Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.2 (focal adhesion kinase)
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The measurement of total calcium (CaT) in biological fluids by flame atomic absorption spectroscopy (FAAS) is one of the more accurate yet practical methods available today. With attention to details at every analytical step, the imprecision of FAAS outlined above can be as low as +/- 0.01 mmol/liter at the 2.65 mmol/liter upper reference level of CaT found in the serum of healthy young adults (a CV of 0.4%). The accuracy of FAAS as judged by measurements of NBS/SRM #909, a lyophilized serum material carrying CaT values assigned by isotope dilution mass spectrometry, can be within +/- 1% (recovery of 99-101%) or less in skilled hands. As our brief section on application suggests, FAAS methods for CaT can be adopted to provide rapid and accurate results in many different biological fluids and tissues.
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PMID:Measurement of total calcium in biological fluids: flame atomic absorption spectrometry. 337 81

A highly sensitive radiochemical neutron activation method for the determination of all rare-earth elements (REE) in NBS biological reference materials is described. The materials are irradiated, dissolved in HF/HCl solutions, mixed with scandium and REE carriers (except La, Pr, Nd, Dy, Er), and the resulting solutions evaporated to dryness. The residues are dissolved in HCl and the REE precipitated as fluorides on addition of HF/NH4F solutions. The REE fluorides were collected, dissolved in a nitric/boric acid solution and the radioactivity of the resulting solutions determined by gamma spectrometry. The concentrations of REE in the NBS SRM Spinach, Orchard Leaves, Pine Needles, and Bovine Liver were found to be in the ng/g to microgram/g range. The relative standard deviations are approximately 8%. The results agreed, within experimental errors, with literature values. The distribution patterns of REE in the NBS materials relative to chondritic meteorites resemble the patterns for geological materials.
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PMID:Rare-earth elements in the NBS standard reference materials spinach, orchard leaves, pine needles and bovine liver. 358 59

The conditions (e.g. pH, resin, particle size, foreign ions) affecting the uptake of Cd(II), Cr(III), Cu(II) and Pb(II) from aqueous solution by the SM-7 (also called XAD-7) resin, were studied. Based on these studies, a two-column method was developed to overcome the effect of complexation by humic substances. The method was successfully tested with the NBS multielement water standard, SRM 1643a, and was subsequently applied to enrich Cd(II), Cr(III), Cu(II) and Pb(II) in 15 drinking water samples from Hamilton, Ontario. The metals were determined using graphite furnace atomic absorption spectrometry. The results for the drinking water samples showed that leaching of copper and lead occurred from the distribution system.
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PMID:Preconcentration of cadmium, chromium, copper and lead in drinking water on the polyacrylic ester resin, XAD-7. 400 60

The concentration of 12 different elements in cigarette tobacco of different brands, commercially made in Bangladesh, was determined using the proton particle-induced x-ray emission (proton PIXE) method. In all the present experiments, proton beams of 2.0 MeV (on the target in air) and about 30 nA current were used for characteristic x-ray excitation. The concentration of the elements (K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb and Sr) was determined by comparison with a calibration obtained from the NBS orchard leaf standard, SRM 1571. The results have been compared with available data on some foreign brands of tobacco and the probable reasons for the difference in the contents of some of the elements found in the Bangladeshi brands are discussed.
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PMID:Multielement proton-induced X-ray emission analysis of Bangladeshi tobacco. 648 Jan 44

Reference systems in clinical chemistry, whether loosely structured or highly organized like the National Reference System for Clinical Chemistry (NRSCC) in the USA are built upon an assemblage of interrelated materials, methods, and agreements. For example, the NRSCC Council has accepted the following items for the measurement of total calcium in human serum: 1) the Reporting Unit (the SI non-coherent molar concentration unit-mmol/l), 2) a Certified Reference Material (NBS/SRM 915 CaCO3), 3) a Definitive Method (IDMS) and 4) a Reference Method (FAAS). Recently, the IDMS measured calcium value has become available on a freeze-dried human serum (NBS/SRM 909) and allows the direct accessment of the accuracy of routine methods, instrument systems, calibrators and control materials. Utilizing the NRSCC reference method and materials for total calcium measurements and the Radiometer System (ICA1) for ionized Ca2+ measurements, we have begun to ask the question, "What are the essential items in a reference system for ionized calcium?" As expected, our initial explorations reveal more problems than answers, thus our very limited and unsophisticated initial data will be presented primarily as a means to ensure discussion. Despite, the electrochemical complexity of the electrochemical interactions, and the technologic differences from one measuring system to another, it is my belief that a reference system capable of widespread acceptance for ionized Ca2+ must be introduced to ensure the long-term integrity and interlaboratory compatibility of this vital physiological measurement.
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PMID:A reference system for ionized calcium. 657 76

With the above exceptions, the participants as a whole have done very well during the past 8 years and their measurements should continue to show improvement. Since mid-1981, the agreement between AIF and NBS has been modified to recover the cost of an SRM production program over the next two or three years in order for the program to eventually become self-supporting. This will benefit not only the current sponsors of the program, but also hospitals and other users of NBS radiopharmaceutical SRMs by having these standards available to the public on a regular continuing basis. The participants in this program have derived many benefits since its inception in 1975. Through the measurement of blind samples which demonstrate traceability to NBS, the companies have made it easier to comply with some of the regulatory requirements of the FDA and NRC when applying for new drug applications. They also receive monthly feedback on their measurement procedures so that they can promptly determine if their measurement procedures or instruments have gone awry. If the results are satisfactory, they receive reassurance and confidence that they are making good measurements and providing accurately dispensed products.
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PMID:U.S. National Bureau of Standards/Atomic Industrial Forum radioactivity measurements assurance program. 664 93

Dry and wet ashing methods have been used in the analysis of garden vegetables for Pb. The reliability of wet ashing has been verified by the method of standard additions. Comparison of dry and wet ashing showed good agreement for a variety of garden vegetables. Sample size was more strictly limited for the wet-ashed samples, which led to lower sensitivity. Vegetable samples are commonly analyzed for a number of trace elements, which introduces additional constraints on sample preparation, notably because of Cd loss on dry ashing. Pretreatment with HNO3/H2SO4 ash aid eliminated Cd loss. Reliability of dry ashing with pretreatment was shown with NBS SRM Orchard Leaves, Pine Needles, Spinach, and Tomato Leaves. The analysis was insensitive to ashing temperature in the range 480-625 degrees C. A practical detection limit for the method is about 2 ppm Pb, dry weight basis (DWB). Care must be exercised to avoid contamination of the sample with lead at this level by improper handling. Segregation and acid washing of glassware and protection of the sample from contact with any object not demonstrably clean was necessary. No evidence was found of Pb contamination at this level from tap water washing of fresh vegetables, forced-air oven drying, or grinding with mortar and pestle. No special clean room facilities or laboratory air purification measures were used. Sensitivity was increased 3-fold by extraction with dithizone in CHCl3 followed by back-extraction into dilute HCl. Detection limits were not improved, however, because of variation in the extraction results. The instrumental method for assessing effective correction for back-ground absorbance showed adequate compensation, although comparison of direct and extractive determinations showed a small but significant difference between the methods of about 1 ppm Pb (DWB).
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PMID:Sample preparation in determination of lead in garden vegetables by flame atomic absorption spectrophotometry. 711 82

A simple and rapid method is described for the determination of lead in foods. The samples are digested in HNO3, HF, and HClO4 and then the lead is determined by atomic absorption spectrophotometry using an electrothermal atomizer with the L'vov platform. Interferences and ways to improve the precision and accuracy of the analysis were studied. Matrix modification using 1% ammonium phosphate alleviated most interferences encountered. The precision and accuracy of the method was evaluated using NBS SRM 1570 Spinach and SRM 1566 Oyster Tissue. The values obtained are in good agreement with the certified values.
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PMID:Innovations in atomic absorption spectrophotometry with electrothermal atomization for determining lead in foods. 711 9

Concentrations of Tin (Sn) were determined in botanical, dietary and biological reference materials (RMs), and in human livers from Japanese and American subjects using atomic absorption spectrophotometry (AAS) and neutron activation analysis (NAA), either in the instrumental mode (INAA) or in the radiochemical mode (RNAA). The mean Sn concentrations (+/- 1 S.D.) found in various RMs are: total diet (NIST SRM-1548) 3.57 +/- 0.52 and 3.61 +/- 0.52 microgram/g by AAS and INAA, respectively; non-fat milk powder (NIST SRM-1549) 2.5 +/- 1.4 ng/g and 1.9 +/- 0.3 ng/g; bovine liver (NBS SRM-1577) 18 +/- 2 and 20 +/- 0.3 ng/g; and citrus leaves (NIST SRM-1542) 0.25 +/- 0.02 and 0.243 +/- 0.006 microgram/g by AAS and RNAA, respectively. These comparisons demonstrate good agreement between the two methods. In apple leaves (NIST SRM-1515) and peach leaves (NIST SRM-1547), the measured concentrations by AAS were 77.1 +/- 20 and 85 +/- 15 ng/g; interferences by 160Tb did not permit an accurate assessment by INAA at this concentration. The Sn results obtained for the American human liver specimens by RNAA ranged from 0.135-0.712 microgram/g wet weight, and the Sn concentrations in Japanese human liver specimens determined by AAS ranged from 0.078-1.122 microgram/g wet weight in 23 individuals. The results from this study show that it is feasible to use INAA/RNAA and AAS in combination to establish recommended values in RMs.
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PMID:Determination of tin in biological materials by atomic absorption spectrophotometry and neutron activation analysis. 801 37

The use of consensus values in external quality assessment schemes (EQAS) involves several problems and should preferably be replaced with target values obtained by methods of high metrological level. However, such values are difficult to obtain. In the present study we transferred values from the NIST (former NBS) certified reference serum SRM 909 to lyophilized and frozen test sera for various inorganic components using flame absorption or flame emission spectrometry. Enzyme values were assigned by laboratories of members of the former Scandinavian Enzyme Committee. The assignment was based on 2-4 determinations each day through 3 days of experiment. A total of 10 laboratories participated in the work. The results were utilized in a Danish EQAS. One practical concern is the fairly long time (9 months) which was needed for production, collection and compiling all data. To get an impression of how much dry chemistry analysers, e.g, could influence consensus values a Kodak Ektachem 700 XR was studied using lyophilized and frozen sera. The results are reported in the annex. On NIST SRM 909 the values found for sodium(I) were 6% too high even though the findings on frozen human sera were accurate. For aspartate aminotransferase a result three times the target values was found on a human lyophilized serum, while the values on the frozen sera only were slightly too high.
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PMID:A programme for assigning target values for external quality assessment schemes in countries with no authorized reference laboratories. Annex. Experiences with deviating results on Ektachem 700 XR. 846 50


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