Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Más filtros












Intervalo de año de publicación
1.
Anaesthesia ; 75(2): 179-186, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31631314

RESUMEN

The aim of this study was to evaluate the effectiveness of cricoid and paralaryngeal force for oesophageal entrance occlusion during induction of anaesthesia. Seventy-four patients were included in this randomised, crossover study. The relative position of the glottis and outer anteroposterior diameter of the upper oesophageal entrance were assessed at baseline, after the application of 30 N cricoid and paralaryngeal force, and after induction of anaesthesia. The occlusion rate of the oesophageal entrance with cricoid and paralaryngeal force was assessed during direct laryngoscopy. The relative position of the upper oesophageal entrance to the glottis changed in 45 out of 74 patients after induction of anaesthesia and during direct laryngoscopy compared with the awake state. The application of cricoid and paralaryngeal force decreased the mean (SD) diameter of the upper oesophageal entrance to a similar degree in awake (8.5 (2.1) mm to 6.4 (1.7) mm and 6.5 (1.6) mm, respectively; p < 0.001) and anaesthetised (8.7 (2.2) mm to 6.5 (1.7) mm and (6.7 (1.9) mm, respectively; p < 0.001) states. During direct laryngoscopy, the occlusion rate of the oesophageal entrance was greater with cricoid compared with paralaryngeal force (46/74 vs. 26/74, respectively; p = 0.002). The relative position of the upper oesophageal entrance to the glottis may change after induction of anaesthesia and during direct laryngoscopy. Cricoid and paralaryngeal force both decrease the diameter of the upper oesophageal entrance in awake and anaesthetised states. Occlusion of the oesophageal entrance is achieved more frequently with cricoid force compared with paralaryngeal force during direct laryngoscopy.


Asunto(s)
Anestesia/métodos , Cartílago Cricoides/anatomía & histología , Esófago/anatomía & histología , Laringoscopía/métodos , Laringe/anatomía & histología , Ultrasonografía/métodos , Estudios Cruzados , Femenino , Humanos , Intubación Intratraqueal/métodos , Masculino , Persona de Mediana Edad , Presión
2.
Anaesthesia ; 70(8): 933-8, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25789568

RESUMEN

Securing a clear airway is important for successful fibreoptic intubation. We investigated whether the jaw-thrust manoeuvre in the 25° semi-sitting position improves airway clearance compared with the supine position in 88 anaesthetised patients randomly assigned to the two positions. After induction of anaesthesia, the fibreoptic bronchoscope was advanced into the mouth along the dorsum of the tongue during the jaw-thrust manoeuvre. Airway clearance was assessed at the level of the soft palate and epiglottis. Patients in the 25° semi-sitting position had clearer airways (judged subjectively by a three-level scale) than those in the supine position at the soft palate level (p = 0.012). At the level of the epiglottis, airway clearance was equally good in both positions. The mean (SD) times to view the vocal cord and carina were shorter in the 25° semi-sitting position (4 (1) s and 8 (1) s, respectively) compared with the supine position (6 (3) s and 11 (3) s; p < 0.001, respectively). The time to achieve intubation was also shorter in the 25° semi-sitting position (21 (5) s) than in the supine position (25 (7) s; p = 0.018).


Asunto(s)
Obstrucción de las Vías Aéreas/prevención & control , Tecnología de Fibra Óptica , Movimientos de la Cabeza , Intubación Intratraqueal/instrumentación , Maxilares , Femenino , Humanos , Intubación Intratraqueal/métodos , Masculino , Persona de Mediana Edad , Postura
3.
Anaesthesia ; 69(6): 591-7, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24749956

RESUMEN

During nasotracheal intubation, the tracheal tube passes through either the upper or lower pathway in the nasal cavity, and it has been reported to be safer that the tracheal tube passes though the lower pathway, just below the inferior turbinate. We evaluated the use of a nasogastric tube as a guide to facilitate tracheal tube passage through the lower pathway, compared with the 'conventional' technique (blind insertion of the tracheal tube into the nasal cavity). A total of 60 adult patients undergoing oral and maxillofacial surgery were included in the study. In 20 out of 30 patients (66.7%) with the nasogastric tube-guided technique, the tracheal tube passed through the lower pathway, compared with 8 out of 30 patients (26.7%) with the 'conventional' technique (p = 0.004). Use of the nasogastric tube-guided technique reduced the incidence and severity of epistaxis (p = 0.027), improved navigability (p = 0.034) and required fewer manipulations (p = 0.001) than the 'conventional' technique.


Asunto(s)
Intubación Intratraqueal/instrumentación , Adulto , Anciano , Epistaxis/prevención & control , Femenino , Humanos , Intubación Intratraqueal/efectos adversos , Intubación Intratraqueal/métodos , Masculino , Persona de Mediana Edad , Cavidad Nasal
4.
Cancer Chemother Pharmacol ; 71(3): 613-8, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23228989

RESUMEN

PURPOSE: Several cytotoxic chemotherapy regimens are active against metastatic breast cancer; however, benefits are modest and overall prognosis remains limited. For anthracycline and taxane-pretreated metastatic breast cancer, there remains a relative paucity of therapies with significant activity. This Phase II study evaluated the combination of capecitabine and oxaliplatin (XELOX) among patients with metastatic breast cancer being treated in the first- or second-line setting. METHODS: Patients received oxaliplatin 85 mg/m(2) on days 1 and 15, and capecitabine 1,500 mg/m(2) twice daily on days 1-7 and 15-21 of a 28-day cycle. Patients were treated until progression or intolerable toxicity. The primary objective was to estimate the objective response rate by the Response Evaluation Criteria in Solid Tumors (RECIST) criteria with tumor assessments every 8 weeks. RESULTS: Ten patients were treated of which 3 had received prior neurotoxic therapy in the metastatic setting. There were no confirmed complete responses, 5 patients had partial response, 4 patients had stable disease for at least 24 weeks, and one patient was unevaluable. Median time to progression (TTP) was 10.4 months (95% lower confidence bound [LCB]: 5.75 months), median progression-free survival (PFS) was 14.2 months (95% LCB: 6.14 months), and median overall survival (OS) was 19 months (95% LCB: 12.8 months). Multiple patients experienced pain syndromes and unusual neuropathies. Other common toxicities included fatigue, diarrhea, and nausea. CONCLUSIONS: XELOX is a promising regimen for anthracycline-pretreated metastatic breast cancer although careful patient selection is indicated and alternate dosing schedules should be explored to minimize neurologic morbidity.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Adolescente , Adulto , Anciano , Antibióticos Antineoplásicos/administración & dosificación , Antineoplásicos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Neoplasias de la Mama/patología , Capecitabina , Intervalos de Confianza , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Supervivencia sin Enfermedad , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/análogos & derivados , Humanos , Persona de Mediana Edad , Metástasis de la Neoplasia/tratamiento farmacológico , Compuestos Organoplatinos/administración & dosificación , Oxaliplatino , Adulto Joven
5.
Clin Exp Immunol ; 164(1): 137-44, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21352199

RESUMEN

Interleukin (IL)-12 is a key factor that induces T helper cell type 1-mediated immunity and inflammatory diseases. In some colitis models, such as IL-10 knock-out (KO) mice, IL-12 triggers intestinal inflammation. An abundant amount of IL-12 is produced by intestinal macrophages in response to stimulation by commensal bacteria in IL-10 KO mice. Intact bacteria are more potent inducers of macrophage IL-12 production than cell surface components in this model. This suggested that cell surface receptor signalling and intracellular pathogen recognition mechanisms are important for the induction of IL-12. We addressed the importance of intracellular recognition mechanisms and demonstrated that signal transducers and activator of transcription 1 (STAT1) signalling activated bacterial phagocytosis and was involved in the induction of abnormal IL-12 production. In IL-10 KO mouse bone marrow-derived (BM) macrophages, Escherichia coli stimulation induced increased IL-12p70 production compared to lipopolysaccharide combined with interferon (IFN)-γ treatment. Significant repression of IL-12 production was achieved by inhibition of phagocytosis with cytochalasin D, and inhibition of de novo protein synthesis with cycloheximide. Induction of IFN regulatory factors-1 and -8, downstream molecules of STAT1 and the key transcription factors for IK-12 transcription, following E. coli stimulation, were mediated by phagocytosis. Interestingly, STAT1 was activated after stimulation with E. coli in IL-10 KO BM macrophages, although IFN-γ could not be detected. These data suggest that molecules other than IFN-γ are involved in hyper-production mechanisms of IL-12 induced by E. coli stimulation. In conclusion, enteric bacteria stimulate excessive IL-12p70 production in IL-10 KO BM macrophages via phagocytosis-dependent signalling.


Asunto(s)
Escherichia coli/inmunología , Interleucina-10/deficiencia , Interleucina-12/inmunología , Macrófagos/inmunología , Animales , Western Blotting , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/microbiología , Células Cultivadas , Escherichia coli/fisiología , Interacciones Huésped-Patógeno/inmunología , Interferón gamma/farmacología , Interleucina-10/genética , Interleucina-12/genética , Interleucina-12/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fagocitosis/inmunología , Fosforilación/efectos de los fármacos , Biosíntesis de Proteínas/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción STAT1/inmunología , Factor de Transcripción STAT1/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología
6.
Nanotechnology ; 21(50): 505201, 2010 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-21098937

RESUMEN

We report a simple and manageable growth method for placing dense three-dimensional Ge quantum dot (QD) arrays in a uniform or a graded size distribution, based on thermally oxidizing stacked poly-SiGe in a layer-cake technique. The QD size and spatial density in each stack can be modulated by conditions of the Ge content in poly-Si(1-x)Ge(x), oxidation, and the underlay buffer layer. Size-dependent internal structure, strain, and photoluminescence properties of Ge QDs are systematically investigated. Optimization of the processing conditions could be carried out for producing dense Ge QD arrays to maximize photovoltaic efficiency.

7.
Hematol Oncol ; 27(1): 11-6, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18668698

RESUMEN

Arsenic trioxide (As(2)O(3)) has established clinical activity in acute promyelocytic leukaemia and has pre-clinical data suggesting activity in lymphoid malignancies. Cell death from As(2)O(3) may be the result of oxidative stress. Agents which deplete intracellular glutathione, such as ascorbic acid (AA), may potentiate arsenic-mediated apoptosis. This multi-institution phase II study investigated a novel dosing schedule of As(2)O(3) and AA in patients with relapsed or refractory lymphoid malignancies. Patients received As(2)O(3) 0.25 mg/kg iv and AA 1000 mg iv for five consecutive days during the first week of each cycle followed by twice weekly infusions during weeks 2-6. Cycles were repeated every 8 weeks. The primary end point was objective response. In a subset of patients, sequential levels of intracellular glutathione and measures of Bcl-2 and Bax gene expression were evaluated in peripheral blood mononuclear cells during treatment. Seventeen patients were enrolled between March 2002 and February 2004. The median age was 71, and the majority of enrolled patients had non-Hodgkin's lymphoma (12/17). Sixteen patients were evaluable, and one patient with mantle cell lymphoma achieved an unconfirmed complete response after five cycles of therapy for an overall response rate of 6%. The trial, which had been designed as a two-stage study, was closed after the first stage analysis due to lack of activity. Haematologic toxicities were the most commonly reported events in this heavily pre-treated population, and comprised the majority of grade 3 and 4 toxicities. Intracellular depletion of glutathione was not consistently observed during treatment. As(2)O(3) and AA in this novel dosing strategy was generally well tolerated but had limited activity in patients with relapsed and refractory lymphoid malignancies.


Asunto(s)
Arsenicales/uso terapéutico , Ácido Ascórbico/uso terapéutico , Leucemia/tratamiento farmacológico , Linfoma/tratamiento farmacológico , Óxidos/toxicidad , Óxidos/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Trióxido de Arsénico , Ácido Ascórbico/toxicidad , Femenino , Glutatión/metabolismo , Humanos , Leucemia Linfocítica Crónica de Células B/tratamiento farmacológico , Linfoma no Hodgkin/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Seguridad
8.
J Environ Manage ; 85(4): 891-9, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17234326

RESUMEN

A multiple regression analysis was used to develop two predictive models of lower heating value (LHV) for municipal solid waste (MSW), using 180 samples gathered from cities and counties in Taiwan during 2001-2002. These models are referred to as the original proposed model (OPM) and the simplified model (SM). The coefficients of multiple determinations for the OPM and SM were 0.983 and 0.975, respectively. To verify the feasibility of the models, a demonstration program based on sampling of MSW in Kaohsiung City was conducted. As a result, the OPM showed superior precision in terms of relative percentage deviation (RPD) and mean absolute percentage error (MAPE), when compared to the conventional models based on the proximate analysis, physical composition and ultimate analysis. The SM was derived by neglecting the three minor physical components used in the OPM. The resulting SM was less precise when compared to the OPM, but it was still acceptable, with a precision level better than the conventional models. It was concluded that the predictability of empirical models could be improved significantly through selection of the appropriate physical components and multiple regression analysis.


Asunto(s)
Incineración , Modelos Teóricos , Administración de Residuos/métodos , Ciudades , Geografía , Análisis de Regresión , Taiwán , Administración de Residuos/estadística & datos numéricos
9.
Clin Rheumatol ; 22(3): 240-3, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14505220

RESUMEN

Although peripheral blood eosinophilia is observed in patients with active inflammatory rheumatoid arthritis (RA), RA is not a recognised cause of pulmonary eosinophilia. We describe a 55-year-old woman affected by chronic eosinophilic pneumonia (CEP) concomitantly with an initiation of RA. Both diseases responded rapidly and completely to high-dose corticosteroid therapy. In this patient, the initiation of RA and CEP was directly related, implying a common pathogenetic link between the two diseases.


Asunto(s)
Artritis Reumatoide/complicaciones , Artritis Reumatoide/diagnóstico , Eosinofilia Pulmonar/complicaciones , Eosinofilia Pulmonar/diagnóstico , Artritis Reumatoide/tratamiento farmacológico , Biopsia con Aguja , Análisis Químico de la Sangre , Enfermedad Crónica , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Inmunohistoquímica , Metilprednisolona/uso terapéutico , Persona de Mediana Edad , Prednisolona/uso terapéutico , Eosinofilia Pulmonar/tratamiento farmacológico , Radiografía Torácica , Medición de Riesgo , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
10.
Chemosphere ; 44(5): 1185-92, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11513407

RESUMEN

Fly ash is a particulate substance containing metal oxides, carbon and other microelements. In this study, fly ashes with different quantities of carbon and minerals prepared by a thermal process in the laboratory were used as adsorbents to investigate the contribution of precipitation and adsorption to the removal of aqueous Cu(II). Experimental results showed that the specific surface area of fly ash increased linearly with the quantity of carbon. The specific surface areas of the carbon and mineral fraction were 60 m2/g and 0.68 m2/g, respectively. The specific adsorption capacities of carbon ranged from 2.2 to 2.8 mg Cu/g carbon, while those for mineral were only about 0.63 to approximately 0.81 mg Cu/g mineral. Consequently, the carbon fraction in fly ash was important in the removal of Cu(II) at pH 5. However, Cu(II) removal owing to precipitation increases with a decreasing carbon fraction and the contribution of copper precipitation was estimated to be approximately 23% to approximately 82% of total removal, depending on the carbon fraction of fly ash.


Asunto(s)
Carbono/química , Cobre/química , Adsorción , Conservación de los Recursos Naturales , Incineración , Minerales , Eliminación de Residuos , Solubilidad
11.
J Biol Chem ; 276(1): 715-21, 2001 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-11024038

RESUMEN

Rat prolactin in the dense cores of secretory granules of the pituitary gland is a Lubrol-insoluble aggregate. In GH(4)C(1) cells, newly synthesized rat prolactin and growth hormone were soluble, but after 30 min about 40% converted to a Lubrol-insoluble form. Transport from the endoplasmic reticulum is necessary for conversion to Lubrol insolubility, since incubating cells with brefeldin A or at 15 degrees C reduced formation of insoluble rat (35)S-prolactin. Formation of Lubrol-insoluble aggregates has protein and cell specificity; newly synthesized human growth hormone expressed in AtT20 cells underwent a 40% conversion to Lubrol insolubility with time, but albumin did not, and human growth hormone expressed in COS cells underwent less than 10% conversion to Lubrol insolubility. del32-46 growth hormone, a naturally occurring form of growth hormone, and P89L growth hormone underwent conversion, although they were secreted more slowly, indicating that there is some tolerance in structural requirements for aggregation. An intracellular compartment with an acidic pH is not necessary for conversion to Lubrol insolubility, because incubation with chloroquine or bafilomycin slowed, but did not prevent, the conversion. GH(4)C(1) cells treated with estradiol, insulin, and epidermal growth factor accumulate more secretory granules and store more prolactin, but not more growth hormone, than untreated cells; Lubrol-insoluble aggregates of prolactin and growth hormone formed to the same extent in hormone-treated or untreated GH(4)C(1) cells, but prolactin was retained longer in hormone-treated cells. These findings indicate that aggregation alone is not sufficient to cause retention of secretory granule proteins, and there is an additional selective process.


Asunto(s)
Hormona de Crecimiento Humana/metabolismo , Macrólidos , Hipófisis/metabolismo , Polietilenglicoles/farmacología , Prolactina/metabolismo , Vesículas Secretoras/metabolismo , Animales , Antibacterianos/farmacología , Brefeldino A/farmacología , Células COS , Cloroquina/farmacología , Dinitrobencenos/farmacología , Retículo Endoplásmico/química , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Factor de Crecimiento Epidérmico/farmacología , Estradiol/farmacología , Hormona de Crecimiento Humana/química , Hormona de Crecimiento Humana/genética , Concentración de Iones de Hidrógeno , Insulina/farmacología , Mutación , Hipófisis/citología , Hipófisis/efectos de los fármacos , Prolactina/química , Prolactina/genética , Transporte de Proteínas/efectos de los fármacos , Ratas , Vesículas Secretoras/química , Vesículas Secretoras/efectos de los fármacos , Solubilidad/efectos de los fármacos , Especificidad por Sustrato , Células Tumorales Cultivadas , Ultracentrifugación
12.
Pharm Res ; 17(6): 670-6, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10955839

RESUMEN

PURPOSE: To identify the growth conditions that would favor the development of a functional primary culture of pigmented rabbit corneal epithelial cells on a permeable support comparable to the intact tissue in bioelectric properties. METHODS: Rabbit corneal epithelial cells were isolated and cultured on precoated fibronectin/collagen/laminin permeable filters. Cells were grown at an air-interface with supplemented DMEM/F12 medium. Immunofluorescence and electron microscopy techniques, respectively, were used to confirm cornea-specific marker and morphological features. Permeability of the cell layers to model polar compounds was evaluated using 14C-mannitol, fluorescein isothiocyanate (FITC) and fluorescein isothiocyanate-dextran of 4,000 molecular weight (FD4). RESULTS: We found that culturing the epithelial cells at an air-interface (AIC) was a critical factor in the formation of tight cell layer and that omitting fetal bovine serum and keeping the concentration of epidermal growth factor at 1 ng/ml were equally important. Phenotypically, the AIC cell layers were found to express cornea-specific 64 kD keratin. Compared with cells cultured under the liquid-covered (LCC) condition, those cultured under AIC exhibited a significantly higher peak transepithelial electrical resistance (TEER) of up to 5 kOhm x cm2, a higher potential difference (PD) of up to 26 mV, and an estimated short-circuit current (Ieq) of 5 microA/cm2 after 7-8 days of culture. These values were comparable to those in the excised cornea. Consistent with the TEER, the AIC cell layers were 4-40 times less permeable to paracellular markers than their LCC counterpart. CONCLUSIONS: The AIC model merits further characterization of drug transport mechanisms as well as drug, formulation, physiological, and pathological factors influencing corneal epithelial drug transport.


Asunto(s)
Córnea/metabolismo , Farmacocinética , Animales , Células Cultivadas , Córnea/citología , Células Epiteliales/metabolismo , Técnica del Anticuerpo Fluorescente , Inmunohistoquímica , Masculino , Microscopía Electrónica , Conejos
13.
Scand J Infect Dis ; 32(1): 101-2, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10716090

RESUMEN

Tsutsugamushi Disease is an acute febrile illness caused by Rickettsia tsutsugamushi, which enters into the human bloodstream through the bite of leptotrombidium. It is characterized by eschar, fever and cutaneous rash. Pericardial effusion in Tsutsugamushi Disease is not a common manifestation, although a high rate of effusion was reported in autopsy in those who had died of the disease. Here, we report a case of Tsutsugamushi pericarditis documented by indirect immunofluorescent test of pericardial fluid, and give a brief review of the literature.


Asunto(s)
Orientia tsutsugamushi/inmunología , Pericarditis/microbiología , Tifus por Ácaros/microbiología , Anciano , Anticuerpos Antibacterianos/sangre , Especificidad de Anticuerpos , Ecocardiografía , Resultado Fatal , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Masculino , Derrame Pericárdico/microbiología , Pericarditis/inmunología , Tifus por Ácaros/patología , Úlcera Cutánea/patología
14.
Biochemistry ; 36(16): 4959-68, 1997 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-9125518

RESUMEN

The ability of amphotericin B (AmB) to form ion-permeable channels in cholesterol containing lipid bilayers was studied by UV/visible absorbance, circular dichroism, and fluorescence spectroscopy. Stable liposomes composed of distearoylphosphatidylcholine, cholesterol, distearoylphosphatidylglycerol, and AmB were prepared so that a wide range of AmB concentrations in the bilayer could be studied. Singular value decomposition analysis (Henry & Hofrichter, 1992) of the circular dichroism spectra of AmB at different AmB/lipid ratios suggests that AmB exists primarily in only two states in the bilayer, a "monomeric" state and an "aggregated" state. The transition from the "monomeric" to the "aggregated" state begins to occur at a critical concentration of 1 AmB per 1000 lipids in the membrane and coincides with the appearance of channel activity. The data support the recent theoretical conclusions of Weakliem et al. (1995) which predict that pore formation in the lipid bilayer will occur when the drug molecule concentration exceeds a critical value. At this critical concentration, it is calculated that a minimum number of 16 AmB molecules per liposome are required to observe channel activity. The results are consistent with the sterol-dependent AmB channel models proposed by de Kruijff and Demel (1974), Andreoli (1974), and Khutorsky (1992). To further elucidate the effects of sterol on AmB-mediated channel formation, liposomes were prepared with varying ratios of cholesterol and AmB. At cholesterol mole percentages greater than 1, channel activity was observed to occur at AmB concentrations just above the critical value. Previous reports show that cholesterol forms "tail-to-tail" dimers at mole percentages greater than 2 (Harris et al., 1995). This suggests that formation of the bilayer-spanning channels by AmB is initiated most efficiently when the tail-to-tail dimer of cholesterol is present. Although the structural nature of the AmB channel could not be unambiguously determined, these experiments provide further evidence in support of the widely held view that AmB's primary mechanism of killing fungal cells occurs by forming ion-permeable channels.


Asunto(s)
Anfotericina B/metabolismo , Canales Iónicos/metabolismo , Membrana Dobles de Lípidos/metabolismo , Colesterol/metabolismo , Dicroismo Circular , Dimetilsulfóxido , Concentración de Iones de Hidrógeno , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta
15.
Gene ; 170(2): 281-3, 1996 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-8666260

RESUMEN

We have isolated and characterized the immediate (1651 bP) 5'-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5'-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2 binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present.


Asunto(s)
N-Acetilglucosaminiltransferasas/genética , Secuencia de Aminoácidos , Clonación Molecular , ADN , Humanos , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Secuencias Reguladoras de Ácidos Nucleicos
16.
J Biotechnol ; 34(2): 149-55, 1994 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-7764847

RESUMEN

To develop a test for diagnosis of human immunodeficiency virus-1 (HIV-1) exposure sensitivity, a part of the gag gene was cloned and expressed in Escherichia coli, using expression vectors containing a trp promoter. The immunoreactivity of recombinant protein was determined using HIV-1 specific antibodies in a Western blot analysis. The recombinant plasmid, pYHCgag3, gag gene was fused to the trpE' gene linked to the hydroxylamine (HA) cleavage recognition sequence which was induced to overexpress a core antigen (gag a.a. 121-398 from plasmid BH10) as fusion protein in the form of insoluble inclusion body. Recombinant gag was purified by a simple single step purification procedure. After partial purification of inclusion bodies and subject to the HA-cleavage treatment, gag protein was further purified to homogeneity using DEAE-Sepharose chromatography. The purified core antigen offered reliable results with high sensitivity and specificity for identification of HIV-1 antibodies when tested in the enzyme-linked immunosorbent assay (ELISA). These results suggest that mass production of recombinant core antigen will provide a valuable resource to HIV-1 serodiagnostics for the screening of large groups of blood donors to prevent HIV-1 infection.


Asunto(s)
Productos del Gen gag/biosíntesis , Genes gag , VIH-1/metabolismo , Proteínas Recombinantes/biosíntesis , Clonación Molecular/métodos , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática/métodos , Escherichia coli , Productos del Gen gag/aislamiento & purificación , Vectores Genéticos , VIH-1/genética , Plásmidos , Proteínas Recombinantes/aislamiento & purificación , Mapeo Restrictivo
17.
Biochem Biophys Res Commun ; 196(2): 780-8, 1993 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-8240354

RESUMEN

Comparative nucleotide sequence studies of a 2.4-kb cDNA fragment (nt -49 to 2361) of Korean-type hepatitis C virus (HCV) were carried out. The nt sequences of the Korean HCV isolates have stronger sequence homologies with type II HCV (Japanese HCV-BK) than with types I (HCV-1) or III (HCV-6). In addition, the net sequences of a part of the core region of ten different samples confirmed that prevalent HCV in Korea belongs to type II with the exception of one sample which belongs to type III. The nt sequence of a cDNA fragment of E2/NS1 region of HCV, from six different serum samples, which comprises the hypervariable regions-1 (HVR-1) and -2 (HVR-2), revealed sequence heterogeneity with type II HCV (75.4 to 80.7% nt homology and 75.5 to 79.7% amino acid homology). However, it was relatively well conserved among the Korean isolates, in fact, aa sequences of HVR-2 as well as HVR-1, converged into two groups. Also we found consensus sequences (T.V.G..AGRTT.G..SLE......K) in HVR-1. Thus, we propose that the conserved patterns in HVR-1 and -2 are characteristics of the six different Korean isolates.


Asunto(s)
Secuencia de Consenso , Variación Genética , Genoma Viral , Hepacivirus/clasificación , Hepacivirus/genética , ARN Viral/sangre , Secuencia de Aminoácidos , Secuencia de Bases , Cartilla de ADN , ADN Complementario , Hepacivirus/aislamiento & purificación , Hepatitis C/sangre , Hepatitis C/microbiología , Humanos , Corea (Geográfico) , Datos de Secuencia Molecular , Oligonucleótidos Antisentido , Reacción en Cadena de la Polimerasa , ARN Viral/aislamiento & purificación , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Proteínas Estructurales Virales/genética
18.
Biotechnol Bioeng ; 27(10): 1482-9, 1985 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18553595

RESUMEN

The characteristics of the degradation of cellulose, soluble starch, and glucose in the acidogenic phase and the effects of the substrate loading rate and biological solids retention time on the methanogenic phase of anaerobic digestion were investigated. The results obtained from continuous experiments using laboratory-scale anaerobic chemostat reactors elucidated the true rate-limiting step of anaerobic digestion. The specific rate of substrate utilization decreased in the following order: glucose, soluble starch, acetic acid, and cellulose. The rate of the hydrolysis of cellulose was so low that this was shown to be the rate-limiting step in overall anaerobic digestion. Among methanogenic bacteria Methanosarcina would provide a higher substrate utilization rate than Methanothrix, and the maximum allowable substrate loading rate in the methanogenic phase was 11.2 g acetic acid/L day.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...