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941.
Scopulariopsis acremonium is a species of saprophytic fungus not previously reported to cause invasive disease in humans, although invasive infections from other species of Scopulariopsis have been reported and are reviewed. Deep infection with this fungus is associated with a high mortality rate. Invasive fungal sinusitis, in general, is a potentially fatal disease that typically affects immunocompromised patients, such as those receiving intensive chemotherapy or undergoing bone marrow transplantation. We report a case of invasive fungal sinusitis caused by Scopulariopsis acremonium in a patient with leukemia, who was successfully treated with amphotericin B, itraconazole, endoscopic sinus surgery, and granulocyte colony-stimulating factor. 相似文献
942.
S Parry J Holder MW Halterman MD Weitzman AR Davis H Federoff JF Strauss 《Canadian Metallurgical Quarterly》1998,152(6):1521-1529
We investigated the transfer of the lacZ reporter gene into human trophoblastic cells using herpes simplex virus and adeno-associated virus vectors. We used an established choriocarcinoma cell line (BeWo cells) that can be induced to terminally differentiate after treatment with cyclic-AMP. Our results demonstrate that transduction of trophoblastic cells by the herpes simplex virus vector, HSV.CMVlac, and the adeno-associated virus vector, AAV.CMVlac, is affected by cellular differentiation. Treatment of BeWo cells with cyclic-AMP reduced transduction by HSV.CMVlac but increased transduction by the AAV vector. In contrast, when BeWo cells were transfected with herpes simplex virus and adeno-associated virus plasmids, lacZ expression was not affected by treatment with cyclic-AMP. Southern blot analysis demonstrated 2.75 times less herpes simplex virus DNA in cyclic-AMP treated BeWo cells, but 2.0 to 7.4 times more adeno-associated virus DNA in treated cells. We conclude that inefficient transduction of differentiated trophoblastic cells with HSV.CMVlac is because of diminished viral entry, whereas cellular differentiation is associated with increased entry of AAV.CMVlac. These observations suggest that adeno-associated virus vectors may be used to modify trophoblast function and study placental physiology. Additionally, trophoblast differentiation leads to alterations in the mechanisms of virus uptake that may affect maternal-to-fetus transmission. 相似文献
943.
CP Cannon CH McCabe S Borzak TD Henry MD Tischler HS Mueller R Feldman ST Palmeri K Ault SA Hamilton JM Rothman WF Novotny E Braunwald 《Canadian Metallurgical Quarterly》1998,97(4):340-349
In fMRI studies, Gaussian filtering is usually applied to improve the detection of activated areas. Such lowpass filtering enhances the signal to noise ratio. However, undesirable secondary effects are a bias on the signal shape and a blurring in the spatial domain. Neighboring activated areas may be merged and the high resolution of the fMRI data compromised. In the temporal domain, activation and deactivation slopes are also blurred. We propose an alternative to Gaussian filtering by restoring the signal using a spatiotemporal Markov Random Field which preserves the shape of the transitions. We define some interaction between neighboring voxels which allows us to reduce the noise while preserving the signal characteristics. An energy function is defined as the sum of the interaction potentials and is minimized using a simulated annealing algorithm. The shape of the hemodynamic response is preserved leading to a better characterization of its properties. We demonstrate the use of this approach by applying it to simulated data and to data obtained from a typical fMRI study. 相似文献
944.
945.
It is shown that theory of the Penning discharge essentially involves taking into account the collective interaction of the electrons in the near-anode region. Following investigations of the Penning discharge in a strong magnetic field (density up to 12 kOe) empirical formulae are proposed for calculating the pumping speed and the minimum operating pressures of getter-ion pumps. Methods of calculation for built-in getter-ion pump parameters and design peculiarities are considered. 相似文献
946.
Two phosphate rocks, one from Pesca (Colombia) and the other from Togo, were acidulated to various degrees with H2SO4 and H3PO4 for evaluation in varying granule size ranges. Products acidulated with H2SO4 were also prepared using different drying temperatures. Phosphorus availability was measured by dry-matter yield and P uptake in greenhouse experiments with maize.It was observed that partial acidulation with H2SO4 was effective in increasing the water-soluble P level of phosphate rock when the drying temperature of the product was not excessive. Crop response and P uptake were both highly correlated to the water solubility of the product. The relative agronomic effectiveness (RAE) of Togo rock increased from 3% when unacidulated to 33%, 47%, and 52% when 20%, 30%, and 40%, respectively, of the H2SO4 required to make SSP was added. Similar results were obtained with Pesca rock. No consistent effect due to granule size was observed.Twenty percent acidulation of Pesca rock with H3PO4 was 53–76% as effective as TSP with a single crop and 79–90% as effective over three cropping periods, showing a potential for high residual value. 相似文献
947.
948.
Repair of ruptured thoracoabdominal aortic aneurysms is complicated by high rates of perioperative paraplegia, renal insufficiency, and mortality. This report describes a patient with a ruptured thoracoabdominal aortic aneurysm in whom preoperative acute renal failure was reversed with hemodialysis, aortic replacement, and renal revascularization. Prompt cerebrospinal fluid drainage reversed delayed-onset postoperative paraplegia and led to immediate, complete neurologic recovery. 相似文献
949.
MD Megonigal EF Rappaport PC Nowell BJ Lange CA Felix 《Canadian Metallurgical Quarterly》1998,16(10):1351-1356
We used single-strand conformation polymorphism (SSCP) analysis of p53 exons 4-8 to screen for possible mutations in 25 pediatric de novo leukemias with translocations of the MLL gene at chromosome band 11q23. Of the 25 patients, 21 were infants. Fifteen cases were acute myeloid leukemia (AML), eight were acute lymphoblastic leukemia (ALL), and two cases were biphenotypic. Nineteen cases were studied at diagnosis and six at time of relapse. p53 mutations were absent in all 19 cases studied at the time of diagnosis. The only mutation was a TGC-->TTC transversion (cys-->phe) at codon 141 in exon 5 in a case of infant ALL at relapse that occurred by subclone evolution after MLL gene translocation. We previously showed that p53 mutations are also absent in pediatric treatment-related leukemias with MLL gene translocations. The absence of p53 mutations at initial transformation may suggest that the anti-apoptotic effect of mutant p53 is not important in leukemias with MLL gene translocations. Alternatively, exogenous DNA damage may be the common feature in treatment-related and de novo cases. Since MLL gene translocations may occur through DNA repair and wild-type p53 is central to DNA repair, the absence of p53 mutations raises the possibility that wild-type p53, not mutant p53, may be important in the genesis of leukemias with these translocations. 相似文献
950.
V Felipo C Hermenegildo C Montoliu M Llansola MD Mi?ana 《Canadian Metallurgical Quarterly》1998,19(4-5):675-681
Ammonia is a main factor in the pathogenesis of hepatic encephalopathy. We found that acute ammonia toxicity is mediated by activation of NMDA receptors. Chronic moderate hyperammonemia prevents acute ammonia toxicity in rats. Chronic exposure of cultured neurons to 1 mM ammonia leads to impaired response of the NMDA receptor to activation by its agonists (due to decreased protein kinase C-mediated phosphorylation) and prevents glutamate (Glu) neurotoxicity. Compounds that prevent ammonia toxicity in mice (e.g. carnitine) also prevent Glu toxicity in cultured neurons. These compounds did not prevent activation of NMDA receptor or the rise of Ca2+. They interfered with subsequent steps in the toxic process. The protective effect of carnitine is mediated by activation of metabotropic Glu receptors. Agonists of mGluRs, especially of mGluR5, prevent Glu toxicity. Agonists of muscarinic receptors also prevent Glu toxicity and there seems to be an interplay between muscarinic and metabotropic Glu receptors in the protective effect. We have tried to identify intracellular events involved in the process of neuronal death. It is known that the rise of Ca2+ is an essential step. Glu leads to depletion of ATP; some compounds (e.g. carnitine) prevent Glu-induced neuronal death without preventing ATP depletion: additional events are required for neuronal death. Glu induces activation of Na+/K+-ATPase, which could be involved in the toxic process. Inhibitors of protein kinase C, calcineurin or nitric oxide synthase prevent Glu toxicity. Our results indicate that Glu toxicity can be prevented at different steps or by activating receptors coupled to the transduction pathways interfering with the toxic process. Agents acting on these steps could prevent excitotoxicity in vivo in animals. 相似文献