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41.
杨娅 Thomas Bartel Loredana Latina Guido Caspari 王新房 Raimund Erbel 《华中科技大学学报(医学英德文版)》2002,22(2):158-163
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re… 相似文献
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Chromogenic ionophore-based methods for spectrophotometric assay of sodium and potassium in serum and plasma 总被引:1,自引:0,他引:1
A Kumar E Chapoteau B P Czech C R Gebauer M Z Chimenti O Raimondo 《Clinical chemistry》1988,34(9):1709-1712
We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivity and selectivity (negligible responses to sodium at 80 to 200 mmol/L in the potassium assay and to potassium at 0 to 10 mmol/L in the sodium assay). The within-run imprecisions are comparable with those for ion-selective electrodes (for K, 1.0% at 4.5 mmol/L; for Na, 1.1% at 136 mmol/L); the analytical range is 2-10 mmol/L for potassium, 80-170 mmol/L for sodium. The results for greater than 100 patients' samples correlated well with results obtained with ion-selective electrodes (r = 0.99 for K, 0.97 for Na). The ready-to-use aqueous reagents will be available under the trade name of ChromoLyte for use with Technicon's RA family of clinical analyzers. 相似文献
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表皮生长因子对牛眼小梁细胞c—fos基因表达的诱导 总被引:4,自引:0,他引:4
目的研究表皮生长因子(epidermalgrowthfactor,EGF)对小梁细胞的作用。方法应用分子杂交技术研究EGF对体外培养的牛眼小梁细胞c-fos基因表达的诱导和3H胸腺核苷酸(3H-thymidineincorparation,3H-TdR)掺入法观察细胞DNA的合成。结果小梁细胞的3H-TdR掺入率随着EGF浓度不同而变化,浓度为20~150ng/ml时,细胞掺入率随浓度增加升高(P<0.01)。与对照组相比,EGF刺激停止生长的小梁细胞0.5小时后,c-fos基因开始表达,1小时后达高峰,至2小时后消失。不同浓度EGF刺激小梁细胞1小时后,c-fos基因表达呈浓度依赖性。结论实验结果表明EGF刺激小梁细胞增殖或进入生长状态,可能与c-fos基因产物的信号传递作用有关。 相似文献
46.
J C Strainer J L Ulmer F Z Yetkin V M Haughton D L Daniels S J Millen 《AJNR. American journal of neuroradiology》1997,18(4):601
PURPOSETo use functional MR imaging to measure the effect of frequency (pitch), intensity (loudness), and complexity of auditory stimuli on activation in the primary and secondary auditory cortexes.METHODSMultiplanar echo-planar images were acquired in healthy subjects with normal hearing to whom auditory stimuli were presented intermittently. Functional images were processed from the echo-planar images with conventional postprocessing methods. The stimuli included pure tones with a single frequency and intensity, pure tones with the frequency stepped between 1,000, 2,000, 3,000, or 4,000 Hz, and spoken text. The pixels activated by each task in the transverse temporal gyrus (TTG) and the auditory association areas were tabulated.RESULTSThe pure tone task activated the TTG. The 1,000-Hz tone activated significantly more pixels in the TTG than did the 4,000-Hz tone. The 4,000-Hz tone activated pixels primarily in the medial TTG, whereas the 1,000-Hz tone activated more pixels in the lateral TTG. Higher intensity tones activated significantly more pixels than did lower intensity tones at the same frequency. The stepped tones activated more pixels than the pure tones, but the difference was not significant. The text task produced significantly more activation than did the pure tones in the TTG and in the auditory association areas. The more complex tasks (stepped tones and listening to text) tended to activate more pixels in the left hemisphere than in the right, whereas the simpler tasks activated similar numbers of pixels in each hemisphere.CONCLUSIONAuditory stimuli activate the TTG and the association areas. Activation in the primary auditory cortex depends on frequency, intensity, and complexity of the auditory stimulus. Activation of the auditory association areas requires more complex auditory stimuli, such as the stepped tone task or text reading. 相似文献
47.
为探讨钙调素在慢性缺氧性肺动脉高压发病中的作用,将40只Wistar大鼠随机分为四组,I组为正常对照组,不接受任何处理。Ⅱ、Ⅲ、Ⅳ组为实验组,分别间断缺氧1、2、3周,而后采用火焰原子吸收分光光度法及磷酸二酯酶法测定四组大鼠肺组织Ca^2+含量及CaM活性。 相似文献
48.
P J Hayden C J Welsh Y Yang W H Schaefer A J Ward J L Stevens 《Chemical research in toxicology》1992,5(2):232-237
Nephrotoxic cysteine conjugates derived from a variety of halogenated alkenes are enzymatically activated via the beta-lyase pathway to yield reactive sulfur-containing metabolites which bind covalently to cellular macromolecules. Mitochondria contain beta-lyase enzymes and are primary targets for binding and toxicity. Previously, mitochondrial protein and/or DNA have been considered as molecular targets for cysteine conjugate metabolite binding. We now report that metabolites of nephrotoxic cysteine conjugates form covalent adducts with rat kidney mitochondrial phospholipids. Rat kidney mitochondria were incubated with the 35S-labeled conjugates S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC), S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine (CTFC), S-(1,2-dichlorovinyl)-L-cysteine, and S-(1,2,3,4,4-pentachlorobutadienyl)-L-cysteine. Quantitation of metabolite binding to whole mitochondria and to mitochondrial protein and lipid fractions revealed that as much as 42% of the 35S-label associated with the mitochondria was found in the lipid fraction. Total lipids were also extracted from 35S-treated mitochondria and separated by thin-layer chromatography. 35S-Containing metabolites were found in the lipid fractions from mitochondria treated with each of the conjugates. Lipids from both [35S]CTFC- and [35S]-TFEC-treated mitochondria contained major 35S-labeled lipid adducts which had similar mobility by thin-layer chromatography. Fatty acid analysis, 19F and 31P NMR spectroscopy, and mass spectrometric analyses confirmed that the major TFEC and CTFC adducts are thioamides of phosphatidylethanolamine. 相似文献
49.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
50.
SRIVASTAVA Z. I.; MATHUR N.; RASTOGI S. K.; GUPTA B. N. 《Occupational medicine (Oxford, England)》1988,38(4):134-136
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease.
Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India 相似文献