Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Phys Rev Lett ; 122(13): 131301, 2019 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-31012624

RESUMEN

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5 GeV/c^{2} using 1.4×10^{4} kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

2.
Eur J Cancer Care (Engl) ; 18(3): 271-9, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19432919

RESUMEN

This study aimed to assess the prevalence of complementary and alternative medicine (CAM) use in a representative cancer population prior to and within 6 months of diagnosis. A total of 304 newly diagnosed cancer patients from two UK cancer centres completed a postal survey. Of them, 100 patients (32.9%) used CAM before their cancer diagnosis, 59 of these CAM users continued post diagnosis. Twenty-nine individuals who had not used CAM before began to use it after their cancer diagnosis, creating a total of 88 (28.9%) CAM users in this sample. Reasons for not using CAM included lack of interest, lack of information or endorsement from professionals and satisfaction with conventional care. For those using CAM before diagnosis but not afterwards, the most common reason was a lack of expert guidance on what was safe to use. The use of CAM medicines bought from health food and other retail outlets was high. Complementary and alternative medicine use in cancer patients is common and demonstrates a complex pattern, but CAM use is not significantly greater than in the general population. Some patients purchase CAM medicines without seeking medical advice, thus risking drug interactions. Research to generate information on safety and efficacy of CAM is required.


Asunto(s)
Terapias Complementarias/estadística & datos numéricos , Conocimientos, Actitudes y Práctica en Salud , Neoplasias/terapia , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Inglaterra , Femenino , Humanos , Masculino , Persona de Mediana Edad , Motivación , Encuestas y Cuestionarios , Adulto Joven
3.
Can J Biochem ; 60(8): 838-42, 1982 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7127189

RESUMEN

Brown adipose tissue (BAT) of rats is known to grow in response to acclimation to cold. The growth is accompanied by changes in mitochondrial polypeptide composition (an increase in the relative proportion of a polypeptide of molecular weight 32,000, known to be associated with the thermogenic proton conductance pathway). The mediator of the change in mitochondrial polypeptide composition is unknown. The objective of these experiments was to find out whether any of the pituitary hormones might be the mediator. Treatment of rats with growth hormone failed to alter BAT size or mitochondrial polypeptide composition. BAT grew and the change in BAT mitochondrial polypeptide composition occurred in cold-acclimated hypophysectomized rats, maintained on thyroxine and corticosterone to ensure their survival in the cold. It is concluded that none of the pituitary hormones is the mediator for the cold-induced change in BAT mitochondrial polypeptide composition or is required to exert a direct effect on BAT for cold-induced BAT growth to occur. It also seems unlikely that more than a maintenance amount of glucocorticoids is required for normal cold-induced growth of BAT; these hormones are thus also unlikely to mediate the change in BAT mitochondrial polypeptide composition. The requirement for no more than a maintenance amount of thyroxine for BAT growth and for the cold-induced change in BAT mitochondrial polypeptide composition confirms previous conclusions drawn from studies on cold-acclimated thyroidectomized rats.


Asunto(s)
Aclimatación , Tejido Adiposo Pardo/fisiología , Frío , Corticosterona/farmacología , Tiroxina/farmacología , Tejido Adiposo Pardo/efectos de los fármacos , Animales , Hipofisectomía , Masculino , Ratas
5.
Am J Physiol ; 241(2): E116-20, 1981 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7270679

RESUMEN

Feeding a "cafeteria" diet for 2 wk to male Holtzman rats resulted in a weight gain that was, on average, only slightly more than that of control rats fed a regular chow diet. Wet weight, DNA, and total protein content of interscapular brown adipose tissue were more than doubled in the cafeteria-fed rats and proliferation of mitochondria paralleled tissue growth. After 2 wk of recovery from cafeteria feeding, the expanded size of the tissue had completely regressed to a normal level. Brown adipose tissue mitochondria of cafeteria-fed rats bound 3 times more purine nucleotides than mitochondria of chow-fed control rats, but no change in the proportion of polypeptides with molecular weight in the region of 32,000 could be detected. The changes in brown adipose tissue and its mitochondria in cafeteria-fed rats correspond to those seen previously in noradrenaline-treated rats, i.e., tissue growth accompanied by mitochondrial proliferation and an unmasking of proton conductance pathways. The increase in 32,000-mol-wt polypeptides seen in brown adipose tissue mitochondria of cold-acclimated rats does not occur in the cafeteria-fed rats. Control mechanisms are presumed to differ, either quantitatively or qualitatively, in the two situations, cold exposure and overeating, which both cause growth of brown adipose tissue.


Asunto(s)
Tejido Adiposo Pardo/fisiología , Conducta Alimentaria/fisiología , Animales , Peso Corporal , Masculino , Mitocondrias/metabolismo , Nucleótidos de Purina/metabolismo , Ratas
6.
Am J Physiol ; 239(1): C18-22, 1980 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7395982

RESUMEN

The size (wet weight, total protein, total cytochrome oxidase) of interscapular brown adipose tissue is reduced to about one-half of normal in the cardiomyopathic hamster (BIO 14.6). The mitochondria are normal in binding of purine nucleotides [guanosine 5'-diphosphate (GDP)] and in proportion of polypeptides in the region of 32,000, both indices of the thermogenic proton conductance pathway, and in specific activity of cytochrome oxidase. Brown adipose tissue of the cardiomyopathic hamster can grow during acclimation to 4 degrees C, but its size remains smaller than in cold-acclimated normal hamsters. Mitochondrial polypeptide composition is not altered by acclimation to cold, but a large increase in mitochondrial GDP binding occurs in both normal and cardiomyopathic hamsters. The reduced calorigenic response of cardiomyopathic hamsters to catecholamines (Horwitz, B.A., and G.E. Hanes, Proc. Soc. Exp. Biol. Med. 147: 393-395, 1974) may, at least in part, be explained by a reduction in the amount of brown adipose tissue, the major site of this response. A defect in control of growth of this tissue in the cardiomyopathic hamster is suggested.


Asunto(s)
Tejido Adiposo Pardo/fisiopatología , Distrofia Muscular Animal/fisiopatología , Adaptación Fisiológica , Factores de Edad , Animales , Peso Corporal , Frío , Cricetinae , Mitocondrias/fisiología , Tamaño de los Órganos
7.
Can J Biochem ; 55(1): 41-2, 1977 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-837245

RESUMEN

Homogenates of liver and kidney tissue from young steers had beta-D-glucosidase (EC 3.2.1.21) activity toward 17alpha-estradiol-3-glucoside, 17beta-estradiol-3-glucoside, 17alpha-estradiol-17-glucoside, and deoxycorticosterone-21-glucoside. The activity towards the phenolic 3-glucosides was largely present in the 100 000 X g supernatant, while that towards 17alpha-estradiol-17-glucoside was concentrated in the microsomes. The use of beef liver preparations for the hydrolysis of steroid 'glucuronide' fractions could result in hydrolysis of other steroid glycosides which might be present.


Asunto(s)
Glucosidasas/metabolismo , Riñón/enzimología , Hígado/enzimología , Animales , Bovinos , Estradiol/análogos & derivados , Cinética , Masculino , Especificidad de Órganos , Relación Estructura-Actividad , Fracciones Subcelulares/enzimología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA