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1.
Understanding the mechanisms of food intake and obesity 总被引:2,自引:1,他引:1
E. T. Rolls 《Obesity reviews》2007,8(S1):67-72
2.
K. A. Rolls P. A. Phillips K. Aldred K. J. Hardy 《Clinical and experimental pharmacology & physiology》1994,21(3):227-230
1. Since plasma renin activity is increased in cyclosporin A (CsA)-induced hypertension in the rat, the role of the vascular renin-angiotensin system (RAS) in CsA-induced hypertension was investigated in rat mesenteric resistance vessels. 2. Female Wistar rats received CsA (10 mg/kg per day, s.c.) or vehicle for 30 days. CsA treatment increased tail-cuff systolic blood pressure (CsA treated 135 ± 3 mmHg vs control 125 ± 1 mmHg, P<0.0001). 3. Mesenteric resistance arteries (200–300 μm) were isolated and mounted in a microvessel myograph. Concentration-response curves to tetradecapeptide renin substrate (10-11-10?6 mol/L), angiotensin I (10-l1-10?6 mol/L) and angiotensin II (10-12-10?6 mol/L) showed no differences between CsA-treated and control groups. 4. Mesenteric vascular angiotensin-converting enzyme (ACE) characteristics were determined by radioligand binding. There were no differences in the content or affinity of ACE between CsA-treated and control rats. 5. These results suggest that the mesenteric vascular RAS does not play a major role in CsA-induced hypertension in the rat. 相似文献
3.
Oscillatory activity is not evident in the primate temporal visual cortex with static stimuli. 总被引:1,自引:0,他引:1
It has been suggested in studies in the visual system of anaesthetized cats that oscillatory activity with a frequency of 40-60 Hz occurs during the presentation of moving visual stimuli and reflects a synchronization process between neurons that could implement the binding together of related neurons into different sets. We found no evidence for such oscillations in the inferior temporal visual cortex and related areas of awake macaques fixating effective static visual stimuli, which for the neurons analysed were faces. We put forward the possibility that temporal synchronization between neurons to implement binding may not be generally used in the visual system as a solution to the binding problem, at least when static objects are being processed and recognised in higher parts of the visual system. 相似文献
4.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2
5.
Sally J Wellard RN BA Renal Cert MN Colleen Rolls RN RM Child Hlth Cert BAppSc Grad Dip Child Development MEdSt de Sales Ferguson RN BA BEd MN 《Journal of advanced nursing》1995,21(4):737-742
An Australian school of nursing's attempt to introduce an evaluation process required by management for clinical educators involved in undergraduate preregistration education is discussed Reliance on student feedback and clinical agencies' perceptions of the quality of teaching were seen as inadequate mechanisms for evaluation The evaluation process adopted incorporated observation of the educators together with self-reflection on their performance We conclude that post-briefings were poorly used and generally not reflective Educators relied heavily on their clinical skills and used a limited range of teaching strategies Whilst evaluation of clinical educators was time consuming and therefore costly, it is argued that it is essential to the integrity of the course The evaluation process has provided direction for support and development of clinical educators within the context of the curriculum 相似文献
6.
7.
A key problem in reinforcement learning is how an animal is able to learn a sequence of movements when the reward signal only occurs at the end of the sequence. We describe how a hierarchical dynamical model of motor function is able to solve the problem of delayed reward in learning movement sequences using associative (Hebbian) learning. At the lowest level, the motor system encodes simple movements or primitives, while at higher levels the system encodes sequences of primitives. During training, the network is able to learn a high level motor program composed of a specific temporal sequence of motor primitives. The network is able to achieve this despite the fact that the reward signal, which indicates whether or not the desired motor program has been performed correctly, is received only at the end of each trial during learning. Use of a continuous attractor network in the architecture enables the network to generate the motor outputs required to produce the continuous movements necessary to implement the motor sequence. 相似文献
8.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
9.
To investigate whether human thirst and drinking during ad lib access to water occur in response to body fluid deficits, we obtained blood samples and visual analog scale thirst ratings from five healthy, volunteer, young men at hourly intervals and when they were thirsty during a normal working day. Although there were significant increases in ratings of thirst, pleasantness of drinking water, mouth dryness and unpleasantness of the taste in the mouth when subjects were thirsty enough to drink compared with intervening intervals, there were no concomitant changes in body fluid variables (microhematocrit, plasma osmolality and plasma sodium, potassium, protein and angiotensin II concentrations). Subjects drank mainly in association with eating and were not overhydrated as indicated by constantly hypertonic urine and significant tubular reabsorption of free water over the experimental period. The results indicate that during free access to water humans become thirsty and drink before body fluid deficits develop, perhaps in response to subtle oropharyngeal cues, and so provide evidence for anticipatory thirst and drinking in man. 相似文献
10.
It is well recognized that the ability to cryopreserve unfertilizedhuman oocytes would make a significant contribution to infertilitytreatment. However, despite considerable interest, very fewsuccessful pregnancies have arisen from cryopreserved oocytesafter thawing, insemination and transfer of the subsequent embryo.The reasons for this lack of progress may well result from adearth of information on how the various biophysical changesduring a cryopreservation regimen affect human oocyte function.Recently, fundamental studies on the effects of cooling, membranepermeability, cryoprotectant addition and ice formation havebeen performed on human oocytes by a number of groups, and theseform the basis of the current review. It is likely that successfulhuman oocyte cryopreservation will only follow once these factorsare fully understood, but the existing base of knowledge shouldprovide a platform for further improvements in the techniquescurrently employed. 相似文献