Comparison of three different methods for measurement of tissue platinum level

We attempted to make a comparison of three methods for tissue platinum; atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS). The determination lim its were 0.05 ng/mL on ICP-MS, 50 ng/mL on ICP-AES, and 200 ngJmL on AAS, and the recovery rates were 97.7 ± 6.9% on ICP-MS, 69.0 ± 3.0% on ICP-AES, and 102.4 ± 4.0% on AAS, respectively. Plat inum was detected by ICP-AES and ICP-MS in human vertebrae, but the level was higher by ICP-AES than by ICP-MS. In the mouse kid ney treated with cisplatin, platinum was detected by ICP-MS, but not by ICP-AES. As cadmium gives the absorption peak close to plat inum, cadmium was measured together with platinum by ICP-AES in the vertebrae. From these, ICP-MS is the most sensitive for measure ment at tissue platinum. The sensitivity of ICP-AES looks worse for measuring the tissue platinum, and it is necessary to take care of the contaminant of metals, especially cadmium. AAS is not suitable for measurement of tissue platinum as in the vertebrae and kidneys, because platinum was not detectable by AAS.     

Comparison of different pointing methods for sound localizability measurement in the vision impaired subjects

In order to find out the most suitable and accurate pointing methods to study the sound localizability of persons with visual impairment, we compared the accuracy of three different pointing methods for indicating the direction of sound sources in a semi-anechoic dark room. Six subjects with visual impairment (two totally blind and four with low vision) participated in this experiment. The three pointing methods employed were (1) directing the face, (2) directing the body trunk on a revolving chair and (3) indicating a tactile cue placed horizontally in front of the subject. Seven sound emitters were arranged in a semicircle 2.0 m from the subject, 0 degrees to +/-80 degrees of the subject's midline, at a height of 1.2 m. The accuracy of the pointing methods was evaluated by measuring the deviation between the angle of the target sound source and that of the subject's response. The result was that all methods indicated that as the angle of the sound source increased from midline, the accuracy decreased. The deviations recorded toward the left and the right of midline were symmetrical. In the whole frontal area (-80 degrees to +80 degrees from midline), both the tactile cue and the body trunk methods were more accurate than the face-pointing method. There was no significant difference in the center (-40 degrees to +40 degrees from midline). In the periphery (-80 degrees and +80 degrees ), the tactile cue pointing method was the most accurate of all and the body trunk method was the next best. These results suggest that the most suitable pointing methods to study the sound localizability of the frontal azimuth for subjects who are visually impaired are the tactile cue and the body trunk methods because of their higher accuracy in the periphery.     

Comparison of methods of temperature measurement in swine

The purpose of these experiments was to test the equivalence of pulmonary artery, urinary bladder, tympanic, rectal and femoral artery methods of temperature measurement in healthy and critically ill swine under clinical intensive care unit (ICU) conditions using a prospective, time series design. First, sensors were tested for error and sensitivity to change in temperature with a precision-controlled water bath and a laboratory-certified digital thermometer for temperatures 34-42 degrees C. There was virtually no systematic (bias) or random (precision) error (<0.2 degrees C). The bladder sensor had the slowest response time to change in temperature (105-120 s). Next, testing was done in an experimental porcine ICU in a non-profit research institution with four male, sedated, and mechanically ventilated domestic farm pigs. The in vivo experiments were conducted over periods of 41-168 h with temperatures measured every 1-5 s. The bladder, tympanic and rectal methods had unacceptable bias (>or=0.5 degrees C) and/or precision (>or=0.2 degrees C). Response time varied from 7 s with the femoral artery method to 280 s (4.7 min) with the tympanic method. We concluded that equivalence of the methods was insufficient for them to be used interchangeably in the porcine ICU. Intravascular monitoring of core body temperature produces optimal measurement of porcine temperature under varying conditions of physiological stability.     

Comparison of three common DNA concentration measurement methods

Accurate measurement of DNA concentration is important for DNA-based biological applications. DNA concentration is usually determined by the ultraviolet (UV) absorption, fluorescence staining, and diphenylamine reaction methods. However, the best method for quality assurance of measurements is unknown. Here, we comprehensively compared these methods using different types of samples. We found that all three methods accurately determined the concentrations of high-purity DNA solutions. After digestion of DNA samples, concentration measurements revealed that the PicoGreen dye method was very sensitive to the degradation of DNA. The three methods displayed different anti-jamming ability when contaminants such as transfer RNA (tRNA), protein, and organic chemicals were included in DNA solutions. The diphenylamine reaction method gave the highest accuracy, with an average error of approximately 10% between measured and true values. The PicoGreen dye method was influenced by tRNA and protein, and the UV absorption method was susceptible to all kinds of impurities. Overall, the diphenylamine reaction method gave the most accurate results when DNA was mixed with contaminants, the PicoGreen dye method was most suitable for degraded DNA samples or DNA extracted from processed products, and the UV absorbance method was best for evaluating the impurities in DNA solutions.     

Comparison of different methods for decision-making in bioequivalence assessment

If the regulatory requirements are symmetrical, the use of symmetrical confidence intervals as a decision rule for bioequivalence assessment leads, as shown by simulations, to better level properties and an inferior power compared to a rule based on shortest confidence intervals. A choice between these two approaches will have to depend on a loss function. For asymmetric regulatory requirements, symmetrical confidence intervals should not be used; however, a decision can still be based on posterior probabilities, pr (theta epsilon [r1, r2]/x), or shortest confidence intervals. For purposes of inference, presentation and interpretation of results, we think that the use of symmetrical confidence intervals alone can be misleading and we therefore recommend that the posterior probabilities and densities, or at least the shortest confidence intervals, be given.     

Comparison of different methods of glucose oxidase immobilization

Glucose oxidase was immobilized by covalent bond to two basic types of sorbents—glycidylmethacrylate copolymers and bead cellulose. These two types of carries were chemically modified, if needed, by the employing various procedures and subsequently used in the immobilization of native and oxidized glucose oxidase. The samples thus obtained were compared with those of immobilized glucose oxidase bound onto some common carriers. Samples which possessed not only a high absolute activity but also adequate mechanical and flow properties were characterized in greater detail with respect to the immobilization efficiency and kinetic properties of bound glucose oxidase.     

Ergosterol determination in Saccharomyces cerevisiae. Comparison of different methods

Several methods for ergosterol determination in two different Saccharomyces cerevisiae strains were tested. The best results were obtained by a simple method including saponification with 8 M KOH, extraction of non-saponifiable lipids and ergosterol determination by reversed phase HPLC. The methods in which the samples were treated with 0.1 M HCl prior to hydrolysis with 2.5 or 4.5 M water-ethanolic KOH underestimated the ergosterol contents.     

Comparison of dynamic oxygen electrode methods for the measurement of KLa

The dynamic oxygen electrode method for measuring K_L a requires the use of a dynamic process model. Six models from the literature are described and compared with respect to their accuracy and ease of use. It is shown theoretically that for sufficient accuracy K_L a should be less than the inverse electrode response time. Experimental measurements demonstrate their application to viscous and nonviscous systems. The liquid diffusion film is shown to cause an important measurement lag that can be accounted for by a first-order time delay. Investigation on the influence of the experimental starting conditions show the importance of the gas and hold-up dynamics. A new method is proposed to simplify the K_L a calculation and to eliminate errors caused by starting conditions. This method, which accounts for gas, film, and electrode dynamical effects, requires only a simple semilog plot of the response data.     

Comparison of fractionation of groundnut proteins by two different methods

The salt-soluble proteins of groundnut meal were fractionated by precipitation with (NH₄)₂SO₄ by increasing the (NH₄)₂SO₄ saturation in steps of 10%. The sharp separation into arachin and conarachin claimed by earlier workers was not achieved, as protein was precipitated at each stage from 20 to 100% saturation with (NH₄)₂SO₄. The fractions so obtained were examined by disc electrophoresis on polyacrylamide gel and the amino acid compositions were determined by ion-exchange chromatography. Differences in both electrophoretic pattern and amino acid composition were found. The protein precipitated by CaCl₂ solution was similar in yield, nitrogen content, electrophoretic pattern, and amino acid composition to the fraction precipitating at 10–20% (NH₄)₂SO₄ saturation. The main differences in amino acid composition of the various fractions precipitated by (NH₄)₂SO₄ were found in the amino acids cystine, methionine, and lysine, which increased with increase in (NH₄)₂SO₄ saturation. The electrophoretic pattern and amino acid composition of “conarachin” varied according to the method of preparation.     

盾叶薯蓣中薯蓣皂甙元不同提取方法的比较

为提高盾叶薯蓣(Dioscorea zingiberensis C.H.Wright)中薯蓣皂甙元得率,在实验室条件下,以薯蓣皂甙元含量为评价指标,采用4因素4水平的正交试验,用高效液相色谱法对16种提取方法所得的薯蓣皂甙元含量进行了比较分析.结果表明,硫酸的浓度对薯蓣皂甙元含量有极显著影响,在实验室条件下,可采用10 g样品加2.0mol·L-1硫酸200 mL水解4 h,水解物用石油醚回流提取5 h,能快速准确提取盾叶薯蓣中的薯蓣皂甙元.