Humanos , Masculino , Persona de Mediana Edad , Síndromes de Compresión Nerviosa/diagnóstico , Síndromes de Compresión Nerviosa/cirugía , Neuropatía Radial/cirugía , Radiografía , Resultado del TratamientoRESUMEN
The reaction mechanism for the biomimetic synthesis of tryptophan from indole and serine in the presence of Ac(2)O in AcOH was investigated. Although the time-course (1)H-NMR spectra of the reaction of 5-methoxyindole with N-acetylserine were measured in the presence of (CD(3)CO)(2)O in CD(3)CO(2)D, the reactive intermediate could not be detected. This reaction was conducted without 5-methoxyindole in order to elucidate the reactive intermediate, but the intermediate could not be isolated from the reaction mixture. Since the intermediate would be expected to have a very short life time, and therefore be very difficult to detect by conventional analytical methods, the structure of the intermediate was elucidated using a 2D-NMR technique, diffusion-ordered spectroscopy (DOSY). Two intermediates were detected and confirmed to be 2-methyl-4-methyleneoxazol-5(4H)-one and 2-methyl-4-hydroxymethyloxazol-5(4H)-one. The present results demonstrated that DOSY is a powerful tool for the detection of unstable intermediates.
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Indoles/química , Serina/química , Triptófano/síntesis química , Anhídridos Acéticos/química , Espectroscopía de Resonancia Magnética , Estructura Molecular , Triptófano/químicaRESUMEN
We aimed at securing sufficient concentrations of (10)B in boron neutron capture therapy (BNCT) by developing a new drug delivery system. We have designed and developed a novel lipid analog and succeeded in using it to develop the new boron component liposome. It consisted of three different kinds of amino acid derivatives and two fatty acids, and could react directly with the peptide synthesized first on resin by Fmoc solid-phase synthesis. In this study, lipid analog conjugated with HIV-TAT peptide (domain of human immunodeficiency virus TAT protein) and boronophenylalanine (BPA) was synthesized and successfully incorporated into liposomes.
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Compuestos de Boro/síntesis química , Terapia por Captura de Neutrón de Boro/métodos , Liposomas/química , Fenilalanina/análogos & derivados , Fármacos Sensibilizantes a Radiaciones/síntesis química , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/síntesis química , Compuestos de Boro/química , Compuestos de Boro/uso terapéutico , Sistemas de Liberación de Medicamentos , Humanos , Isótopos/química , Isótopos/uso terapéutico , Lipopéptidos/síntesis química , Lipopéptidos/química , Lipopéptidos/uso terapéutico , Potenciales de la Membrana , Neoplasias/radioterapia , Tamaño de la Partícula , Fenilalanina/síntesis química , Fenilalanina/química , Fenilalanina/uso terapéutico , Fármacos Sensibilizantes a Radiaciones/química , Fármacos Sensibilizantes a Radiaciones/uso terapéutico , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/química , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/uso terapéuticoRESUMEN
Stress fracture of the carpal scaphoid is very rare. We present stress fracture of the scaphoid in an adolescent gymnast who was treated with internal fixation. Key pointsThere is a risk of stress fracture of the scaphoid in gymnast.Internal fixation with a screw is one of the good options for stress fracture of the scaphoid.
RESUMEN
We report a rare case of subcutaneous peroneus longus tendon rupture associated with os peroneum fracture. Three dimensional computed tomographic scan was useful to understand this disorder. We treated the patient with excision of fractured os peroneum and tenodesis of the proximal stump of the ruptured peroneus longus tendon to the lateral aspect of the calcaneus. Key pointsIn order to understand a rare case of subcutaneous peroneus longus tendon rupture associated with os peroneum fracture, three dimensional computed tomographic scan was useful.The patient was treated with excision of fractured os peroneum and tenodesis of the proximal stump of the ruptured peroneus longus tendon to the lateral aspect of the calcaneus.
RESUMEN
A series of novel and potent 3-amidinophenylsulfonamide derivatives of factor Xa inhibitors were designed and synthesized using an amidoxime prodrug strategy. We focused on systemic clearance of parent compounds in rats, and performed in vivo pharmacokinetic screening. Incorporation of a carboxymethoxy group markedly improved systemic clearance (compound 43), and the related amidoxime 44 showed sufficient prodrug conversion. Compound 45, the double prodrug of 43, exhibited practicable bioavailability after oral administration in rats. Among the various compounds under investigation, KFA-1982 was selected for clinical development.
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Amidinas/síntesis química , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/farmacología , Inhibidores del Factor Xa , Sulfonamidas/síntesis química , Sulfonamidas/farmacología , Administración Oral , Amidinas/farmacología , Animales , Disponibilidad Biológica , Química Farmacéutica/métodos , Diseño de Fármacos , Humanos , Ratones , Modelos Químicos , Estructura Molecular , Oximas/química , Profármacos/química , Tripsina/químicaRESUMEN
A series of amyloid-beta aggregation inhibitors composed of a molecular recognition element (KLVFF) and an aggregation-disrupting part (having an electrostatic and hydrophilic nature) based on amino acid analogs have been synthesized. A quartz-crystal microbalance (QCM) method was applied and found to be very successful in evaluating the inhibitory activity of the Abeta aggregation, which was observed when the frequency was increased. The QCM can detect a mass change with differences in frequency that correspond to a 1 Hz frequency decrease per 30 pg mass increase on a 4.9 mm(2) electrode. Furthermore, bioassay results showed no toxicity of the inhibitor itself against IMR-32 neuroblastoma cells, and remarkably reduced cytotoxicities of both Abeta1-40 and Abeta1-42 were exhibited in the presence of these inhibitors. The KLVFF-(EEX)3 derivative was the most efficient Abeta aggregation among the inhibitors examined here.
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Péptidos beta-Amiloides/química , Péptidos/química , Cuarzo , Secuencia de Aminoácidos , Estudios de Evaluación como Asunto , Humanos , Datos de Secuencia Molecular , Células Tumorales CultivadasRESUMEN
A novel lipid analog based on amino acids for liposome modification was developed. It consisted of three different kinds of amino acid derivatives and two fatty acids, and can react directly with the peptide synthesized first on resin by Fmoc solid-phase synthesis. In this study, lipid analog conjugated with HIV-TAT peptide (domain of human immunodeficiency virus TAT protein) was synthesized and successfully incorporated into liposome. The liposome containing the lipopeptide bearing HIV-TAT exhibited efficient cellular uptake.
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Química Farmacéutica/métodos , Productos del Gen tat/química , Lípidos/química , Liposomas/química , Péptidos/química , Animales , Células COS , Chlorocebus aethiops , Cromatografía Líquida de Alta Presión , Diseño de Fármacos , Ácidos Grasos/química , Espectroscopía de Resonancia Magnética , Modelos Químicos , Conformación Molecular , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Brominations of unprotected aromatic amino acids such as phenylalanine, tyrosine, and glycine, with bromoisocyanuric acid mono sodium salt (BICA-Na) were conducted in 60% aq. H(2)SO(4) at 0 degrees C to give a mixture of mono-brominated products in good yield. Unexpectedly, meta-bromophenylglycine was obtained as main product accompanied by ortho- and para-substituted products, while phenylalanine gave only ortho- and para-substituted products. Bromination of 2-phenylethylamine or benzylamine showed a tendency similar to the corresponding amino acids.