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1.
Acta Psychiatr Scand ; 140(3): 205-216, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31265120

RESUMEN

OBJECTIVE: Several studies have found an increase in hippocampal volume following electroconvulsive therapy (ECT), but the effect on cortical thickness has been less investigated. We aimed to examine the effects of ECT on cortical thickness and their associations with clinical outcome. METHOD: Using 3 Tesla MRI scanner, we obtained T1-weighted brain images of 18 severely depressed patients at three time points: before, right after and 6 months after a series of ECT. The thickness of 68 cortical regions was extracted using Free Surfer, and Linear Mixed Model was used to analyze the longitudinal changes. RESULTS: We found significant increases in cortical thickness of 26 regions right after a series of ECT, mainly within the frontal, temporal and insular cortex. The thickness returned to the baseline values at 6-month follow-up. We detected no significant decreases in cortical thickness. The increase in the thickness of the right lateral orbitofrontal cortex was associated with a greater antidepressant effect, r = 0.75, P = 0.0005. None of the cortical regions showed any associations with cognitive side effects. CONCLUSION: The increases in cortical thickness induced by ECT are transient. Further multimodal MRI studies should examine the neural correlates of these increases and their relationship with the antidepressant effect.


Asunto(s)
Corteza Cerebral/patología , Trastorno Depresivo/patología , Trastorno Depresivo/terapia , Terapia Electroconvulsiva , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Corteza Cerebral/diagnóstico por imagen , Trastorno Depresivo/diagnóstico por imagen , Femenino , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
2.
Mol Psychiatry ; 20(10): 1179-87, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26055427

RESUMEN

In a positron-emission tomography (PET) study with the ß-amyloid (Aß) tracer [(18)F]-florbetaben, we previously showed that Aß deposition in transgenic mice expressing Swedish mutant APP (APP-Swe) mice can be tracked in vivo. γ-Secretase modulators (GSMs) are promising therapeutic agents by reducing generation of the aggregation prone Aß42 species without blocking general γ-secretase activity. We now aimed to investigate the effects of a novel GSM [8-(4-Fluoro-phenyl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl]-[1-(3-methyl-[1,2,4]thiadiazol-5-yl)-piperidin-4-yl]-amine (RO5506284) displaying high potency in vitro and in vivo on amyloid plaque burden and used longitudinal Aß-microPET to trace individual animals. Female transgenic (TG) APP-Swe mice aged 12 months (m) were assigned to vehicle (TG-VEH, n=12) and treatment groups (TG-GSM, n=12), which received daily RO5506284 (30 mg kg(-1)) treatment for 6 months. A total of 131 Aß-PET recordings were acquired at baseline (12 months), follow-up 1 (16 months) and follow-up 2 (18 months, termination scan), whereupon histological and biochemical analyses of Aß were performed. We analyzed the PET data as VOI-based cortical standard-uptake-value ratios (SUVR), using cerebellum as reference region. Individual plaque load assessed by PET remained nearly constant in the TG-GSM group during 6 months of RO5506284 treatment, whereas it increased progressively in the TG-VEH group. Baseline SUVR in TG-GSM mice correlated with Δ%-SUVR, indicating individual response prediction. Insoluble Aß42 was reduced by 56% in the TG-GSM versus the TG-VEH group relative to the individual baseline plaque load estimates. Furthermore, plaque size histograms showed differing distribution between groups of TG mice, with fewer small plaques in TG-GSM animals. Taken together, in the first Aß-PET study monitoring prolonged treatment with a potent GSM in an AD mouse model, we found clear attenuation of de novo amyloidogenesis. Moreover, longitudinal PET allows non-invasive assessment of individual plaque-load kinetics, thereby accommodating inter-animal variations.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Placa Amiloide/tratamiento farmacológico , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/patología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Compuestos de Anilina/síntesis química , Compuestos de Anilina/farmacología , Animales , Estudios de Casos y Controles , Angiopatía Amiloide Cerebral/terapia , Modelos Animales de Enfermedad , Femenino , Estudios Longitudinales , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Placa Amiloide/diagnóstico por imagen , Placa Amiloide/enzimología , Placa Amiloide/metabolismo , Tomografía de Emisión de Positrones/métodos , Estilbenos/síntesis química , Estilbenos/farmacología
3.
Ultraschall Med ; 36(6): 550-62; quiz 563-5, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26274379

RESUMEN

Ultrasound elastography is an established method for characterization of focal lesions in the breast. Different techniques and analyses of the images may be used for the characterization. This article addresses the use of ultrasound elastography in breast cancer diagnosis. In the first part of the article the techniques behind both strain- and shear-wave-elastography are explained and followed by a section on how to obtain adequate elastography images and measurements. In the second part of the article the application of elastography as an adjunct to B-mode ultrasound in clinical practice is described, and the potential diagnostic gains and limitations of elastography are discussed.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Diagnóstico por Imagen de Elasticidad/métodos , Ultrasonografía Mamaria/métodos , Femenino , Humanos , Imagen Multimodal , Sensibilidad y Especificidad
4.
Ultraschall Med ; 36(4): 369-74, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25905815

RESUMEN

PURPOSE: To evaluate the ability of strain elastography to predict malignancy in patients with soft tissue tumors, and to compare three evaluation methods of strain elastography: strain ratios, strain histograms and visual scoring. MATERIALS AND METHODS: 60 patients with 61 tumors were analyzed in the study. All patients were referred due to suspicion of malignant soft tissue tumors after diagnostic imaging (contrast-enhanced MRI, CT or PET-CT). Ultrasound-guided biopsy was preceded by the recording of strain elastography video clips, which were evaluated in consensus between three investigators. Strain ratio, strain histogram analysis and visual scoring using a five-point visual scale were compared with the final pathology from either biopsy or resection of the tumors. RESULTS: The difference between the mean strain ratio for malignant and benign tumors was significant (p = 0.043). The mean strain ratios for malignant and benign tumors were 1.94 (95% CI [0.37; 10.21]) and 1.35 (95% CI [0.32; 5.63]), respectively. There were no significant differences for strain histograms or visual scoring. Liposarcomas had lower mean strain ratio, strain histogram values, and visual scoring than other malignant tumors. When analyzing a subgroup of patients without fat-containing tumors (n = 46), based on appearance on MRI or CT, the difference between the mean strain ratios for malignant and benign tumors increased (p = 0.014). CONCLUSION: The mean strain ratios of malignant tumors were significantly higher than the mean strain ratios of benign tumors. There was no significant difference for strain histograms and visual scoring. Strain ratios may be used as an adjunct in soft tissue tumor diagnosis, possibly minimizing the number of biopsies.


Asunto(s)
Diagnóstico por Imagen de Elasticidad/métodos , Sarcoma/diagnóstico por imagen , Neoplasias de los Tejidos Blandos/diagnóstico por imagen , Biopsia con Aguja , Medios de Contraste , Diagnóstico Diferencial , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Imagen Multimodal , Tomografía de Emisión de Positrones , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos X , Ultrasonografía Intervencional
5.
Neurobiol Dis ; 62: 73-85, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24051278

RESUMEN

Pilocarpine-induced status epilepticus (SE), which results in temporal lobe epilepsy (TLE) in rodents, activates the JAK/STAT pathway. In the current study, we evaluate whether brief exposure to a selective inhibitor of the JAK/STAT pathway (WP1066) early after the onset of SE affects the severity of SE or reduces later spontaneous seizure frequency via inhibition of STAT3-regulated gene transcription. Rats that received systemic WP1066 or vehicle at the onset of SE were continuously video-EEG monitored during SE and for one month to assess seizure frequency over time. Protein and/or mRNA levels for pSTAT3, and STAT3-regulated genes including: ICER, Gabra1, c-myc, mcl-1, cyclin D1, and bcl-xl were evaluated in WP1066 and vehicle-treated rats during stages of epileptogenesis to determine the acute effects of WP1066 administration on SE and chronic epilepsy. WP1066 (two 50mg/kg doses) administered within the first hour after onset of SE results in transient inhibition of pSTAT3 and long-term reduction in spontaneous seizure frequency. WP1066 alters the severity of chronic epilepsy without affecting SE or cell death. Early WP1066 administration reduces known downstream targets of STAT3 transcription 24h after SE including cyclin D1 and mcl-1 levels, known for their roles in cell-cycle progression and cell survival, respectively. These findings uncover a potential effect of the JAK/STAT pathway after brain injury that is physiologically important and may provide a new therapeutic target that can be harnessed for the prevention of epilepsy development and/or progression.


Asunto(s)
Encéfalo/fisiopatología , Piridinas/uso terapéutico , Factor de Transcripción STAT3/antagonistas & inhibidores , Estado Epiléptico/tratamiento farmacológico , Tirfostinos/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Muerte Celular , Giro Dentado/efectos de los fármacos , Giro Dentado/metabolismo , Modelos Animales de Enfermedad , Electroencefalografía , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Fosforilación , Pilocarpina , Piridinas/farmacocinética , Ratas , Ratas Sprague-Dawley , Factor de Transcripción STAT3/metabolismo , Convulsiones/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Estado Epiléptico/inducido químicamente , Estado Epiléptico/metabolismo , Estado Epiléptico/fisiopatología , Tirfostinos/farmacocinética
6.
J Neurosci Res ; 92(10): 1307-18, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24801281

RESUMEN

Neurotrophins, such as brain-derived neurotrophic factor (BDNF), are initially expressed in a precursor form (e.g., pro-BDNF) and cleaved to form mature BDNF (mBDNF). After pilocarpine-induced status epilepticus (SE), increases in neurotrophins regulate a wide variety of cell-signaling pathways, including prosurvival and cell-death machinery in a receptor-specific manner. Pro-BDNF preferentially binds to the p75 neurotrophin receptor (p75(NTR) ), whereas mBDNF is the major ligand of the tropomyosin-related kinase receptor. To elucidate a potential role for p75(NTR) in acute stages of epileptogenesis, rats were injected prior to and at onset of SE with LM11A-31, a small-molecule ligand that binds to p75(NTR) to promote survival signaling and inhibit neuronal cell death. Modulation of early p75(NTR) signaling and its effects on electrographic SE, SE-induced neurodegeneration, and subsequent spontaneous seizures were examined after LM11A-31 administration. Despite an established neuroprotective effect of LM11A-31 in several animal models of neurodegenerative disorders (e.g., Alzheimer's disease, traumatic brain injury, and spinal cord injury), high-dose LM11A-31 administration prior to and at onset of SE did not reduce the intensity of electrographic SE, prevent SE-induced neuronal cell injury, or inhibit the progression of epileptogenesis. Further studies are required to understand the role of p75(NTR) activation during epileptogenesis and in seizure-induced cell injury in the hippocampus, among other potential cellular pathologies contributing to the onset of spontaneous seizures. Additional studies utilizing more prolonged treatment with LM11A-31 are required to reach a definite conclusion on its potential neuroprotective role in epilepsy.


Asunto(s)
Anticonvulsivantes/uso terapéutico , Isoleucina/análogos & derivados , Morfolinas/uso terapéutico , Receptores de Factor de Crecimiento Nervioso/metabolismo , Estado Epiléptico/tratamiento farmacológico , Análisis de Varianza , Animales , Anticonvulsivantes/sangre , Ondas Encefálicas/efectos de los fármacos , Modelos Animales de Enfermedad , Electroencefalografía , Fluoresceínas , Isoleucina/sangre , Isoleucina/uso terapéutico , Morfolinas/sangre , Agonistas Muscarínicos/toxicidad , Proteínas del Tejido Nervioso , Pilocarpina/toxicidad , Ratas , Ratas Sprague-Dawley , Receptores de Factores de Crecimiento , Receptores de Factor de Crecimiento Nervioso/química , Análisis Espectral , Estado Epiléptico/inducido químicamente , Factores de Tiempo
7.
Br J Neurosurg ; 26(1): 94-5, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21591854

RESUMEN

In this article, we report on a rare case of spinal seeding from a cerebral anaplastic oligodendroglioma presenting with signs of medullar compression. We discuss the prevalence, mechanisms and imaging findings of spinal seeding in various gliomas. A suitable clinical treatment and follow up for these patients is suggested.


Asunto(s)
Neoplasias Encefálicas , Siembra Neoplásica , Oligodendroglioma/secundario , Paraplejía/etiología , Neoplasias de la Columna Vertebral/secundario , Adulto , Resultado Fatal , Humanos , Imagen por Resonancia Magnética , Masculino
8.
Sci Rep ; 12(1): 13284, 2022 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-35918401

RESUMEN

Pulmonary hypertension (PH) is classified into five clinical diagnostic groups, including group 1 [idiopathic pulmonary arterial hypertension (IPAH) and connective tissue disease-associated PAH (CTD-aPAH)] and group 4 (chronic thromboembolic pulmonary hypertension (CTEPH)). PH is a progressive, life-threatening, incurable disease. The pathological mechanisms underlying PH remain elusive; recent evidence has revealed that abnormal metabolic activities in the endothelium may play a crucial role. This research introduces a novel approach for studying PH endothelial function, building on the genome-scale metabolic reconstruction of the endothelial cell (EC) to investigate intracellular metabolism. We demonstrate that the intracellular metabolic activities of ECs in PH patients cluster into four phenotypes independent of the PH diagnosis. Notably, the disease severity differs significantly between the metabolic phenotypes, suggesting their clinical relevance. The significant metabolic differences between the PH phenotypes indicate that they may require different therapeutic interventions. In addition, diagnostic capabilities enabling their identification is warranted to investigate whether this opens a novel avenue of precision medicine.


Asunto(s)
Enfermedades del Tejido Conjuntivo , Hipertensión Pulmonar , Endotelio/metabolismo , Hipertensión Pulmonar Primaria Familiar/metabolismo , Humanos , Pulmón/metabolismo
9.
AJNR Am J Neuroradiol ; 43(2): 223-229, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34969666

RESUMEN

BACKGROUND AND PURPOSE: The Normal Pressure Hydrocephalus Radscale is a combined scoring of 7 different structural imaging markers on preoperative brain CT or MR imaging in patients with idiopathic normal pressure hydrocephalus: callosal angle, Evans Index, Sylvian fissure dilation, apical sulcal narrowing, mean temporal horn diameter, periventricular WM lesions, and focal sulcal dilation. The purpose of this retrospective study was to assess the performance of the Normal Pressure Hydrocephalus Radscale in distinguishing idiopathic normal pressure hydrocephalus shunt responders from nonresponders. MATERIALS AND METHODS: The preoperative MR imaging and CT scans of 119 patients with idiopathic normal pressure hydrocephalus were scored using the Normal Pressure Hydrocephalus Radscale. A summary shunt-response score assessed within 6 months from ventriculoperitoneal shunt surgery, combining the effect on cognition, gait, and urinary incontinence, was used as a reference. The difference between the mean Normal Pressure Hydrocephalus Radscale for responders and nonresponders was tested using the Student t test. The area under the curve was calculated for the Normal Pressure Hydrocephalus Radscale to assess shunt response. To ascertain reproducibility, we assessed the interobserver agreement between the 2 independent observers as intraclass correlation coefficients for the Normal Pressure Hydrocephalus Radscale for 74 MR imaging scans and 19 CT scans. RESULTS: Ninety-four (79%) of 119 patients were shunt responders. The mean Normal Pressure Hydrocephalus Radscale score for shunt responders was 8.35 (SD, 1.53), and for nonresponders, 7.48 (SD, 1.53) (P = .02). The area under the curve for the Normal Pressure Hydrocephalus Radscale was 0.66 (range, 0.54-0.78). The intraclass correlation coefficient for the Normal Pressure Hydrocephalus Radscale was 0.86 for MR imaging and 0.82 for CT. CONCLUSIONS: The Normal Pressure Hydrocephalus Radscale showed moderate discrimination for shunt response but cannot, on its own, be used for selecting patients with idiopathic normal pressure hydrocephalus for shunt surgery.


Asunto(s)
Hidrocéfalo Normotenso , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Encéfalo/cirugía , Humanos , Hidrocéfalo Normotenso/complicaciones , Hidrocéfalo Normotenso/diagnóstico por imagen , Hidrocéfalo Normotenso/cirugía , Neuroimagen/métodos , Reproducibilidad de los Resultados , Estudios Retrospectivos
11.
Ultraschall Med ; 36(6): 637-8, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27045149
12.
Am J Transplant ; 9(6): 1420-6, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19459826

RESUMEN

We previously described a 54% decline in renal function at 6 months after lung transplantation (LTx). We hypothesized that this decline is a very early event following LTx. Thirty-one consecutive patients (16 females/15 males), mean age 49 (+/-13) years, with emphysema, cystic fibrosis/bronchiectasis or idiopathic pulmonary fibrosis were included in an analysis of renal function before and after LTx. The glomerular filtration rate (GFR) was measured using the (51)Cr-ethylenediaminetetra acetic acid plasma clearance single injection technique (mGFR) at baseline before transplantation and at 1, 2, 3 and 12 weeks postoperatively. Mean mGFR declined from 103 +/- 18 to 65 +/- 22, 53 +/- 16 and 57 +/- 18 mL/min/1.73m(2) at 1-, 3- and 12-weeks post-LTx (p < 0.0001), respectively. In a time-dependent repeated measures ANOVA, risk factors for a decline in mGFR posttransplant included: time (p < 0.0001), acute renal failure within 2 weeks post-LTx (p = 0.0003), use of heart and lung machine (p = 0.04), and the use of ephedrine (p = 0.048), as well as increasing age, older than 18 years at LTx (p = 0.006). These data demonstrate that renal function, measured with an isotope method, decreases dramatically during the first week after LTx.


Asunto(s)
Ácido Edético , Tasa de Filtración Glomerular/fisiología , Trasplante de Pulmón/efectos adversos , Lesión Renal Aguda/etiología , Adulto , Radioisótopos de Cromo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
13.
Transplant Proc ; 49(9): 2161-2168, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29149977

RESUMEN

BACKGROUND: The lack of lung transplant donors has necessitated the use of donors with a smoking history and donors of older age. We have evaluated the effects of donor smoking history and age on recipient morbidity and mortality with baseline values of pulmonary function and survival free of chronic lung allograft dysfunction (CLAD) as morbidity variables. METHODS: This is a retrospective analysis of 588 consecutive lung transplant recipients and their corresponding 454 donors. Donors were divided into three groups: group 1 included smokers, group 2 nonsmokers, and group 3 had unknown smoking status; these were further divided into three age groups: group A: 0 to 39 years; group B: 40 to 54 years; and group C: ≥55 years. RESULTS: One hundred fifty-one donors were former or actual smokers, 175 were nonsmokers, and 128 had unknown smoking histories. Baseline forced expiratory volume in 1 second, forced vital capacity, and diffusion capacity of carbon monoxide were lowest in the groups who received lungs from a smoking donor. CLAD-free survival was identical in all smoking groups, and overall survival was better both for lungs from nonsmoking donors and donors with unknown smoking status compared to lungs from smoking donors. One hundred sixty-nine donors were in age group A, 203 in B, and 82 in C. Baseline forced expiratory volume in 1 second, forced vital capacity, and diffusion capacity of carbon monoxide were lowest in the groups who received lungs from donors older than 55 years. Overall survival as well as CLAD-free survival was significantly lower with donors ≥55 years. CONCLUSIONS: Donor smoking history and older donor age impact lung function, mortality, and CLAD-free survival after transplantation. Because of a shortage of organs, extended donor criteria may be considered while taking waiting list mortality into account.


Asunto(s)
Factores de Edad , Trasplante de Pulmón/mortalidad , Disfunción Primaria del Injerto/etiología , Fumar/efectos adversos , Donantes de Tejidos , Adolescente , Adulto , Niño , Preescolar , Femenino , Supervivencia de Injerto , Humanos , Lactante , Recién Nacido , Pulmón/patología , Trasplante de Pulmón/efectos adversos , Trasplante de Pulmón/métodos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Adulto Joven
14.
Ultrasound Int Open ; 2(4): E106-E112, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27896334

RESUMEN

Atherosclerosis is a widespread disease that accounts for nearly 3-quarters of deaths due to cardiovascular disease. Ultrasound elastography might be able to reliably identify characteristics associated with vulnerable plaques. There is a need for the evaluation of elastography and its ability to distinguish between vulnerable and stable plaques. The aim of this paper is to provide an overview of the literature on vascular elastography. A systematic search of the available literature for studies using elastography for assessing atherosclerotic plaques was conducted using the MEDLINE, Embase, Cochrane Library and Web of Science databases. A standardized template was used to extract relevant data following the PRISMA 2009 checklist. 20 articles were included in this paper. The studies were heterogeneous. All studies reported that elastography was a feasible technique and provided additional information compared to B-mode ultrasound alone. Most studies reported higher strain values for vulnerable plaques. Ultrasound elastography has potential as a clinical tool in the assessment of atherosclerotic plaques. Elastography is able to distinguish between different plaque types, but there is considerable methodological variation between studies. There is a need for larger studies in a clinical setting to determine the full potential of elastography.

15.
Biochim Biophys Acta ; 860(3): 503-9, 1986 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-3741864

RESUMEN

Cytochrome b5 is incorporated into vesicles of the endoplasmic reticulum as protein-lysophosphatidylcholine micelles. Cytochrome b5 becomes firmly bound to the membrane and at the same time lysophosphatidylcholine is acylated by acyltransferases of the endoplasmic reticulum and converted into the membrane component phosphatidylcholine. The possibility of an insertion of cytochrome b5 into the endoplasmic reticulum in vivo by this mechanism is discussed.


Asunto(s)
Grupo Citocromo b/metabolismo , Retículo Endoplásmico/metabolismo , Carboxipeptidasas , Citocromos b5 , Detergentes , Lisofosfatidilcolinas/metabolismo , Micelas
16.
Biochim Biophys Acta ; 735(2): 225-33, 1983 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-6138098

RESUMEN

A method is described for reconstitution of a protein into lipid vesicles using one of the natural detergents lysophosphatidylcholine or lysophosphatidic acid. The intestinal microvillus enzyme, aminopeptidase N (EC 3.4.11.2) is incorporated into lipid vesicles prepared from a total lipid extract of the microvillus membrane. The method is based on fusion of aminopeptidase-lysophospholipid micelles with liposomes prepared by sonication. The incorporation of the protein into the lipid bilayer is analyzed by gel permeation chromatography and sucrose density gradient centrifugation. The coincidence of the protein and lipid profiles is used to evaluate protein incorporation. The incorporation is visualized by electron microscopy with negative staining. The method has the advantage of using natural detergents, lysophospholipids, which are minor but natural constituents of biological membranes. The method could be of value as a tool in studies of mechanisms of insertion of newly synthesized proteins into biological membranes.


Asunto(s)
Aminopeptidasas/metabolismo , Detergentes , Membrana Dobles de Lípidos , Lisofosfatidilcolinas , Ácidos Fosfatidicos , Tensoactivos , Animales , Antígenos CD13 , Intestino Delgado/enzimología , Lisofosfolípidos , Microvellosidades/enzimología , Porcinos
17.
Biochim Biophys Acta ; 647(2): 188-95, 1981 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-6170331

RESUMEN

Microvillus membrane vesicles from pig small intestine were isolated by a method based on hypotonic lysis, Mg2+-aggregation of contaminants and differential centrifugation. The purity of the membrane vesicles were established by measuring the activity of marker enzymes and the RNA and DNA content. The membranes were found free of contamination by other subcellular membrane fragments, except for a minor contamination with basolateral plasma membranes. The lipid composition was established and, based on weight percentage, the membrane contained neutral lipids, phospholipids, neutral glycolipids and gangliosides in the weight ratio of 18 : 50 : 29 : 2%. The amount of individual phospholipids and glycolipids were quantitated. Phosphatidylethanolamine, -choline, -serine, -inositol and sphingomyelin made up 17, 17, 6, 5 and 5%, respectively of the total lipid. The major glycolipids were two monohexosylceramides containing glucose and galactose as the carbohydrate component, a dihexosylceramide containing galactose as the only carbohydrate component and two pentahexosylceramides containing fucose, galactose, glucose and hexosamine (either N-acetylglucosamine or N-acetylgalactosamine) in the molar ratio of 1 : 2 : 1 : 1.


Asunto(s)
Membrana Celular/metabolismo , Intestino Delgado/ultraestructura , Metabolismo de los Lípidos , Microvellosidades/metabolismo , Fosfatasa Alcalina/metabolismo , Aminopeptidasas/metabolismo , Animales , Metabolismo de los Hidratos de Carbono , Fraccionamiento Celular , ADN/metabolismo , Glucolípidos/metabolismo , Fosfolípidos/metabolismo , ARN/metabolismo , Complejo Sacarasa-Isomaltasa/metabolismo , Porcinos
18.
Biochim Biophys Acta ; 815(2): 215-22, 1985 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-3995025

RESUMEN

Pig liver cytochrome b5 is reconstituted into lipid vesicles by a method whereby cytochrome b5-lysophospholipid micelles are fused with liposomes. The reconstitution method inserts cytochrome b5 into the lipid bilayer in a mode which renders the C-terminal part of cytochrome b5 nonsusceptible to attack by carboxypeptidase Y. The effect of the lipid composition of the vesicles on the mode of insertion has been examined, when cytochrome b5 is reconstituted using the presently described method and methods previously used to reconstitute this protein, namely the direct incorporation method and the cholate dialysis method.


Asunto(s)
Carboxipeptidasas/metabolismo , Grupo Citocromo b , Animales , Grupo Citocromo b/metabolismo , Citocromos b5 , Ácido Desoxicólico , Detergentes , Ácidos Grasos , Liposomas , Hígado/enzimología , Lisofosfatidilcolinas , Proteínas de la Membrana/metabolismo , Micelas , Relación Estructura-Actividad , Porcinos
19.
Biochim Biophys Acta ; 689(1): 12-20, 1982 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-7104346

RESUMEN

Microvillus membrane vesicles from pig small intestine, isolated by hypotonic lysis, Mg2+ aggregation of contaminants and differential centrifugation, have been further purified by immunoadsorbent chromatography. The vesicles adhere to an immunoadsorbent prepared by coupling antibodies raised against three of the principal proteins of the brush border membrane (aminopeptidase, sucrase-isomaltase and lactase) to Sepharose 4B. After the contaminants are removed by washing, the adherent vesicles are released from the immunoabsorbent by applying shear forces. The purity of the immunoadsorbed vesicles has been established by electron microscopy and by measuring the activity of marker enzymes. The enrichment factor is 1.17 +/- 0.02 for aminopeptidase and 0.70 +/- 0.05 for 5'-nucleotidase. The contamination of the preparation before immunoadsorption constitutes 10% of the membrane protein and consists mainly of basolateral membrane fragments as judged from marker enzyme determinations and the lipid composition.


Asunto(s)
Membrana Celular/ultraestructura , Intestino Delgado/ultraestructura , Microvellosidades/ultraestructura , Animales , Fraccionamiento Celular/métodos , Cromatografía de Afinidad/métodos , Mucosa Intestinal/ultraestructura , Microscopía Electrónica , Sefarosa/análogos & derivados , Porcinos
20.
Cell Signal ; 7(6): 583-9, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8588974

RESUMEN

Isolated insulin receptors were inserted into hepatocytes by fusion with receptor-lysophospholipid micelles. The number of receptors was increased approximately two times as monitored by insulin binding experiments. Addition of exogenous receptors resulted in increased receptor autophosphorylation. The exogenous added receptors could be coupled to the intracellular effector system as shown by increased phosphorylation of the insulin receptor substrate 1, IRS-1, and by increased glycogen synthesis. The co-incorporated lysophospholipid was partly metabolized to phospholipid. This method for introducing insulin receptors into cells represents a novel system to study the pathway of insulin signalling and may provide information as to the role of variation of receptor number in insulin action in cellular metabolism of specific cells.


Asunto(s)
Hígado/citología , Receptor de Insulina , Animales , Células Cultivadas , Glucógeno/biosíntesis , Humanos , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina , Lisofosfolípidos , Fusión de Membrana , Micelas , Fosfoproteínas/metabolismo , Fosforilación , Ratas , Ratas Wistar , Receptor de Insulina/metabolismo , Transducción de Señal
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