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131.
132.
GJ Juvenal LB Pregliasco L Krawiec LV Bocanera D Silberschmidt MA Pisarev 《Canadian Metallurgical Quarterly》1997,7(5):795-800
The sympathetic nervous system plays a role in the regulation of thyroid function. In FRTL-5 rat thyroid cells, norepinephrine (NE) acutely depresses intracellular I- by increasing I- efflux. The present study was undertaken to determine the effect of NE on iodide transport after a longer time period. NE inhibited the ability of thyrotropin (TSH) to induce iodide uptake by FRTL-5 cells after 48 or 72 hours, but not after 24 hours. The effect of NE was more evident with increasing concentrations of TSH. NE did not modify the rate of I- efflux. Inhibition was associated with a decrease in the Vmax and no change in the Km for iodide influx. To determine if this was a generalized effect of NE on thyroid cell membrane, the uptake of alpha-aminoisobutyric acid (a nonmetabolizable aminoacid) and of 2-deoxyglucose was measured. NE did not inhibit TSH stimulation of the uptake of the two compounds. NE inhibited the action of dibutyryl cAMP (dbcAMP) on iodide uptake in a similar manner to TSH, but did not alter the cyclic adenosine monophosphate (cAMP) levels increased by TSH. The effects of different adrenoreceptor agonists and antagonists demonstrated that norepinephrine acts through an alpha1-adrenergic receptor. 相似文献
133.
Three key aspects of Florence Nightingale remarkable life are examine. First, the influence during her formative years: the education and guidance provided by her father, the resistance by her family when she decided to become a nurse; and the rejection by Nightingale of the societal expectations of a woman in the Victorian era. Secondly, her professional life is examined, in particular how she appears to have been viewed by certain members of society, and how it turn she viewed them. It is anticipated that her position as an early feminist will be postulated and illuminated. Thirdly, an analysis of her personal and professional life indicates a way forward for the nursing profession. 相似文献
134.
Within-stem variation of mechanical properties of Maritime pine timber (Pinus pinaster Ait.) as function of tree class quality and location of the specimens on the stem (percentage of stem height, distance to pith and orientation) is discussed. The results show a strong and consistent effect of the distance to pith on all mechanical properties studied. A trend for the decrease of mechanical properties along the stem (from butt to top) was detected probably due to the growing presence of juvenile wood caused by tree taper and vicinity to crown. Juvenile wood thus seems to play a decisive role on the within-stem variation of mechanical properties. A clear increase on bending strength (55%), modulus of elasticity parallel to grain (99%), compression strength parallel to grain (44%) and tension strength perpendicular to grain (27%) for distance to pith from 10% to 90% of the trunk radius was observed at all tree height levels studied. Orientation (north or south location on the stem) appears to be negligible.
Variation der mechanischen Eigenschaften im Stammholz von maritimer Kiefer (Pinus pinaster Ait.)
Zusammenfassung In der vorliegenden Arbeit werden Schwankungen mechanischer Eigenschaften im Stammholz von maritimer Kiefer (Pinus pinaster Ait.) als Funktion von Baumklassenqualität und Ort der Probenentnahme auf dem Stamm (Prozent der Stammhöhe, Entfernung zur Markröhre und Faserorientierung) diskutiert. Die Ergebnisse zeigen einen gleichbleibend starken Einfluss des Abstands zur Markröhre auf alle untersuchten mechanischen Eigenschaften. Festgestellt wurde eine Tendenz zur Abnahme der mechanischen Eigenschaften entlang des Stammes von unten nach oben, was vermutlich auf die Zunahme des Anteils von Juvenilholz bei gleichzeitiger Stammverjüngung in Richtung Baumkrone zurückzuführen ist. So scheint Juvenilholz eine entscheidende Rolle bei Schwankungen mechanischer Eigenschaften in Stammholz zu spielen. Eine klare Zunahme des Einflusses auf die Biegefestigkeit (55%), auf den E-Modul parallel zur Faser (99%), auf die Längsdruck - (44%) und Zugfestigkeit (27%) senkrecht zur Faser bei Entfernung zur Markröhre von 10–90% des Baumumfanges wurde auf allen Ebenen der Stammhöhe festgestellt. Die Faserrichtung (Nord- oder Südorientierung) scheint keine Rolle zu spielen.相似文献
135.
UC Wieshmann GJ Barker MR Symms PA Bartlett JM Stevens SD Shorvon 《Canadian Metallurgical Quarterly》1998,40(8):483-489
Breast reconstruction has been the subject of many controversies. It now seems generally agreed however that the operation has no deleterious influence on the follow up of breast cancer patients and that it has favorable psychologic effects. Breast reconstruction can be performed either by using prostheses or analogous tissues. These two different modalities have each their own advantages and limitations. Deep knowledge of the techniques and their indications allows to select the most appropriate approach in the individual patient and, thus, to improve long term results. 相似文献
136.
137.
Over the last period of time, a large number of scorpion toxins have been characterized. These peptidyl inhibitors of K+ channels have been very useful as probes for determining the molecular architecture of these channels, for purifying channels from native tissue and determining their subunit composition, for developing the pharmacology of K+ channels, and for determining the physiologic role that K+ channels play in target tissues. The large knowledge that we have developed regarding K+ channel function would not have been possible without the discovery of these peptidyl inhibitors. It is expected that as more novel peptides are discovered, our understanding of K+ channel structure and function will be further enhanced. 相似文献
138.
This study investigates direct hippocampal efferent projections to the temporal lobe of the rhesus monkey. Tritiated amino acid injections were placed into the hippocampal formation to identify terminal fields, and complementary fluorescent retrograde tracer injections were placed into the cortex to identify the cells of origin. Tritiated amino acid injections into CA1, prosubicular, or subicular subfields produced anterograde label over parts of the parahippocampal gyrus and temporal pole. Injections of fluorescent retrograde tracers demonstrated that these projections originate from longitudinal strips of neurons that occupy part of the CA1 subfield as well as from strips of neurons in adjacent prosubicular and subicular subfields. Thus, an injection into area TH of the posterior parahippocampal gyrus labeled neurons in a longitudinal strip of proximal CA1 (i.e., near CA2) as well as a strip in the subiculum; injections into areas TF, TL, 35, or Pro labeled neurons in a longitudinal strip of distal CA1 (i.e., near the prosubiculum) as well as one in the prosubiculum; and an injection into area TFO labeled neurons in a longitudinal strip in the middle of CA1. These strips of neurons extended longitudinally throughout the entire rostrocaudal length of the hippocampus. These results demonstrate that, in the monkey, CA1 projections to cortex arise topographically from longitudinally oriented strips of neurons that occupy only a part of the transverse extent of CA1 but that cover most of the anteroposterior extent of the hippocampus. Thus, in the monkey, CA1 is not a single uniform entity and may have a unique role as a source of direct hippocampal projections to the cerebral cortex. 相似文献
139.
The influence of anti-IGF-1 and anti-transforming growth factor beta (TGF-beta) neutralizing antibodies on preadipocyte differentiation and secretion of IGFBPs was examined in serum free porcine stromal-vascular cultures. Cultures were stained for morphological analysis and conditioned media were collected for: TGF-beta determination by ELISA, IGF-1 by RIA, and IGFBP analysis by ligand blotting. After 6 d of treatment, anti-TGF-beta increased fat proportions by 2.7 fold compared to controls. Anti-IGF-1 decreased fat cell proportions by 14-fold. Anti-TGF-beta increased concentrations of IGF-1 5.8-fold and IGFBP-2 and IGFBP-3 by 8- and 7-fold in conditioned media whereas IGFBP-4 decreased 5-fold. Anti-IGF-1 increased concentrations of IGFBP-2 and 3 by 9- and 35-fold, respectively. TGF-beta increased concentrations of IGFBP-1, 2 and 3 by 3-fold, 18-fold and 3-fold, respectively, after 9 d in culture (6 d of treatment). There was no change in TGF-beta levels in anti-IGF-1 treated cultures compared to controls. Control antibodies and negative controls had no effect. These results provide evidence that endogenously produced IGF-1 and TGF-beta has a major influence on preadipocyte differentiation in serum free media by modulating IGFBP production/secretion. 相似文献
140.