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1.
Carbohydr Polym ; 285: 119222, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35287852

RESUMO

The implementation of cellulose as a green alternative to classical polymers sparks research on the synthesis of defined derivatives of this biopolymer for various high-tech applications. Apart from the scientific challenge, the in vitro synthesis of cellulose using a bottom-up approach provides specimens with absolutely accurate substituent patterns and degrees of polymerization, not accessible from native cellulose. Synthetic cellulose exhibiting a comparably high degree of polymerization (DP) was obtained starting from cellobiose by biocatalytic synthesis implementing cellulase. Cationic ring-opening polymerization has been established in the last two decades, representing an excellent means of precise modification with regards to regio- and stereoselective substitution. This method rendered isotopically enriched cellulose as well as enantiomers of native cellulose ("l-cellulose", "d,l-cellulose") accessible. In this review, techniques for in vitro cellulose synthesis are summarized and critically compared - with a special focus on more recent developments. This is complemented by a brief overview of alternative enzymatic approaches.


Assuntos
Celulase , Celulose , Celobiose , Polímeros , Estereoisomerismo
2.
J Gen Fam Med ; 23(1): 67, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35004116
3.
J Gen Fam Med ; 22(6): 334-340, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34754711

RESUMO

BACKGROUND: Population aging requires more physician home visits, and various measures need to be taken to reduce the burden on visiting physicians. However, the incidence and associated factors of burdensome emergency home visits remain unclear. We aimed to reveal the incidences of emergency home visits among cancer and noncancer patients and examine how visiting nurses affect those. METHODS: We performed a prospective cohort study across three clinics in Japan and enrolled the patients receiving home visits within a 3-month study period. We calculated the incidence rates using person-time at risk and conducted a Cox regression in the analysis of risks for emergency home visits. RESULTS: A total of 278 patients were analyzed. The incidences of emergency home visits among the overall, the cancer, and the noncancer home care patients were 1.61, 7.23, and 1.37 per 10 person-months, respectively. The adjusted hazard ratios of a cancer-bearing state and visiting nurse service use were 4.71 (95% confidence interval [CI], 2.60-8.52) and 1.85 (95% CI, 1.77-1.94), respectively. CONCLUSIONS: The incidence of emergency home visits among cancer patients was around five times greater than noncancer patients. Our study did not demonstrate that visiting nurses prevent emergency home visits. Further studies are needed to clarify how visiting nurses reduce physicians' burden.

4.
Anal Biochem ; 630: 114327, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364857

RESUMO

Angiotensin (Ang) peptides are the main effectors of the renin-angiotensin system (RAS) regulating diverse physiological conditions and are involved in renal and vascular diseases. Currently, quantitative analyses of Ang peptides in human plasma mainly rely on radioimmunoassay-based methods whose reported levels are quite divergent. Analyses are further complicated by the potential of Ang peptides to bind to solid surfaces, to be enzymatically decomposed during sample preparation, and to undergo post-translational modifications. A column switching-parallel LC/ESI-SRM/MS method has been developed for seven Ang peptides (Ang I, Ang II, Ang III, Ang IV, Ang 1-9, Ang 1-7, and Ang A) in human plasma. Aqueous acetonitrile (5%) containing 50 mM arginine (Arg) as a dissolving solution and a combination of protease inhibitors with formic acid were used to prevent adsorption and enzymatic degradation, respectively. Plasma samples were simply deproteinized with acetonitrile followed by clean-up with an on-line trap column via column-switching. Stable isotope dilution with [13C5,15N1-Val]-Ang peptides as internal standards was employed for quantitative analysis. The current methodology has been successfully applied to determine the plasma levels of Ang peptides in healthy participants, suggesting future applicability to studies of various diseases related to RAS.


Assuntos
Angiotensinas/sangue , Análise Química do Sangue , Peptídeos/sangue , Adulto , Cromatografia Líquida , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Espectrometria de Massas por Ionização por Electrospray , Adulto Jovem
5.
Carbohydr Polym ; 253: 117235, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33278992

RESUMO

Cellulosic material is capable of permanently retaining nitrogen compounds (mostly having amino functions), which is reflected in a residual nitrogen content (in the low per mille range to the low percent range) of some pulps and certain lab samples. Merely adsorptively bound compounds can be removed by mild acidic washing, but part of the nitrogen seems to be resistant and very tightly bound, and thus not accessible for removal by washing. Tertiary and aromatic amines are not retained in this way, but only primary and secondary amines. There is only a weak correlation between the "firmly bound nitrogen" and the carbonyl content in cellulosics (because of oxidative damage), so that possible aminal, Schiff base and enamine structures can hardly be relevant as major nitrogen sources. However, there is a very good linear correlation between the ISO brightness (chromophore content) in aged pulps and the residual nitrogen content. In particular the concentration of the cellulosic key chromophore 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) determines the permanent N-binding capacity of the pulp. DHBQ reacts very readily with primary and secondary amines under ambient conditions to 2,5-diamino-substituted [1,4]-benzoquinones, which have very low solubility (because of zwitterionic resonance contributions) and thus remain on/in the pulp. Examples of nitrogen fixation in pulps are the binding of piperidine (a common amine catalyst in derivatization reactions), amine degradation products of the cellulose solvent NMMO, dimethylamine in materials processed from the cellulose solvent DMAc/LiCl, imidazole (a degradation product of 1-alkyl-3-methylimidazolium ionic liquids), and of amino groups in proteins after enzymatic treatment. The nature of the respective DHBQ-amine addition compound has been verified by complete structure determination.

6.
Jpn J Infect Dis ; 72(5): 285-291, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30918148

RESUMO

An advanced and fully automated chemiluminescent enzyme immunoassay for the hepatitis C virus core antigen (HCVcAg) was recently developed in Japan. We aimed to evaluate its clinical utility. The new Fujirebio assay (Lumipulse Presto HCVcAg [LP-Presto]) was compared with 2 conventional assays (Lumipulse Ortho HCVcAg [LP-Ortho] and Abbott's Architect HCVcAg). Basic assessments of LP-Presto (reproducibility, stability, range of quantitation, and specificity) were performed on 220 frozen sera (83 positive and 137 negative by LP-Ortho) and 206 fresh sera (all negative by LP-Ortho). Correlation analysis was performed and the rates of concordance for each assay were determined. Additionally, the frozen sera of 42 hyperimmunoglobulinemia patients, including 3 unmeasurable by LP-Ortho, were tested by LP-Presto. All the basic assessments of LP-Presto were consistent with the results of LP-Ortho and Architect. The concordance rate between LP-Presto and LP-Ortho for the 220 frozen sera was 99.5% (219/220), and that between LP-Presto and Architect was 99.1% (218/220). LP-Presto (HCVcAg cut-off value; 20 fmol/L) was fully consistent with LP-Ortho (100%), which found 343 sera negative for HCVcAg. All 42 hyperimmunoglobulinemic sera were measurable using LP-Presto. In conclusion, the performance of LP-Presto was rapid and reliable, and nonspecific test results due to hyperimmunoglobulinemia were reduced when LP-Presto was used. Therefore, LP-Presto is a high-quality HCVcAg assay that shows promising applications.


Assuntos
Hepatite C/diagnóstico , Técnicas Imunoenzimáticas/métodos , Medições Luminescentes/métodos , Proteínas do Core Viral/análise , Adulto , Idoso de 80 Anos ou mais , Automação Laboratorial/métodos , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
7.
Endosc Int Open ; 6(9): E1134-E1139, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30211304

RESUMO

Background and study aims We developed the Endoscopic Operation Robot (EOR) version 3, offering built-in haptic feedback and manipulation of the entire scope with one hand. Manipulation of the flexible endoscope is done entirely remotely. However, inclusion of haptic feedback places a huge burden on the system. Our purpose in this study was to determine whether haptic feedback is needed in remote manipulation of a flexible endoscope. Methods Five endoscopists performed total colonoscopy using a colonoscopy training model. A trial was conducted in which the endoscope was inserted up to the cecum five times with haptic feedback and five times without haptic feedback. Insertion time, maximum and mean haptic force, and incidence of sigmoid colon overstretching were compared between groups. Results Insertion time was significantly shorter with haptic feedback than without, and overstretching of the sigmoid colon was less frequent. Insertion could thus be performed without using excessive force. Conclusion Haptic feedback is useful for remote control manipulation of flexible endoscopes.

8.
Hepatol Res ; 48(3): E203-E212, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28834042

RESUMO

AIM: Serum low-density lipoprotein cholesterol (LDL-C) increases during treatment of chronic hepatitis C (CHC) with interferon-free direct-acting antivirals (DAAs). We sought to compare the changes of serum lipid profiles caused by three regimens. METHODS: A total of 216 CHC patients were enrolled. Among 170 patients infected with hepatitis C virus (HCV) genotype 1b, 85 received daclatasvir plus asunaprevir (DCV/ASV) and 85 received sofosbuvir plus ledipasvir (SOF/LDV). Forty-six infected with HCV genotype 2 received sofosbuvir plus ribavirin (SOF/RBV). Serum total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol, and triglyceride were measured at baseline and 4, 8, 12 (for all regimens), and 24 weeks (for DCV/ASV) during treatment (4w, 8w, 12w, and 24w, respectively) and 12 and 24 weeks after treatment (p12w and p24w, respectively). RESULTS: In 69 (81.2%) patients who received DCV/ASV and achieved a sustained virologic response at 24 weeks after the end of treatment (SVR24), TC and LDL-C increased significantly from baseline to p24w. In 84 (98.8%) treated with SOF/LDV who achieved SVR24, TC and LDL-C increased significantly from baseline to 8w, and TC decreased significantly from 8w to p12w. The 45 (97.8%) who received SOF/RBV and achieved SVR24 showed no significant changes. At 12w, TC and LDL-C increased to a greater degree in patients receiving SOF/LDV than in those receiving DCV/ASV or SOF/RBV. CONCLUSION: During treatment with DAAs, the serum lipid profile may reflect not only recovery from the disruption of lipid metabolism induced by HCV, but also the pharmacological effects of DAAs. Further investigations are needed to elucidate the effect of DAAs on serum lipid profiles.

9.
IEEE Int Conf Rehabil Robot ; 2017: 646-651, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28813893

RESUMO

This paper addresses the mechanical structure and control method of a redundant drive robot (RDR) to produce compliant motions, and show how the design parameters of the RDR can effect the produced motions and the mechanical and performance limitations of the actuators of the RDR. The structure and control method of the RDR can have been proper to produce compliant motions, but the effect of the design parameters of the RDR to the mechanical and performance limitations have not been clear. Therefore, the feasibility of producing compliant motions in the case of the prototype of the RDR is confirmed by conducting simulations and experiments, and then the design parameters of the RDR to the mechanical and performance limitations are verified by conducting simulations.


Assuntos
Desenho de Equipamento/métodos , Robótica/instrumentação , Reabilitação do Acidente Vascular Cerebral , Fenômenos Biomecânicos , Eletroencefalografia , Humanos , Reabilitação do Acidente Vascular Cerebral/instrumentação , Reabilitação do Acidente Vascular Cerebral/métodos , Reabilitação do Acidente Vascular Cerebral/normas
10.
Neuroreport ; 28(13): 828-832, 2017 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-28628557

RESUMO

Near-infrared spectroscopy studies in children with attention deficit hyperactivity disorder (ADHD) have shown excessive prefrontal activity responsible for coping with interference. However, it is possible that the previous results were influenced by verbal, reading, and memory developments. The flanker task is an interference task that does not require a verbal response, reading, or memorization. We examined activity in the superior frontal cortex (SFC) during the flanker task in 12 children with ADHD and 14 children with typical development using near-infrared spectroscopy. SFC activity was significantly greater in children with ADHD than in those with typical development. The results showed excessive interference coping activity in children with ADHD irrespective of verbal, reading, and memory development. Moreover, SFC activity was positively correlated with the inattention subscale score of the ADHD rating scale. We suggest that children with ADHD need greater SFC activation to cope with interference, and the inefficient mechanism is demanding and hard to sustain, which causes inattention symptoms of children with ADHD.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/patologia , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Lobo Frontal/irrigação sanguínea , Hemodinâmica/fisiologia , Criança , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/fisiopatologia , Humanos , Masculino , Testes Neuropsicológicos , Oxiemoglobinas/metabolismo , Estimulação Luminosa , Espectroscopia de Luz Próxima ao Infravermelho
11.
Rinsho Byori ; 64(12): 1335-40, 2016 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-30676009

RESUMO

Purpose: We aimed to evaluate the performance of an HIV antigen-antibody combination assay (fourth-generation) by comparing it with second generation assays that detect anti-HIV. Methods: A total of 105,439 HIV screening tests were performed from January 2004 to March 2015; the second - and fourth generation assays were used for 75,302 and 30,137 samples, respectively. Samples positive on a screening test were confirmed by anti-HIV-1 western blotting (WB) and nucleic acid amplification. By the results of confirmation tests, the efficacies of the second and fourth generation assays were estimated. The clinical backgrounds with false-positive samples were examined. Results: Of 75,302 samples, 136(0.18%) were positive by the second-generation assay; 14 were confirmed positives, and 122 were false positives. Of 30,137 samples, 18(0.06%) were positive by the fourth-generation assay; 6 were confirmed positives, and 12 were false positives. The reliability of the positives by fourth-generation assay was significantly improved (p=0.006) Samples form individuals with malignant neoplasms were frequently false positive by both the second and fourth-generation assays. Of 67 samples performed by WB, 10 samples, including 6 from patients with a malignancy, showed indeterminate results. All indeterminate samples were found to have antibodies responding to HIV core protein. Conclusion: The fourth-generation assay had satisfactory reliability of the positives for HIV screening. Antibodies responding to HIV core protein may result in false positive HIV screening tests. [Original]


Assuntos
Anticorpos Antivirais/imunologia , Complexo Antígeno-Anticorpo/imunologia , Antígenos Virais/imunologia , Infecções por HIV/diagnóstico , HIV-1/imunologia , Adolescente , Idoso , Reações Falso-Positivas , Humanos , Programas de Rastreamento
12.
J Neurogenet ; 29(4): 169-73, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26577029

RESUMO

In the pupal stage, the fly body undergoes extensive metamorphic remodeling, in which programmed cell death plays a critical role. We studied two of the constituent processes in this remodeling, salivary gland degeneration and breakdown of the eclosion muscle, which are triggered by an increase and a decrease in the circulating steroid hormone ecdysone at the start and end of metamorphosis, respectively. We found that knockdown of zeste (z), a gene encoding a sequence-specific DNA-binding protein implicated in transvection, in salivary gland cells advances the initiation of their degeneration, whereas z knockdown in neurons delays muscle breakdown. We further showed that knockdown of an ecdysone-inducible gene, E74, retards salivary gland degeneration with little effect on eclosion muscle breakdown. We propose that Z tunes the sensitivity of ecdysone targets to this hormone in order to ensure a high safety margin so that the cell death program will be activated when the ecdysone titer is at a sufficiently high level that is reached only at a defined stage during metamorphosis.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Doenças das Glândulas Salivares/genética , Glândulas Salivares/patologia , Fatores Etários , Animais , Animais Geneticamente Modificados , Proteínas de Ligação a DNA/genética , Drosophila , Proteínas de Drosophila/genética , Músculos , Doenças Musculares/genética , Pupa , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo
13.
Biol Reprod ; 93(4): 90, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26333992

RESUMO

Leucine-rich repeat-containing G protein-coupled receptor 4 (Lgr4) is a type of membrane receptor with a seven-transmembrane structure. LGR4 is homologous to gonadotropin receptors, such as follicle-stimulating hormone receptor (Fshr) and luteinizing hormone/choriogonadotropin receptor (Lhcgr). Recently, it has been reported that Lgr4 is a membrane receptor for R-spondin ligands, which mediate Wnt/beta-catenin signaling. Defects of R-spondin homolog (Rspo1) and wingless-type MMTV integration site family, member 4 (Wnt4) cause masculinization of female gonads. We observed that Lgr4(-/-) female mice show abnormal development of the Wolffian ducts and somatic cells similar to that in the male gonads. Lgr4(-/-) female mice exhibited masculinization similar to that observed in Rspo1-deficient mice. In Lgr4(-/-) ovarian somatic cells, the expression levels of lymphoid enhancer-binding factor 1 (Lefl) and Axin2 (Axin2), which are target genes of Wnt/beta-catenin signaling, were lower than they were in wild-type mice. This study suggests that Lgr4 is critical for ovarian somatic cell specialization via the cooperative signaling of Rspo1 and Wnt/beta-catenin.


Assuntos
Ovário/crescimento & desenvolvimento , Ovário/fisiologia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/fisiologia , Animais , Proteína Axina/biossíntese , Proteína Axina/genética , Ciclo Estral/genética , Ciclo Estral/fisiologia , Feminino , Hormônios Esteroides Gonadais/biossíntese , Fator 1 de Ligação ao Facilitador Linfoide/biossíntese , Fator 1 de Ligação ao Facilitador Linfoide/genética , Camundongos , Camundongos Knockout , Ovário/citologia , Gravidez , Diferenciação Sexual/genética , Superovulação/genética , Superovulação/fisiologia , Trombospondinas/genética , Trombospondinas/fisiologia , Via de Sinalização Wnt/genética , Ductos Mesonéfricos/crescimento & desenvolvimento
14.
Front Hum Neurosci ; 9: 417, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26236223

RESUMO

Phonological awareness is essential for reading, and is common to all language systems, including alphabetic languages and Japanese. This cognitive factor develops during childhood, and is thought to be associated with shifts in brain activity. However, the nature of this neurobiological developmental shift is unclear for speakers of Japanese, which is not an alphabetical language. The present study aimed to reveal a shift in brain functions for processing phonological information in native-born Japanese children. We conducted a phonological awareness task and examined hemodynamic activity in 103 children aged 7-12 years. While younger children made mistakes and needed more time to sort phonological information in reverse order, older children completed the task quickly and accurately. Additionally, younger children exhibited increased activity in the bilateral dorsolateral prefrontal cortex (DLPFC), which may be evidence of immature phonological processing skills. Older children exhibited dominant activity in the left compared with the right DLPFC, suggesting that they had already acquired phonological processing skills. We also found significant effects of age and lateralized activity on behavioral performance. During earlier stages of development, the degree of left lateralization appears to have a smaller effect on behavioral performance. Conversely, in later stages of development, the degree of left lateralization appears to have a stronger influence on behavioral performance. These initial findings regarding a neurobiological developmental shift in Japanese speakers suggest that common brain regions play a critical role in the development of phonological processing skills among different languages systems, such as Japanese and alphabetical languages.

15.
Chem Biol Interact ; 239: 87-99, 2015 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-26111765

RESUMO

Polyunsaturated fatty acids are highly susceptible to oxidation induced by reactive oxygen species and enzymes, leading to the formation of lipid hydroperoxides. The linoleic acid (LA)-derived hydroperoxide, 13-hydroperoxyoctadecadienoic acid (HPODE) undergoes homolytic decomposition to reactive aldehydes, 4-oxo-2(E)-nonenal (ONE), 4-hydroxy-2(E)-nonenal, trans-4,5-epoxy-2(E)-decenal (EDE), and 4-hydroperoxy-2(E)-nonenal (HPNE), which can covalently modify peptides and proteins. ONE and HNE have been shown to react with angiotensin (Ang) II (DRVYIHPF) and modify the N-terminus, Arg(2), and His(6). ONE-derived pyruvamide-Ang II (Ang P) alters the biological activities of Ang II considerably. The present study revealed that EDE and HPNE preferentially modified the N-terminus and His(6) of Ang II. In addition to the N-substituted pyrrole of [N-C4H2]-Ang II and Michael addition products of [His(6)(EDE)]-Ang II, hydrated forms were detected as major products, suggesting considerable involvement of the vicinal dihydrodiol (formed by epoxide hydration) in EDE-derived protein modification in vivo. Substantial amounts of [N-(EDE-H2O)]-Ang II isomers were also formed and their synthetic pathway might involve the tautomerization of a carbinolamine intermediate, followed by intramolecular cyclization and dehydration. The main HPNE-derived products were [His(6)(HPNE)]-Ang II and [N-(HPNE-H2O)]-Ang II. However, ONE, HNE, and malondialdehyde-derived modifications were dominant, because HPNE is a precursor of these aldehydes. A mixture of 13-HPODE and [(13)C18]-13-HPODE (1:1) was then used to determine the major modifications derived from LA peroxidation. The characteristic doublet (1:1) observed in the mass spectrum and the mass difference of the [M+H](+) doublet aided the identification of Ang P (N-terminal α-ketoamide), [N-ONE]-Ang II (4-ketoamide), [Arg(2)(ONE-H2O)]-Ang II, [His(6)(HNE)]-Ang II (Michael addition product), [N-C4H2]-Ang II (EDE-derived N-substituted pyrrole), [His(6)(HPNE)]-Ang II, [N-(9,12-dioxo-10(E)-dodecenoic acid)]-Ang II, and [His(6)(9-hydroxy-12-oxo-10(E)-decenoic acid)]-Ang II as the predominant LA-derived modifications. These modifications could represent the majority of lipid-derived modifications to peptides and proteins in biological systems.


Assuntos
Angiotensina II/química , Ácidos Linoleicos/química , Peróxidos Lipídicos/química , Aldeídos/química , Ácido Ascórbico/química , Aspartame/química , Isótopos de Carbono/química , Compostos de Epóxi/química , Isomerismo , Malondialdeído/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
16.
Endoscopy ; 47(9): 815-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25910062

RESUMO

BACKGROUND AND AIMS: The next generation of flexible endoscopy platforms such as The Master and Slave Transluminal Endoscopic Robot (MASTER) is primarily for remote control manipulation of forceps, but manipulation of the flexible endoscope itself still depends on conventional techniques. We have developed the Endoscopic Operation Robot (EOR) ver.3, which incorporates haptic feedback to provide complete remote control flexible-endoscope manipulation. The present study aimed to evaluate the performance of the EOR ver.3. METHOD: A colonoscopy training model was used with scope insertion to the cecum. Force during insertion and insertion time (seconds) to the cecum were evaluated. The data were compared by colon zone and experience level (trainee or expert). RESULTS: The mean insertion time into the cecum was 118.54 ±â€Š89.42 seconds. Stronger force and torque were required for deeper insertion of the scope. Expert and trainee endoscopists differed in the insertion time to the cecum, maximum counterclockwise torque, mean clockwise torque, and mean counterclockwise torque. CONCLUSION: The EOR ver.3 has operability with which endoscopists can easily familiarize themselves.


Assuntos
Colonoscopia/instrumentação , Procedimentos Cirúrgicos Robóticos/instrumentação , Competência Clínica , Colonoscopia/educação , Desenho de Equipamento , Humanos , Curva de Aprendizado , Procedimentos Cirúrgicos Robóticos/educação
17.
Chem Res Toxicol ; 28(1): 59-70, 2015 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-25422125

RESUMO

The hydroxyl radical-mediated oxidation of peptides and proteins constitutes a large group of post-translational modifications that can result in structural and functional changes. These oxidations can lead to hydroxylation, sulfoxidation, or carbonylation of certain amino acid residues and cleavage of peptide bonds. In addition, hydroxyl radicals can convert the N-terminus of peptides to an α-ketoamide via abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. In the present study, we identified N-terminal cyclization as a novel modification mediated by a hydroxyl radical. The reaction of angiotensin (Ang) II (DRVYIHPF) and the hydroxyl radical generated by the Cu(II)/ascorbic acid (AA) system or UV/hydrogen peroxide system produced N-terminal cyclized-Ang II (Ang C) and pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The structure of Ang C was confirmed by mass spectrometry and comparison to an authentic standard. The subsequent incubation of isolated Ang P in the presence of Cu(II)/AA revealed that Ang P was the direct precursor of Ang C. The proposed mechanism involves the formation of a nitrogen-centered (aminyl) radical, which cyclizes to form a five-membered ring containing the alkoxy radical. The subsequent ß-scission reaction of the alkoxyl radical results in the cleavage of the terminal CH3CO group. The initial aminyl radical can be stabilized by chelation to the Cu(II) ions. The affinity of Ang C toward the Ang II type 1 receptor was significantly lower than that of Ang II or Ang P. Ang C was not further metabolized by aminopeptidase A, which converts Ang II to Ang III. Hydroxyl radical-mediated N-terminal cyclization was also observed in other Ang peptides containing N-terminal alanine, arginine, valine, and amyloid ß 1-11 (DAEFRHDSGYE).


Assuntos
Amidas/química , Radical Hidroxila/química , Peptídeos/química , Cromatografia Líquida , Ciclização , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Chem Res Toxicol ; 27(4): 637-48, 2014 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-24568234

RESUMO

We have previously reported that N-terminal α-ketoamide peptides can be formed through 4-oxo-2(E)-nonenal (ONE)-derived oxidative decarboxylation of aspartic acid (Asp), which converts angiotensin (Ang) II (DRVYIHPF) to pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The pyruvamide group significantly inhibits Ang P binding to the Ang II type 1 receptor, which mediates the major biological effects of Ang II. In the present study, we found that ONE can also introduce an α-ketoamide moiety at the N-terminus of peptides containing N-terminal residues other than Asp. Subsequent investigation of alternative biosynthetic pathways for N-terminal α-ketoamide peptides revealed that hydroxyl radical-mediated formation is a much more efficient route. The proposed mechanism involves initial abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. The resulting N-terminal α-ketoamide is then converted to the D- and L-amino acids by nonenzymatic transamination in the presence of pyridoxamine (PM). The formation of the epimeric N-terminus depended on the incubation time and the concentration of PM, and increased further upon the addition of Cu(II) ions. A conversion of approximately 60% after three days of incubation was observed for Ang P. We propose that the reaction intermediate contains a prochiral α-carbon and is stabilized by the chelate effect of Cu(II) ions. The ONE- and hydroxyl radical-derived formation of N-terminal α-ketoamide and its transamination in the presence of PM were also observed in amyloid ß 1-11 (DAEFRHDSGYE), where the N-terminal Asp was converted to epimeric alanine. This suggests that these N-terminal modifications could occur in vivo and modulate the biological functions of peptides and proteins.


Assuntos
Amidas/química , Peptídeos/química , Aminação , Sequência de Aminoácidos , Cromatografia Líquida , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
19.
J Atheroscler Thromb ; 21(2): 151-60, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24096936

RESUMO

AIM: The high-density lipoprotein cholesterol(HDL-C) level is a major negative risk factor for atherosclerotic diseases dependent on various lifestyle parameters. Changes in the lifestyle of Japanese individuals over the past several decades is believed to have increased their total cholesterol levels and the incidence of cardiovascular disease in Japan. It is therefore important to assess the long-term trends in the HDL-C levels with respect to public health in the community. METHODS: In this study, accumulated data for the serum/plasma HDL-C levels published in cohort studies and obtained during health checkup programs in Japan were analyzed with respect to timedependent changes. RESULTS: The levels of HDL-C have continuously and significantly increased over the past 20 years by 12-15% according to the National Health and Nutrition Study, other cohort studies and commercially available data. On the other hand, the non-HDL-cholesterol levels demonstrated no changes or only a slight decrease during the same period. This finding is consistent with several sets of data obtained from health checkup programs. The commercially measured levels of serum apoA-I, an independent parameter of serum HDL, also showed a similar long-term increase, supporting the above findings. CONCLUSION: We concluded that the serum/plasma HDL concentrations in Japanese individuals, selectively, have increased continuously and significantly over the past 20 years or more. The reasons for this phenomenon and the consequent public health outcomes have yet to be investigated.


Assuntos
Biomarcadores/sangue , Doenças Cardiovasculares/epidemiologia , HDL-Colesterol/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Apolipoproteína A-I/sangue , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/etiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Seguimentos , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Incidência , Lactente , Recém-Nascido , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Programas Nacionais de Saúde , Prognóstico , Medição de Risco , Adulto Jovem
20.
Anal Biochem ; 449: 59-67, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24361714

RESUMO

Metabolic activation of drugs frequently generates electrophilic products that may undergo covalent binding to biological macromolecules, such as proteins and DNA. The resulting covalent adducts are of considerable concern in drug discovery and development. Several strategies for assessing the potential risks of candidate drugs have been reported. Of these, glutathione trapping is the most commonly used method together with mass spectrometry. Furthermore, drug-mediated protein modifications have been studied using serum albumin and CYP enzymes to clarify target amino acids and mechanism-based inhibition, respectively. In this article, we introduce a practical way to screen drug-mediated protein modifications. The method, referred to as "predicted multiple selected reaction monitoring," is based on the selected reaction monitoring (SRM) strategy, but targets all possible chemically modified tryptic peptides. The creation of SRM lists may require patience; however, this strategy could facilitate more sensitive screening compared with the common strategy of data-dependent product ion scanning. Ketoprofen-N-hydroxysuccinimidyl ester (equivalent to glucuronide) and N-acetyl-p-benzoquinone imine (NAPQI) were allowed to react with human serum albumin as a model experiment. Using this strategy, 11 ketoprofen-adduction sites (at Lys(137, 195, 199, 212, 351, 402, 432, 436, 525, 536, and 541)) and 1 NAPQI-adduction site (at Cys(34)) were easily identified.


Assuntos
Benzoquinonas/metabolismo , Iminas/metabolismo , Cetoprofeno/análogos & derivados , Albumina Sérica/química , Albumina Sérica/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Cisteína/análise , Cisteína/metabolismo , Humanos , Cetoprofeno/metabolismo , Lisina/análise , Lisina/metabolismo , Espectrometria de Massas/métodos , Dados de Sequência Molecular , Preparações Farmacêuticas/metabolismo , Ligação Proteica
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