Comparison of four methods for measuring femoral anteversion

This study evaluates the most valid and reproducible method for directly measuring anteversion (torsion) in dried femora using a commercially available measuring machine. Each femur was placed horizontally on the surface of the machine and readings were obtained from the head, the shaft distal to the lesser trochanter, and the distal end. Using computer software, four different anteversion angles were calculated: the center head-neck line to the retrocondylar line (Method 1); the center head-neck line to the transcondylar line (Method 2); the anterior head-trochanter line to the retrocondylar line (Method 3); and the anterior head-trochanter line to the transcondylar line (Method 4). The methods were applied to 20 femora, which were measured twice by one observer. The most reproducible method of measuring femoral anteversion uses the bone surfaces on the anterior aspect of the head and greater trochanter and on the posterior aspect of the condyles (Method 3.95% confidence limits of ± 0.4°). The other methods are shown to be reproducible to ±2.4°, ±3.3° and ±1.7° (Methods 1, 2, and 4, respectively, 95% confidence limits). Conversion factors between the different methods are: 12.5° + 0.8 x (anteversion angle) to change each of Method 2 to Method 1 and Method 4 to Method 3; and 8° + 0.7 x (anteversion angle) to change each of Method 1 to Method 3 and Method 2 to Method 4 (correct to within ±3°). © 1993 Wiley-Liss, Inc.     

Comparison of methods for identifying resistant herpes simplex virus and measuring antiviral susceptibility.

BACKGROUND: A number of in vitro assays are used to determine susceptibility of HSV to antiviral agents, but results from these in vitro assays do not necessarily correlate with treatment outcome. OBJECTIVES: A method with improved capability for identifying an isolate as acyclovir (ACV) or penciclovir (PCV) resistant when resistance is borderline could greatly improve the management of HSV disease. STUDY DESIGN: A comparative evaluation of four in vitro assays, plaque reduction (PRA), DNA hybridization, plating efficiency (PEA) and plaque autoradiography (PAR) was performed to accurately identify and measure resistance of a TK-altered clinical HSV isolate (HSV-1 N4) from a patient who was non-responsive to ACV treatment. Two established criteria for the prediction of antiviral resistance, IC(50)> or =2.0 microg/ml or an IC(50) greater than 10x above a sensitive virus IC(50), as well as testing in human (MRC-5) and nonhuman (Vero and CV-1 monkey kidney) cell lines were evaluated. RESULTS: The PRA and DNA hybridization assays accurately identified HSV-1 N4 as ACV(r) in human cells when using the 10x above sensitive virus IC(50) resistance criterion. Moreover, the PEA and PAR assays failed to classify HSV-1 N4 as drug resistant and indicate that these technologies alone are inadequate for identifying resistant virus. CONCLUSIONS: The data presented herein indicate that the PRA and DNA hybridization assays most accurately identified an otherwise borderline-resistant isolate as drug resistant: (i) when a sensitive virus is used within each individual assay as a control, (ii) when ACV and PCV susceptibility is evaluated in human cells, and (iii) when the 10x above sensitive IC(50) criterion is used to classify a virus as drug-resistant. Testing of additional clinical samples is warranted to further confirm these findings.     

Comparison of microelectrode, DMO, and methylamine methods for measuring intracellular pH.

The intracellular pH (pHi) of giant barnacle muscle fibers was measured with glass microelectrodes and also calculated from the distribution of 5,5-dimethyl-2,4-oxazolidinedione (DMO) and methylamine (MA). Simultaneously applying any two of these methods to muscle fibers of the same barnacle, we found the pH measured with an intracellular electrode (pH-Elec) to be about 0.06 higher than the DMO-derived pH (pH-DMO), and pH-DMO to be about 0.10 higher than the MA-derived pH (p-ma). in studies on the pHi of squid giant axons, we found that pH-Elec (7.35) and pH-DMO (7.36) were not significantly different. In the barnacle experiments, DMO required about 30 min to reach a steady-state distribution, while MA required more than 5 h. The deviations of pH-DMO and pH-MA from pH-Elec for the barnacle can be explained by a) an error in the assumed intracellular pKa' of DMO or MA, b) membrane permeability to the ionic form of DMO or MA, or c) intracellular compartmentalization. Included is a detailed study of the apparent dissociation constant of DMO as affected by temperature, and ionic strength and composition.     

流式细胞术定量检测细胞凋亡3种方法的比较研究

目的：探讨流式细胞术定量检测细胞凋亡３种方法的价值。方法：同时使用ＰＩ染色，ＴＵＮＥＬ及Ａｎｎｅｘｉｎ Ｖ／ＰＩ３壹量检测地塞米松处理小鼠的胸腺细胞凋亡发生率。结果：ＰＩ染色，Ａｎｎｅｘｉｎ Ｖ／ＰＩ，ＴＵＮＥＬ３种方法凋亡检出率分别为２７．１９％，３２．２８％，５０．１７％，两者之间均有显著差异。     

免疫学技术与方法流式细胞术定量检测细胞 凋亡3种方法的比较研究

目的探讨流式细胞术定量检测细胞凋亡3种方法的价值。方法同时使用PI染色、TUNEL及Annexin V/PI 3种方法定量检测地塞米松处理小鼠的胸腺细胞凋亡发生率。结果PI染色、Annexin V/PI、TUNEL 3种方法凋亡检出率分别为27.19%、32.28%、50.17%，两两之间均有显著差异(P＜0.01)。但仅Annexin V/PI法可将正常细胞、凋亡细胞、死亡细胞区分开来。结论Annexin V/PT法是目前最为理想的凋亡定量检测方法。     

Comparison of different methods of measuring protein and albumin in pigeon sera

Columbine serum total protein (TP) and albumin concentrations were determined using the biuret method and the bromocresol green dye binding (BCG) method or serum protein electrophoresis on cellulose acetate membranes (SPE). Results obtained using human and pigeon standards were compared. When pigeon albumin was used as a standard. TP values were consistently higher compared with values obtained using human protein as a standard. However, there was a high correlation between the results obtained with the two standards. The correlation between the BCG method and SPE for serum albumin determination was poor, irrespective of the standard used. The method cannot be recommended for pigeon blood. For avian clinical practice it is advised to establish TP concentration using the biuret method and a human standard and to calculate albumin concentration from the results of TP and SPE.     

Comparison of plaque- and flow cytometry-based methods for measuring dengue virus neutralization

As dengue vaccines enter clinical trials, there is a need for rapid and quantitative assays to measure neutralization. We have developed flow-based neutralization assays which generated results similar to those generated by the established, plaque reduction neutralization test. The flow assays are an improvement, as they use human cells and allow for high-throughput screening.     

Comparison of different methods of measuring albumin concentration in ring-necked pheasants

The purpose of this study was to compare albumin concentrations in ring-necked pheasants (Phasianus colchicus) using two different dye-binding methods: the bromocresol green (BCG) and bromocresol purple (BCP). High positive correlation was observed for albumin in BCG and BCP methods. Compared to BCP, the BCG-binding method yielded significantly higher (p?<?0.0001) albumin values for adult female ring-necked pheasants.     

Plasma hemoglobin. Comparison between 2 methods of determination

The methods used to titrate plasmatic haemoglobin, an analysis which is of great interest to cardiac surgery, must be very accurate because the levels are much lower than those found in whole blood. This work introduces a comparison between two methods: the ammoniacal water method and Cripps's differential method. After studying various criteria (repeatability, limit of detection, accuracy, reference values, stability of the reaction), and after studying the correlation between each method and the benzidin method, used as reference method, as well as the correlation between all of them, Cripp's method turns out to be the closest to the benzidin method, as well as being simpler, more accurate, more specific, and also easier to use than the ammoniacal water method, the only problem occurring at the stage of the preparation of the standard solution.     

Comparison of three methods for measuring factor VIII levels in plasma

We compared 1-stage clot-based, chromogenic, and immunoassay methods for measuring factor VIII in plasma with a focus on the measurement of elevated levels of factor VIII. The chromogenic assay showed the best interassay imprecision for factor VIII levels near 150 IU/dL. The best correlation was between the 1-stage clot-based and chromogenic factor VIII assays (r2 = 0.934), and the lowest correlation was between the 1-stage clot-based and antigenic factor VIII assays (r2 = 0.821). The presence of heparin, low-molecular-weight heparin, lepirudin, or lupus inhibitors in the sample resulted in major interference in the 1-stage clot-based assay but not the chromogenic or antigenic factor VIII assays. Overall, the chromogenic factor VIII activity assay was the optimal method, showing good precision, the best overall correlation with other assays, and no interference from heparin, low-molecular-weight heparin, lepirudin, or lupus inhibitors.     

Comparison of scintigraphic count-volume and geometric methods for measuring left ventricular ejection fraction

A comparison of geometric and count-volume scintigraphic methods for measuring left ventricular ejection fraction (EF) is presented. The particular count-volume method used is a modification of an established first-pass technique. It is shown that a modification of the technique is necessary to prevent a positive bias in the EF estimate due to Poisson noise. Using the same simulated data, EF estimates by the modified technique were always closer to the actual EF volume than were the estimates by the original method. Maximum Likelihood estimates were also more accurate than were the other two estimates. In 56 patients with either acute myocardial infarcts or unstable angina pectoris, the scintigraphic single-plane gated geometric method tended to overestimate EF in each of the patient groups when compared with the geometry-independent count-volume estimates. The results also point out that the error in the geometric estimates tended to be greater for larger ejection fractions and appears to be due to the systematic underestimation of end-systolic volumes. This work was supported in part by NSF Grant ENG 73–03789 A02, by NIH Ischemic SCOR Grant HL-17669, and by NIH Grant HL-17777.     

Comparison of electrophoretic and dye-binding methods for measuring albumin concentrations in female turkeys

Albumin concentrations in female Bronze turkeys were compared using agarose gel electrophoresis (AGE) and the bromocresol green (BCG) dye-binding method. The correlation coefficient observed for albumin in the BCG and AGE methods was low, and statistical differences were observed at paired t test (p?<?0.0001). Compared with electrophoresis, the BCG-binding method yielded significantly lower albumin values for female turkeys during laying season.     

Comparison of methods for measuring longitudinal brain change in cognitive impairment and dementia

PURPOSE: The goal of this project was to compare MRI measures of hippocampal, entorhinal cortex (ERC), and whole brain longitudinal change in cognitively normal elderly controls (C), non-demented subjects with cognitive impairment (CI), and demented (D) subjects. METHODS: 16 C, 6 CI, and 7 D subjects of comparable age were studied with MRI twice, at least 1 year apart. Longitudinal change in total brain size was measured by several methods, including computerized segmentation, non-linear warping, and change in the fluid/tissue boundaries between cerebrospinal fluid (CSF) and brain. Change in hippocampal volume was measured by semi-automated methods, and ERC volumes were manually measured. RESULTS: The annual rate of atrophy was greater in D versus C and D versus CI for cortical gray matter (cGM) (P=0.009 and 0.002), hippocampus (P=0.0001 and 0.002), and for the change in the fluid/tissue boundary (P=0.03 and 0.03). The annual rate of atrophy of ERC was greater in both CI and D versus C (P=0.01 and 0.0002). No significant differences between groups were found using non-linear warping. CONCLUSIONS: In CI, the greatest annual rates of atrophy were in ERC, while in D the greatest annual rates of atrophy were in hippocampus and cortex. Progressive ERC atrophy was observed with a greater degree of cognitive impairment, while hippocampal and cortical atrophy were only observed in demented subjects.     

Comparison of methods for measuring antibiotic consumption in an intensive care unit

Hospitals worldwide are working on minimizing unnecessary use of antimicrobials. To assess actual changes of antimicrobial usage, correct and precise measurements are necessary. This study aimed to compare data on the purchase of antibiotics from the pharmacy and the administration of antibiotics to patients, respectively, in an intensive care unit (ICU). Data were obtained from the Neurointensive Care Unit (NICU) at Rigshospitalet, Denmark. During a 23‐month period, comprising 10 770 bed‐days (BD), the ward purchased 16 908 defined daily doses (DDD) of antibiotics from the pharmacy, and 15 130 DDD and 41 304 individual doses were administered. Intraclass correlation coefficients (ICCs) were calculated; control and runcharts and a Bland–Altman plot were constructed. Pharmacy sales and drug administration data showed no systematic variation over time with a monthly overestimation of pharmacy sales data of 10% (95% confidence interval (CI), 6.20–14.3%) for all antibiotics, and 7% (95% CI: 1.81–11.1%) for broad‐spectrum antibiotics. The antibiotic consumption, without bed‐days, has a clinically acceptable ICC of >0.70 and no systematic difference is suggested by the Bland–Altman plot. In this study of a large NICU, whose antibiotic consumption varied at random, pharmacy sales data were an acceptable approximation of the actual summarized drug consumption.     

Comparison of normalization methods for measuring immune markers in cervical secretion specimens

Ophthalmic sponges are used to collect undiluted cervical secretions for assessment of markers of genital tract immunity. Heterogeneity in absorbed and extracted sample volumes requires normalization in order to make valid inter-individual comparisons. We evaluated the performance of adjustment by weight and total protein on normalizing inter-individual variability of immune marker measurement due to differences in volume collection. Normalization to total protein resulted in a minimal loss of usable specimens and a significant reduction in the correlation of immune marker concentration to specimen weight compared to weight adjustment. Total protein normalization appeared to be more effective than weight adjustment in reducing the dependence of cervical immune marker concentrations on differences in specimen volume.     

Comparison between two finite-element modelling methods for measuring change in craniofacial form

Finite-element modelling of form change is a useful morphometric technique for measuring differences between anatomical patterns. Two different finite-element algorithms currently are used. One method requires normalized coordinates as input data, while the second method uses globalized coordinates as input data. This study determines whether the two finite-element methods provide equivalent measures of three-dimensional form change when applied to the nasal septa of embryonic mice. Computer models of the nasal septa from mice of 15 and 17 days gestation were generated. Homologous landmarks were identified so that each nasal septum was represented by a tetrahedral finite-element. These elements were subjected to both finite-element modelling methods. Results show that the two algorithms use different interpolation functions and yield dissimilar intermediate results, but generate identical strain matrices as well as equivalent principal extensions, directions of form change, variables of form change, and graphical displays. Therefore, results are directly comparable from studies using either finite-element modelling method.     

Comparison between two finlte-element modelling methods for measuring change in craniofacial form

Finite-element modelling of form change is a useful morphometric technique for measuring differences between anatomical patterns. Two different finite-element algorithms currently are used. One method requires normalized coordinates as input data, while the second method uses globalized coordinates as input data. This study determines whether the two finite-element methods provide equivalent measures of three-dimensional form change when applied to the nasal septa of embryonic mice. Computer models of the nasal septa from mice of 15 and 17 days gestation were generated. Homologous landmarks were identified so that each nasal septum was represented by a tetrahedral finite-element. These elements were subjected to both finite-element modelling methods. Results show that the two algorithms use different interpolation functions and yield dissimilar intermediate results, but generate identical strain matrices as well as equivalent principal extensions, directions of form change, variables of form change, and graphical displays. Therefore, results are directly comparable from studies using either finite-element modelling method.