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51.
A microculture assay for murine granulocyte-macrophage colony- stimulating factor (GM-CSF) has been developed using fetal liver GM colony-forming cells (CFC) isolated by fluorescence-activated cell sorting. These GM-CFC are free of mature hemopoietic cells, such as granulocytes and macrophages, which may interfere with direct assays for GM-CSF. The assay procedure allows the quantitation of GM-CSF within 48 hr by measuring the number of cells produced from 50 GM-CFC in microcultures (15 microliter). The assay is particularly simple to set up and score and yet, because of the reduced volumes, this assay is still capable of detecting 0.2 pg (i.e., 0.2 U) of GM-CSF within 48 hr, i.e., 100 times less GM-CSF than the conventional soft agar assay. By allowing the microcultures to develop for 7 days, the extra proliferation allows a further tenfold increase in the sensitivity of CSF detection. The time and cost of setting up hundreds of GM-CSF assays for fractions from chromatographic columns, e.g., reverse phase high performance liquid chromatography, is reduced by at least five- fold. Enough GM-CFC can be isolated and stored frozen in one afternoon to provide sufficient cells for the daily assay of 200 samples of GM- CSF for several months. Microassay results for several sources of GM- CSF at different stages of purification are compared to the results obtained from the soft agar assay. 相似文献
52.
O Falusi AL French EC Seaberg PC Tien DH Watts H Minkoff E Piessens A Kovacs K Anastos MH Cohen 《Clinical infectious diseases》2002,35(11):1414-1417
We assessed the prevalence and predictors of latent Toxoplasma infection in a large group of human immunodeficiency virus (HIV)-infected and HIV-uninfected at-risk US women. The prevalence of latent Toxoplasma infection was 15% (380 of 2525 persons) and did not differ by HIV infection status. HIV-infected women aged > or =50 years and those born outside of the United States were more likely to have latent Toxoplasma infection, with prevalences of 32% and 41%, respectively. 相似文献
53.
Test-retest reproducibility of quantitative CBF measurements using FAIR perfusion MRI and acetazolamide challenge. 总被引:5,自引:0,他引:5
Yi-Fen Yen Aaron S Field Eric M Martin Narter Ari Jonathan H Burdette Dixon M Moody Atsushi M Takahashi 《Magnetic resonance in medicine》2002,47(5):921-928
The reproducibility of quantitative cerebral blood flow (CBF) measurements using MRI with arterial spin labeling and acetazolamide challenge was assessed in 12 normal subjects, each undergoing the identical experimental procedure on two separate days. CBF was measured on a 1.5T scanner using a flow-sensitive alternating inversion recovery (FAIR) pulse sequence, performed both at baseline and 12 min after intravenous administration of acetazolamide. T(1) was measured in conjunction with the FAIR scan in order to calculate quantitative CBF. The CBF maps were segmented to separate gray matter (GM) from white matter (WM) for region-of-interest (ROI) analyses. Post- acetazolamide CBF values (ml/100 g/min, mean +/- SD) of 87.5 +/- 12.5 (GM) and 46.1 +/- 10.8 (WM) represented percent increases of 37.7% +/- 24.4% (GM) and 40.1% +/- 24.4% (WM). Day-to-day differences in baseline CBF were -1.7 +/- 6.9 (GM) and -1.4 +/- 4.7 (WM) or, relative to the mean CBF over both days for each subject, -2.5% +/- 11.7% (GM) and -3.8% +/- 13.6% (WM) Day- to-day differences in absolute post-ACZ CBF increase were -2.5 +/- 6.8 (GM) and 2.7 +/- 9.4 (WM) or, relative to the mean CBF increase over both days for each subject, -4.7% +/- 13.3% (GM) and 9.1% +/- 26.2% (WM). Thus, FAIR- based CBF measurements show satisfactory reproducibility from day to day, but with sufficient variation to warrant caution in interpreting longitudinal data. The hemispheric asymmetry of baseline CBF and post-acetazolamide CBF increases varied within a narrower range and should be sensitive to small changes related to disease or treatment. 相似文献
54.
Percutaneous transjejunal approaches to the biliary system 总被引:2,自引:0,他引:2
55.
De Klein A; Riegman PH; Bijlsma EK; Heldoorn A; Muijtjens M; den Bakker MA; Avezaat CJ; Zwarthoff EC 《Human molecular genetics》1998,7(3):393-398
We describe a G-->A transition within intron 5 of the NF2 gene. This
mutation creates a consensus splice branch point sequence. To our knowledge
this is the first report of a mutation that creates a functional branch
point sequence in a human hereditary disorder. The new branch point
sequence is located 18 bp upstream of a consensus splice acceptor site. A
consensus splice donor site is found 106 bp 3' of the acceptor site. Asa
consequence the G-->A transition results in an alternatively spliced
mRNA containing an additional exon 5a of 106 bp derived from intron
sequences. We cloned the mutant cDNA and show that due to an in-frame stop
codon the cDNA codes for a truncated NF2 protein. The mutation was observed
in three affected members of an NF2 family. In a tumour of one of the
family members both alternatively spliced and wild-type mRNA were found,
although the wild-type allele of the gene is absent due to an interstitial
deletion on chromosome 22. We also show that immunoprecipitations reveal
the presence of full-length wild-type NF2 protein in the tumour lysate.
These data support the hypothesis that some degree of normal splicing of
the mutant precursor RNA is taking place. It is therefore likely that this
residual activity of the mutant allele explains the relatively mild
phenotype in the family. These data also indicate that complete
inactivation of the gene is not required for tumour formation.
相似文献
56.
Thurman EC; Walker J; Jayaraman S; Manjunath N; Ardman B; Green JM 《International immunology》1998,10(5):691-701
Accessory molecule interactions can be critical in determining the outcome
of a T cell's encounter with antigen. Cell adhesion proteins may augment T
cell responses by facilitating TCR engagement of the antigen-MHC complex,
while co-stimulatory molecules may deliver distinct signals that modulate T
cell responsiveness. CD43 (leukosialin, sialophorin) has been suggested to
influence cell activation by steric hindrance based upon the large size and
glycosylation of the protein, as well as the relative abundance of the
protein on the cell surface. In this paper we examine both in vitro and in
vivo T cell-dependent responses in CD43-deficient mice. We demonstrate that
T cells from CD43-deficient mice are hyper-responsive following both in
vivo and in vitro activation, and that this is observed in response to not
only TCR-CD3-mediated stimulation, but also following receptor-independent
activation. This data suggests that mechanisms other than non-specific
steric hindrance are important in the regulation of T cell activation by
CD43.
相似文献
57.
58.
Emergency room radiography of asthma: an efficacy study 总被引:2,自引:0,他引:2
59.
Two cases of left atrial myxoma were evaluated with magnetic resonance (MR) imaging. In both cases, the myxoma was clearly defined as to its location, origin, and size. In one case, the myxoma prolapsed through the mitral valve. Our study indicates that MR imaging is valuable in the diagnosis of myxomas. 相似文献
60.