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1.
The cardiovascular responses induced by exercise are initiated by two primary mechanisms: central command and reflexes originating in exercising muscles. Although our understanding of cardiovascular responses to exercise in mice is progressing, a murine model of cardiovascular responses to muscle contraction has not been developed. Therefore, the purpose of this study was to characterize the cardiovascular responses to muscular contraction in anesthetized mice. The results of this study indicate that mice demonstrate significant increases in blood pressure (13.8 +/- 1.9 mmHg) and heart rate (33.5 +/- 11.9 beats/min) to muscle contraction in a contraction-intensity-dependent manner. Mice also demonstrate 23.1 +/- 3.5, 20.9 +/- 4.0, 21.7 +/- 2.6, and 25.8 +/- 3.0 mmHg increases in blood pressure to direct stimulation of tibial, peroneal, sural, and sciatic hindlimb somatic nerves, respectively. Systemic hypoxia (10% O(2)-90% N(2)) elicits increases in blood pressure (11.7 +/- 2.6 mmHg) and heart rate (42.7 +/- 13.9 beats/min), while increasing arterial pressure with phenylephrine decreases heart rate in a dose-dependent manner. The results from this study demonstrate the feasibility of using mice to study neural regulation of cardiovascular function during a variety of autonomic stimuli, including exercise-related drives such as muscle contraction. 相似文献
2.
Genotypic and environmental (soil water regime and N level) variation in carbon isotope discrimination (CID) in relation to
the gas exchange, transpiration efficiency (A/T), and biomass production were investigated in field experiments using eleven rice (Oryza sativa L.) genotypes. The results showed that genotype was more dominant for variation in CID than in total biomass. Genotypic ranking
in CID was consistent across environments because of small genotype × environment interactions. Japonica genotypes tended
to have lower CID than indica genotypes. Higher soil water and lower N rate significantly increased CID. Variation in CID
was slightly smaller for water regime than for genotype. There was a negative correlation between CID andA/T among genotypes within water regimes. Genotypic variation in CID was associated mainly with variation in stomatal conductance
under all soil water regimes and with photosynthetic capacity in late growth stages under aerobic soil conditions. The decrease
in CID at higher N was probably due to lower stomatal conductance under aerobic soil conditions and to higher photosynthetic
rates under submerged soil conditions. The correlation between biomass and CID was not clear in aerobic soil, whereas it was
positive in submerged soil, which indicated that the significance of lower or higher CID for improving biomass productivity
may differ under different soil water regimes. Overall, the results implied a possible use of CID as a selection criterion
for genotypic improvement inA/T and productivity in rice. 相似文献
3.
Tissue-specific and developmental regulation of rod opsin chimeric genes in transgenic mice. 总被引:13,自引:0,他引:13
Chimeric gene fusions between 4.4 kb of rod opsin 5' flanking sequence fused to a diphtheria toxin gene and 4.4 kb or 500 bp of rod opsin 5' flanking sequence fused to the E. coli IacZ gene were used to generate transgenic mice for analysis of cell type-specific expression and temporal and spatial distribution of reporter gene product during retinal development. Opsin-diphtheria toxin transgene expression evoked photoreceptor-specific cell death. The 4.4 kb opsin-IacZ transgene followed temporal and spatial gradients of expression that approximate opsin expression. The 500 bp opsin fragment targeted expression to photoreceptors, but expression was weaker and nonuniform, suggesting that elements located upstream may be required for enhanced and uniform spatial expression. 相似文献
4.
Judith S. Renes Maria A. J. de Ridder Petra E. Breukhoven Annemieke J. Lem Anita C. S. Hokken-Koelega 《PloS one》2012,7(12)
Background
Growth hormone (GH) treatment has become a frequently applied growth promoting therapy in short children born small for gestational age (SGA). Children born SGA have a higher risk of developing attention deficit hyperactivity disorder (ADHD). Treatment of ADHD with methylphenidate (MP) has greatly increased in recent years, therefore more children are being treated with GH and MP simultaneously. Some studies have found an association between MP treatment and growth deceleration, but data are contradictory.Objective
To explore the effects of MP treatment on growth in GH-treated short SGA childrenMethods
Anthropometric measurements were performed in 78 GH-treated short SGA children (mean age 10.6 yr), 39 of whom were also treated with MP (SGA-GH/MP). The SGA-GH/MP group was compared to 39 SGA-GH treated subjects. They were matched for sex, age and height at start of GH, height SDS at start of MP treatment and target height SDS. Serum insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) levels were yearly determined. Growth, serum IGF-I and IGFBP-3 levels during the first three years of treatment were analyzed using repeated measures regression analysis.Results
The SGA-GH/MP group had a lower height gain during the first 3 years than the SGA-GH subjects, only significant between 6 and 12 months of MP treatment. After 3 years of MP treatment, the height gain was 0.2 SDS (±0.1 SD) lower in the SGA-GH/MP group (P = 0.17). Adult height was not significantly different between the SGA-GH/MP and SGA-GH group (−1.9 SDS and −1.9 SDS respectively, P = 0.46). Moreover, during the first 3 years of MP treatment IGF-I and IGFBP-3 measurements were similar in both groups.Conclusion
MP has some negative effect on growth during the first years in short SGA children treated with GH, but adult height is not affected. 相似文献5.
William J. Foley Allen McIlwee Ivan Lawler Lem Aragones Andrew P. Woolnough Nils Berding 《Oecologia》1998,116(3):293-305
Many ecological studies rely heavily on chemical analysis of plant and animal tissues. Often, there is limited time and money
to perform all the required analyses and this can result in less than ideal sampling schemes and poor levels of replication.
Near infrared reflectance spectroscopy (NIRS) can relieve these constraints because it can provide quick, non-destructive
and quantitative analyses of an enormous range of organic constituents of plant and animal tissues. Near infrared spectra
depend on the number and type of CH, NH and OH bonds in the material being analyzed. The spectral features are then combined with reliable compositional or functional
analyses of the material in a predictive statistical model. This model is then used to predict the composition of new or unknown
samples. NIRS can be used to analyze some specific elements (indirectly – e.g., N as protein) or well-defined compounds (e.g.,
starch) or more complex, poorly defined attributes of substances (e.g., fiber, animal food intake) have also been successfully
modeled with NIRS technology. The accuracy and precision of the reference values for the calibration data set in part determines
the quality of the predictions made by NIRS. However, NIRS analyses are often more precise than standard laboratory assays.
The use of NIRS is not restricted to the simple determination of quantities of known compounds, but can also be used to discriminate
between complex mixtures and to identify important compounds affecting attributes of interest. Near infrared reflectance spectroscopy
is widely accepted for compositional and functional analyses in agriculture and manufacturing but its utility has not yet
been recognized by the majority of ecologists conducting similar analyses. This paper aims to stimulate interest in NIRS and
to illustrate some of the enormous variety of uses to which it can be put. We emphasize that care must be taken in the calibration
stage to prevent propagation of poor analytical work through NIRS, but, used properly, NIRS offers ecologists enormous analytical
power.
Received: 10 October 1997 / Accepted: 12 May 1998 相似文献
6.
Elodie Poiroux Christine Cavaro-Ménard Stéphanie Leruez Jean Michel Lemée Isabelle Richard Mickael Dinomais 《PloS one》2015,10(11)
Many of the brain structures involved in performing real movements also have increased activity during imagined movements or during motor observation, and this could be the neural substrate underlying the effects of motor imagery in motor learning or motor rehabilitation. In the absence of any objective physiological method of measurement, it is currently impossible to be sure that the patient is indeed performing the task as instructed. Eye gaze recording during a motor imagery task could be a possible way to “spy” on the activity an individual is really engaged in. The aim of the present study was to compare the pattern of eye movement metrics during motor observation, visual and kinesthetic motor imagery (VI, KI), target fixation, and mental calculation. Twenty-two healthy subjects (16 females and 6 males), were required to perform tests in five conditions using imagery in the Box and Block Test tasks following the procedure described by Liepert et al. Eye movements were analysed by a non-invasive oculometric measure (SMI RED250 system). Two parameters describing gaze pattern were calculated: the index of ocular mobility (saccade duration over saccade + fixation duration) and the number of midline crossings (i.e. the number of times the subjects gaze crossed the midline of the screen when performing the different tasks). Both parameters were significantly different between visual imagery and kinesthesic imagery, visual imagery and mental calculation, and visual imagery and target fixation. For the first time we were able to show that eye movement patterns are different during VI and KI tasks. Our results suggest gaze metric parameters could be used as an objective unobtrusive approach to assess engagement in a motor imagery task. Further studies should define how oculomotor parameters could be used as an indicator of the rehabilitation task a patient is engaged in. 相似文献
7.
A full saturated linkage map of<Emphasis Type="Italic"> Picea abies</Emphasis> including AFLP,SSR, ESTP, 5S rDNA and morphological markers 总被引:3,自引:0,他引:3
Acheré V Faivre-Rampant P Jeandroz S Besnard G Markussen T Aragones A Fladung M Ritter E Favre JM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(8):1602-1613
Based on an F1 progeny of 73 individuals, two parental maps were constructed according to the double pseudo-test cross strategy. The paternal map contained 16 linkage groups for a total genetic length of 1,792 cM. The maternal map covered 1,920 cM, and consisted of 12 linkage groups. These parental maps were then integrated using 66 intercross markers. The resulting consensus map covered 2,035 cM and included 755 markers (661 AFLPs, 74 SSRs, 18 ESTPs, the 5S rDNA and the early cone formation trait) on 12 linkage groups, reflecting the haploid number of chromosomes of Picea abies. The average spacing between two adjacent markers was 2.6 cM. The presence of 39 of the SSR and/or ESTP markers from this consensus map on other published maps of different Picea and Pinus species allowed us to establish partial linkage group homologies across three P. abies maps (up to five common markers per linkage group). This first saturated linkage map of P. abies could be therefore used as a support for developing comparative genome mapping in conifers.Communicated by O. Savolainen 相似文献
8.
9.
Michelle Lem Jason B. Coe Derek B. Haley Elizabeth Stone William O'Grady 《Anthrozo?s》2016,29(1):123-136
Street-involved youth represent a particularly vulnerable subsection of the homeless population and are at increased risk of health problems, substance abuse, and depression. Qualitative research has demon- strated that animal companions help homeless youth cope with loneliness, are motivators for positive change, such as decreasing drug or alcohol use, provide unconditional love without judgement, and improve youths’ sense of health. To quantitatively investigate the association between depression and pet ownership among street-involved youth, a cross-sectional study was per- formed with a convenience sample of 189 street-involved youths who were surveyed in four cities in Ontario, Canada, 89 of whom were pet owners and 100 of whom were not. Logistic regression modelling found pet ownership to be negatively associated with depression in the study population (controlling for gender, regular use of drugs, and time since youth left home), with the odds of being depressed three times greater for youths who did not own pets. While pet ownership among street-involved youth has many liabilities, includ- ing impairing youths’ ability to access shelter, services, and housing and employment opportunities, companion animals may offer both physical and psychosocial benefits that youth have difficult attaining. This finding highlights the importance of increased awareness among youth service providers of the potential impacts of pet ownership for street-involved youth. 相似文献
10.
Bonhomme J Le Goff L Lemée V Gargala G Ballet JJ Favennec L 《Parasitology international》2011,60(3):327-330
The intestinal protozoan Giardia duodenalis includes 2 genetically distinct assemblages, A and B, which are responsible for human infections. Little is known so far on the genotypes of G. duodenalis human isolates in France. The present characterization of 19 French clinical isolates was aimed at determining their genotype patterns and associations with clinical symptoms, and in vivo metronidazole resistance, respectively. Based on both triose-phosphate isomerase (tpi) and β-giardin (bg) gene sequences, twelve isolates were identified as assemblage A, and 7 as assemblage B for the 2 gene loci. Sub-genotyping heterogeneities were observed in 15/19 isolates attributed to either A or B assemblage. They include frequent mismatches and intra-assemblage discordances and mixed positions, which were found more frequently in tpi than in bg sequences, and in assemblage B than in assemblage A sequences. No association was found between sub-genotypes, clinical symptoms and metronidazole sensitivity. Present data underline the need for improvements in the standardization of G. duodenalis multilocus genotyping approach for further molecular epidemiologic studies of giardiasis. 相似文献