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1.
J Med Virol ; 96(5): e29653, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38712746

RESUMEN

The magnitude of the effect of human T-lymphotropic virus 1 (HTLV-1) infection on uveitis remains unclear. We conducted a cross-sectional study in a highly endemic area of HTLV-1 in Japan. The study included 4265 residents (men, 39.2%), mostly middle-aged and older individuals with a mean age of 69.9 years, who participated in our surveys between April 2016 and September 2022. We identified HTLV-1 carriers by screening using chemiluminescent enzyme immunoassays and confirmatory tests, and the proportion of carriers was 16.1%. Participants with uveitis were determined from the medical records of all hospitals and clinics where certified ophthalmologists practiced. We conducted logistic regression analyses in an age- and sex-adjusted model to compute the odds ratio (OR) and 95% confidence interval (CI) of uveitis according to HTLV-1 infection status. Thirty-two (0.8%) participants had uveitis. For HTLV-1 carriers, the age- and sex-adjusted OR (95% CI) of uveitis was 3.27 (1.57-6.72) compared with noncarriers. In conclusion, HTLV-1 infection was associated with a higher risk of uveitis among mostly middle-aged and older Japanese residents in a highly endemic HTLV-1 area. Our findings suggest that physicians who treat HTLV-1 carriers should assess ocular symptoms, and those who diagnose patients with uveitis should consider HTLV-1 infection.


Asunto(s)
Portador Sano , Infecciones por HTLV-I , Virus Linfotrópico T Tipo 1 Humano , Uveítis , Humanos , Femenino , Masculino , Japón/epidemiología , Uveítis/epidemiología , Uveítis/virología , Infecciones por HTLV-I/epidemiología , Estudios Transversales , Anciano , Persona de Mediana Edad , Prevalencia , Virus Linfotrópico T Tipo 1 Humano/aislamiento & purificación , Portador Sano/epidemiología , Portador Sano/virología , Adulto , Anciano de 80 o más Años , Enfermedades Endémicas , Adulto Joven
2.
Chem Pharm Bull (Tokyo) ; 70(5): 351-358, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35491191

RESUMEN

Oxaliplatin (l-OHP) is a third-generation platinum (Pt) agent approved for the treatment of patients with advanced colorectal cancer. Despite the fact that l-OHP has shown clinical therapeutic efficacy and better tolerability compared with other Pt agents, the use of l-OHP has been limited to clinical settings because of dose-limiting side effects such as cumulative neurotoxicity and acute dysesthesias, which can be severe. In preclinical and clinical studies, our group and several others have attempted the delivery of l-OHP to solid tumors via encapsulation in PEGylated liposomes. Herein, we review these attempts.


Asunto(s)
Antineoplásicos , Neoplasias Colorrectales , Antineoplásicos/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Humanos , Liposomas , Compuestos Organoplatinos/uso terapéutico , Oxaliplatino , Polietilenglicoles
3.
Mol Pharm ; 15(2): 403-409, 2018 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-29287147

RESUMEN

Microsynchrotron radiation X-ray fluorescence spectrometry (µ-SR-XRF) is an X-ray procedure that utilizes synchrotron radiation as an excitation source. µ-SR-XRF is a rapid, nondestructive technique that allows mapping and quantification of metals and biologically important elements in cell or tissue samples. Generally, the intratumor distribution of nanocarrier-based therapeutics is assessed by tracing the distribution of a labeled nanocarrier within tumor tissue, rather than by tracing the encapsulated drug. Instead of targeting the delivery vehicle, we employed µ-SR-XRF to visualize the intratumoral microdistribution of oxaliplatin (l-OHP) encapsulated within PEGylated liposomes. Tumor-bearing mice were intravenously injected with either l-OHP-containing PEGylated liposomes (l-OHP liposomes) or free l-OHP. The intratumor distribution of l-OHP within tumor sections was determined by detecting the fluorescence of platinum atoms, which are the main elemental components of l-OHP. The l-OHP in the liposomal formulation was localized near the tumor vessels and accumulated in tumors at concentrations greater than those seen with the free form, which is consistent with the results of our previous study that focused on fluorescent labeling of PEGylated liposomes. In addition, repeated administration of l-OHP liposomes substantially enhanced the tumor accumulation and/or intratumor distribution of a subsequent dose of l-OHP liposomes, presumably via improvements in tumor vascular permeability, which is also consistent with our previous results. In conclusion, µ-SR-XRF imaging efficiently and directly traced the intratumor distribution of the active pharmaceutical ingredient l-OHP encapsulated in liposomes within tumor tissue. µ-SR-XRF imaging could be a powerful means for estimating tissue distribution and even predicting the pharmacological effect of nanocarrier-based anticancer metal compounds.


Asunto(s)
Antineoplásicos/farmacocinética , Imagen Molecular/métodos , Neoplasias/diagnóstico por imagen , Oxaliplatino/farmacocinética , Espectrometría por Rayos X/métodos , Animales , Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Portadores de Fármacos/química , Composición de Medicamentos/métodos , Estudios de Factibilidad , Humanos , Liposomas , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Nanopartículas/química , Neoplasias/tratamiento farmacológico , Oxaliplatino/administración & dosificación , Polietilenglicoles/química , Distribución Tisular
4.
Chaos ; 28(8): 083119, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30180643

RESUMEN

Some layered silicates are composed of positive ions, surrounded by layers of ions with opposite sign. Mica muscovite is a particularly interesting material, because there exist fossil and experimental evidence for nonlinear excitations transporting localized energy and charge along the cation rows within the potassium layers. This evidence suggests that there are different kinds of excitations with different energies and properties. Some of the authors proposed recently a one-dimensional model based on physical principles and the silicate structure. The main characteristic of the model is that it has a hard substrate potential and two different repulsion terms, between ions and nuclei. In a previous work with this model, it was found the propagation of crowdions, i.e., lattice kinks in a lattice with substrate potential that transport mass and charge. They have a single specific velocity and energy coherent with the experimental data. In the present work, we perform a much more thorough search for nonlinear excitations in the same model using the pseudospectral method to obtain exact nanopteron solutions, which are single kinks with tails, crowdions, and bi-crowdions. We analyze their velocities, energies, and stability or instability and the possible reasons for the latter. We relate the different excitations with their possible origin from recoils from different beta decays and with the fossil tracks. We explore the consequences of some variation of the physical parameters because their values are not perfectly known. Through a different method, we also have found stationary and moving breathers, that is, localized nonlinear excitations with an internal vibration. Moving breathers have small amplitude and energy, which is also coherent with the fossil evidence.

5.
Cancer Sci ; 108(9): 1864-1869, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28643902

RESUMEN

Immune modulation of the tumor microenvironment has been reported to participate in the therapeutic efficacy of many chemotherapeutic agents. Recently, we reported that liposomal encapsulation of oxaliplatin (l-OHP) within PEGylated liposomes conferred a superior antitumor efficacy to free l-OHP in murine colorectal carcinoma-bearing mice through permitting preferential accumulation of the encapsulated drug within tumor tissue. However, the contribution of the immune-modulatory properties of liposomal l-OHP and/or free l-OHP to the overall antitumor efficacy was not elucidated. In the present study, therefore, we investigated the effect of liposomal encapsulation of l-OHP within PEGylated liposomes on the antitumor immunity in both immunocompetent and immunodeficient mice. Liposomal l-OHP significantly suppressed the growth of tumors implanted in immunocompetent mice, but not in immunodeficient mice. In immunocompetent mice, liposomal l-OHP increased the tumor MHC-1 level and preserved antitumor immunity through decreasing the number of immune suppressor cells, including regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages, which collectively suppress CD8+ T cell-mediated tumor cells killing. In contrast, free l-OHP ruined antitumor immunity. These results suggest that the antitumor efficacy of liposomal l-OHP is attributed, on the one hand, to its immunomodulatory effect on tumor immune microenvironment that is superior to that of free l-OHP, and on the other hand, to its direct cytotoxic effect on tumor cells.


Asunto(s)
Antineoplásicos/administración & dosificación , Neoplasias Colorrectales/inmunología , Factores Inmunológicos/administración & dosificación , Compuestos Organoplatinos/administración & dosificación , Animales , Línea Celular Tumoral , Neoplasias Colorrectales/tratamiento farmacológico , Ensayos de Selección de Medicamentos Antitumorales , Antígenos de Histocompatibilidad Clase I/metabolismo , Liposomas , Masculino , Ratones Endogámicos BALB C , Ratones Desnudos , Trasplante de Neoplasias , Oxaliplatino
6.
Toxicol Appl Pharmacol ; 337: 76-84, 2017 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-29054682

RESUMEN

Liposomalization causes alteration of the pharmacokinetics of encapsulated drugs, and allows delivery to tumor tissues through passive targeting via an enhanced permeation and retention (EPR) effect. PEGylated liposomal doxorubicin (Doxil®, Lipo-DXR), a representative liposomal drug, is well-known to reduce cardiotoxicity and increase the anti-tumor activity of DXR, but to induce the hand-foot syndrome (HFS) as a result of skin DXR accumulation, which is one of its severe adverse effects. We have developed a new liposomal preparation of oxaliplatin (l-OHP), an important anti-tumor drug for treatment of colorectal cancer, using PEGylated liposomes (Lipo-l-OHP), and showed that Lipo-l-OHP exhibits increased anti-tumor activity in tumor-bearing mice compared to the original preparation of l-OHP. However, whether Lipo-l-OHP causes HFS-like skin toxicity similar to Lipo-DXR remains to be determined. Administration of Lipo-l-OHP promoted accumulation of platinum in rat hind paws, however, it caused negligible morphological and histological alterations on the plantar surface of the paws. Administration of DiI-labeled empty PEGylated liposomes gave almost the same distribution profile of dyes into the dermis of hind paws with DXR as in the case of Lipo-DXR. Treatment with Lipo-l-OHP, Lipo-DXR, DiI-labeled empty PEGylated liposomes or empty PEGylated liposomes caused migration of CD68+ macrophages into the dermis of hind paws. These findings suggest that the skin toxicity on administration of liposomalized drugs is reflected in the proinflammatory characteristics of encapsulated drugs, and indicate that Lipo-l-OHP with a higher anti-cancer effect and no HFS may be an outstanding l-OHP preparation leading to an improved quality of life of cancer patients.


Asunto(s)
Antineoplásicos/administración & dosificación , Doxorrubicina/análogos & derivados , Compuestos Organoplatinos/administración & dosificación , Absorción Cutánea , Piel/metabolismo , Administración Intravenosa , Animales , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/toxicidad , Doxorrubicina/administración & dosificación , Doxorrubicina/química , Doxorrubicina/farmacocinética , Doxorrubicina/toxicidad , Composición de Medicamentos , Síndrome Mano-Pie/etiología , Liposomas , Masculino , Compuestos Organoplatinos/química , Compuestos Organoplatinos/farmacocinética , Compuestos Organoplatinos/toxicidad , Oxaliplatino , Polietilenglicoles/administración & dosificación , Polietilenglicoles/química , Polietilenglicoles/farmacocinética , Polietilenglicoles/toxicidad , Ratas Sprague-Dawley , Piel/efectos de los fármacos , Piel/patología , Distribución Tisular
7.
Phys Rev Lett ; 117(1): 014101, 2016 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-27419571

RESUMEN

We present a particular type of one-dimensional nonlinear lattice that supports smoothly propagating discrete breathers. The lattice is constructed by imposing a particular symmetry on its potential function. This symmetry crucially affects the profile and motion of a traveling discrete breather. We show that any traveling discrete breather is truly localized with no tail and can smoothly propagate with a constant velocity. Theoretical analysis using an average Lagrangian explains this numerical observation.

8.
Anal Bioanal Chem ; 407(23): 7135-44, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26164306

RESUMEN

Vaginal fluid is one of the most common body fluids found at crime scenes. Discriminating vaginal fluid from other body fluids is important in forensic science; however, few potential protein markers have been reported to date. Proteomic methods for identifying protein markers have gained attention, although few reports have applied this technology to forensic protein markers. Therefore, to identify characteristic vaginal proteins, we examined various body fluids (nasal secretions, saliva, urine, semen, vaginal fluids, and sweat) using liquid chromatography/electrospray ionization time-of-flight mass spectrometry and peptide mass fingerprinting. We identified three components (average molecular mass values 17,237 ± 2, 18,063 ± 2, and 15,075 ± 1) detectable only in vaginal samples: two human small proline-rich protein 3 (SPRR3) isoforms and a human fatty acid-binding protein 5 (FABP5) with an acetylated (+42) N-terminal region lacking the initiator methionine residue (-131). Using ELISA, these yielded markedly high average values in vaginal fluids. The mass spectra of these proteins were not detected in infant saliva but were detected in the vaginal fluid throughout the menstrual cycle. The results of forensic analysis (detection limit, mixed body fluid samples, casework samples, and blind samples) suggest that these proteins are potential forensic markers. In conclusion, high SPRR3 and FABP5 expression levels, which may be used as potential markers for vaginal fluid identification in forensic science, were detected in vaginal fluids from healthy adults.


Asunto(s)
Líquidos Corporales/química , Proteínas Ricas en Prolina del Estrato Córneo/análisis , Proteínas de Unión a Ácidos Grasos/análisis , Mapeo Peptídico/métodos , Violación/diagnóstico , Vagina/química , Biomarcadores/análisis , Biomarcadores/química , Cromatografía Líquida de Alta Presión/métodos , Femenino , Medicina Legal/métodos , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrometría de Masas en Tándem/métodos
9.
Mol Ther ; 19(11): 2040-7, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21878904

RESUMEN

5-Fluorouracil (5-FU) is broadly considered the drug of choice for treating human colorectal cancer (CRC). However, 5-FU resistance, mainly caused by the overexpression of antiapoptotic proteins such as Bcl-2, often leads ultimately to treatment failure. We here investigated the effect of Bcl-2 gene silencing, using small interfering RNA (siRNA) (siBcl-2), on the efficacy of 5-FU in CRC. Transfection of siBcl-2 by a Lipofectamine2000/siRNA lipoplex effectively downregulated Bcl-2 expression in the DLD-1 cell line (a CRC), resulting in significant cell growth inhibition in vitro upon treatment with 5-FU. For in vivo treatments, S-1, an oral formulation of Tegafur (TF), a prodrug of 5-FU, was used to mimic 5-FU infusion. The combined treatment of polyethylene glycol (PEG)-coated siBcl-2-lipoplex and S-1 showed superior tumor growth suppression in a DLD-1 xenograft model, compared to each single treatment. Surprisingly, daily S-1 treatment enhanced the accumulation of PEG-coated siBcl-2-lipoplex in tumor tissue. We propose a novel double modulation strategy in cancer treatment, in which chemotherapy enhances intratumoral siRNA delivery and the delivered siRNA enhances the chemosensitivity of tumors. Combination of siRNA-containing nanocarriers with chemotherapy may compensate for the limited delivery of siRNA to tumor tissue. In addition, such modulation strategy may be considered a promising therapeutic approach to successfully managing 5-FU-resistant tumors.


Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias/terapia , ARN Interferente Pequeño , Animales , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Terapia Combinada , Combinación de Medicamentos , Técnicas de Silenciamiento del Gen , Silenciador del Gen , Genes bcl-2 , Terapia Genética , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neoplasias/tratamiento farmacológico , Ácido Oxónico/farmacología , Ácido Oxónico/uso terapéutico , ARN Interferente Pequeño/metabolismo , Tegafur/farmacología , Tegafur/uso terapéutico , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Phys Rev E ; 105(2-1): 024140, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35291156

RESUMEN

We construct one-dimensional nonlinear lattices having the special property such that the umklapp process vanishes and only the normal processes are included in the potential functions. These lattices have long-range quartic nonlinear and nearest-neighbor harmonic interactions with/without harmonic onsite potential. We study heat transport in two cases of the lattices with and without harmonic onsite potential by nonequilibrium molecular dynamics simulation. It is shown that the ballistic heat transport occurs in both cases, i.e., the scaling law κ∝N holds between the thermal conductivity κ and the lattice size N. This result directly validates Peierls's hypothesis that only the umklapp processes can cause the thermal resistance while the normal ones do not.

11.
Acta Med Okayama ; 65(5): 299-306, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22037266

RESUMEN

Postmortem degradation of DNA was quantitatively estimated. Brain, liver, kidney and muscle samples were obtained from sacrificed rats left at 20℃ or 4℃. The quantity of DNA was measured by real-time PCR using a primer set for a sequence in the Rsrc 1 gene. When the quantity of amplified DNA using 10ng Human Genomic DNA was defined as 100 RFU, the quantities in the brain, liver, kidney and skeletal muscle (each 2µg of dry weight) on the day of sacrifice were 253±11, 338±22, 556±14 and 531±12 Relative Fluorescence Units (RFU), respectively (mean±S.E., n=5). The quantity of amplified DNA decreased to below 10 RFU in 1-3 weeks in the liver, kidney and skeletal muscle at 20℃, while that in the brain was more than 10 RFU for six weeks, demonstrating the usefulness of the brain as a sample for DNA analysis of decaying corpses. It was suggested that quantifying the amplified DNA in the brain at 20℃ and in the liver at 4℃ as well as the ratio of the quantity of amplified DNA in the liver to the brain at 4℃ might be useful for diagnosing time of death. This study provides the first quantitative analysis of the postmortem progress of DNA degradation in the corpse.


Asunto(s)
Cadáver , ADN/metabolismo , Cambios Post Mortem , Animales , Encéfalo/metabolismo , Humanos , Riñón/metabolismo , Hígado/metabolismo , Músculos/metabolismo , Ratas , Ratas Sprague-Dawley , Temperatura , Factores de Tiempo
12.
J Pharm Sci ; 110(12): 3937-3945, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34246630

RESUMEN

Here, we investigated whether or not the characteristics of the oxaliplatin-induced sweet taste sensitivity were altered by PEGylated liposomalization of oxaliplatin (liposomal oxaliplatin), which enhances its anticancer efficacy. Liposomal oxaliplatin and oxaliplatin were intravenously and intraperitoneally, respectively, administered to male Sprague-Dawley rats at the total dose of 8 mg/kg. A brief-access test for evaluation of sweet taste sensitivity on day 7 revealed that both liposomal oxaliplatin and oxaliplatin decreased the sensitivity of rats, the degree with the former being greater than in the case of the latter. Liposomalization of oxaliplatin increased the accumulation of platinum in lingual non-epithelial tissues, through which taste nerves passed. The lingual platinum accumulation induced by not only liposomal oxaliplatin but also oxaliplatin was decreased on cooling of the tongue during the administration. In the current study, we revealed that liposomalization of oxaliplatin exacerbated the oxaliplatin-induced decrease of sweet taste sensitivity by increasing the accumulation of platinum/oxaliplatin in lingual non-epithelial tissues. These findings may suggest that reduction of liposomal oxaliplatin distribution to the tongue on cooling during the administration prevents exacerbation of the decrease of sweet taste sensitivity, maintaining the quality of life and chemotherapeutic outcome in patients.


Asunto(s)
Antineoplásicos , Papilas Gustativas , Animales , Antineoplásicos/farmacología , Humanos , Masculino , Oxaliplatino , Calidad de Vida , Ratas , Ratas Sprague-Dawley , Gusto , Papilas Gustativas/fisiología
13.
Cancer Sci ; 101(11): 2470-5, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20731663

RESUMEN

Metronomic chemotherapy has been advocated recently as a novel chemotherapeutic regimen. Polyethylene glycol (PEG)-coated liposomes are well known to accumulate in solid tumors by virtue of the highly permeable angiogenic blood vessels characteristic for growing tumor tissue, the so-called "enhanced permeability and retention (EPR) effect". To expand the range of applications and investigate the clinical value of the combination strategy, the therapeutic benefit of metronomic S-1 dosing in combination with oxaliplatin (l-OHP)-containing PEG-coated liposomes was evaluated in a murine colon carcinoma-bearing mice model. S-1 is an oral fluoropyrimidine formulation and metronomic S-1 dosing is a promising alternative to infused 5-FU in colorectal cancer therapy. Therefore, the combination of S-1 with l-OHP may be an alternative to FOLFOX (infusional 5-FU/leucovorin (LV) in combination with l-OHP), which is a first-line therapeutic regimen of a colorectal carcinoma. The combination of oral metronomic S-1 dosing with intravenous administration of liposomal l-OHP formulation exerted excellent antitumor activity without severe overlapping side-effects, compared with either metronomic S-1 dosing, free l-OHP or liposomal l-OHP formulation alone or metronomic S-1 dosing plus free l-OHP. We confirmed that the synergistic antitumor effect is due to prolonged retention of l-OHP in the tumor on account of the PEG-coated liposomes, presumably via alteration of the tumor microenvironment caused by the metronomic S-1 treatment. The combination regimen proposed here may be a breakthrough in treatment of intractable solid tumors and an alternative to FOLFOX in advanced colorectal cancer therapy with acceptable tolerance and preservation of quality of life (QOL).


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Modelos Animales de Enfermedad , Carga Tumoral/efectos de los fármacos , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/química , Línea Celular Tumoral , Neoplasias Colorrectales/patología , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Sinergismo Farmacológico , Humanos , Liposomas , Masculino , Ratones , Ratones Endogámicos BALB C , Compuestos Organoplatinos/administración & dosificación , Oxaliplatino , Ácido Oxónico/administración & dosificación , Polietilenglicoles/química , Tegafur/administración & dosificación , Resultado del Tratamiento
14.
ACS Appl Bio Mater ; 3(5): 3226-3235, 2020 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-35025365

RESUMEN

Recently, studies have been carried out to combine surface-enhanced Raman spectroscopy substrates that are based on either localized surface plasmon or surface plasmon polariton structures. By combining these two systems, the individual drawbacks of each can be overcome. However, the manufacturing methods involved so far are sophisticated, labor-intensive, expensive, and technically demanding. We propose a facile method for the fabrication of a flexible plasmonic nanoslit surface-enhanced Raman scattering (SERS) sensor. We utilized the pattern on periodic optical disks as an inexpensive substitute for printing the periodic pattern on polydimethylsiloxane with soft imprint lithography. The Ag nanoslits were fabricated by serial bideposition using the dynamic oblique angle deposition technique. The nanoslit structures were physically and optically characterized, and the experimental results were compared to the results of the numerical simulation: Monte Carlo and finite-difference time-domain simulation. The AgNS samples showed excellent SERS performance with an enhancement factor of ∼105 and a limit of detection of 5 × 10-7 g/mL for a Rhodamine 6G solution. Their biosensing capability was demonstrated by the sensing of bilirubin.

15.
Phys Rev E Stat Nonlin Soft Matter Phys ; 79(2 Pt 2): 026603, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19391859

RESUMEN

We analyze the modulational instability of the zone boundary mode (ZBM) and the band edge modes (BEMs) in a one-dimensional nonlinear diatomic lattice and obtain rigorous results. Some numerical calculations of modulational instability in these modes are presented. These results indicate that the modulational instability of the BEMs leads to excitation of the discrete breathers (DBs) in the band gap, while that of the ZBM leads to excitation of the DBs above the phonon band.

16.
Int J Pharm ; 564: 237-243, 2019 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-31002935

RESUMEN

Liposomal anticancer drugs have been developed with improved clinical effects and reduced side effects. We have developed a PEGylated liposomal formulation of oxaliplatin that has anticancer effects in animal models of colorectal cancer with a favorable toxicity profile. To move this formulation into clinical development, a formulation that is stable during long term storage is needed, which has similar pharmacokinetics and therapeutic activity against solid tumors to the original formulation. In this study, we found that PEGylated liposomal oxaliplatin showed no changes in particle size after long term storage (12 months at 2-8 °C), but phospholipid degradation had occurred. Hence, the stored formulation had compromised membrane integrity, resulting in decreased in vivo circulation times of the liposomes. To improve the stability during long-term storage, a screening study to obtain an appropriate stabilizer was carried out. The buffer 2-morpholinoethansulfonic acid (MES) attenuated not only phospholipid degradation but also oxaliplatin degradation, unlike most other excipients. After 12 months storage at 2-8 °C in the presence of MES only slight degradation of phospholipids in PEGylated liposomal oxaliplatin occurred, resulting in similar in vivo pharmacokinetic profiles of the encapsulated oxaliplatin to the original formulation. Long term stability of PEGylated liposomal oxaliplatin was achieved by addition of MES, resulting in long circulation half-lives in vivo, a property which would be expected to lead to increased suppression of tumor growth and reduced side effects. Our formulation may now be suitable for clinical development.


Asunto(s)
Ácidos Alcanesulfónicos/química , Antineoplásicos/química , Morfolinas/química , Oxaliplatino/química , Polietilenglicoles/química , Ácidos Alcanesulfónicos/administración & dosificación , Ácidos Alcanesulfónicos/farmacocinética , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Preparaciones de Acción Retardada/administración & dosificación , Preparaciones de Acción Retardada/química , Preparaciones de Acción Retardada/farmacocinética , Almacenaje de Medicamentos , Liposomas , Masculino , Ratones Endogámicos BALB C , Morfolinas/administración & dosificación , Morfolinas/farmacocinética , Oxaliplatino/administración & dosificación , Oxaliplatino/farmacocinética , Polietilenglicoles/administración & dosificación , Polietilenglicoles/farmacocinética
17.
Phys Rev E ; 100(2-1): 022206, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31574752

RESUMEN

In this article we perform a thorough analysis of breathers in a one-dimensional model for a layered silicate for which there exists fossil and experimental evidence of moving excitations along the close-packed lines of the K^{+} layers. Some of these excitations are likely breathers with a small energy of about 0.2 eV as the numerically obtained breathers described in the present model. Moving breathers as exact solutions of the dynamical equations are obtained at the price of being generically associated with a plane wave, a wing, with finite amplitude, although this amplitude can be very small. We call them pterobreathers. For some frequencies the wings disappear and the solutions become exact moving breathers with no wings, showing the phenomenon of supertransmission of energy. We perform a theoretical analysis of pterobreathers in systems with substrate potential and show that they are characterized by a single frequency in the moving frame plus the frequency of the wings. We have also studied high-energy stationary breathers which transform into single and double kinks and stable multibreathers with very strong localization.

18.
J Radiat Res ; 49(2): 133-46, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18219183

RESUMEN

Ionizing radiation induces multiple damaged sites (clustered damage) together with isolated lesions in DNA. Clustered damage consists of closely spaced lesions within a few helical turns of DNA and is considered to be crucial for understanding the biological consequences of ionizing radiation. In the present study, two types of DNA, supercoiled plasmid DNA and linear lambda DNA, were irradiated with gamma-rays, carbon ion beams, and iron ion beams, and the spectra and yield of isolated DNA damage and bistranded clustered DNA damage were fully analyzed. Despite using different methods for damage analysis, the experiments with plasmid and lambda DNA gave largely consistent results. The spectra of both isolated and clustered damage were essentially independent of the quality of the ionizing radiation used for irradiation. The yields of clustered damage as well as of isolated damage decreased with the different radiation beams in the order gamma> C > Fe, thus exhibiting an inverse correlation with LET [gamma (0.2 keV/microm) < C (13 keV/microm) < Fe (200 keV/microm)]. Consistent with in vitro data, the yield of chromosomal DNA DSBs decreased with increasing LET in Chinese hamster cells irradiated with carbon ion beams with different LETs, suggesting that the decrease in the yield of clustered damage with increasing LET is not peculiar to in vitro irradiation of DNA, but is common for both in vitro and in vivo irradiation. These results suggest that the adverse biological effect of the ionizing radiation is not simply accounted for by the yield of clustered DNA damage, and that the complexity of the clustered damage needs to be considered to understand the biological consequences of ionizing radiation.


Asunto(s)
Radioisótopos de Carbono , Daño del ADN , ADN/efectos de la radiación , Rayos gamma , Radioisótopos de Hierro , Animales , Cricetinae , ADN de Cadena Simple/efectos de la radiación , Transferencia Lineal de Energía , Radiación Ionizante
19.
Nucleic Acids Res ; 34(5): 1540-51, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16547199

RESUMEN

Endonuclease III (Endo III) is a base excision repair enzyme that recognizes oxidized pyrimidine bases including thymine glycol. This enzyme is a glycosylase/lyase and forms a Schiff base-type intermediate with the substrate after the damaged base is removed. To investigate the mechanism of its substrate recognition by X-ray crystallography, we have synthesized oligonucleotides containing 2'-fluorothymidine glycol, expecting that the electron-withdrawing fluorine atom at the 2' position would stabilize the covalent intermediate, as observed for T4 endonuclease V (Endo V) in our previous study. Oxidation of 5'- and 3'-protected 2'-fluorothymidine with OsO4 produced two isomers of thymine glycol. Their configurations were determined by NMR spectroscopy after protection of the hydroxyl functions. The ratio of (5R,6S) and (5S,6R) isomers was 3:1, whereas this ratio was 6:1 in the case of the unmodified sugar. Both of the thymidine glycol isomers were converted to the corresponding phosphoramidite building blocks and were incorporated into oligonucleotides. When the duplexes containing 2'-fluorinated 5R- or 5S-thymidine glycol were treated with Escherichia coli endo III, no stabilized covalent intermediate was observed regardless of the stereochemistry at C5. The 5S isomer was found to form an enzyme-DNA complex, but the incision was inhibited probably by the fluorine-induced stabilization of the glycosidic bond.


Asunto(s)
Desoxirribonucleasa (Dímero de Pirimidina)/metabolismo , Inhibidores Enzimáticos/química , Proteínas de Escherichia coli/metabolismo , Oligonucleótidos/síntesis química , Timidina/análogos & derivados , Inhibidores Enzimáticos/síntesis química , Isomerismo , Oligonucleótidos/química , Oligonucleótidos/metabolismo , Compuestos Organofosforados/síntesis química , Compuestos Organofosforados/química , Especificidad por Sustrato , Timidina/química , Proteínas Virales/metabolismo
20.
Phys Rev E ; 97(6-1): 062218, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30011521

RESUMEN

A mechanism of long-range couplings is proposed to realize low-frequency discrete breathers without on-site potentials. The realization of such discrete breathers requires a gap below the band of linear eigenfrequencies. Under the periodic boundary condition of a one-dimensional lattice and the limit of large population, we show theoretically that the long-range couplings universally open the gap below the band irrespective of the coupling functions, while the short-range couplings cannot. The existence of the low-frequency discrete breathers, spatial localization, and stability are numerically analyzed from long range to short range.

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