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11.
Synopsis We conducted laboratory trials to test the vulnerability of young white sturgeon, Acipenser transmontanus, to predation when an alternative prey was available. In trials with two species of predators, we observed two feeding patterns.
When equal numbers of white sturgeon and goldfish, Carassius auratus, were available, prickly sculpins, Cottus asper, ingested more white sturgeon. Conversely, northern pikeminnow, Ptychocheilus oregonensis, ate more juvenile coho salmon, Oncorhynchus kisutch, than white sturgeon in three out of four sets of trials, but ate more white sturgeon in one set of trials. White sturgeon
size and the availability of cover did not affect the proportions of prey species ingested. Our results indicate that predation
may be affecting survival of white sturgeon larvae and juveniles in the wild and could be one factor limiting recruitment
of young-of-the-year white sturgeon in some locations. 相似文献
12.
Sofie De Cooman Nathalie De Mey Bram BC Dewulf Rik Carette Thierry Deloof Maurice Sosnowski Andre M De Wolf Jan FA Hendrickx 《BMC anesthesiology》2008,8(1):1-6
Background
Current analgesics have drawbacks such as delays in acquisition, lag-times for effect, and side effects. We recently presented a preliminary report of a new analgesic method involving a two-minute sciatic nerve press, which resulted in immediate short-term relief of pain associated with dental and renal diseases. The present study investigated whether this technique was effective for pain associated with other disease types, and whether the relief was effective for up to one hour.Methods
This randomized, placebo-controlled, parallel-group trial was conducted in four hospitals in Anhui Province, China. Patients with pain were sequentially recruited by participating physicians during clinic visits, and 135 patients aged 15 – 80 years were enrolled. Dental disease patients included those with acute pulpitis and periapical abscesses. Renal disease patients included those with kidney infections and/or stones. Tumor patients included those with nose, breast, stomach and liver cancers, while Emergency Room patients had various pathologies. Patients were randomly assigned to receive a "sciatic nerve press" in which pressure was applied simultaneously to the sciatic nerves at the back of both thighs, or a "placebo press" in which pressure was applied to a parallel region on the front of the thighs. Each fist applied a pressure of 11 – 20 kg for 2 minutes. Patients rated their level of pain before and after the procedure.Results
The "sciatic nerve press" produced immediate relief of pain in all patient groups. Emergency patients reported a 43.5% reduction in pain (p < 0.001). Significant pain relief for dental, renal and tumor patients lasted for 60 minutes (p < 0.001). The peak pain relief occurred at the 10 – 20th minutes, and the relief decreased 47% by the 60th minutes.Conclusion
Two minutes of pressure on both sciatic nerves produced immediate significant short-term conduction analgesia. This technique is a convenient, safe and powerful method for the short-term treatment of clinical pain associated with a diverse range of pathologies.Trial registration
Current Controlled Trials ACTRN012606000439549 相似文献13.
An extension of the Coulomb?Amontons law is proposed in terms of interaction details that involve the (simplified) renormalization of an nth level scheme. The coefficient of friction (COF) is obtained in a general exponential (nonlinear) form that is characteristic of a virtually infinite (or many body) level of the interaction map. However, its application to a hydration repulsion bilayered system that is prone to facilitated lubrication is taken as linearly confined, albeit with an inclusion of a decisive repelling force/pressure factor. Some perspective on related systems that are rather far from biotribological issues is also addressed.
相似文献14.
Jacek Siódmiak Jan J. Uher Ivan Santamaría-Holek Natalia Kruszewska Adam Gadomski 《Journal of biological physics》2007,33(4):313-329
A superdiffusive random-walk action in the depletion zone around a growing protein crystal is considered. It stands for a
dynamic boundary condition of the growth process and competes steadily with a quasistatic, curvature-involving (thermodynamic)
free boundary condition, both of them contributing to interpret the (mainly late-stage) growth process in terms of a prototype
ion-channeling effect. An overall diffusion function contains quantitative signatures of both boundary conditions mentioned
and indicates whether the new phase grows as an orderly phase or a converse scenario occurs. This situation can be treated
in a quite versatile way both numerically and analytically, within a generalized Smoluchowski framework. This study can help
in (1) elucidating some dynamic puzzles of a complex crystal formation vs biomolecular aggregation, also those concerning
ion-channel formation, and (2) seeing how ion-channel-type dynamics of non-Markovian nature may set properly the pace of model
(dis)ordered protein aggregation. 相似文献
15.
Nuttall ME Lee JC Murdock PR Badger AM Wang FL Laydon JT Hofmann GA Pettman GR Lee JA Parihar A Van Wagenen BC Fox J Gowen M Johnson RK Mattern MR 《Journal of biomolecular screening》1999,4(5):269-278
Xenopus laevis melanophores stably expressing 7-transmembrane G-protein-coupled receptors were established and evaluated, either as a primary screening utility for antagonists of the human calcium receptor, or as a screen to assign function to binding inhibitors of human cannabinoid receptors. Stably or transiently expressing melanophores responded selectively to respective effectors of the human calcium, cannabinoid, and neurokinin-1 receptors. Several selective cannabinoid receptor-binding inhibitors of known potency were characterized as agonists or antagonists of the human peripheral cannabinoid (CB(2)) receptor. The results were consistent with changes in cAMP content of hCB(2)-transfected human embryonic kidney (HEK) cells challenged with the same CB(2)-binding antagonists. A stable melanophore cell line expressing the human calcium receptor was used to screen a compound collection directly for functional antagonists, several of which were confirmed as antagonists in secondary screens by stimulating parathyroid hormone (PTH) secretion from bovine parathyroid cells. The percentage of hits in this cell-based screen was reasonably low (1.2%), indicating minimal interference due to toxic effects and validating melanophores as a primary screening modality. Also described is the development of a novel procedure for cryopreservation and reconstitution of cells retaining functional human receptors. () 相似文献
16.
Jacob J. Michaelson Yujian Shi Madhusudan Gujral Hancheng Zheng Dheeraj Malhotra Xin Jin Minghan Jian Guangming Liu Douglas Greer Abhishek Bhandari Wenting Wu Roser Corominas Áine Peoples Amnon Koren Athurva Gore Shuli Kang Guan Ning Lin Jasper Estabillo Therese Gadomski Balvindar Singh Kun Zhang Natacha Akshoomoff Christina Corsello Steven McCarroll Lilia M. Iakoucheva Yingrui Li Jun Wang Jonathan Sebat 《Cell》2012
17.
Lack of geographic variation in anonymous nuclear polymorphisms in the American oyster, Crassostrea virginica 总被引:1,自引:0,他引:1
Comparing geographic variation of noncoding nuclear DNA polymorphisms,
which presumably are neutral to natural selection, with geographic
variation of allozymes is potentially a good way to detect the effects of
selection on allozyme polymorphisms. A previous study of four anonymous
nuclear markers in the American oyster, Crassostrea virginica, found
dramatic differences in allele frequency between the Gulf of Mexico and the
Atlantic Ocean. In contrast, 14 allozyme polymorphisms were fairly uniform
in frequency between the two areas. This led to the conclusion that all of
the allozyme polymorphisms were kept uniform in frequency by balancing
selection. To test the robustness of this pattern, six additional anonymous
nuclear DNA polymorphisms were surveyed in oysters from Panacea, Fla, and
Charleston, S.C. on the Gulf and Atlantic coasts, respectively. Unlike the
previously studied DNA markers, the six DNA polymorphisms examined here
show geographic variation that is not significantly greater than that of
allozymes. The reason for the discrepancy between the two sets of DNA
polymorphisms is unclear.
相似文献
18.
A Gadomski I Zmudzka H Wójtowicz 《Polski tygodnik lekarski (Warsaw, Poland : 1960)》1990,45(21-22):422-424
The efficiency of antiemetic drugs was investigated in 36 children with neoplasia (mainly of hematopoietic system) in the course of 83 cycles of chemotherapy. The following antiemetic drugs were investigated: Fenactil (brand of chlorpromazine), Torecan (brand of thienylpromazine maleate), Aviomarin (brand of dimenhydrinate), Decadron (brand of dexamethasone), Primperan (brand of metoclopramid), and placebo. The most efficient was dexamethasone which prevented vomiting in 54% cycles of chemotherapy and diminished their intensity in the remaining cycles. No adverse reactions were noted. Efficacy of Fenactil, Torecan, Aviomarin, and Primperan was similar to that of placebo. 相似文献
19.
Andreas A Ioannides Peter BC Fenwick Elina Pitri Lichan Liu 《Nonlinear biomedical physics》2010,4(Z1):S11
Background
Identifying eye movement related areas in the frontal lobe has a long history, with microstimulation in monkeys producing the most clear-cut results. For humans, however, there is still no consensus about the location and the extent of the frontal eye field (FEF). There is also no simple non-invasive method for unambiguously defining the FEF in individual subjects, a prerequisite for clinical applications. Here we explore the use of magnetoencephalography (MEG) for the non-invasive identification and characterization of FEF activity in an individual subject.Methods
We mapped human brain activity before, during and after saccades by applying tomographic analysis to MEG data. Statistical parametric maps and circular statistics produced plausible FEF loci, but no unambiguous definition for individual subjects. Here we first computed the spectral decomposition and correlation with electrooculogram (EOG) of the tomographic brain activations. For each of these two measures statistical comparisons were made between different saccades.Results
In this paper, we first review the frontal cortex activations identified in earlier animal and human studies and place the putative human FEFs in a well-defined anatomical framework. This framework is then used as reference for describing the results of new Fourier analysis of the tomographic solutions comparing active saccade tasks and their controls. The most consistent change in the dorsal frontal cortex was at the putative left FEF, for both saccades to the left and right. The asymmetric result is consistent with the 1-way callosal traffic theory. We also showed that the new correlation analysis had its most consistent change in the contralateral putative FEF. This result was obtained for EOG latencies before saccade onset with delays of a few hundreds of milliseconds (FEF activity leading the EOG) and only for visual cues signaling the execution of a saccade in a previously defined saccade direction.Conclusions
The FEF definition derived from microstimulation describes only one of the areas in the dorsal lateral frontal lobe that act together to plan, prepare and execute a saccade. The definition and characterization of these areas in an individual subject can be obtained from non-invasive MEG measurements.20.
BC Wilson D Burnett R Rappaport LJ Parry EK Fletcher 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2009,153(1):69-74
Relaxins are peptides similar in secondary structure to insulins. In teleost genomes, five or six relaxin genes have been identified. Two relaxins group closely with mammalian relaxin-3 on phylogenetic analysis and are named relaxin-3a and b. We refer to the remainder as relaxins c to f. Ovarian expression of relaxin-3a, d and f genes, and the relaxin-3 receptor gene Rxfp3, was studied in Danio rerio using RT-PCR. Immunohistochemistry was used to determine the distribution of relaxin-3 peptides and RXFP3 in the ovary of Fundulus heteroclitus (killifish). Thirdly, enzyme immunoassays and ovarian follicular culture were used to determine the effect of treatment with human recombinant relaxin-3 on the production of 17beta-estradiol and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one in killifish ovarian follicles. Relaxin-3a, d, f, and Rxfp3 genes were expressed regardless of sex or reproductive condition. Relaxin-3 immunostaining was present in mid to late follicular stages within cortical alveoli of the oocyte cytopasm, whereas receptor staining was localized to follicular cells. Treatment with relaxin-3 enhanced 17beta-estradiol production in early and late maturing follicles, but did not have an effect in vitellogenic follicles. Relaxin-3 appeared to suppress the release of MIS production. This suggests that relaxin peptides may be involved with estradiol-dependant events in follicular development. 相似文献