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1.
Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study 下载免费PDF全文
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Evaluation of three substitutes for Percoll in sperm isolation by density gradient centrifugation 总被引:9,自引:4,他引:9
Silane-coated silica particle solutions (ISolate(TM) and PureSperm)TM)) and
iodixanol (OptiPrep(TM)) were compared to polyvinylpyrrolidone (PVP)-coated
silica particles (Percoll(TM)) in their efficacy to recover spermatozoa by
gradient centrifugation for use in assisted reproductive procedures.
Efficacy was assessed in terms of percentages of sperm recovery, sperm
vitality and motility, normal sperm morphology and normal sperm chromatin
condensation. No significant difference was found in the recovery of
spermatozoa for men with both normal sperm counts and oligozoospermia,
between PVP-coated and silane-coated particle solutions. Iodixanol had
significantly lower sperm recovery compared to the other products. Sperm
vitality, progressive motility, normal morphology and normal chromatin
condensation did not differ significantly between any of the sperm
isolation products.
相似文献
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Characterization of clinical isolates of Klebsiella pneumoniae from 19 laboratories using the National Committee for Clinical Laboratory Standards extended-spectrum beta-lactamase detection methods 总被引:4,自引:0,他引:4 下载免费PDF全文
Steward CD Rasheed JK Hubert SK Biddle JW Raney PM Anderson GJ Williams PP Brittain KL Oliver A McGowan JE Tenover FC 《Journal of clinical microbiology》2001,39(8):2864-2872
Extended-spectrum beta-lactamases (ESBLs) are enzymes found in gram-negative bacilli that mediate resistance to extended-spectrum cephalosporins and aztreonam. In 1999, the National Committee for Clinical Laboratory Standards (NCCLS) published methods for screening and confirming the presence of ESBLs in Klebsiella pneumoniae, Klebsiella oxytoca, and Escherichia coli. To evaluate the confirmation protocol, we tested 139 isolates of K. pneumoniae that were sent to Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology) from 19 hospitals in 11 U.S. states. Each isolate met the NCCLS screening criteria for potential ESBL producers (ceftazidime [CAZ] or cefotaxime [CTX] MICs were > or =2 microg/ml for all isolates). Initially, 117 (84%) isolates demonstrated a clavulanic acid (CA) effect by disk diffusion (i.e., an increase in CAZ or CTX zone diameters of > or =5 mm in the presence of CA), and 114 (82%) demonstrated a CA effect by broth microdilution (reduction of CAZ or CTX MICs by > or =3 dilutions). For five isolates, a CA effect could not be determined initially by broth microdilution because of off-scale CAZ results. However, a CA effect was observed in two of these isolates by testing cefepime and cefepime plus CA. The cefoxitin MICs for 23 isolates that failed to show a CA effect by broth microdilution were > or =32 microg/ml, suggesting either the presence of an AmpC-type beta-lactamase or porin changes that could mask a CA effect. By isoelectric focusing (IEF), 7 of the 23 isolates contained a beta-lactamase with a pI of > or =8.3 suggestive of an AmpC-type beta-lactamase; 6 of the 7 isolates were shown by PCR to contain both ampC-type and bla(OXA) genes. The IEF profiles of the remaining 16 isolates showed a variety of beta-lactamase bands, all of which had pIs of < or =7.5. All 16 isolates were negative by PCR with multiple primer sets for ampC-type, bla(OXA), and bla(CTX-M) genes. In summary, 83.5% of the K. pneumoniae isolates that were identified initially as presumptive ESBL producers were positive for a CA effect, while 5.0% contained beta-lactamases that likely masked the CA effect. The remaining 11.5% of the isolates studied contained beta-lactamases that did not demonstrate a CA effect. An algorithm based on phenotypic analyses is suggested for evaluation of such isolates. 相似文献
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R. N. Scott R. H. Brittain R. R. Caldwell A. B. Cameron V. A. Dunfield 《Medical & biological engineering & computing》1980,18(1):65-69
Progress in the development of a system to provide sensory feedback of the pinch force of an artificial hand is described.
Design criteria relating to electrocutaneous stimulation and compatibility with myoelectric control are discussed. Details
of a practical system, presently in use by two amputees prior to full-scale clinical evaluation, are presented. 相似文献
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The recent fundamental transformation in government policy on the National Health Service has far-reaching implications for all types of health-care information provision and use. This paper highlights the new opportunities, as well as the major issues, these developments have generated. 相似文献
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MacDougall JD Brittain M MacDonald JR McKelvie RS Moroz DE Tarnopolsky MA Moroz JS 《Medicine and science in sports and exercise》1999,31(12):1876-1879
PURPOSE: Mean arterial blood pressure (mean arterial pressure (MAP)) at rest is conventionally estimated as the product of the diastolic pressure plus one-third of the pulse pressure. Since pulse wave forms and the duration of diastole change during exercise, one might question the validity of this prediction equation for the exercise state. Our purpose was to test this by directly measuring blood pressure over a wide range of exercise intensities. METHODS: Pressure was recorded by arterial catheterization in 29 subjects performing progressive exercise and/or constant-load exercise at different intensities. Actual MAP was measured by integrating the area under the pulse curve and compared it with the value which was predicted from systolic and diastolic measures over heart rates ranging from 100 to 200 beats x min(-1). RESULTS: Predicted values were quite close to actual MAP, and the accuracy of the prediction equation changed minimally with increased exercise intensity. CONCLUSION: This method provides a valid estimation of MAP during exercise. 相似文献
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The two-stage design involves sample size recalculation using an interim variance estimate. Stein proposed the design in 1945; biostatisticians recently have shown renewed interest in it. Wittes and Brittain proposed a modification aimed at greater efficiency; Gould and Shih proposed a similar procedure, but with a different interim variance estimate based on blinded data. We compare the power of Stein's original test, an idealized version of the Wittes-Brittain test, and a theoretical optimal test which can be approximated in practice. We also compare two procedures that control the conditional type I error rate given the actual final sample size: Gould and Shih's procedure and a newly proposed 'second segment' procedure. The comparison among the first three procedures indicates that the Stein test is, unexpectedly, the test of choice under the original design alternative, whereas the approximate-optimal and Wittes-Brittain procedures appear to have superior power for detecting smaller treatment differences. As between the latter two procedures, the second segment procedure is more powerful when many observations are likely to be taken after the interim resizing, whereas otherwise the Gould-Shih procedure is superior. 相似文献