Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Cephalalgia ; 43(5): 3331024231173354, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37138462

RESUMEN

BACKGROUND: Recent pharmacovigilance studies suggested that cluster headache could be a potential adverse effect after coronavirus disease-2019 (COVID-19) vaccination; however, the possibility of coincidence could not be excluded. Detailed case studies might help elucidate their potential link and implicate potential pathogenic mechanisms. METHODS: Patients who developed cluster headache in close temporal relationship to COVID-19 vaccination were identified from two tertiary medical centers in Japan and Taiwan respectively through 2021-2022. Detailed characteristics of the headaches and time between the onset of the index cluster episode and antecedent COVID-19 vaccination were reported. In patients with previous cluster headaches, the duration from previous bout was also recorded. RESULTS: Six patients with new cluster headache bout 3-17 days after COVID-19 vaccination were identified. Two of them were de novo cases. The others either had been attack-free for a long time or developed new cluster bout in seasons atypical to prior bouts. The vaccines included mRNA, viral vector, or protein subunit vaccines. CONCLUSIONS: COVID-19 vaccines, regardless of vaccine types, may elicit de novo or relapse of cluster headache. Future studies are needed to confirm the potential causality and explore the potential pathogenic mechanism.


Asunto(s)
COVID-19 , Cefalalgia Histamínica , Humanos , Vacunas contra la COVID-19/efectos adversos , COVID-19/prevención & control , Vacunación/efectos adversos , Cefalea/etiología
2.
Cephalalgia ; 42(3): 266-272, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34407651

RESUMEN

BACKGROUND: Headache is an adverse event of coronavirus 2019 (COVID-19) vaccination. Whether patients with history of headache suffer more from vaccination-induced headaches is unknown. We aimed to uncover if headache patients develop more headaches after COVID-19 mRNA vaccination than healthy controls. METHODS: We performed a questionnaire survey for nursing staff in our hospital from April to May 2021. Based on baseline characteristics, we divided the participants into migraine, non-migrainous headache, and healthy control, and examined the occurrence and features of headache after COVID-19 vaccinations. RESULTS: We included 171 participants (15.2% migraine and 24.6% non-migrainous headache). Headache incidence after vaccinations was significantly higher in the migraine (69.2%) and non-migrainous headache (71.4%) groups than in the healthy control (37.9%) group. The incidence of headaches was significantly higher after the second dose compared to the first (45.6% vs. 20.5%). CONCLUSION: Migraineurs and non-migrainous headache participants developed more headaches compared to the healthy controls after COVID-19 vaccination.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Estudios Transversales , Cefalea/epidemiología , Cefalea/etiología , Humanos , Incidencia , Vacunación/efectos adversos
3.
BMC Neurol ; 22(1): 512, 2022 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-36585619

RESUMEN

OBJECTIVE: To evaluate the efficacy and safety of galcanezumab in patients with migraine in a real-world setting in Japan. BACKGROUND: Galcanezumab is the first anti-calcitonin gene-related peptide monoclonal antibody approved in Japan. To the best of our knowledge, no real-world studies on galcanezumab have been published in any international journal from Japan. METHODS: We retrospectively examined patients with migraine who received three doses of galcanezumab between August 2021 and February 2022 at the Keio University Hospital. We assessed changes in monthly migraine days, responder rate, and migraine-associated and premonitory symptoms. We also investigated injection site reactions and adverse events. RESULTS: Fifty-two patients received three doses of galcanezumab during the study period. Compared with those at baseline, the monthly migraine days decreased by 5.9 days (95% confidence interval, 4.2-7.7) at 3 months. The 50% responder rate was 61.5% at 3 months. A total of 64.9%, 50.0%, and 63.9% of patients showed improvement in the severity of photophobia, phonophobia, and nausea/vomiting, respectively. Premonitory symptoms without subsequent headache were reported in 62.5% of patients. Moreover, injection site reaction was the most common adverse event (34.6%). CONCLUSION: This study revealed the efficacy and safety of galcanezumab for migraineurs in Japan. Galcanezumab also improved migraine-associated symptoms. However, despite a reduction in headaches, premonitory symptoms without subsequent headache were reported in > 50% of the patients at 3 months.


Asunto(s)
Anticuerpos Monoclonales Humanizados , Anticuerpos Monoclonales , Trastornos Migrañosos , Humanos , Anticuerpos Monoclonales/efectos adversos , Método Doble Ciego , Cefalea/tratamiento farmacológico , Japón/epidemiología , Trastornos Migrañosos/tratamiento farmacológico , Estudios Retrospectivos , Resultado del Tratamiento
5.
J Neurol Sci ; 456: 122851, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38181653

RESUMEN

BACKGROUND: We previously developed an optimized q-space diffusional MRI technique (normalized leptokurtic diffusion [NLD] map) to delineate the demyelinated lesions of multiple sclerosis (MS) patients. Herein, we evaluated the utility of NLD maps to discern the white matter abnormalities in normal-appearing white matter (NAWM) and the abnormalities' possible associations with physical and cognitive disabilities in MS. METHODS: We conducted a retrospective observational study of MS patients treated at our hospital (Jan. 2012 to Dec. 2022). Clinical and MRI data were collected; Processing Speed Test (PST) data were obtained when possible. For a quantitative analysis of the NLD maps, we calculated the NLD index as GVROI/GVREF, where GV is a mean grayscale value in the regions of interest (ROIs) and the reference area (REF; cerebrospinal fluid). RESULTS: One hundred-one individuals with MS were included. The lower corpus callosum and non-lesional WM NLD index were associated with worse Expanded Disability Status Scale (EDSS) and PST scores. The NLD indexes in the corpus callosum (p < 0.0001) and non-lesional white matter (p < 0.0001) were significantly reduced in progressive MS compared to relapsing-remitting MS. We categorized MS severity as moderate/severe (EDSS score ≥ 4 points) and mild (EDSS score < 4 points). The NLD indexes in the corpus callosum (p < 0.0001) and non-lesional white matter (p < 0.0001) were significantly lower in the moderate/severe MS group compared to the mild MS group. CONCLUSION: The NLD map revealed abnormalities in the non-lesional white matter, providing valuable insights for evaluating manifestations in MS patients.


Asunto(s)
Esclerosis Múltiple Recurrente-Remitente , Esclerosis Múltiple , Sustancia Blanca , Humanos , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/patología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Imagen de Difusión por Resonancia Magnética , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagen , Esclerosis Múltiple Recurrente-Remitente/patología , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología
6.
Front Immunol ; 15: 1382320, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38711503

RESUMEN

Myasthenia gravis (MG), primarily caused by acetylcholine receptor (AChR) autoantibodies, is a chronic autoimmune disorder causing severe muscle weakness and fatigability. In particular, seronegative MG constitutes 10%-15% of MG cases and presents diagnostic challenges especially in early-onset female patients who often show severe disease and resistance to immunosuppressive therapy. Furthermore, the immunopathology of seronegative MG remains unclear. Thus, in this study, we aimed to elucidate the pathogenic mechanism of seronegative MG using scRNA-seq analysis and plasma proteome analysis; in particular, we investigated the relationship between immune dysregulation status and disease severity in refractory seronegative MG. Employing single-cell RNA-sequencing and plasma proteome analyses, we analyzed peripheral blood samples from 30 women divided into three groups: 10 healthy controls, 10 early-onset AChR-positive MG, and 10 refractory early-onset seronegative MG patients, both before and after intravenous immunoglobulin treatment. The disease severity was evaluated using the MG-Activities of Daily Living (ADL), MG composite (MGC), and revised 15-item MG-Quality of Life (QOL) scales. We observed numerical abnormalities in multiple immune cells, particularly B cells, in patients with refractory seronegative MG, correlating with disease activity. Notably, severe MG cases had fewer regulatory T cells without functional abnormalities. Memory B cells were found to be enriched in peripheral blood cells compared with naïve B cells. Moreover, plasma proteome analysis indicated significantly lower plasma protein levels of soluble CD22, expressed in the lineage of B-cell maturation (including mature B cells and memory B cells), in refractory seronegative MG patients than in healthy donors or patients with AChR-positive MG. Soluble CD22 levels were correlated with disease severity, B-cell frequency, and RNA expression levels of CD22. In summary, this study elucidates the immunopathology of refractory seronegative MG, highlighting immune disorders centered on B cells and diminished soluble CD22 levels. These insights pave the way for novel MG treatment strategies focused on B-cell biology.


Asunto(s)
Linfocitos B , Miastenia Gravis , Lectina 2 Similar a Ig de Unión al Ácido Siálico , Humanos , Miastenia Gravis/inmunología , Miastenia Gravis/sangre , Femenino , Adulto , Linfocitos B/inmunología , Lectina 2 Similar a Ig de Unión al Ácido Siálico/inmunología , Persona de Mediana Edad , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Inmunoglobulinas Intravenosas/uso terapéutico , Receptores Colinérgicos/inmunología , Índice de Severidad de la Enfermedad , Adulto Joven , Proteoma
7.
Neurol Neuroimmunol Neuroinflamm ; 11(3): e200234, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38657185

RESUMEN

BACKGROUND AND OBJECTIVES: Anti-IgLON5 disease is an autoimmune neurodegenerative disorder characterized by various phenotypes, notably sleep and movement disorders and tau pathology. Although the disease is known to be associated with the neuronal cell adhesion protein IgLON5, the physiologic function of IgLON5 remains elusive. There are conflicting views on whether autoantibodies cause loss of function, activation of IgLON5, or inflammation-associated neuronal damage, ultimately leading to the disease. We generated IgLON5 knockout (-/-) mice to investigate the functions of IgLON5 and elucidate the pathomechanism of anti-IgLON5 disease. METHODS: IgLON5 knockout (-/-) mice underwent behavioral tests investigating motor function, psychiatric function (notably anxiety and depression), social and exploratory behaviors, spatial learning and memory, and sensory perception. Histologic analysis was conducted to investigate tau aggregation in mice with tauopathy. RESULTS: IgLON5-/- mice had poorer performance in the wire hang and rotarod tests (which are tests for motor function) than wild-type mice. Moreover, IgLON5-/- mice exhibited decreased anxiety-like behavior and/or hyperactivity in behavior tests, including light/dark transition test and open field test. IgLON5-/- mice also exhibited poorer remote memory in the contextual fear conditioning test. However, neither sleeping disabilities assessed by EEG nor tau aggregation was detected in the knockout mice. DISCUSSION: These results suggest that IgLON5 is associated with activity, anxiety, motor ability, and contextual fear memory. Comparing the various phenotypes of anti-IgLON5 disease, anti-IgLON5 disease might partially be associated with loss of function of IgLON5; however, other phenotypes, such as sleep disorders and tau aggregation, can be caused by gain of function of IgLON5 and/or neuronal damage due to inflammation. Further studies are needed to elucidate the role of IgLON5 in the pathogenesis of anti-IgLON5 diseases.


Asunto(s)
Moléculas de Adhesión Celular Neuronal , Ratones Noqueados , Fenotipo , Animales , Masculino , Ratones , Ansiedad/inmunología , Autoanticuerpos/sangre , Conducta Animal/fisiología , Moléculas de Adhesión Celular Neuronal/deficiencia , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Tauopatías/fisiopatología , Tauopatías/inmunología , Humanos
8.
Intern Med ; 2023 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-37612080

RESUMEN

Cerebral venous thrombosis (CVT) is challenging to diagnose, as it presents with variable symptoms. We encountered a complicated case of CVT that mimicked limbic encephalitis due to sensory aphasia. Based on the characteristic magnetic resonance imaging findings, this 72-year-old Japanese man was later confirmed to have CVT, the cause of which was periodontitis due to Eikenella corrodens, a Gram-negative facultative anaerobic that is part of the mouth's normal flora. The symptoms improved without sequelae following anticoagulation treatment and antibiotics. Clinicians should consider CVT as a differential diagnosis when unexplainable neurological symptoms suggesting limbic encephalitis are observed.

9.
Intern Med ; 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37722898

RESUMEN

Objective This study examined the prevalence of migraine in nurses in Japan, which, to our knowledge, has not been documented in English. Methods From April to May 2021, we administered a questionnaire to 229 nurses working at Keio University Hospital to investigate the prevalence and characteristics of headache among nurses in Japan. Headaches were classified as migraine or tension-type headache (TTH) based on the International Classification of Headache Disorders-3 (ICHD-3). Results In total, 80 patients (34.9%) had primary headaches, including 47 (20.5%) with migraine and probable migraine and 33 (14.4%) with TTH and probable TTH. We found a significant difference in the Numerical Rating Scale score, nausea and vomiting, photophobia, phonophobia, and aggravation by routine physical activity between migraine and TTH. The specificities for a migraine diagnosis were 100% and 93.9% for nausea/vomiting and photophobia, respectively. Only 8.8% of patients had their headaches diagnosed by a physician. Conclusion Migraines have a high prevalence (>20%) among nurses and are often under-diagnosed. In many cases, headache-associated symptoms are more important than laterality or other characteristics for the diagnosis. Many nurses are treated for headaches without a correct diagnosis. Further education regarding primary headaches may be necessary for health practitioners as well as society.

10.
Phys Rev Lett ; 108(1): 017203, 2012 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-22304283

RESUMEN

The performance of spintronic devices critically depends on three material parameters, namely, the spin polarization in the current (P), the intrinsic Gilbert damping (α), and the coefficient of the nonadiabatic spin transfer torque (ß). However, there has been no method to determine these crucial material parameters in a self-contained manner. Here we show that P, α, and ß can be simultaneously determined by performing a single series of time-domain measurements of current-induced spin wave dynamics in a ferromagnetic film.

11.
PLoS One ; 17(9): e0273720, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36067203

RESUMEN

Myasthenia gravis (MG) is the most common autoimmune neuromuscular disorder, and is more common in women than in men. Anemia is also more common in women. The purpose of this study was to investigate factors associated with anemia and the negative impact of anemia in female MG patients. We investigated factors related to MG and anemia in 215 female patients with MG, who were attending the MG clinic of Keio Hospital between January and December 2021. We statistically evaluated clinical factors related to anemia in patients with and without anemia. Eighty-five patients (40%) had anemia in the past, and 130 patients did not have anemia in the past. There were no significant differences in age at study, age at MG onset, body mass index, or frequency of autoantibodies between the anemia and non-anemia groups. MG severity evaluated by the MG Foundation of America classification was greater in the anemia group than in the non-anemia group. History of anemia was associated with immunosuppressive treatment, such as prednisolone and calcineurin inhibitor treatment. There was a correlation between hemoglobin levels and the MG-quality of life score. Long term immunosuppressive therapy can cause anemia in female MG patients. Anemia may negatively affect the quality of life of female MG patients.


Asunto(s)
Anemia , Miastenia Gravis , Anemia/complicaciones , Anemia/tratamiento farmacológico , Autoanticuerpos , Inhibidores de la Calcineurina/uso terapéutico , Femenino , Humanos , Inmunosupresores/uso terapéutico , Masculino , Miastenia Gravis/tratamiento farmacológico , Calidad de Vida
12.
J Neuroimmunol ; 371: 577950, 2022 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-35994947

RESUMEN

Thymoma with immunodeficiency is sometimes accompanied by myasthenia gravis (MG), but the clinical characteristics have not been elucidated. This study aimed to characterize its clinical and immunological features. Of the 132 thymoma-associated MG patients, 9 patients presented with immunodeficiency. All suffered from severe pneumonia, and most had invasive thymoma and autoimmune disorders. DRB1*08:03 and DQB1*06:01 alleles were frequently detected. Compared to group without immunodeficiency, they showed no significant differences in the severity of MG, significantly lower IgG concentrations and higher mortality rate. Thymoma-associated MG with immunodeficiency is a distinct subset requiring special attention to prevent infection during the follow-up period.


Asunto(s)
Miastenia Gravis , Timoma , Neoplasias del Timo , Alelos , Humanos , Miastenia Gravis/complicaciones , Timectomía , Timoma/complicaciones , Neoplasias del Timo/complicaciones
13.
Phys Rev Lett ; 106(17): 176601, 2011 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-21635054

RESUMEN

We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the noninteracting model, reaching 1.8±0.2.

14.
Org Biomol Chem ; 9(24): 8313-20, 2011 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-22068299

RESUMEN

In this study, we investigated the stability and structure of artificial base pairs that contain cyclohexyl rings. The introduction of a single pair of isopropylcyclohexanes into the middle of DNA slightly destabilized the duplex. Interestingly, as the number of the "base pairs" increased, the duplex was remarkably stabilized. A duplex with six base pairs was even more stable than one containing six A-T pairs. Thermodynamic analysis revealed that changes in entropy and not enthalpy contributed to duplex stability, demonstrating that hydrophobic interactions between isopropyl groups facilitated the base pairing, and thus stabilized the duplex. NOESY of a duplex containing an isopropylcyclohexane-methylcyclohexane pair unambiguously demonstrated its "pairing" in the duplex because distinct NOEs between the protons of cyclohexyl moieties and imino protons of both of the neighboring natural base pairs were observed. CD spectra of duplexes tethering cyclohexyl moieties also showed a positive-negative couplet that is characteristic of the B-form DNA duplex. Taken together, these results showed that cyclohexyl moieties formed base pairs in the DNA duplex without severely disturbing the helical structure of natural DNA. Next, we introduced cyclohexyl base pairs between pyrene and nucleobases as an "insulator" that suppresses electron transfer between them. We found a massive increase in the quantum yield of pyrene due to the efficient shielding of pyrene from nucleobases. The cyclohexyl base pairs reported here have the potential to prepare highly fluorescent labeling agents by multiplying fluorophores and insulators alternately into DNA duplexes.


Asunto(s)
Ciclohexanos/química , ADN/química , Fluorescencia , Pirenos/química , Emparejamiento Base , Modelos Moleculares , Conformación Molecular
15.
Gynecol Oncol Rep ; 37: 100799, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34150974

RESUMEN

Locally advanced cervical cancer occasionally induces pyometra, but there have been no reports of meningitis where pyometra is the cause of infection. Here, we report a case of Listeria monocytogenes meningitis related to pyometra during concurrent chemoradiotherapy (CCRT) in a cervical cancer patient. The patient, a 77-year-old woman, was diagnosed with Stage IIB (FIGO 2018) cervical adenocarcinoma, and CCRT was initiated. Pyometra was exacerbated during CCRT, and after her first brachytherapy, she presented at our hospital with fever and decreased consciousness level. After admission to the Intensive Care Unit, the patient lost consciousness and experienced frequent seizures; tracheal intubation was required. Whole-body computed tomography revealed pyometra; therefore, transvaginal removal of the abscess was performed. Laboratory tests and vital signs indicated septic shock, and meropenem was administered. L. monocytogenes was detected in the abscess from the uterine cavity and the blood cultures on the third day of hospitalization. A lumbar puncture was performed on the same day to investigate whether the patient had meningitis. A FilmArray meningitis/encephalitis panel test of the spinal fluid revealed L. monocytogenes. After the diagnosis of meningitis with L. monocytogenes, ampicillin and gentamicin were started, and the blood test results gradually improved. Five months after the initial episode, her consciousness recovered, however she still received mechanical ventilatory support. L. monocytogenes infections can occur in patients undergoing chemotherapy, even without the use of steroids or immunosuppressive agents. In cases with pyometra, intrauterine manipulation can increase the risk of severe infection.

16.
Biochim Biophys Acta ; 1787(9): 1106-11, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19265669

RESUMEN

125I-labeled (trifluoromethyl)phenyldiazirinyl acetogenin, [125I]TDA, a photoaffinity labeling probe of acetogenin, photo-cross-links to the ND1 subunit of bovine heart mitochondrial NADH-ubiquinone oxidoreductase (complex I) with high specificity [M. Murai, A. Ishihara, T. Nishioka, T. Yagi, and H. Miyoshi, (2007) The ND1 subunit constructs the inhibitor binding domain in bovine heart mitochondrial complex I, Biochemistry 46 6409-6416.]. To identify the binding site of [125I]TDA in the ND1 subunit, we carried out limited proteolysis of the subunit cross-linked by [125I]TDA using various proteases and carefully analyzed the fragmentation patterns. Our results revealed that the cross-linked residue is located within the region of the 4th to 5th transmembrane helices (Val144-Glu192) of the subunit. It is worth noting that an excess amount of short-chain ubiquinones such as ubiquinone-2 (Q2) and 2-azido-Q2 suppressed the cross-linking by [125I]TDA in a concentration-dependent way. Although the question of whether the binding sites for ubiquinone and different inhibitors in complex I are identical remains to be answered, the present study provided, for the first time, direct evidence that an inhibitor (acetogenin) and ubiquinone competitively bind to the enzyme. Considering the present results along with earlier photoaffinity labeling studies, we propose that not all inhibitors acting at the terminal electron transfer step of complex I necessarily bind to the ubiquinone binding site itself.


Asunto(s)
Acetogeninas/metabolismo , Bovinos , Complejo I de Transporte de Electrón/química , Complejo I de Transporte de Electrón/metabolismo , Animales , Sitios de Unión , Electroforesis en Gel de Poliacrilamida , Mitocondrias Cardíacas , Modelos Biológicos , Unión Proteica
17.
J Am Chem Soc ; 132(17): 6223-30, 2010 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-20380398

RESUMEN

By using perylene and pyrene as fluorophores, we have designed various fluorophore assemblies that mimic inorganic quantum dots in showing a high emission intensity, a large Stokes' shift, and a modulated emission maximum. For this purpose, we utilized two kinds of duplex motifs with D-threoninols as scaffolds: cluster and interstrand-wedged motifs. In the cluster motif, fluorophores are introduced into both strands to produce tentative pseudo-"base-pairs", in which the dyes strongly interact with each other and form dimers, trimers, or hexamers. In the interstrand-wedged motif, a base-pair is inserted between the fluorophores to suppress their direct interaction. These two motifs were applied to accumulate dyes within a DNA duplex, depending on their emission properties. Since pyrene exhibits strong excimer emission, the emission at 500 nm of a pyrene cluster motif strongly increased as the number of accumulated dyes increased, whereas the interstrand-wedged motif quenched pyrene monomer emission. In contrast, assembled perylenes, which are mostly quenched by dimerization, showed intense monomer emission in the interstrand-wedged motif, whereas perylene cluster motifs strongly suppressed perylene emission. These two motifs were then applied to the heteroassembly of pyrenes and perylenes. Both a large Stokes' shift and a modulation of the emission maximum, which are also characteristics of inorganic quantum dots, were successfully realized using fluorescent resonance energy transfer (FRET) and exciplex formation. These fluorophore assemblies thus obtained could be enzymatically ligated to longer DNA, demonstrating that this technique has the potential to be a versatile labeling agent for biomolecules.


Asunto(s)
ADN/química , Colorantes Fluorescentes/química , Perileno/química , Pirenos/química , Puntos Cuánticos , Animales , Transferencia Resonante de Energía de Fluorescencia , Humanos , Insulina/genética
18.
Chemistry ; 16(38): 11554-7, 2010 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-20799301

RESUMEN

Quenched: Perylenediimide (PDI) is highly quenched by nucleobases, which greatly restricts its application as a fluorescent probe. Here, we propose "insulator base pairs" tethering cyclohexane ring through D-threoninol. When "insulator base pairs" were inserted between PDI and nucleobases, the quantum yield of PDI drastically increased several thousand-fold. The "insulator base pairs" reported here also have the potential to increase the quantum yields of other fluorophores.


Asunto(s)
ADN/química , Imidas/química , Perileno/análogos & derivados , Emparejamiento Base , Ciclohexanos/química , ADN/metabolismo , Colorantes Fluorescentes , Perileno/química , Teoría Cuántica , Temperatura de Transición
19.
Chemistry ; 16(8): 2479-86, 2010 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-20066689

RESUMEN

To increase the apparent Stokes' shift of perylene, pyrene (donor) and perylene (acceptor) were assembled in a DNA duplex to achieve the efficient fluorescence resonance energy transfer (FRET) from pyrene to perylene. Multiple donors were introduced in the vicinity of acceptors through D-threoninol and natural base pairs were inserted between the dyes. Accordingly, donors and acceptors could be accumulated inside the DNA without forming an undesired excimer/exciplex. When two pyrene moieties were located in proximity to one perylene with one base pair inserted between them, efficient FRET occurred within the duplex. Thus, strong emission at 460 nm was observed from perylene when excited at 345 nm at which pyrene has its absorption. The apparent Stokes' shift became as large as 115 nm with a high apparent FRET efficiency (Phi>1). However, the introduction of more than two pyrenes did not enhance the fluorescence intensity of perylene, due to the short Förster radius (R(0)) of the donor pyrene. Next, this FRET system was used to enlarge the Stokes' shift of the DNA probe, which can discriminate a one-base deletion mutant from wild type with a model system by incorporation of multiple donors into DNA. Two perylene moieties were tethered to the DNA on both sides of the intervening base, and two pyrenes were further inserted in the vicinity of the perylenes as an antenna. Hybridization of this FRET probe with a fully matched DNA allowed monomer emission of perylene when the pyrenes were excited. In contrast, excimer emission was generated by hybridization with a one-base deletion mutant. Thus, the apparent Stokes' shift was enhanced without loss of efficiency in the detection of the deletion mutant.


Asunto(s)
Sondas de ADN/química , ADN/química , Pirenos/química , Secuencia de Aminoácidos , Emparejamiento Base , Sondas de ADN/síntesis química , Fluorescencia , Transferencia Resonante de Energía de Fluorescencia , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Temperatura
20.
Biochemistry ; 48(4): 688-98, 2009 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-19128036

RESUMEN

The diverse inhibitors of bovine heart mitochondrial complex I (NADH-ubiquinone oxidoreductase) are believed to share a common large binding domain with partially overlapping sites, though it remains unclear how these binding sites relate to each other. To obtain new insight into the inhibitor binding domain in complex I, we synthesized a photoreactive azidoquinazoline {[(125)I]-6-azido-4-(4-iodophenethylamino)quinazoline, [(125)I]AzQ}, in which a photolabile azido group was introduced into the toxophoric quinazoline ring to allow specific cross-linking, and carried out a photoaffinity labeling study using bovine heart submitochondrial particles. Analysis of the photo-cross-linked proteins by peptide mass fingerprinting and immunoblotting revealed that [(125)I]AzQ specifically binds to the 49 kDa and ND1 subunits with a frequency of approximately 4:1. The cross-linking was completely blocked by excess amounts of other inhibitors such as acetogenin and fenpyroximate. Considerable cross-linking was also detected in the ADP/ATP carrier and 3-hydroxybutyrate dehydrogenase, though it was not associated with dysfunction of the two proteins. The partial proteolysis of the [(125)I]AzQ-labeled 49 kDa subunit by V8-protease and N-terminal sequencing of the resulting peptides revealed that the amino acid residue cross-linked by [(125)I]AzQ is within the sequence region Thr25-Glu143 (118 amino acids). Furthermore, examination of fragment patterns generated by exhaustive digestion of the [(125)I]AzQ-labeled 49 kDa subunit by V8-protease, lysylendopeptidase, or trypsin strongly suggested that the cross-linked residue is located within the region Asp41-Arg63 (23 amino acids). The present study has revealed, for the first time, the inhibitor binding site in complex I at the sub-subunit level.


Asunto(s)
Complejo I de Transporte de Electrón/metabolismo , Mitocondrias Cardíacas/enzimología , Etiquetas de Fotoafinidad/metabolismo , Quinazolinas/antagonistas & inhibidores , Secuencia de Aminoácidos , Animales , Sitios de Unión/genética , Sitios de Unión/fisiología , Bovinos , Cristalografía por Rayos X , Complejo I de Transporte de Electrón/química , Complejo I de Transporte de Electrón/genética , Mitocondrias Cardíacas/genética , Datos de Secuencia Molecular , Estructura Terciaria de Proteína/genética , Estructura Terciaria de Proteína/fisiología , Quinazolinas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA