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1.
Stem Cell Res ; 79: 103459, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38896971

RESUMEN

Here we present the generation of HIMRi006-A and HIMRi007-A Pompe disease (PD) patient derived human induced pluripotent stem cell (hiPSC) lines. HIMRi006-A represents an infantile onset disease (IOPD) phenotype caused by a homozygous c.307 T > G mutation in the GAA gene. HIMRi007-A is characterized by heterozygous mutations c.-32-13 T > G/c.1716C > G and is associated with an adult onset of disease symptoms (LOPD). Both lines are generated via lentiviral expression of OCT4, SOX2, KLF4, and c-MYC. The lines display a typical embryonic stem cell morphology, express pluripotency markers, retain a normal karyotype (46, XX/XY) and have the differentiation capacity in all three germ layers. Altogether, both lines provide a resource tool to the community for future in depth molecular studies of PD pathomechanism.


Asunto(s)
Enfermedad del Almacenamiento de Glucógeno Tipo II , Células Madre Pluripotentes Inducidas , Factor 4 Similar a Kruppel , Humanos , Enfermedad del Almacenamiento de Glucógeno Tipo II/patología , Enfermedad del Almacenamiento de Glucógeno Tipo II/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Diferenciación Celular , Línea Celular , Masculino , Lactante , Mutación , Femenino
2.
Stem Cell Res ; 76: 103320, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38309149

RESUMEN

Here we introduce the human induced pluripotent stem cell lines (hiPSCs), HIMRi004-A and HIMRi005-A from dermal fibroblasts of a 48-year-old female (HIMRi004-A) carrying missense mutation that translate to the first described filamin C isoform p.W2710X and from a 56-year-old female (HIMRi005-A) carrying a recently described mutation in the same domain p.Y2704X. Both lines are generated via lentiviral expression of OCT4, SOX2, KLF4 and c-MYC. The lines display a typical embryonic stem cell-like morphology, express pluripotency markers, retain a normal karyotype (46, XX) and have the differentiation capacity in all three germ layers. The two lines can be used to elucidate the pathomechanisms of FLNC myofibrillar myopathies and to develop novel therapeutic options.


Asunto(s)
Células Madre Pluripotentes Inducidas , Femenino , Humanos , Persona de Mediana Edad , Diferenciación Celular/genética , Línea Celular , Dimerización , Fibroblastos/metabolismo , Filaminas/genética , Filaminas/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Factor 4 Similar a Kruppel , Mutación/genética
3.
Cerebellum ; 12(1): 48-58, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22562748

RESUMEN

Sequelae in children following cerebellar tumor removal surgery are well defined, and predictors for poor recovery include lesions of the cerebellar nuclei and the inferior vermis. Dynamic reorganization is thought to promote functional recovery in particular within the first year after surgery. Yet, the time course and mechanisms of recovery within this critical time frame are elusive and longitudinal studies are missing. Thus, a group of children and adolescents (n = 12, range 6-17 years) were followed longitudinally after cerebellar surgery and compared to age- and gender-matched controls (n = 11). Patients were examined (1) within the first days, (2) 3 months, and (3) 1 year after surgery. Each time behavioral tests of balance and upper limb motor function, ataxia rating, and a MRI scan were performed. Data were used for subsequent lesion-symptom mapping of cerebellar function. Behavioral improvements continued beyond 3 months, but were not complete in all patients after 1 year. At that time, remaining deficits were mild. Within the first 3 months, cerebellar lesion volumes were notably reduced by vanishing edema. Reduction in edema affecting the deep cerebellar nuclei but not reduction of total cerebellar lesion volume was a major predictor of early functional recovery. Persistent impairment in balance and upper limb function was linked to permanent lesions of the inferior vermis and the deep cerebellar nuclei.


Asunto(s)
Astrocitoma/fisiopatología , Astrocitoma/cirugía , Neoplasias Cerebelosas/fisiopatología , Neoplasias Cerebelosas/cirugía , Recuperación de la Función , Adolescente , Astrocitoma/patología , Ataxia Cerebelosa/patología , Ataxia Cerebelosa/fisiopatología , Ataxia Cerebelosa/cirugía , Neoplasias Cerebelosas/patología , Niño , Quiste Dermoide/patología , Quiste Dermoide/fisiopatología , Quiste Dermoide/cirugía , Ependimoma/patología , Ependimoma/fisiopatología , Ependimoma/cirugía , Femenino , Glioblastoma/patología , Glioblastoma/fisiopatología , Glioblastoma/cirugía , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Meduloblastoma/patología , Meduloblastoma/fisiopatología , Meduloblastoma/cirugía , Destreza Motora , Equilibrio Postural
4.
Stem Cell Res ; 72: 103220, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37839261

RESUMEN

Here we introduce the human induced pluripotent stem cell lines (hiPSCs), HIMRi002-A and HIMRi003-A, generated from cultured dermal fibroblasts of 61-year-old (HIMRi002-A) and 38-year-old (HIMRi003-A) female patients, carrying a known heterozygous pathogenic variant (p.A46T) in the Caveolin 3 (CAV3) gene, via lentiviral expression of OCT4, SOX2, KLF4 and c-MYC. HIMRi002-A and HIMRi003-A display typical embryonic stem cell-like morphology, carry the p.A46T CAV3 gene mutation, express several pluripotent stem cell markers, retain normal karyotype (46, XX) and can differentiate in all three germ layers. We postulate that the HIMRi002-A and HIMRi003-A iPSC lines can be used for the characterization of CAV3-associated pathomechanisms and for developing new therapeutic options.


Asunto(s)
Células Madre Pluripotentes Inducidas , Enfermedades Musculares , Células Madre Pluripotentes , Humanos , Femenino , Persona de Mediana Edad , Células Madre Pluripotentes Inducidas/metabolismo , Factor 4 Similar a Kruppel , Enfermedades Musculares/metabolismo , Enfermedades Musculares/patología , Fibroblastos/metabolismo , Mutación , Diferenciación Celular/genética
5.
AJNR Am J Neuroradiol ; 42(11): 1956-1961, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34556476

RESUMEN

BACKGROUND AND PURPOSE: The acute phase of aneurysmal SAH is characterized by a plethora of impending complications with the potential to worsen patients' outcomes. The aim of this study was to evaluate whether an elaborated CTP-based imaging protocol during the acute aneurysmal SAH phase is able to prevent delayed infarctions and contribute to a better outcome. MATERIALS AND METHODS: In 2012, an elaborated CTP-based protocol was implemented for the management of patients with aneurysmal SAH. Retrospective analysis of patients with aneurysmal SAH treated from 2010 to 2013 was performed, comparing the patients treated before (group one, 2010-2011) with those treated after the protocol implementation (group two, 2012-2013) with regard to delayed infarctions and outcome according to the mRS at 3-months' follow-up. RESULTS: A total of 133 patients were enrolled, of whom 57 were included in group 1, and 76, in group 2. There were no significant differences between the groups concerning baseline characteristics. In the multivariate analysis, independent predictors of a good outcome (mRS ≤ 2) were younger age (P < .001), lower World Federation of Neurosurgical Societies grade (P < .001), absence of delayed infarction (P = .01), and management according to the CTP protocol (P = .01). Larger or multiple infarctions occurred significantly more often in group 1 compared with group 2 (88% versus 33% of all delayed infarctions, P = .03). The outcome in group 2 was significantly better compared with group 1 (P = .005). CONCLUSIONS: The findings suggest that implementation of an elaborated CTP protocol is associated with a better outcome. An earlier initiation of further diagnostics and treatment with prevention of large territorial and/or multiple infarctions might have led to this finding.


Asunto(s)
Hemorragia Subaracnoidea , Humanos , Perfusión , Estudios Retrospectivos , Hemorragia Subaracnoidea/diagnóstico por imagen , Hemorragia Subaracnoidea/terapia , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
6.
Eur J Pain ; 19(7): 966-72, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25395191

RESUMEN

BACKGROUND: Triptans are agonists to 5-HT 1B/D/F receptors, which are present on nociceptive neurons not only within but also beyond the trigeminal system. The aim of this study was to investigate whether zolmitriptan interacts with peptidergic nociceptive afferents in human skin. METHODS: Twenty participants (13 women, median age: 25; interquartile range: 23-26 years) entered the randomized, double-blind, cross-over study. Electrically induced neurogenic flare and pain was assessed after either placebo or zolmitriptan on the ventral thigh. Mechanical pain thresholds were investigated at baseline and after electrical stimulation at the stimulation site. RESULTS: The size of the neurogenic flare (F = 10.9; p = 0.002) as well as electrically induced pain were significantly reduced by zolmitriptan (F = 4.46; p = 0.041). Moreover, electrically induced pinprick hyperalgesia was significantly decreased by zolmitriptan compared with placebo (F = 6.243; p = 0.017). CONCLUSIONS: Triptans may have effects outside of the trigeminal system and reduce electrically evoked neurogenic inflammation and pain in human skin.


Asunto(s)
Inflamación Neurogénica/prevención & control , Oxazolidinonas/farmacología , Dolor/prevención & control , Agonistas de Receptores de Serotonina/farmacología , Piel , Triptaminas/farmacología , Adulto , Estudios Cruzados , Método Doble Ciego , Estimulación Eléctrica , Femenino , Humanos , Masculino , Trastornos Migrañosos/tratamiento farmacológico , Neuronas Aferentes/efectos de los fármacos , Nociceptores/efectos de los fármacos , Dimensión del Dolor , Umbral del Dolor/efectos de los fármacos , Estimulación Física , Adulto Joven
7.
Protein Sci ; 9(11): 2246-50, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11152135

RESUMEN

Conformational changes are essential for the activity of many proteins. If, or how fast, internal fluctuations are related to slow conformational changes that mediate protein function is not understood. In this study, we measure internal fluctuations of the transport protein lactose permease in the presence and absence of substrate by tryptophan fluorescence spectroscopy. We demonstrate that nanosecond fluctuations of alpha-helices are enhanced when the enzyme transports substrate. This correlates with previously published kinetic data from transport measurements showing that millisecond conformational transitions of the substrate-loaded carrier are faster than those in the absence of substrate. These findings corroborate the hypothesis of the hierarchical model of protein dynamics that predicts that slow conformational transitions are based on fast, thermally activated internal motions.


Asunto(s)
Proteínas de Escherichia coli , Proteínas de Transporte de Membrana/química , Proteínas de Transporte de Monosacáridos , Simportadores , Triptófano/química , Animales , Anisotropía , Línea Celular , Cinética , Proteínas de Transporte de Membrana/metabolismo , Modelos Estadísticos , Modelos Teóricos , Fotones , Conformación Proteica , Espectrometría de Fluorescencia , Factores de Tiempo
8.
J Med Chem ; 32(1): 183-92, 1989 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-2909730

RESUMEN

(3-Phenyl-7-flavonoxy)propanolamines have been shown to exhibit antihypertensive activity in spontaneously hypertensive rats. Although they are structurally similar to classical beta-adrenergic blocking compounds, their activity is not due to inhibition of beta-adrenoceptors. In the present study, a series of simple flavonoxypropanolamines was prepared to further explore the structural requirements for the antihypertensive effect of these compounds. A structure-activity relationship of these derivatives indicates that the position of the oxypropanolamine side chain, the hydroxy group of the side chain, steric bulkiness and length of N substituents, degree of the N-substitution, phenyl group at the 2-position of the chromone nucleus, and substituents of the phenyl group or B ring of the flavone play significant roles in imparting pharmacological effects. In addition, there is a good correlation between the antihypertensive activity and depletion of myocardial norepinephrine. Of these analogues tested, the most effective one was flavodilol. Only the 8-substituted analogue 6 was found to be a beta-antagonist. Flavodilol was chosen for in-depth pharmacological, toxicological, and clinical evaluation.


Asunto(s)
Antihipertensivos/síntesis química , Flavonoides/síntesis química , Propanolaminas/síntesis química , Glándulas Suprarrenales/metabolismo , Animales , Química Encefálica/efectos de los fármacos , Catecolaminas/metabolismo , Fenómenos Químicos , Química , Cromatografía Líquida de Alta Presión , Flavonoides/farmacología , Corazón/efectos de los fármacos , Masculino , Miocardio/metabolismo , Propanolaminas/farmacología , Ratas , Ratas Endogámicas SHR , Relación Estructura-Actividad
9.
Transplantation ; 58(11): 1241-6, 1994 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-7992368

RESUMEN

The effect on intestinal nutrient transport of the immunosuppressive drugs cyclosporin A (CsA), cyclosporin G (CsG), and rapamycin (RAP) was determined in New Zealand white rabbits. Rabbits received oral doses of CsA (20 mg/kg/day), CsG (10 mg/kg/day), or RAP (1 mg/kg/day) for 10 days. Animals receiving RAP had decreased food intake and weight gain compared with controls. This correlated with a decrease in both total ileal weight and corresponding mucosal weight. CsA and CsG administration had no effect on food intake, total weight gain, or intestinal weight. Villus surface area was significantly decreased in all groups as compared with controls. Jejunal uptake of D-glucose as well as 1 medium and 4 long chain fatty acids was not affected by drug administration, while both mucosal-to-serosal and net 3-0-methylglucose fluxes were increased (P < 0.05) in the jejunum by all 3 drugs. In the ileum, the rates of uptake of D-glucose as well as stearic and linoleic acids were increased in animals treated with RAP compared with controls. There was an increase in the ileal values of the maximal transport rate (Vmax) and apparent Michaelis constant (Km*) in RAP, and a fall in the Vmax and Km* in CsG. CsG administration resulted in a decreased cholesterol uptake in both jejunum and ileum, and a decreased D-glucose uptake in the ileum compared with controls. These differences in glucose uptake among groups could not be attributed to variations in body, intestinal, or mucosal weights. It is unlikely that the changes observed in CsA- and CsG-treated animals would have nutritional importance, as these animals gained weight normally. In addition, in these animals the changes mainly occurred in the ileum, not in the jejunum, where most glucose is absorbed, and the associated alterations in the values of the Vmax and Km* would lead to reciprocal changes in the rates of uptake of varying luminal concentrations of glucose. In contrast, these changes are likely to be of more importance in RAP-treated animals, since they failed to gain weight normally. The significance of these findings needs to be established in chronically treated animals.


Asunto(s)
Íleon/metabolismo , Inmunosupresores/farmacología , Yeyuno/metabolismo , Administración Oral , Animales , Colesterol/farmacocinética , Ciclosporina/farmacología , Ciclosporinas/farmacología , Ácidos Grasos/farmacocinética , Glucosa/farmacocinética , Íleon/efectos de los fármacos , Inmunosupresores/administración & dosificación , Mucosa Intestinal/anatomía & histología , Yeyuno/efectos de los fármacos , Masculino , Polienos/farmacología , Conejos , Sirolimus , Aumento de Peso/efectos de los fármacos
10.
J Org Chem ; 65(21): 6932-9, 2000 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-11031012

RESUMEN

A new method for the synthesis of [1,4]oxazepin-7-ones from readily available aldehydes and alpha-amino alcohols was developed using the Baylis-Hillman reaction as the key step. To determine the scope and limitations of the method, a mixture library was synthesized from six aldehydes and six alpha-amino alcohols on the soluble polymer support poly(ethylene glycol) 5000 monomethyl ether (MeOPEG) via split synthesis and analyzed by GC-EIMS. Those oxazepines that were formed predominantly were resynthesized in a parallel synthesis and fully characterized. Thus, we have shown that split synthesis on MeOPEG can be an efficient method to rapidly screen the substrate spectrum of a newly developed reaction sequence.

11.
Lipids ; 29(2): 117-27, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8152345

RESUMEN

Glucose uptake into jejunal brush border membrane (BBM) varies along the crypt-villus axis (CVA). In the present study, the question was addressed whether uptake of the essential long-chain fatty acid linoleic acid also varies along the CVA. Using agitation techniques, five jejunal enterocyte fractions were sequentially isolated from female New Zealand white rabbits. A sixth and final fraction of lower-villus/crypt cells was obtained by the scraping of the remaining jejunal mucosa. Cell fraction along the CVA was proven histologically, by noting decreasing alkaline phosphatase activities in sequentially isolated fractions, and by demonstrating [3H-methyl]thymidine uptake mainly in the final fraction of the lower villus/crypt cells. BBM vesicles were prepared from the upper, mid- and lower-villus/crypt enterocyte fractions, using differential centrifugation and divalent ion precipitation. D-Glucose uptake into each fraction showed an Na(+)-gradient dependent time-course "overshoot" with linear uptake to 15 s and a subsequent decline to a steady-state plateau. Varying D-glucose concentrations from 50-1000 microM demonstrated saturation kinetics of uptake, with maximal transport rates (Vmax) and Michaelis affinity constants (Km) varying between fractions; the Km and Vmax were both lowest in the upper-villus fraction. A linear relationship existed between linoleic acid concentration (25-200 microM) and uptake in each fraction. Linoleic acid uptake was equivalent in all fractions when expressed per mg protein, but when expressed in terms of the estimated minimal BBM, vesicle surface area uptake was greater in the upper- than in the lower-villus/crypt fractions. Thus, BBM vesicle uptake of both linoleic acid and glucose vary along the crypt-villus axis of the rabbit jejunum.


Asunto(s)
Glucosa/metabolismo , Yeyuno/metabolismo , Ácidos Linoleicos/metabolismo , Microvellosidades/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Transporte Biológico , ADN/metabolismo , Femenino , Glicósido Hidrolasas/metabolismo , Técnicas In Vitro , Mucosa Intestinal/metabolismo , Cinética , Ácido Linoleico , Conejos , Timidina Quinasa/metabolismo , beta-Fructofuranosidasa
12.
Lipids ; 29(12): 851-8, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7854011

RESUMEN

Diabetes-associated changes in intestinal uptake of nutrients are modified by isocaloric variations in the type of dietary lipids, and are associated with alterations in the phospholipid and fatty acyl content of the intestinal brush border membrane. The present study was designed to test the hypothesis that diet- and diabetes-associated changes in enterocyte microsomal membrane phospholipids are due to variations in the activity of two phospholipid metabolizing enzymes, 1,2-diacylglycerol:CDPcholine cholinephosphotransferase (CPT) and phosphatidylethanolamine methyltransferase (PEMT). Adult female Wistar rats were fed one of four semisynthetic diets--beef tallow low in cholesterol (BT), beef tallow high in cholesterol (BTC), fish oil low in cholesterol (FO) or fish oil high in cholesterol. In half of the animals, diabetes mellitus was produced by injection of streptozotocin. Jejunal and ileal enterocyte microsomes (EMM) were isolated and analyzed for cholesterol and phospholipids, as well as for CPT and PEMT activities. In control animals, feeding FO reduced EMM total phospholipids including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol. Feeding FO resulted in a greater than 95% reduction in the activity of CPT. Diabetes was associated with increased jejunal EMM total phospholipids including sphingomyelin (SM) and PE, without associated changes in CPT or PEMT. Dietary cholesterol supplementation did not affect EMM total cholesterol or phosphlipid composition in control rats fed BT or FO, but was associated with an increase in EMM cholesterol in diabetic rats fed BT or FO. A decrease in total phospholipids due to a decline in SM, PC and PE in diabetic rats fed FO was not associated with changes in the activities of CPT or PEMT in EMM.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Colesterol en la Dieta/administración & dosificación , Diabetes Mellitus Experimental/metabolismo , Grasas Insaturadas en la Dieta/administración & dosificación , Ácidos Grasos Omega-3/administración & dosificación , Mucosa Intestinal/metabolismo , Lípidos de la Membrana/metabolismo , Animales , Colesterol/análisis , Femenino , Intestinos/ultraestructura , Microsomas/metabolismo , Fosfolípidos/análisis , Ratas , Ratas Wistar
13.
J Am Dent Assoc ; 111(4): 567-76, 1985 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3863855

RESUMEN

This investigation proposed and evaluated a submucosally administered standard dose drug combination containing .6 mgm/kgm alphaprodine hydrochloride and .3 mgm/kgm hydroxyzine hydrochloride, in conjunction with nitrous oxide, oxygen, and lidocaine with epinephrine, in the sedation and treatment of uncooperative pediatric dental patients. Observations from this study include: The technique was successful in attaining a desirable, conscious sedation level that was characterized by rapid onset, maintenance throughout treatment, and rapid reversibility with naloxone and 100% oxygen. The protective airway reflexes remained intact during the procedures. Vital signs remained fairly constant throughout the treatment. Respiratory rate was slightly depressed during the sedation, but hemoglobin oxygen saturation levels remained constant. There were no incidences of respiratory depression, hypoxia, or apnea either during or after treatment, and no emergency medical or resuscitative efforts were necessary. Twenty-four hours after the appointment, few patients complained of the experience and more than half stated that they looked forward to returning. In view of these findings, the techniques and drug combination described in this investigation appear to provide a safe and effective means for the sedation and treatment of uncooperative pediatric dental patients. It should be emphasized, however, that the dentist using these methods should have a thorough knowledge of the agents involved, the ability to monitor patients and recognize possible adverse reactions, and the capacity to respond to any emergency situations should they arise. Consequently, only practitioners who have had extensive training and experience in all forms of anesthesia, especially pediatric anesthesia, should consider the use of these agents in their practices. It should be emphasized further that the agents and techniques should be used only for conscious sedation, the light level of sedation during which the patient retains the ability present before sedation to independently maintain an airway and respond appropriately to verbal command, and not for any deeper forms of anesthesia.


Asunto(s)
Alfaprodina/administración & dosificación , Conducta Infantil , Atención Odontológica/psicología , Hidroxizina/administración & dosificación , Medicación Preanestésica , Anestesia Dental , Niño , Preescolar , Conducta Cooperativa , Quimioterapia Combinada , Epinefrina , Femenino , Hemodinámica , Humanos , Lidocaína , Masculino , Óxido Nitroso , Factores de Tiempo
14.
Ultraschall Med ; 18(6): 258-61, 1997 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-9491492

RESUMEN

PURPOSE: Determination of normal values for fetal thyroid size in the 2nd half of pregnancy. METHOD: In 211 pregnant women (completed 20th to 41st week for pregnancy) without thyroid disease the fetal thyroid was measured and characterized by 5 parameters: right lobe transverse and p.a. diameter, left lobe transverse and p.a. diameter, right lobe and left lobe transverse including trachea. The level of measurement was a horizontal section of the neck with circular image of the trachea (centrally) and with the carotids as lateral limiting markers. RESULTS: The trend lines and regression coefficients of the parameters are shown in relation to week of pregnancy. The transverse diameter of both thyroid lobes including the trachea grows from 10 mm (20th week of pregnancy) to 20 mm (40th week of pregnancy). The transverse and p.a. diameters of either lobe double in the 2nd half of pregnancy. CONCLUSION: The normal values presented can help in early diagnosis of fetal thyroid hypertrophy.


Asunto(s)
Desarrollo Embrionario y Fetal/fisiología , Glándula Tiroides/embriología , Ultrasonografía Prenatal , Antropometría , Cefalometría , Femenino , Humanos , Hiperplasia , Recién Nacido , Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo , Valores de Referencia , Glándula Tiroides/diagnóstico por imagen
15.
J Fluoresc ; 4(4): 337-8, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24233610

RESUMEN

For our investigations on orientational motions of membrane proteins with the method of time-resolved fluorescence anisotropy decay (TRFA), we first wanted to test the use of tryptophan fluorescence in detecting slow motions on the time scale of tens of nanoseconds and to get more insight into the possible motions of membrane proteins by investigating a simple system. We performed TRFA measurements on a short α-helical 21-amino acid peptide in different environments (Vogel, H.,et al. Proc. Natl. Acad. Sci. USA 85, 5067-5071, 1988). In each case, we got three relexation time constants. The longest of these depends strongly on changes in the environment, whereas the two shorter times show only weak dependencies. So we conclude that the longest time belongs to the rotational diffusion of the entire peptide and the other to internal motions.

16.
Stomatol DDR ; 29(4): 307-13, 1979 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-377580

RESUMEN

The diffusion test yielded no satisfactory results. In the tube test, both the spray and the solvent (in a dilution of 1:4 and 1:8, respectively) proved to be bacteriostatically active against enterococci, Staphylococcus aureus, Escheria coli, Proteus, and Pseudomonas aeruginosa. These germs were killed within 30 minutes in the test for bactericidal activity, whereas the reference substance (1% phenol) required 1--2 hours, except against the last-named germ. Even the copolymer exerted a bactericidal effect, it is true, but only within 8 or 24 hours. The following results were obtained from the spray test with agar plate cultures: Streptococcus viridans species, streptococci, Diplococcus pneumoniae, Escheria coli, and Proteus were killed, whereas others survived under the plastic film for up to 9 days. Klebsiella and Pseudomonas aeruginosa had grown through the film within 7 days. In vivo experiments demonstrated a very potent antibacterial activity on the skin under the spray film.


Asunto(s)
Acrilatos/farmacología , Bacterias/efectos de los fármacos , Metacrilatos/farmacología , Apósitos Oclusivos , Acetatos/farmacología , Aerosoles , Ensayos Clínicos como Asunto , Combinación de Medicamentos , Evaluación de Medicamentos , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Piel/microbiología , Factores de Tiempo
17.
Biophys J ; 72(1): 326-34, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8994617

RESUMEN

The membrane protein porin and a synthetic polypeptide of 21 hydrophobic residues were inserted into detergent micelles or lipid membranes, and the fluorescence of their single tryptophan residue was measured in the time-resolved and polarized mode. In all cases, the tryptophan fluorescence exhibits a long-lifetime component of about 20 ns. This long-lifetime component was exploited to detect slow orientational motions in the range of tens of nanoseconds via the anisotropy decay. For this purpose, the analysis of the anisotropy has to be extended to account for different orientations of the dipoles of the short- and long-lifetime components. This is demonstrated for porin and the polypeptide solubilized in micelles, in which the longest relaxation time reflects the rotational diffusion of the micelle. When the polypeptide is inserted into lipid membranes, it forms a membrane-spanning alpha-helix, and the slowest relaxation process is interpreted as reflecting orientational fluctuations of the helix.


Asunto(s)
Modelos Teóricos , Péptidos/química , Porinas/química , Conformación Proteica , Triptófano , Difusión , Dimiristoilfosfatidilcolina , Polarización de Fluorescencia , Liposomas , Micelas , Fosfatidiletanolaminas , Fosfatidilgliceroles , Rhodobacter capsulatus , Rotación
18.
Can J Physiol Pharmacol ; 75(5): 351-6, 1997 May.
Artículo en Inglés | MEDLINE | ID: mdl-9250367

RESUMEN

HT-29 human colon carcinoma cells in culture have many characteristics of enterocytes, and these cells have been used by others to study intestinal drug and nutrient transport and metabolism. When grown in glucose-containing medium, HT-29 cells are largely undifferentiated (HT-29glu), but when grown in the absence of glucose but in the presence of galactose (HT-29gal), the population of cells is mostly differentiated. This study was undertaken with HT-29glu and HT-29gal cells to study the uptake of palmitic acid (16:0), linoleic acid (18:2), and cholesterol. The relationship between concentration and uptake of 16:0, 18:2, and cholesterol was linear in HT-29glu and HT-29gal cells, with the relative values of the slopes of this relationship being 18:2 > > 16:0 > > cholesterol. The rates of uptake of these lipids were at least three times higher in HT-29gal than in HT-29glu cells. In HT-29glu cells, the relative rates of uptake of the sugars at 32 mM were D-glucose = galactose > fructose > > alpha-methylglucose. Uptake of these sugars was much greater in HT-29gal than in HT-29glu cells. When 100 microM forskolin was added to the incubation medium for 7 days post-confluency, which stimulates the activity of adenylate cyclase and thereby increases the intracellular synthesis of cAMP, there was no effect on the uptake of the lipids or the sugars in either HT-29glu or HT-29gal cells. Thus, (i) differentiated HT-29gal cells transport larger amounts of lipids and sugars than do undifferentiated HT-29glu cells; (ii) forskolin has no effect on the uptake of lipids or sugars in these cells. This human cell culture system may be useful to study the in vitro transport of lipids, to establish the role of cell differentiation on these uptake processes, and to determine the potential role of selected intracellular signals.


Asunto(s)
Colesterol/farmacocinética , Células HT29/metabolismo , Ácidos Linoleicos/farmacocinética , Ácido Palmítico/farmacocinética , Absorción , Diferenciación Celular , Colforsina/farmacología , Fructosa/farmacocinética , Galactosa/farmacocinética , Glucosa/farmacocinética , Humanos , Ácido Linoleico , Metilglucósidos/metabolismo
19.
Eur J Biochem ; 266(2): 477-83, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10561588

RESUMEN

Ligand binding to proteins often causes large conformational changes. A typical example is maltose-binding protein (MBP), a member of the family of periplasmic binding proteins of Gram-negative bacteria. Upon binding of maltose, MBP undergoes a large structural change that closes the binding cleft, i.e. the distance between its two domains decreases. In contrast, binding of the larger, nonphysiological ligand beta-cyclodextrin does not result in closure of the binding cleft. We have investigated the dynamic properties of MBP in its different states using time-resolved tryptophan fluorescence anisotropy. We found that the 'empty' protein exhibits strong internal fluctuations that almost vanish upon ligand binding. The measured relaxation times corresponding to internal fluctuations can be interpreted as originating from two types of motion: wobbling of tryptophan side-chains relative to the protein backbone, and orientational fluctuations of entire domains. After binding of a ligand, domain motions are no longer detectable and the fluctuations of some of the tryptophan side-chains become rather restricted. This transformation into a more rigid state is observed upon binding of both ligands, maltose and the larger beta-cyclodextrin. The fluctuations of tryptophan side-chains in direct contact with the ligand, however, are affected in a slightly different way by the two ligands.


Asunto(s)
Proteínas Portadoras/química , beta-Ciclodextrinas , Secuencias de Aminoácidos , Anisotropía , Proteínas Portadoras/metabolismo , Ciclodextrinas/metabolismo , Cinética , Lactosa/metabolismo , Ligandos , Proteínas de Unión a Maltosa , Modelos Químicos , Unión Proteica , Conformación Proteica , Estructura Terciaria de Proteína , Espectrometría de Fluorescencia , Factores de Tiempo
20.
Digestion ; 55(6): 405-9, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7705553

RESUMEN

Trans fatty acids are produced in the manufacture of margarine, and these hydrogenated fatty acids may have a deleterious effect on the reduction in fasting levels of serum cholesterol anticipated from the feeding of cis polyunsaturated fatty acids. We undertook this study in rats to test the effect of feeding trans fatty acids on the intestinal uptake of glucose, fatty acids and cholesterol. Adult female Wistar rats were fed for 2 weeks semisynthetic, isocaloric diets containing no oleic acid (18:1), cis 18:1 or trans 18:1. There was no difference between the three dietary groups in the animals' food consumption or body weight gain. Rats fed trans 18:1 had an approximately 20% decline in the total weight of the ileum as compared with controls fed no 18:1, and therefore there was also a decline in the percentage of the ileal tissue comprised of mucosa. When comparing rats fed trans 18:1 with those fed cis 18:1 or no 18:1, there was no difference in the uptake of varying concentrations of D-glucose when expressed as nmol.100 mg tissue-1.min-1 or nmol.100 mg mucosal-1.min-1 for jejunum or for ileum. Also, there was no difference in the value of the maximal transport rate (Vmax), Michaelis constant (Km), or the contribution of passive uptake of glucose assessed with L-glucose. There was no diet-associated change in the jejunal or ileal uptake of a medium-chain length fatty acid (lauric acid), a long-chain length saturated fatty acid (palmitic acid), a monounsaturated fatty acid (oleic acid), two polyunsaturated fatty acids (linoleic and linolenic acids), or cholesterol. Thus, we conclude that 2 weeks' feeding of trans fatty acid to rats has no influence on the jejunal or ileal uptake of glucose, fatty acids or cholesterol.


Asunto(s)
Colesterol/metabolismo , Grasas de la Dieta/metabolismo , Ácidos Grasos Insaturados/metabolismo , Glucosa/metabolismo , Intestino Delgado/metabolismo , Absorción , Animales , Grasas de la Dieta/administración & dosificación , Ácidos Grasos Insaturados/administración & dosificación , Femenino , Modelos Lineales , Masculino , Ratas , Ratas Sprague-Dawley , Ratas Wistar
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