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101.
In order to evaluate the modulatory effects of manganese, high fat diet fed and alloxan diabetic rats were taken and the changes
in the glucose oxidation, glycerol release and effects of manganese on these parameters were measured from adipose tissue.
An insulin-mimetic effect of manganese was observed in the adipose tissue in the controls and an additive effect of insulin
and manganese on glucose oxidation was seen when Mn2+ was addedin vitro. The flux of glucose through the pentose phosphate pathway and glycolysis was significantly decreased in high fat fed animals.
Although thein vitro addition of Mn2+ was additive with insulin when14CO2 was measured from control animals, it was found neither in young diabetic animals (6–8 weeks old) nor in the old (16 weeks
old). Both insulin and manganese caused an increased oxidation of carbon-1 of glucose and an increase of its incorporation
into14C-lipids in the young control animals; the additive effect of insulin and manganese suggests separate site of action. This
effect was decreased in fat fed animals, diabetic animals and old animals. Manganese alone was found to decrease glycerol
in both the control and diabetic adipose tissue inin vitro incubations. The results of the effects of glucose oxidation, lipogenesis, and glycerol release in adipose tissue of control
and diabetic animals of different ages are presented together with the effect of manganese on adipose tissue from high fat
milk diet fed animals. 相似文献
102.
Hansson E Muyderman H Leonova J Allansson L Sinclair J Blomstrand F Thorlin T Nilsson M Rönnbäck L 《Neurochemistry international》2000,37(2-3):317-329
Astroglia have the capacity to monitor extracellular glutamate (Glu) and maintain it at low levels, metabolize Glu, or release it back into the extracellular space. Glu can induce an increase in astroglial cell volume with a resulting decrease of the extracellular space, and thereby alter the concentration of extracellular substances. Many lines of evidence show that K(+) can be buffered within the astroglial gap-junction-coupled network, and recent results show that gap junctions are permeable for Glu. All these events occur dynamically: the astroglial network has the capacity to interfere actively with neurotransmission, thereby contributing to a high signal-to-noise ratio for the Glu transmission. High-quality neuronal messages during normal physiology can then be maintained. With the same mechanisms, astroglia might exert a neuroprotective function in situations of moderately increased extracellular Glu concentrations, i.e., corresponding to conditions of pathological hyper-excitability, or corresponding to early stages of an acute brain injury. If the astroglial functions are failing, neuronal dysfunction can be reinforced. 相似文献
103.
This study examined selective attention to tactile dimensions by combining a selective cueing paradigm with a test of integrality. In Experiment 1, subjects selectively attended to changes in the frequency or duration of pairs of vibrotactile stimuli and identified the higher frequency or longer duration stimulus. In Experiment 2, using surface gratings in an identical experimental procedure, subjects identified the rougher or longer duration stimulus. In both experiments, greater performance accuracy was found on trials where the cue correctly (valid) predicted the changing dimension, vs incorrectly (invalid) cued or no-cue (neutral) trials. More errors on the invalidly vs neutrally cued trials show the cost of focal attention. Increases in performance on validly vs neutrally cued trials show a benefit of filtering irrelevant stimuli in the cued conditions. Results effectively demonstrate focal attention to tactile features. Tests of integrality, in terms of the effects of correlated change in both dimensions, showed no redundancy gain for either vibrotactile or grating tasks, suggesting that frequency and roughness are separable from stimulus duration. Interference of negative correlated change for frequency but not roughness discriminations may be explained by differences in task difficulty. 相似文献
104.
SOX8 expression during chick embryogenesis 总被引:4,自引:0,他引:4
We have isolated the SOX8 gene from the chicken embryo. This gene shows a high degree of sequence homology to SOX9 and SOX10. Detailed analysis of SOX8 expression by whole-mount in situ shows a dynamic and restricted expression pattern during chick development. SOX8 is expressed in the somitic derivative, the dermomyotome, the developing heart, pancreas, enteric neurone system, limb and the neural tube. This is the first detailed expression analysis of SOX8 in any species 相似文献
105.
ASW: a gene with conserved avian W-linkage and female specific expression in chick embryonic gonad 总被引:1,自引:0,他引:1
O'Neill M Binder M Smith C Andrews J Reed K Smith M Millar C Lambert D Sinclair A 《Development genes and evolution》2000,210(5):243-249
Vertebrates exhibit a variety of sex determining mechanisms which fall broadly into two classes: environmental or genetic.
In birds and mammals sex is determined by a genetic mechanism. In mammals males are the heterogametic sex (XY) with the Y
chromosome acting as a dominant determiner of sex due to the action of the testis-determining factor, SRY. In birds females
are the heterogametic sex (ZW); however, it is not known whether the W chromosome carries a dominant ovary-determining gene,
or whether Z chromosome dosage determines sex. Using an experimental approach, which assumes only that the sex-determining
event in birds is accompanied by sex-specific changes in gene expression, we have identified a novel gene, ASW (Avian Sex-specific W-linked). The putative protein for ASW is related to the HIT (histidine triad) family of proteins. ASW shows female-specific expression in genital ridges and maps to the chicken W chromosome. In addition, we show that, with
the exception of ratites, ASW is linked to the W chromosome in each of 17 bird species from nine different families of the class Aves.
Received: 18 October 1999 / Accepted: 10 January 2000 相似文献
106.
Hypoxia/hypoglycemia-induced amino acid release is decreased in vitro by preconditioning 总被引:1,自引:0,他引:1
Johns L Sinclair AJ Davies JA 《Biochemical and biophysical research communications》2000,276(1):134-136
The aim of this study was to investigate the effects of preconditioning on amino acid neurotransmitter release, induced by hypoxia/hypoglycaemia, from rat brain cortical slices. Tissue, perfused with artificial cerebrospinal fluid (aCSF) at 37 degrees C with zero glucose and gassed with 95% nitrogen and 5% carbon dioxide, showed a fivefold increase in glutamate release with little effect on gamma-aminobutyric acid (GABA) release. Preconditioning, with three 5-min periods of hypoxia/hypoglycaemia preceding continuous hypoxia/hypoglycaemia, significantly decreased glutamate release whilst significantly elevating GABA release. These results suggest that GABA may reduce the release of glutamate and consequently decrease the neurotoxic effects of glutamate. 相似文献
107.
108.
109.
J Frank S Sinclair S Hogg-Johnson H Shannon C Bombardier D Beaton D Cole 《CMAJ》1998,158(12):1625-1631
Despite the publication in the mid-1990s of comprehensive practice guidelines for the management of acute low-back pain, both in the United States and elsewhere, this ubiquitous health problem continues to be the main cause of workers'' compensation claims in much of the Western world. This paper represents a synthesis of the intervention studies published in the last 4 years and is based on a new approach to categorizing these studies that emphasizes the stage or phase of back pain at the time of intervention and the site or agent of the intervention. Current thinking suggests that medical management in the first 3-4 weeks after the onset of pain should be generally conservative. Several studies of rather heterogeneous interventions focusing on return to work and implemented in the subacute stage (3-4 to 12 weeks after the onset of pain) have shown important reductions in time lost from work (by 30% to 50%). There is substantial evidence indicating that employers who promptly offer appropriately modified duties can reduce time lost per episode of back pain by at least 30%, with frequent spin-off effects on the incidence of new back-pain claims as well. Finally, newer studies of guidelines-based approaches to back pain in the workplace suggest that a combination of all these approaches, in a coordinated workplace-linked care system, can achieve a reduction of 50% in time lost due to back pain, at no extra cost and, in some settings, with significant savings. 相似文献
110.
Hypohydration effects on skeletal muscle performance and metabolism: a 31P-MRS study 总被引:1,自引:0,他引:1
Montain Scott J.; Smith Sinclair A.; Mattot Ralph P.; Zientara Gary P.; Jolesz Ferenc A.; Sawka Michael N. 《Journal of applied physiology》1998,84(6):1889-1894
The purpose of this study was to determinewhether hypohydration reduces skeletal muscle endurance and whetherincreased H+ andPi might contribute to performancedegradation. Ten physically active volunteers (age 21-40 yr)performed supine single-leg, knee-extension exercise to exhaustion in a1.5-T whole body magnetic resonance spectroscopy (MRS) system wheneuhydrated and when hypohydrated (4% body wt).31P spectra were collected at arate of one per second at rest, exercise, and recovery, and weregrouped and averaged to represent 10-s intervals. The desired hydrationlevel was achieved by having the subjects perform 2-3 h ofexercise in a warm room (40°C dry bulb, 20% relative humidity)with or without fluid replacement 3-8 h before the experiment.Time to fatigue was reduced (P < 0.05) by 15% when the subjects were hypohydrated [213 ± 12 vs. 251 ± 15 (SE) s]. Muscle strength was generally notaffected by hypohydration. Muscle pH andPi/-ATP ratio were similarduring exercise and at exhaustion, regardless of hydration state. The time constants for phosphocreatine recovery were also similar betweentrials. In summary, moderate hypohydration reduces muscle endurance,and neither H+ norPi concentration appears to berelated to these reductions. 相似文献