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1.
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Reto Treier Andreas Steingoetter Michael Fried Werner Schwizer Peter Boesiger 《Magnetic resonance in medicine》2007,57(3):568-576
Fast T(1) mapping techniques are a valuable means of quantitatively assessing the distribution and dynamics of intravenously or orally applied paramagnetic contrast agents (CAs) by noninvasive imaging. In this study a fast T(1) mapping technique based on the variable flip angle (VFA) approach was optimized for accurate T(1) quantification in abdominal contrast-enhanced (CE) MRI. Optimization methods were developed to maximize the signal-to-noise ratio (SNR) and ensure effective RF and gradient spoiling, as well as a steady state, for a defined T(1) range of 100-800 ms and a limited acquisition time. We corrected B(1) field inhomogeneities by performing an additional measurement using an optimized fast B(1) mapping technique. High-precision in vitro and abdominal in vivo T(1) maps were successfully generated at a voxel size of 2.8 x 2.8 x 15 mm(3) and a temporal resolution of 2.3 s per T(1) map on 1.5T and 3T MRI systems. The application of the proposed fast T(1) mapping technique in abdominal CE-MRI enables noninvasive quantification of abdominal tissue perfusion and vascular permeability, and offers the possibility of quantitatively assessing dilution, distribution, and mixing processes of labeled solutions or drugs in the gastrointestinal tract. 相似文献
3.
Severe burns and scalds are still frequent. If the burn victim is a child, it should ideally be taken care of in a pediatric burn center, where both the burn and child-related needs are specifically met. The goals of burn care are to preserve life, to preserve function, to limit physical and psychological sequelae and to provide social reintegration. The system of burn care essentially consists of adequate initial resuscitation followed by early surgery aimed at rapid and definitive wound closure. Vigorous nutritional support as well as early rehabilitation and continuous psychosocial care are of paramount importance. The paper summarizes the essentials of pediatric burn care (burn surgery excluded). 相似文献
4.
We report on 3 children with traumatic spinal cord injury. All of them had normal x-rays of the vertebral column. There were no abnormalities of the spinal cord in myelography or magnetic resonance imaging. Although these situations are often associated with a poor neurological prognosis, we observed very unusual recoveries in these 3 cases. 相似文献
5.
Optimal surgical therapy of severe burns in children has been controversial for a long time. A review of the current literature shows that prompt surgical excision of necrotic tissue and immediate autografting have become the standard in most burn centers. The authors present a concept based on prompt excision of third degree burns and discuss the problems of intermediate cover arising in massive burns. 相似文献
6.
7.
Summary Development of third-stage larvae ofDipetalonema viteae within subcutaneously implanted micropore chambers proceeded in all hosts tested up to the fourth-stage larvae and occasionally to adolescent worms. In the jird the timing of development was comparable to a natural infection. Although the mouse is an insusceptible host, larval development could take place, but was very slow. Two intraperitoneal inoculations of living thirdstage larvae into mice induced the production of antibodies against the larval cuticle and against common antigens. In such immune mice the development of third- and fourth-stage larvae within micropore chambers was significantly inhibited, larval mortality was increased, and the larval motility was impaired. 相似文献
8.
Andreas W. Jehle Judith Forgo J. Biber Eleanor Lederer Reto Krapf Heini Murer 《Pflügers Archiv : European journal of physiology》1998,437(1):149-154
Insulin-like growth factor (IGF)-I and vanadate increase Na-dependent phosphate (Na/Pi) cotransport in opossum kidney (OK) cells. To gain more information about the mechanisms by which IGF-I and vanadate stimulate
Na/Pi-cotransport, we measured type II Na/Pi-cotransporter (NaPi-4) protein abundance by Western blot analysis and investigated the effects of protein synthesis and tyrosine
kinase inhibitors. The key findings in the present studies are as follows. First, incubation in IGF-I (10–8 M) and/or vanadate (10–3 M) for 3 h led to a non-additive 1.4-fold increase in Na/Pi-cotransport activity which was paralleled by a 1.5- to 2-fold increase in NaPi-4 protein. Second, actinomycin D did not abolish
the increase in Na/Pi-cotransport and cycloheximide did not prevent the IGF-I-induced increase in Na/Pi-cotransport and NaPi-4 protein. Third, among the protein kinase inhibitors tested, only staurosporine substantially reduced
the stimulation of Na/Pi-cotransport. In conclusion, the stimulatory effect of IGF-I on Na/Pi-cotransport is paralleled by an increased expression of NaPi-4 protein that is independent of protein synthesis and therefore
results from increased protein stability. The observation that IGF-I and/or vanadate lead to similar increases in Na/Pi-cotransport and NaPi-4 protein abundance provides further evidence that the stimulation of Na/Pi-cotransport by IGF-I and vanadate involves protein tyrosine phosphorylation of the same signalling molecules.
Received: 1 May 1998 / Received after revision: 25 August 1998 / Accepted: 1 September 1998 相似文献
9.
Fluctuating asymmetries are small random deviations from perfect symmetry in bilateral traits caused by the inability of individuals to cope with stress during development. The degree of asymmetry of secondary sexual characters is supposed to convey information about a male's phenotypic and/or genetic quality, and females are thus expected to use bilateral symmetry as a cue in mate choice. We offered female three-spined sticklebacks (Gasterosteus aculeatus L.) that had been inbred for one generation and outbred control females the choice between computer-animated male models differing exclusively in the symmetry of their pelvic spines. Inbred females exhibited a significantly stronger preference for the symmetric model than outbred females, suggesting that females of relatively poor quality are more prepared to pay the costs of choosiness and obtain higher marginal benefits from their discrimination than females of better quality. 相似文献
10.
Ectopic bone formation associated with mesenchymal stem cells in a resorbable calcium deficient hydroxyapatite carrier 总被引:6,自引:0,他引:6
Kasten P Vogel J Luginbühl R Niemeyer P Tonak M Lorenz H Helbig L Weiss S Fellenberg J Leo A Simank HG Richter W 《Biomaterials》2005,26(29):5879-5889
Bone substitute materials can induce bone formation in combination with mesenchymal stem cells (MSC). The aim of the current study was to examine ectopic in vivo bone formation with and without MSC on a new resorbable ceramic, called calcium deficient hydroxyapatite (CDHA). Ceramic blocks characterized by a large surface (48 m2/g) were compared with beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA) ceramics (both ca. 0.5 m2/g surface) and demineralized bone matrix (DBM). Before implantation in the back of SCID mice carriers were freshly loaded with 2x10(5) expanded human MSC or loaded with cells and kept under osteogenic conditions for two weeks in vitro. Culture conditions were kept free of xenogenic supplements. Deposits of osteoid at the margins of ceramic pores occurred independent of osteogenic pre-induction, contained human cells, and appeared in 416 MSC/CDHA composites compared to 216 MSC/beta-TCP composites. ALP activity was significantly higher in samples with MSC versus empty controls (p<0.001). Furthermore, ALP was significantly (p<0.05) higher for all ceramics when compared to the DBM matrix. Compared to previous studies, overall bone formation appeared to be reduced possibly due to the strict human protocol. Ectopic bone formation in the novel biomaterial CDHA varied considerably with the cell pool and was at least equal to beta-TCP blocks. 相似文献