RESUMEN
Root rots are one of the main biotic constraints to common bean (Phaseolus vulgaris L.) production, causing losses estimated at 221 000 metric tons a year in sub-Saharan Africa. Until recently, root rots in Ugandan common bean agroecologies were mostly caused by Pythium and Fusarium spp., especially in high altitude areas. But now, severe root rots are observed in low and medium altitude agroecologies characterized by dry and warm conditions. The objective of our study was therefore to ascertain the current prevalence and incidence of common bean root rot diseases in Ugandan common bean agroecologies. Our results show that root rots were present in all seven agroecologies surveyed. Overall, the most rampant root rot was southern blight caused by Sclerotium rolfsii Sacc., followed by root rots caused by Fusarium spp., Pythium spp. and Rhizoctonia solani, respectively. Our study clearly showed the influence of environmental conditions on the prevalence and incidence of common bean root rots. While Fusarium and Pythium root rots are favoured under low air temperature and high air humidity in highland areas, high incidence of southern blight is favoured by warm and moist conditions of lowland areas. The prevalence and incidence of common bean root rots was mapped, providing a reliable baseline for future studies. Similarly, hotspots identified for common bean root rots will be a very useful resource for evaluation of germplasm and breeding lines for resistance to root rots.
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BACKGROUND: X-linked lymphoproliferative syndrome type 2 is a rare hereditary immunodeficiency caused by mutations in the XIAP gene. This immunodeficiency frequently results in hemophagocytic lymphohistiocytosis, although hypogammaglobulinemia and dysgammaglobulinemia are also common. OBJECTIVE: We identified 17 patients from 12 Japanese families with mutations in XIAP. The Glu349del mutation was observed in 3 patients, each from a different family. Interestingly, these patients exhibited dysgammaglobulinemia but not hemophagocytic lymphohistiocytosis. We conducted an immunological study of patients carrying Glu349del and other mutations to elucidate the pathogenic mechanisms of dysgammaglobulinemia in patients with mutations in the XIAP gene. PATIENTS AND METHODS: We performed an immunological study of 2 patients carrying the Glu349del mutation and 8 patients with other mutations. RESULTS: Flow cytometry showed that the percentage of memory B cells in patients with a mutation in XIAP was lower than that observed in the healthy controls. The patients with the Glu349del mutation had a lower percentage of memory B cells than those with other mutations. Ig production was reduced in patients with the Glu349del mutation. Increased susceptibility to apoptosis was observed in the patients with other mutations. Susceptibility to apoptosis was normal in patients with Glu349del. Microarray analysis indicated that expression of Ig-related genes was reduced in patients with the Glu349del mutation and that the pattern was different from that observed in the healthy controls or patients with other mutations in XIAP. CONCLUSIONS: Patients carrying the Glu349del mutation in the XIAP gene may have a clinically and immunologically distinct phenotype from patients with other XIAP mutations. The Glu349del mutation may be associated with dysgammaglobulinemia.
Asunto(s)
Disgammaglobulinemia/genética , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Trastornos Linfoproliferativos/genética , Mutación , Proteína Inhibidora de la Apoptosis Ligada a X/genética , Adolescente , Apoptosis , Pueblo Asiatico/genética , Linfocitos B/inmunología , Estudios de Casos y Controles , Células Cultivadas , Niño , Preescolar , Análisis Mutacional de ADN , Disgammaglobulinemia/diagnóstico , Disgammaglobulinemia/etnología , Disgammaglobulinemia/inmunología , Femenino , Citometría de Flujo , Perfilación de la Expresión Génica/métodos , Enfermedades Genéticas Ligadas al Cromosoma X/diagnóstico , Enfermedades Genéticas Ligadas al Cromosoma X/etnología , Enfermedades Genéticas Ligadas al Cromosoma X/inmunología , Predisposición Genética a la Enfermedad , Humanos , Memoria Inmunológica , Inmunofenotipificación/métodos , Lactante , Japón , Trastornos Linfoproliferativos/diagnóstico , Trastornos Linfoproliferativos/etnología , Trastornos Linfoproliferativos/inmunología , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Linaje , Fenotipo , Linfocitos T/inmunología , Linfocitos T/patologíaRESUMEN
An experiment with a newly developed high-resolution kaon spectrometer and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab. The ground state of a neutron-rich hypernucleus, (Λ)(7)He, was observed for the first time with the (e, e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The (Λ)(7)He binding energy supplies the last missing information of the A = 7, T = 1 hypernuclear isotriplet, providing a new input for the charge symmetry breaking effect of the ΛN potential.
RESUMEN
BACKGROUND: During 2005-2007, we experienced sporadic isolations of multidrug-resistant (MDRP) Pseudomonas aeruginosa from wards in a general hospital in Hiroshima. The objective of this study was to analyze epidemiology relationships and the mode of spread of the strains. METHODS: Clonality was assessed using pulsed-field gel electrophoresis (PFGE) and serotyping. MICs were determined using the microdilution broth method. Investigations of the affected patients' movements and environmental sampling from the affected wards were conducted. RESULTS: An abrupt increase in MDRP isolations began at the end of 2005 and ended in February 2007. A total of 25 MDRP strains were sporadically isolated from nine wards. Fourteen strains were genotypically and serologically identical. Analysis of the patients' movements identified that six of the 14 MDRP-positive patients became positive for MDRP when they were in the intensive care unit (ICU), and two became positive after the patients moved from the ICU to another nursing unit. Four MDRP strains were isolated from patients who did not stay in the ICU and were in ward E6, which had the second highest number of isolations. In July 2006, environmental sampling of the hospital identified a toilet brush in ward E6 that was contaminated with MDRP that was genotypically and serologically identical to the clinical isolates. CONCLUSIONS: Our study suggests that the sporadic increase in MDRP isolates during 2005-2007 in the general hospital in Hiroshima was due to an epidemic of an MDRP clone. Continuity and spread of infection was probably due to cross infection and contamination in the hospital with the MDRP strain.
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Infección Hospitalaria/epidemiología , Farmacorresistencia Bacteriana Múltiple , Epidemias , Infecciones por Pseudomonas/epidemiología , Pseudomonas aeruginosa/aislamiento & purificación , Electroforesis en Gel de Campo Pulsado , Hospitales Generales , Humanos , Unidades de Cuidados Intensivos , Japón/epidemiología , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/efectos de los fármacos , SerotipificaciónRESUMEN
AIMS: Shopping carts and handheld shopping baskets in supermarkets are subject to accidental bacterial contamination through contacts with a variety of food. We investigated the prevalence of Staphylococcus aureus on the handles of handheld shopping baskets in four supermarkets distantly located in Osaka district, Japan. METHODS AND RESULTS: Fifty two strains of Staph. aureus were isolated from 760 basket handles. Among these, six strains were positive for staphylococcal enterotoxin B (SEB) production, representing 12% of total. This SEB producer ratio is considerably higher than among Staph. aureus isolated from nasal swabs of the supermarket workers (2%) and from independently collected clinical specimens (4%). These SEB-producing Staph. aureus strains from the basket handles are clonal and belong to ST12. Coagulase typing showed that they are in group VII, which is the most common cause of food poisoning in Japan. Biofilm assays indicated that SEB gene (seb)-positive strains including this clone produced a significantly higher amount of biofilm than seb-negative strains. CONCLUSIONS: The frequent isolation of seb-positive Staph. aureus on shopping basket handles raises the possibility that they could be a hidden reservoir for Staph. aureus with a potential to cause food poisoning and draws attention to the importance of shopping basket sanitation.
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Enterotoxinas/genética , Microbiología de Alimentos , Staphylococcus aureus/aislamiento & purificación , Coagulasa/clasificación , Industria de Alimentos , Japón , Staphylococcus aureus/clasificación , Staphylococcus aureus/genéticaRESUMEN
STUDY DESIGN: A prospective clinical study. OBJECTIVE: The purpose of this study was to evaluate prospectively a large group of patients with thoracolumbar burst fractures who were treated with a posterior/anterior combined procedure and to report on the surgical outcomes, complications and radiographic results. METHODS: A total of 100 consecutive patients were surgically managed with posterior instrumentation, anterior decompression and anterior strut grafting. There were 71 males and 29 females; the mean age was 36 years. Patients with osteoporotic delayed vertebral body collapse were excluded. The mean follow-up period was 30 months. Surgical outcomes such as operative time, blood loss and sagittal alignment were investigated. A neurological assessment was performed by a rating system based on the American Spine Injury Association impairment scale. An interbody fusion was judged using plain X-ray and computed tomographic scans. RESULTS: The mean operative time was 256 min and the mean operative bleeding was 985 ml. Most of the patients were ambulatory within 3 days after surgery. Of the 76 patients with neurological injury, 54 (71.1%) recovered function following surgery. The mean local kyphosis angle was 12.2° kyphotic preoperatively and 0.8° lordotic at the final observation. The mean correction angle was 15.7° and correction loss was 2.6°. No instrumentation failure was observed and the postoperative fusion rate was 99%. CONCLUSIONS: Posterior/anterior combined surgery with posterior pedicle screws and hooks fixation, and reconstruction by simultaneous strut grafting and anterior decompression, achieved short segment fixation and can be a useful option for surgically treating thoracolumbar burst fractures.
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Fijadores Internos/normas , Vértebras Lumbares/cirugía , Procedimientos Neuroquirúrgicos/instrumentación , Fracturas de la Columna Vertebral/cirugía , Fusión Vertebral/instrumentación , Vértebras Torácicas/cirugía , Adolescente , Adulto , Anciano , Femenino , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/patología , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/métodos , Estudios Prospectivos , Radiografía , Estudios Retrospectivos , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/patología , Fusión Vertebral/métodos , Vértebras Torácicas/diagnóstico por imagen , Vértebras Torácicas/patología , Adulto JovenRESUMEN
We have shown previously that the inactivation of the zinc finger gene Krox-20 affects hindbrain segmentation, resulting in the elimination of rhombomeres 3 and 5. We demonstrate here that Krox-20 homozygous mutant mice exhibit abnormally slow respiratory and jaw opening rhythms, indicating that a modification of hindbrain segmentation influences the function of neuronal networks after birth. Central neuronal networks that control respiratory frequency are made predominantly depressant by the elimination of a previously undescribed rhythm-promoting system. Recordings of rhythmic activity from the isolated hindbrain following progressive tissue transections indicate that the reorganization takes place in the caudal pontine reticular formation. The newborn (PO) Krox-20-/- mice, in which apneas are ten times longer than in wild-type animals, may be a valuable model for the study of life-threatening apneas during early infancy.
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Proteínas de Unión al ADN/fisiología , Red Nerviosa/fisiología , Neuronas/fisiología , Puente/fisiología , Factores de Transcripción/fisiología , Animales , Animales Recién Nacidos , Tronco Encefálico/fisiología , Cerebelo/fisiología , Proteínas de Unión al ADN/genética , Proteína 2 de la Respuesta de Crecimiento Precoz , Femenino , Humanos , Técnicas In Vitro , Recién Nacido , Ratones , Naloxona/farmacología , Placenta/fisiología , Pletismografía , Embarazo , Respiración/efectos de los fármacos , Respiración/fisiología , Síndrome de Dificultad Respiratoria del Recién Nacido , Médula Espinal/fisiología , Factores de Transcripción/genética , Saco Vitelino/fisiología , Dedos de ZincRESUMEN
Although codeine is the most prominent and centrally acting antitussive agent, the precise sites and mode of its action have not been fully understood yet. In the present study, we examined the effects of codeine on synaptic transmission in second-order neurons of the nucleus tractus solitarius (NTS), which is the first central relay site receiving tussigenic afferent fibers, by using whole-cell patch-clamp recordings in guinea-pig brainstem slices. Codeine (0.3-3 mM) significantly decreased the amplitude of excitatory postsynaptic currents (EPSCs) evoked by electrical stimulation of the tractus solitarius in a naloxone-reversible and concentration-dependent manner, but it had no effect on the decay time of evoked EPSCs (eEPSCs). The inhibition of eEPSCs was accompanied by an increased paired-pulse ratio of two consecutive eEPSCs. The inward current induced by application of AMPA remained unchanged after codeine application. A voltage-sensitive K+ channel blocker, 4-aminopyridine (4-AP) attenuated the inhibitory effect of codeine on eEPSCs. These results suggest that codeine inhibits excitatory transmission from the primary afferent fibers to the second-order NTS neurons through the opioid receptors that activate the 4-AP sensitive K+ channels located at presynaptic terminals.
Asunto(s)
Analgésicos Opioides/farmacología , Codeína/farmacología , Ácido Glutámico/fisiología , Receptores Presinapticos/efectos de los fármacos , Núcleo Solitario/fisiología , Transmisión Sináptica/efectos de los fármacos , 4-Aminopiridina/farmacología , 6-Ciano 7-nitroquinoxalina 2,3-diona/farmacología , Animales , Interpretación Estadística de Datos , Electrofisiología , Antagonistas de Aminoácidos Excitadores/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Cobayas , Masculino , Potenciales de la Membrana/efectos de los fármacos , Naloxona/farmacología , Antagonistas de Narcóticos/farmacología , Técnicas de Placa-Clamp , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio/efectos de los fármacos , Receptores AMPA/efectos de los fármacos , Núcleo Solitario/efectos de los fármacosRESUMEN
The recovery of phosphorus from sewage and sludge treatment systems is particularly important because it is a limited resource and a large proportion of the phosphorus currently used in Japan must be imported. We have been experimentally evaluating recovery methods with sulphide. In this study, we focussed on the extraction of phosphate from the sludge, and sought to achieve a greater extraction efficiency and to validate the extraction mechanism. We conducted three experiments, i.e. a sludge-type experiment, a coagulant ratio of pre-coagulated sludge experiment, and a concentration of pre-coagulated sludge experiment. Phosphate was extracted not with normal sewage sludge but with pre-coagulated sludge and FePO4 reagent at S/Fe = 1.0-2.0. A coagulant ratio of 23mg Fe L(-1) was required in the precoagulation process to effectively extract phosphate. A high concentration of pre-coagulated sludge was required for the phosphate extraction. The mass balance was calculated, and 44.0% of phosphorus was extracted to supernatant, and 98.5% of iron and 98.3% of sulphur (44.1% of sulphur was sulphide). Thus, phosphate can be selectively separated from iron by the phosphate extraction method with NaHS, and phosphorus and iron can be recovered and reused at sewage treatment plants using ferric chloride as a coagulant.
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Fosfatos/aislamiento & purificación , Aguas del Alcantarillado/química , Sulfuros/química , Cloruros , Conservación de los Recursos Naturales , Compuestos Férricos/química , Hierro/química , Hierro/aislamiento & purificación , Fosfatos/química , Eliminación de Residuos Líquidos/métodosRESUMEN
Section of motor nerve fibers (axotomy) elicits a variety of morphofunctional responses in the motoneurons in the motor nuclei. Later than the fifth post-operational day after section of the facial nerve, synapse elimination occurs in the facial motoneuron pool, leading to gradual abolishment of synaptic input-driven activities of the axotomized motoneurons. However, it remains unknown how the amount of synaptic input changes during this period between the axotomy and the synaptic elimination. Here we examined a hypothesis that axotomy of the motoneurons itself modifies the synaptic inputs to the motoneurons. One day after axotomy, the postsynaptic currents, mostly mediated by non-N-methyl-D-aspartic acid (non-NMDA) receptors, recorded from the axotomized facial motoneurons in the acute slice preparations of the rats were of higher frequency and larger amplitude than those in the intact motoneurons. This difference was not observed after the third post-operational day and appeared earlier than the changes in the electrophysiological properties and increase in the number of dead neurons in the axotomized motor nucleus. The larger postsynaptic current frequency of the axotomized motoneurons was observed both in the absence and in the presence of tetrodotoxin citrate, suggesting that increased excitability and facilitated release underlie the postsynaptic current frequency increase. These results suggest that synaptic re-organization occurs in the synapses of motoneurons at an early stage following axotomy.
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Tronco Encefálico/citología , Traumatismos del Nervio Facial/fisiopatología , Neuronas Motoras/fisiología , Transmisión Sináptica/fisiología , 6-Ciano 7-nitroquinoxalina 2,3-diona/farmacología , Factores de Edad , Animales , Animales Recién Nacidos , Axotomía/métodos , Antagonistas de Aminoácidos Excitadores/farmacología , Femenino , Lateralidad Funcional , Inmunohistoquímica/métodos , Técnicas In Vitro , Masculino , Potenciales de la Membrana/fisiología , Neuronas Motoras/efectos de los fármacos , Técnicas de Placa-Clamp/métodos , Ratas , Ratas Wistar , Bloqueadores de los Canales de Sodio/farmacología , Estilbamidinas/metabolismo , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/efectos de la radiación , Sinaptofisina/metabolismo , Tetrodotoxina/farmacología , Factores de TiempoRESUMEN
Boerhaave syndrome is a rare disease and needs an exact diagnosis and a proper treatment plan because of its terrible clinical course. We experienced a case of Boerhaave syndrome that thoracoscopy and intraoperative upper gastrointestinal (GI) endoscopy was very effective. Sixty-four-year-old man realized chest and back pain after vomitting. Esophageal perforation was suspected, but 64 hours had passed already when we started a surgical treatment. By the thoracoscopy and intraoperative endoscopy, lower esophageal perforation and infectious pleural effusion were found. Therefore, we selected a surgical treatment under the assistance of thoracoscopy. Secondly, a simple closure and intracostal muscle overlapping was performed with small incisional thoracotomy. Postoperative complication, such as mediastinal abscess, has not occurred. Thoracoscopy and intraoperative upper GI endoscopy was effective for an appropriate diagnosis and treatment of Boerhaave syndrome.
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Endoscopía Gastrointestinal , Perforación del Esófago/diagnóstico , Perforación del Esófago/cirugía , Toracoscopía , Humanos , Cuidados Intraoperatorios , Masculino , Persona de Mediana Edad , Derrame Pleural/diagnóstico , Derrame Pleural/cirugíaRESUMEN
The case was a 59-year-old man who has a history of left mediastinal tumor resection with left phrenicectomy. The elevated diaphragm revealed by chest X-ray 7 years after the operation led to diagnosis of diaphragmatic eventration. Since any symptom was seen in the early period, "wait and watch" strategy was done for management. Both the abdominal enlarged feeling and the dyspnea on effort were appeared 10 years after the operation. Under the speculation of these symptoms related to the elevated abdominal organs came up with diaphragmatic eventration, surgical method the plication of the diaphragm was performed. The diaphragm was plicated by interrupted suture as opening the diaphragm to avoid injury the abdominal organs, and reinforced with the Marlex mesh. We used artificial mesh to reinforce the thin diaphragm with exceptation of prevent the postoperative recurrence, because a result of the etiological process of the case was considered as disuse atrophy of diaphragm after phrenicectomy.
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Diafragma/inervación , Eventración Diafragmática/etiología , Neoplasias del Mediastino/cirugía , Nervio Frénico/cirugía , Complicaciones Posoperatorias , Eventración Diafragmática/cirugía , Humanos , Masculino , Persona de Mediana Edad , Mallas QuirúrgicasRESUMEN
Primary pulmonary meningiomas are quite rare, and their occurrence has been reported only sporadically. A 49-year-old, asymptomatic female was hospitalized for the evaluation of a coin lesion in the left lung radiography. She has no history of previous neoplasm or symptom referable to the central nervous system. Chest computed tomography (CT) demonstrated a 9 x 14 mm, round, noncalcified, well-demarcated lesion in the left upper lobe of the lung (S(1+2)). For diagnostic purposes, enucleation of the tumor was performed. The resected specimen revealed histologically classical typical meningioma. Because postoperative magnetic resonance imaging (MRI) of the brain did not show any intracranial mass, this case was and diagnosed as a primary pulmonary meningioma. The patient was discharged with no complication, and alive without recurrence of disease 14 months after surgery.
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Neoplasias Pulmonares/diagnóstico , Meningioma/diagnóstico , Femenino , Humanos , Persona de Mediana EdadRESUMEN
Novel N-substituted phthalimides (2-substituted 1H-isoindole-1,3-diones) were prepared, and their effects on tumor necrosis factor-alpha (TNF-alpha) production by human leukemia cell line HL-60 stimulated with 12-O-tetradecanoylphorbol 13-acetate (TPA) or okadaic acid (OA) were examined. A structure-activity relationship study of the N-phenylphthalimides and N-benzylphthalimides revealed that their enhancing effect on TPA-induced TNF-alpha production by HL-60 cells and their inhibiting effect on OA-induced TNF-alpha production by HL-60 cells are only partially correlated.
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Células HL-60/efectos de los fármacos , Factores Inmunológicos/química , Factores Inmunológicos/farmacología , Ftalimidas/química , Ftalimidas/farmacología , Factor de Necrosis Tumoral alfa/biosíntesis , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células HL-60/fisiología , Humanos , Factores Inmunológicos/síntesis química , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Estructura Molecular , Ácido Ocadaico/farmacología , Rotación Óptica , Ftalimidas/síntesis química , Relación Estructura-Actividad , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
Four aldehyde reductases, F1, F2, F3, and F4, were isolated from rabbit liver cytosol to homogeneity by various chromatographic techniques. F2 is an aldehyde reductase with a molecular weight of 32,000, which resembled aldehyde reductases of human liver and pig kidney in properties. It was inhibited in a noncompetitive way by alpha-ketoglutarate and oxaloacetate with Ki values of 4 x 10(-5) M. The other three enzymes were NADPH-dependent aromatic aldehyde-ketone reductases. F1 and F3 were monomeric enzymes with molecular weights of 38,000 and 29,000, respectively. F4 showed a molecular weight of 78,000 on gel filtration, but sodium dodecyl sulfate gel electrophoresis revealed two different subunits with molecular weights of 26,000 and 24,000. The molar ratio of NADPH : F1, F2, or F3 binding was 1 : 1, whereas that of NADPH:F4 binding was 3 : 1. The number of thiol groups in order molecule of F1, F2, F3, and F4, was 4, 4, 4, and 5, respectively. The enzyme activity of F3 was inhibited by addition of an equal mole amount of PCMB. Only F4 was inhibited by metal chelating agents. F1 also catalyzed the interconversion of 3(17)-keto and 3(17) beta-hydroxysteroids, whereas F3 catalyzed oxidoreduction of some 3 alpha-hydroxysteroids of the 5 alpha-series. These results suggest that F1 and F3 are 3(17) beta-hydroxysteroid dehydrogenase and 3 alpha-hydroxysteroid dehydrogenase, respectively. Endogenous substrates for F4 could not be identified in this work. F1 showed the lowest Km value for reduction of aldehydes and ketones among the four reductases. It has been suggested that F1 is the primary enzyme responsible for the reduction of endogeneous aldehydes and xenobiotic aldehydes and ketones in vivo.
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Aldehído Oxidorreductasas/metabolismo , Cetona Oxidorreductasas/metabolismo , Hígado/enzimología , Aldehído Oxidorreductasas/aislamiento & purificación , Animales , Humanos , Isoenzimas/aislamiento & purificación , Isoenzimas/metabolismo , Cetona Oxidorreductasas/aislamiento & purificación , Riñón/enzimología , Cinética , Peso Molecular , Conejos , Especificidad de la Especie , Esteroides , Especificidad por Sustrato , PorcinosRESUMEN
NADPH-dependent enzymatic reduction of aromatic aldehydes and ketones observed in the cytosol of guinea pig liver was mediated by at least three distinct reductases (AR 1, AR 2, and AR 3), which were separated by DEAE-cellulose chromatography. By several procedures AR 2 and AR 3 were purified to homogeneity, but AR 1 could be purified only 30-fold because of the small amount. These enzymes were found to have similar molecular weights of 34,000 to 36,000 and similar Stokes radii of about 2.5 nm. AR 3 was identical to aldehyde reductase [EC 1.1.1.2] in substrate specificity for aromatic aldehydes and D-glucuronate and specific inhibition by barbiturates. AR 1 and AR 2 acted on aromatic ketones and cyclohexanone as well as aromatic aldehydes at optimal pHs of 5.4 and 6.0, respectively, and were immunochemically distinguished from AR 3. AR 1 was the most sensitive to sulfhydryl reagents, and AR 2 was more stable at 50 degrees C than the other enzymes. Similar heterogeneity was observed in the kidney enzymes, but other tissues had little aldehyde reductase activity and contained only AR 3. In addition, lung contained a high molecular weight aromatic ketone reductase different from the above reductases.
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Aldehído Oxidorreductasas/metabolismo , Cetona Oxidorreductasas/metabolismo , Hígado/enzimología , Aldehído Oxidorreductasas/aislamiento & purificación , Animales , Citosol/enzimología , Cobayas , Inmunodifusión , Cetona Oxidorreductasas/aislamiento & purificación , Cinética , Especificidad por SustratoRESUMEN
Peptaibols comprise a family of peptide antibiotics with high contents of 2-aminoisobutyric acid (Aib) residues and C-terminal amino alcohols. These peptides form alpha-helical structures leading to voltage-gated ion channels in lipid membranes. In the present study, amphiphilic helical Aib-containing peptides of various chain-lengths, Ac-(Aib-Lys-Aib-Ala)n-NH2 (n = 1-5), were designed to investigate the mechanisms of the aggregation and transmembrane orientation of helical motifs in lipid bilayer membranes. Peptide synthesis was performed by the conventional stepwise Fmoc solid-phase method. The crude peptides were obtained in high yields (66-85%) with high purities (69-95%). Conformational analysis of the synthetic peptides was performed by CD spectroscopy. It was found that these peptides take on highly helical structures, and the helicity of the peptides increases with an increase in chain-length. The longest peptide, Ac-(Aib-Lys-Aib-Ala)5-NH2, self-aggregates and adopts a barrel-stave conformation in liposomes. Ac-(Aib-Lys-Aib-Ala)5-NH2 exhibited potent antimicrobial activity against Gram-positive bacteria. Patch-clamp measurements revealed that this peptide can form well-defined ion channels with a long lifetime at relatively low transbilayer potentials and peptide concentrations. For this peptide, the single-channel conductance of the most frequent event is 227 pS, which could be related to a single-state tetrameric pore.
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Canales Iónicos/química , Canales Iónicos/metabolismo , Oligopéptidos/química , Oligopéptidos/metabolismo , Secuencia de Aminoácidos , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacología , Dicroismo Circular , Bacterias Grampositivas/efectos de los fármacos , Técnicas In Vitro , Membrana Dobles de Lípidos/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Modelos Químicos , Oligopéptidos/farmacología , Estructura Secundaria de Proteína , Relación Estructura-ActividadRESUMEN
We have developed in new-born mice a ventral tilted-horizontal slice preparation for pontine stimulation and recording of spontaneous respiratory-like rhythmic trains of glutamatergic excitatory postsynaptic potentials (EPSPs) in medullary neurons. Electrical stimulations (10-50 Hz for 100-500 ms) of the caudal pontine reticular formation triggered a burst of EPSPs, recycling of the rhythmic activity and persistent increase of the rhythmic behaviour. These results identify a ventral pontine pathway that promotes rhythm generating mechanisms in the medulla and probably derives from a population of lateral reticular neurons identified in the embryonic hindbrain and eliminated after inactivation of the early developmental gene Krox-20.