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1.
Clin Radiol ; 70(8): 815-21, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25944645

RESUMEN

AIM: To assess the prevalence and radiological findings of macronodules in patients with thoracic sarcoidosis. MATERIALS AND METHODS: Data was collected regarding 226 patients with pathologically proven thoracic sarcoidosis. Among them, macronodules defined as well-defined nodules greater than 5 mm were found in 58 patients. The macronodules were evaluated by their number, size, margin, shape, lobar location, distance from the pleura, and temporal change. Patients were classified into two groups, patients with macronodules (n = 58) and without macronodules (n = 168). The level of serum angiotensin-converting enzyme (ACE), systemic involvement, and the maximum standardized uptake value (maxSUV) on (18)F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in both groups were then compared. RESULTS: A total of 216 macronodules were identified in 58 patients. The mean number of macronodules per patient was 3.3, and the mean size was 6.3 mm. Most of the macronodules were located in lower lobes (63.4%) and showed round-to-ovoid (95.8%) shape. The mean distance from the pleura was 5 mm. In 76% of the 63 nodules that were followed using CT scanning, any interval changes in size was also accompanied by the same change in mediastinal lymphadenopathy. On comparison of the two groups, the presence of lymphadenopathy, parenchymal involvement, and the maxSUV of thoracic lymphadenopathy were shown to be statistically different. CONCLUSION: Well-defined macronodules greater than 5 mm were not uncommonly seen in patients with thoracic sarcoidosis. The macronodules are usually located in the lower lobes near the pleura, and the interval changes in mediastinal lymphadenopathy may be associated with similar changes in the size of nodules.


Asunto(s)
Enfermedades Linfáticas/diagnóstico por imagen , Sarcoidosis/diagnóstico por imagen , Enfermedades Torácicas/diagnóstico por imagen , Adulto , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Peptidil-Dipeptidasa A/sangre , Tomografía de Emisión de Positrones/métodos , Radiofármacos , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos
2.
Clin Radiol ; 69(6): e285-90, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24630134

RESUMEN

AIM: To assess the relationship between chest computed tomography (CT) findings of patients with toxocariasis and levels of serological markers. MATERIALS AND METHODS: A total of 38 cases of patients diagnosed with toxocariasis by enzyme-linked immunosorbent assay (ELISA), CT, and serological markers were retrospectively reviewed. The presence of nodule with or without ground-glass opacity (GGO) halo, consolidation, focal GGO, pleural effusion, and lymphadenopathy at chest CT were evaluated. Statistical analysis was performed with the Fisher's exact test. RESULTS: The most common chest CT findings were nodule (n = 12, 31.6%) and focal GGO (n = 12, 31.6%). In patients with normal eosinophil levels, focal GGO (n = 9, 37.5%) was the most common finding. In contrast, nodule with a GGO halo (n = 7, 50%) was the most common finding in the eosinophilia group. Nodule with a GGO halo was more common in the eosinophilia group, with a statistically significant difference (p = 0.017). Nodule was more common in the eosinophilia group, and focal GGO was more common in the normal eosinophil group. CONCLUSION: The most common chest CT findings in toxocariasis were nodule with or without GGO halo, and focal GGO. In the eosinophilia group, nodule with a GGO halo was significantly more frequent. Other CT findings did not show a statistically significant relationship with serological markers.


Asunto(s)
Enfermedades Pulmonares Parasitarias/diagnóstico por imagen , Toxocariasis/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Ensayo de Inmunoadsorción Enzimática , Eosinófilos , Femenino , Humanos , Inmunoglobulina E/sangre , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Tomografía Computarizada Multidetector , Estudios Retrospectivos , Nódulo Pulmonar Solitario , Adulto Joven
3.
Clin Radiol ; 67(12): 1179-86, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22766482

RESUMEN

AIM: To assess initial and follow-up CT findings of invasive pulmonary aspergillosis (IPA) in solid organ transplant (SOT) recipients using new diagnostic criteria, and to compare initial CT findings of survivors with those of patients who died. MATERIALS AND METHODS: Forty-six adult SOT patients who met the 2008 EORTC/MSG criteria for proven or probable invasive pulmonary aspergillosis were assessed. Initial CT findings of the 21 survivors and 15 patients who died of IPA-related causes were compared using the internationally recognized thoracic glossary of terms. The extents of the largest lesions in each of 18 surviving were measured and changes of those lesions were recorded. RESULTS: Consolidation or mass was the most common finding, observed in 33 of 46 patients (72%), followed by large nodules (59%), ground-glass opacity (50%), and infarcted consolidation (48%). Consolidation or mass was significantly less frequent in survivors than in patients who died (62% versus 93%). Cavitation was more common (43% versus 13%), and significantly smaller (7.5 cm(2) versus 19 cm(2), p = 0.014) in survivors. Follow-up CT in survivors showed that the halo sign resolved rapidly within 4 weeks. The extent of consolidation, infarcted consolidation, and internal low-density area decreased gradually with time to reduce to half the size in 3 weeks. Large nodules persisted for the first 7 days (84%), followed by slow regression. CONCLUSION: Consolidation or mass is the most common CT finding of IPA in SOT recipients. Absence of consolidation or mass and presence of small cavities may be associated with better prognosis. The time for resolution of each pattern after treatment varies.


Asunto(s)
Aspergilosis Pulmonar Invasiva/diagnóstico por imagen , Trasplante de Órganos , Complicaciones Posoperatorias/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Anciano , Biopsia , Distribución de Chi-Cuadrado , Medios de Contraste , Diagnóstico Diferencial , Femenino , Humanos , Huésped Inmunocomprometido , Aspergilosis Pulmonar Invasiva/patología , Masculino , Persona de Mediana Edad , Tasa de Supervivencia
4.
J Nanosci Nanotechnol ; 11(1): 256-61, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21446436

RESUMEN

Si-based CMOS technology is facing a serious challenge in terms of power consumption and variability. The increasing costs associated with physical scaling have motivated a search for alternative approaches. Hybridization of nano-electromechanical (NEM)-switch and Si-based CMOS devices has shown a theoretical feasibility for power management, but a huge technical gap must be bridged before a nanoscale NEM switch can be realized due to insufficient material development and the limited understanding of its reliability characteristics. These authors propose the use of a multilayer graphene as a nanoscale cantilever material for a nanoscale NEM switchwith dimensions comparable to those of the state-of-the-art Si-based CMOS devices. The optimal thickness for the multilayer graphene (about five layers) is suggested based on an analytical model. Multilayer graphene can provide the highest Young's modulus among the known electrode materials and a yielding strength that allows more than 15% bending. Further research on material screening and device integration is needed, however, to realize the promises of the hybridization of NEM-switch and Si-based CMOS devices.


Asunto(s)
Grafito/química , Sistemas Microelectromecánicos/métodos , Nanotecnología/métodos , Semiconductores , Metales/química , Óxidos/química
5.
Water Sci Technol ; 64(12): 2389-94, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22170832

RESUMEN

Odor emissions and sludge disposals have become most challenging issues in many sludge treatment plants, and separate chemical oxidation processes have been commonly employed for these problems. It is, therefore, necessary to develop a combined process that simultaneously reduces the odor emissions and the amount of waste sludge. In this study, a non-thermal plasma reactor using a dielectric barrier discharge type was employed to treat a gas stream contaminated with 10 ppm(v) of H(2)S, and then the ozone-laden gas stream was supplied to a sludge stabilizer to reduce the organic constituents. The specific energy input to the plasma was varied to investigate the performance of the combined process. When the specific energy inputs were 200, 260, and 360 J/L, the rates of ozone generation from the plasma reactor were 0.036, 0.070, 0.144 g-O(3)/h, respectively. At these experimental conditions, the removal efficiencies of H(2)S were 60, 75, and >99%, and total chemical oxygen demand (TCOD) reduction efficiencies of 33, 61 and 67% were observed. In addition, a soluble organic fraction of the sludge increased at ratios of 1.9, 8.9, and 10.7%, respectively. Consequently, the combined process effectively and simultaneously reduced the odor compounds as well as the organic constituents and particles in the waste sludge.


Asunto(s)
Gases em Plasma , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Sulfuro de Hidrógeno , Odorantes , Oxidación-Reducción , Contaminantes Químicos del Agua
7.
Science ; 265: 756-9, 1994 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-11539187

RESUMEN

The infrared absorption spectrum of a linear, 13-atom carbon cluster (C13) has been observed by using a supersonic cluster beam-diode laser spectrometer. Seventy-six rovibrational transitions were measured near 1809 wave numbers and assigned to an antisymmetric stretching fundamental in the 1 sigma g+ ground state of C13. This definitive structural characterization of a carbon cluster in the intermediate size range between C10 and C20 is in apparent conflict with theoretical calculations, which predict that clusters of this size should exist as planar monocyclic rings.


Asunto(s)
Carbono/química , Rayos Láser , Espectrofotometría Infrarroja/métodos , Fenómenos Astronómicos , Astronomía , Carbono/análisis , Isótopos de Carbono , Técnicas de Química Analítica/métodos , Isomerismo
9.
Int J Tuberc Lung Dis ; 22(5): 504-509, 2018 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-29663954

RESUMEN

BACKGROUND: As mentioned in the 'Action Strategy for TB Safe Korea' in March 2017, almost 2 million Koreans were screened for latent tuberculous infection (LTBI) in 2017. As a preliminary step, the Korean Institute of Tuberculosis (KIT) screened 23 824 individuals from various population groups. The present study aimed to characterise the data collected from the screening programme using the QuantiFERON®-TB Gold In-Tube (QFT) assay. METHODS: Interferon-gamma release assays were performed using the manual QFT or automated DS2 instruments. Statistical analyses were performed using Stata software. Turnaround time (TAT) was defined as the average time required from submission of whole blood samples by each regional laboratory to the reporting of results by the central laboratory. RESULTS: Seventeen individuals (0.1%) had indeterminate results on repeat testing, 4519 (18.98%) screened positive and 19 288 (81.0%) were screen-negative. The group of social welfare workers had the highest positivity rate, at 27.2%. Of the 11 regions in Korea, the Gyeonggi Region had the highest positivity rate, at 25.8%. The overall mean ± standard deviation for TAT was 3.05 ± 1.66. CONCLUSION: These findings provide information on LTBI prevalence in a Korean population, and will be helpful in implementing the LTBI screening strategy for those participating in the Action Strategy for TB Safe Korea.


Asunto(s)
Ensayos de Liberación de Interferón gamma , Tuberculosis Latente/diagnóstico , Tuberculosis Latente/epidemiología , Tamizaje Masivo/métodos , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Interferón gamma/análisis , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , República de Corea/epidemiología , Distribución por Sexo , Trabajadores Sociales/estadística & datos numéricos , Factores de Tiempo , Adulto Joven
10.
Nat Commun ; 9(1): 1476, 2018 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-29662058

RESUMEN

The Northern Hemisphere experienced dramatic changes during the last glacial, featuring vast ice sheets and abrupt climate events, while high northern latitudes during the last interglacial (Eemian) were warmer than today. Here we use high-resolution aerosol records from the Greenland NEEM ice core to reconstruct the environmental alterations in aerosol source regions accompanying these changes. Separating source and transport effects, we find strongly reduced terrestrial biogenic emissions during glacial times reflecting net loss of vegetated area in North America. Rapid climate changes during the glacial have little effect on terrestrial biogenic aerosol emissions. A strong increase in terrestrial dust emissions during the coldest intervals indicates higher aridity and dust storm activity in East Asian deserts. Glacial sea salt aerosol emissions in the North Atlantic region increase only moderately (50%), likely due to sea ice expansion. Lower aerosol concentrations in Eemian ice compared to the Holocene are mainly due to shortened atmospheric residence time, while emissions changed little.

11.
Mol Cell Biol ; 19(3): 2044-50, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10022891

RESUMEN

Expression of genes encoding starch-degrading enzymes is regulated by glucose repression in the yeast Saccharomyces cerevisiae. We have identified a transcriptional repressor, Nrg1, in a genetic screen designed to reveal negative factors involved in the expression of STA1, which encodes a glucoamylase. The NRG1 gene encodes a 25-kDa C2H2 zinc finger protein which specifically binds to two regions in the upstream activation sequence of the STA1 gene, as judged by gel retardation and DNase I footprinting analyses. Disruption of the NRG1 gene causes a fivefold increase in the level of the STA1 transcript in the presence of glucose. The expression of NRG1 itself is inhibited in the absence of glucose. DNA-bound LexA-Nrg1 represses transcription of a target gene 10.7-fold in a glucose-dependent manner, and this repression is abolished in both ssn6 and tup1 mutants. Two-hybrid and glutathione S-transferase pull-down experiments show an interaction of Nrg1 with Ssn6 both in vivo and in vitro. These findings indicate that Nrg1 acts as a DNA-binding repressor and mediates glucose repression of the STA1 gene expression by recruiting the Ssn6-Tup1 complex.


Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Glucosa/farmacología , Proteínas Represoras/metabolismo , Saccharomyces cerevisiae/genética , Transactivadores/genética , Dedos de Zinc , Secuencia de Aminoácidos , Secuencia de Bases , Medios de Cultivo , ADN de Hongos , Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Proteínas Represoras/genética , Factor de Transcripción STAT1 , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae
12.
Diagn Interv Imaging ; 97(4): 443-9, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26896374

RESUMEN

PURPOSE: To compare the radiation dose and image quality, focused mainly on cardiac pulsation artifact, between high-pitch low-dose chest computed tomography (HP-LDCT) and standard low-dose chest CT (LDCT). PATIENTS AND METHODS: One hundred patients underwent HP-LDCT (50 patients) or LDCT (50 patients). Scan parameters were the same except for the pitch and gantry rotation time: 3.0 vs. 1.2 and 0.28s vs. 0.5s, respectively. Objective image noise at five regions and subjective image quality, such as noise, artifacts, cardiac pulsation artifacts, and overall diagnostic acceptability, were evaluated using a five-point scale. The significance level for all tests was set at P<0.05. RESULTS: The dose-length products (DLPs) with HP-LDCT and LDCT were 90.2±4.3mGycm and 103.1±6.4mGycm, respectively (P<0.01). DLP of HP-LDCT showed a 13% reduction versus LDCT. Objective image noise was not significantly different. Cardiac pulsation artifacts showed a significant reduction on HP-LDCT (P<0.01). Other subjective image quality parameters of HP-LDCT were similar to those of LDCT. The overall diagnostic acceptability of HP-LDCT was better than that of LDCT (P<0.01). CONCLUSIONS: HP-LDCT showed a 13% mean radiation dose reduction with no deterioration in image quality due to cardiac pulsation artifacts.


Asunto(s)
Artefactos , Corazón/fisiología , Dosis de Radiación , Tomografía Computarizada por Rayos X/métodos , Estudios de Factibilidad , Femenino , Humanos , Persona de Mediana Edad
13.
Cell Death Differ ; 11(9): 1009-16, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15131590

RESUMEN

Apoptosis induced by nonsteroidal anti-inflammatory drugs (NSAIDs) is involved not only in the production of NSAID-induced gastric lesions but also in the antitumor activity of these drugs. The endoplasmic reticulum (ER) stress response is a cellular mechanism that aids in protecting the ER against ER stressors and is involved in ER stressor-induced apoptosis. Here, we examine the relationship between this response and NSAID-induced apoptosis in cultured guinea-pig gastric mucosal cells. Exposure of cells to indomethacin, a commonly used NSAID, induced GRP78 as well as CHOP, a transcription factor involved in apoptosis. Three factors that positively regulate CHOP expression (ATF6, ATF4 and XBP-1) were activated and/or induced by indomethacin. NSAIDs other than indomethacin (diclofenac, ibuprofen and celecoxib) also induced CHOP. Monitoring of the transcriptional activities of ATF6 and CHOP by luciferase assay revealed that both were stimulated in the presence of indomethacin. Furthermore, indomethacin-induced apoptosis was suppressed in cultured guinea-pig gastric mucosal cells by expression of the dominant-negative form of CHOP, or in peritoneal macrophages from CHOP-deficient mice. These results suggest that ER stress response-related proteins, particularly CHOP, are involved in NSAID-induced apoptosis.


Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Apoptosis , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/patología , Factor de Transcripción Activador 4 , Animales , Northern Blotting , Celecoxib , Línea Celular , Supervivencia Celular , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Diclofenaco/farmacología , Relación Dosis-Respuesta a Droga , Chaperón BiP del Retículo Endoplásmico , Activación Enzimática , Mucosa Gástrica/patología , Genes Reporteros , Cobayas , Proteínas de Choque Térmico/metabolismo , Peróxido de Hidrógeno/farmacología , Ibuprofeno/farmacología , Immunoblotting , Indometacina/farmacología , Luciferasas/metabolismo , Macrófagos/metabolismo , Microscopía Fluorescente , Chaperonas Moleculares/metabolismo , Plásmidos/metabolismo , Pirazoles/farmacología , ARN Mensajero/metabolismo , Factores de Transcripción del Factor Regulador X , Sulfonamidas/farmacología , Factores de Tiempo , Factores de Transcripción/metabolismo , Transcripción Genética , Transfección , Proteína 1 de Unión a la X-Box
14.
Bioresour Technol ; 96(10): 1175-82, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15683909

RESUMEN

The optimization of submerged culture conditions and nutritional requirements was studied for the production of exopolysaccharide (EPS) from Agrocybe cylindracea ASI-9002 using the statistically based experimental design in a shake flask culture. Both maximum mycelial biomass and EPS were observed at 25 degrees C. The optimal initial pH for the production of mycelial biomass and EPS were found to be pH 4.0 and pH 6.0, respectively. Subsequently, optimum concentration of each medium component was determined using the orthogonal matrix method. The optimal combination of the media constituents for mycelial growth was as follows: maltose 80 g/l, Martone A-1 6 g/l, MgSO4 x 7H2O 1.4 g/l, and CaCl2 1.1 g/l; for EPS production: maltose 60 g/l, Martone A-1 6 g/l, MgSO4 x 7H2O 0.9 g/l, and CaCl2 1.1 g/l. Under the optimal culture condition, the maximum EPS concentration achieved in a 5-l stirred-tank bioreactor indicated 3.0 g/l, which is about three times higher than that at the basal medium.


Asunto(s)
Agaricales/crecimiento & desarrollo , Biomasa , Reactores Biológicos , Micelio/crecimiento & desarrollo , Polisacáridos/biosíntesis , Agricultura/métodos , Técnicas de Cultivo , Concentración de Iones de Hidrógeno
15.
Biochem Pharmacol ; 62(11): 1439-47, 2001 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-11728380

RESUMEN

We studied the effect of DW2282-,[(S)-(+)-4-phenyl-1-[N-(4-aminobenzoyl)-indoline-5-sulfonyl-4,5-dihydro-2-imidazolone].hydrochloride], a newly developed anti-cancer agent, on cell proliferation, cell cycle progression, and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. DW2282, a diarylsulfonylurea compound, was cytotoxic to HL-60 cells, with an IC(50) of 1.0 microg/mL. Treatment with DW2282 fragmented DNA in a concentration- and time-dependent manner, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that DW2282-treated HL-60 cells were hypodiploid, in terms of DNA content, and were arrested at the G(2)/M phase. The cell cycle arrest was reversible upon the removal of DW2282. HL-60 cells also underwent distinct morphological changes in response to DW2282 treatment, including the appearance of elongated cells with conical tails and other apoptotic characteristics. G(2)/M phase cell cycle arrest was accompanied by a decrease in the levels of cdc2, a protein that plays a critical role for progression through the G(2)/M phase. Treatment of HL-60 cells with DW2282 was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of poly(ADP-ribose) polymerase. Taken together, these results demonstrate that DW2282 dramatically suppressed HL-60 cell growth by inducing apoptosis after G(2)/M phase arrest. These findings are consistent with the possibility that G(2)/M phase arrest was mediated by the down-regulation of cdc2 levels in HL-60 cells. The data also suggest that DW2282 triggered apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease. These results provide important new information towards understanding the mechanisms by which DW2282 and other diarylsulfonylureas mediate their therapeutic effects.


Asunto(s)
Antineoplásicos/farmacología , Apoptosis , Fase G2/efectos de los fármacos , Imidazoles/farmacología , Mitosis/efectos de los fármacos , Sulfonas/farmacología , Proteína Quinasa CDC2/metabolismo , Caspasa 3 , Caspasas/metabolismo , División Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Células HL-60 , Humanos , Leucemia Promielocítica Aguda , Poli(ADP-Ribosa) Polimerasa-1 , Poli(ADP-Ribosa) Polimerasas , Proteínas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis
16.
Exp Mol Med ; 31(3): 122-5, 1999 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-10551259

RESUMEN

High selectivity provided by biomolecules such as antibodies and enzymes has been exploited during the last two decades for development of biosensors. Of particular importance are efficient immobilization methods for biomolecules in order to preserve their biological activities. In this study, we have evaluated immobilization strategies for an anti-DNA antibody on a self-assembled monolayer of omega-functionalized thiols. The antibody was immobilized via peptide bond formation between the primary amines in the antibody and the carboxyl groups on the self-assembled monolayer. The peptide bond coupling was achieved by activating COOH groups on the surface through N-Hydroxysuccimide (NHS)-ester formation, followed by acylation of NH2 group in the antibody. DNA binding activity of the immobilized antibody was examined by counting beta emission from 35S-labeled DNA.


Asunto(s)
Anticuerpos Antinucleares , ADN/análisis , Radioinmunoensayo/métodos , ADN/inmunología , Proteínas de Unión al ADN/química , Oro , Membranas Artificiales , Reacción en Cadena de la Polimerasa , Polivinilos/química , Ácido Tióctico/química
17.
Mol Cells ; 9(3): 300-8, 1999 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-10420990

RESUMEN

The metB gene encoding cystathionine y-synthase, the second enzyme of methionine biosynthetic pathway, was isolated from a pSL109-based Corynebacterium glutamicum gene library via complementation of an Escherichia coli metB mutant. A DNA-sequence analysis of the cloned DNA identified an open-reading frame of 1161 bp which encodes a protein with the molecular weight of 41,655 comprising of 386 amino acids. The putative protein product showed good amino acid-sequence homology to its counterpart in other organisms. Introduction of a plasmid carrying the cloned metB into the C. glutamicum resulted in a 10-fold increase in cystathionine gamma-synthase activities, demonstrating the identity of the cloned gene. The C. glutamicum metB mutant which was generated by the site-specific integration of the cloned DNA into its chromosome did not lose the ability to grow on glucose minimal medium lacking supplemental methionine. The growth rate of the mutant strain was also comparable to that of the parental strain. These data indicate that, in addition to the transsulfuration pathway, other methionine biosynthetic pathways may be present in C. glutamicum.


Asunto(s)
Liasas de Carbono-Oxígeno/genética , Corynebacterium/genética , Corynebacterium/metabolismo , Genes Bacterianos , Metionina/biosíntesis , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Corynebacterium/enzimología , ADN Bacteriano/genética , Expresión Génica , Prueba de Complementación Genética , Datos de Secuencia Molecular , Mutación , Homología de Secuencia de Aminoácido
18.
Eur J Cancer Prev ; 13(5): 419-24, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15452455

RESUMEN

Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has been found to be involved in various pathophysiological processes, including inflammation and carcinogenesis, the modulators of NO synthesis or expression have been considered as potential anti-inflammatory and cancer chemopreventive agents. In this study, to procure the iNOS inhibitors from natural products, we evaluated 57 methanol extracts of natural products including Korean indigenous plants for the inhibition of NO formation on lipopolysaccharide (LPS)-activated mouse macrophage-like RAW 264.7 cells. As a result, several extracts including those from Actinodaphne lancifolia, Calystegia soldanella, Caryratia japonica, Citrus dachibana, Dystaenia takeshimana, Erysimum aurantiacum, Hovenia undulata, Stewartia koreana and Viburnum awabuki showed potent inhibitory activities of NO production (>70% inhibition at the test concentration of 40 microg/ml). In particular, the extract of Calystegia soldanella showed a potential inhibition of NO production in a dose-dependent manner (IC50=4.3 microg/ml). Subsequent study also exhibited that the extract of Calystegia soldanella significantly suppressed iNOS protein and gene expression in a dose-dependent manner. These results suggest that Calystegia soldanella might be a new potential candidate for developing an iNOS inhibitor from natural products and also could be warranted for further elucidation of active principles for the development of new anti-inflammatory and/or cancer chemopreventive agents.


Asunto(s)
Calystegia/química , Óxido Nítrico Sintasa/biosíntesis , Óxido Nítrico/metabolismo , Extractos Vegetales/farmacología , Animales , Técnicas de Cultivo de Célula , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Inflamación , Lipopolisacáridos/toxicidad , Macrófagos , Ratones , Óxido Nítrico Sintasa/farmacología
19.
Phytochemistry ; 58(7): 1015-24, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11730864

RESUMEN

Arginase (EC 3.5.3.1) was purified to homogeneity from root tissues of three-year-old ginseng (Panax ginseng C.A. Meyer), shade plant, and was found to be an extraordinarily large molecule relatively stable to heat. The enzyme was decameric having a molecular mass of 352,000 Da, with an optimal temperature and pH of 60 degrees C and 9.5, respectively. Analogues of arginine could not replace it as substrate, and a cysteine residue is at or near the active site. Maximum activity was obtained with Mn(2+) and Co(2+) also activated the proteins, whereas, both agmatine and 5'-deoxy-methylthioadenosine were inhibitors. Specific activities of the enzyme in sliced ginseng roots were increased by plant hormones such as GA(3), IAA, kinetin and putrescine, whereas the activities of the purified enzyme were unaffected by putrescine. Increases in arginase activities by these plant hormones could affect metabolism of polyamine intracellularly.


Asunto(s)
Arginasa/aislamiento & purificación , Panax/enzimología , Raíces de Plantas/enzimología , Agmatina/farmacología , Arginasa/antagonistas & inhibidores , Arginasa/química , Arginasa/metabolismo , Desoxiadenosinas/farmacología , Inhibidores Enzimáticos/farmacología , Estabilidad de Enzimas , Calor , Concentración de Iones de Hidrógeno , Cinética , Peso Molecular , Especificidad por Sustrato , Tionucleósidos/farmacología
20.
J Agric Food Chem ; 49(10): 4646-55, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11600002

RESUMEN

One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.


Asunto(s)
Antioxidantes/análisis , Bepridil/análogos & derivados , Ácido Clorogénico/análogos & derivados , Picratos , Hojas de la Planta/química , Poaceae/química , Animales , Antioxidantes/química , Antioxidantes/farmacología , Bepridil/química , Compuestos de Bifenilo , Ácido Clorogénico/análisis , Ácido Clorogénico/farmacología , Inhibidores Enzimáticos/farmacología , Depuradores de Radicales Libres , Peroxidación de Lípido , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-Dawley , Superóxidos/química , Xantina Oxidasa/antagonistas & inhibidores
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