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At least 523 records · Page 29Linked to original sources
PubMed1982

Investigations on vasogenic and cytotoxic brain edema, comparing results from X-ray microanalysis and flame photometry.

In these studies vasogenic brain edema has been induced by implantation of rat glioma cells RGI 2.2 into BD-IX rats while cytotoxic edema pas produced by permanent regional ischemia in the mongolian gerbil. In the gerbil sodium concentration was raised from 201 meq/kg d.w. (dry weight) [p/b (peak/background) = 0] to 269 meq/kg d.w. (p/b = 0.25; 2 hours) and 651 meq/kg d.w. [p/b = 0.71; 24 hours), whereas potassium concentration decreased from 373 meq/kg d.w. (p/b = 1.69) to 337 meq/kg d.w. (p/b = 1.65) and 152 meq/kg d.w. (p/b = 0.53). In the rat tumor sodium and potassium concentrations were 279 meq/kg d.w. (p/b = 0.44) and 510 meq/kg d.w. (p/b = 1.94). Non-tumorous tissue contained 237 meq/kg d.w. (p/b = 0) and 517 meq/kg d.w. (p/b = 1.98). In addition X-ray microanalysis could show that chlorine behaves like sodium, whereas the concentration of phosphorus and sulphur remains nearly constant. X-ray microanalysis in this case proved to be useful in the localization and quantification of different elements. The main disadvantage, however, is the reduced sensitivity for light elements, e.g. sodium, which cannot be determined in normal brain.

Animals↗
PubMed1977

Photometry of inulin and polyfructosan by use of a cysteine/tryptophan reaction.

Described are a macromethod for measuring 2 to 30 mug of polyfructoside in sample volumes of 0.5 ml and a micromethod for measuring 40 to 400 ng in 10-mul samples. The absorptivity of the cysteine/tryptophan color product is 2.5-to 10-fold those found with use of five other colorimetric methods for inulin. The method is highly specific for alkali-stable polyfructoside. Color, measured at 515 nm, was maximal on development at 56 degrees C for 25 min in dilute (57-58% by vol) sulfuric acid, after the addition of the combined cysteine hydrochloride/tryptophan reagent. Analytical recoveries of inulin and polyfructosan from plasma and urine were complete. With initial alkaline heating, the endogenous blank inulinoid values averaged 0.6 +/- 0.47 (SD) mg/liter for plasma and 0.05 +1- 0.024 mg/min for urine. The coefficient of variation of the macromethod was less then 3%; that for the micromethod ranged from 1.3 to 6.3%. The micromethod appears adaptable to the determination of nanogram quantities of polyfructoside in nanoliter volumes of biological fluids.

Adult↗
PubMed1998

[Effect of glucose on the aqueous infrared spectrum (bloodless determination of blood glucose by tissue photometry)].

The creation of a noninvasive (without blood collection) method for measuring blood glucose concentrations, convenient for patients, is practically important, because the treatment of diabetics requires constant many-year monitoring of the alimentary component of glycemia. Use of IR spectra is impeded by the interference of strong bands of water absorption, whose concentration in the tissues is almost 1000 times higher than that of glucose. We investigated the effects of glucose, albumen, and blood serum on the structure of water absorption bands in the 1400-1600, 960, 1153, and 2000-2400 nm bands. The method of differentiated spectra was used. Glucose cleaved the negative aqueous band on the differential spectrum with 1410 and 1455 nm peaks and a positive 1590 nm peak with the isobestic point at 1540 nm. Albumen and serum proteins caused similar, although somewhat different effects, not preventing the use of the above wavelengths for the creation of a noninvasive device, because the concentrations of proteins and electrolytes are not changed after food intake if the homeostasis is intact.

Albumins↗
PubMed2004

Comparison of different methods for uranium determination in water.

Photometry, laser photometry, liquid scintillation (LSC), gamma spectrometry and alpha spectrometry were used for estimating waterborne uranium concentration. The chemical procedures applied were pre-concentration, liquid extraction, chromatographic resin extraction and precipitation. Our results show that laser photometry is an easy and accurate method capable of estimating low uranium concentrations, parts of micrograms per litre. It is not applicable for higher concentrations, difficult water matrixes and isotope determination. The classical photometry is complementary, resolving the problem related to high concentrations, practically up to 10 mg/l. Alpha and gamma spectrometry resolve the problem of precise isotope determination, but with the disadvantage of hard chemical preparation and long measurement times. An intermediate method is LSC, with the problem of isotope estimation, due to poor energy resolution.

Environmental Monitoring↗
PubMed2005

High-speed digital imaging method for ciliary beat frequency measurement.

The aim of this study was to develop a high-speed digital imaging system and related software for ciliary beat frequency (CFB) analysis in order to establish an automated and reliable method that is observer independent and faster compared to the conventional computerized microscope photometry method. Using primary human nasal epithelial cell cultures, the CBF was recorded with a computerized microscope photometry system and a high-speed digital imaging system. To obtain a wide range of frequencies, glycocholate (0.5%) and chlorocresol (0.005%) were used as ciliostimulatory and cilio-inhibitory reference compounds, respectively. The mean values in hertz (+/- s.d.) obtained with the photometry and high-speed digital imaging systems were: controls 8.2 +/- 0.9 and 7.9 +/- 1.1; chlorocresol 5.0 +/- 0.9 and 5.1 +/- 1.1; glycocholate 9.8 +/- 1.0 and 9.7 +/- 0.8. A similar increase (by 20 and 24%) and decrease (by 38 and 35%) in CBF was determined by the two methods after glycocholate and chlorocresol treatment, respectively. The mean difference between the photometry and high-speed digital imaging methods was 0.2 +/- 0.6 Hz, and the Bland-Altman limits of agreement were from -1.0 to +1.4 Hz, suggesting that the results obtained by these two methods could be used interchangeably. These results show the reliability of the high-speed digital imaging system and the software developed for in-vitro CBF measurements. The advantages of the system include: (i) fast data acquisition and calculation, (ii) whole field automated CBF analysis and (iii) reduction in selection bias.

Cells, Cultured↗
PubMed1997

Caffeine and halothane sensitivity of intracellular Ca2+ release is altered by 15 calcium release channel (ryanodine receptor) mutations associated with malignant hyperthermia and/or central core disease.

Malignant hyperthermia (MH) and central core disease (CCD) are autosomal dominant disorders of skeletal muscle in which a potentially fatal hypermetabolic crisis can be triggered by commonly used anesthetic agents. To date, 17 mutations in the human RYR1 gene encoding the Ca2+ release channel of skeletal muscle sarcoplasmic reticulum (the ryanodine receptor) have been associated with MH and/or CCD. Although many of these mutations have been linked to MH and/or CCD, with high lod (log of the odds favoring linkage versus nonlinkage) scores, others have been found in single, small families. Independent biochemical evidence for a causal role for these mutations in MH is available for only two mutants. Mutations corresponding to the human MH mutations were made in a full-length rabbit RYR1 cDNA, and wild type and mutant cDNAs were transfected into HEK-293 cells. After about 48 h, intact cells were loaded with the fluorescent Ca2+ indicator, fura-2, and intracellular Ca2+ release, induced by caffeine or halothane, was measured by photometry. Ca2+ release in cells expressing MH or CCD mutant ryanodine receptors was invariably significantly more sensitive to low concentrations of caffeine and halothane than Ca2+ release in cells expressing wild type receptors or receptors mutated in other regions of the molecule. Linear regression analysis showed that there is a strong correlation (r = 0.95, p < 0.001) between caffeine sensitivity of different RYR1 mutants measured by the cellular Ca2+ photometry assay and by the clinical in vitro caffeine halothane contracture test (IVCT). The correlation was weaker, however, for halothane (r = 0.49, p > 0.05). Abnormal sensitivity in the Ca2+ photometry assay provides supporting evidence for a causal role in MH for each of 15 single amino acid mutations in the ryanodine receptor. The study demonstrates the usefulness of the cellular Ca2+ photometry assay in the assessment of the sensitivity to caffeine and halothane of specific ryanodine receptor mutants.

Animals↗
PubMed1983

[High resolution cell recognition and flow cytometry as means to automated cytodiagnosis].

Measurement and quantification are the prerequisites of automated cell diagnosis. The goal of the analysis is to recognize quantitative differences for the classification of benign and malignant cells. Absorption and fluorescence dyes can be bound to definite cell components proportional to their amounts and can be determined photometrically. In static photometry the cells are spread out in a single layer on a glass slide. By examining the cell point by point a scanning image can be obtained. These high resolution photometric measurements provide many individual data on relatively few cells. In flow photometry the cells are suspended in a fluid. The fluid flows past the lens of the microscope. Because each cell remains in front of the lens for only a brief period, it is possible to detect only one or few parameters per cell. These zero or low resolution flow photometric procedures provide few individual data on a great number of cells. Hybrid procedures combine flow photometry with subsequent high resolution photometry of the individual cell. To make this possible suspicious cells are sorted out from the flowing fluid and deposited on a slide. In individual cases the efficiency of visual diagnosis is almost achieved by machines.

Autoanalysis↗
PubMed1985

Detecting arterial and venous obstruction in flaps.

Island skin flaps based on the latissimus dorsi muscle were raised in domestic pigs. Flap circulation, maintained only by the vascular pedicle, was monitored by laser Doppler flowmetry, laser photometry, and transcutaneously measured carbon dioxide tension. Both arterial and venous occlusion were accompanied by very low laser Doppler flow values. In laser photometry, the backscattered intensity of light remained unchanged or was slightly increased during arterial occlusion. In response to venous occlusion, however, the light intensity decreased markedly. Transcutaneous carbon dioxide tension increased in both venous and arterial occlusion. When venous outflow pressure was raised incrementally, both the laser Doppler flow value and the total backscattered light intensity fell proportionately. Laser Doppler flowmetry might thus be useful clinically to detect decreased blood flow in transferred flaps, and laser photometry may determine if the decreased flow is related to the arterial or venous side.

Animals↗
PubMed1985

Detecting changes of arterial and venous blood flow in flaps.

Island skin flaps based on the latissimus dorsi muscle were raised in domestic pigs. Simultaneous recordings of laser Doppler flowmetric and laser photometric values were made on the skin in the middle of the flap. Occlusion of either the artery or the vein of the pedicle was accompanied by very low laser Doppler flow values. In laser photometry the total intensity of backscattered light remained unchanged or was sightly increased during arterial occlusion. In response to venous occlusion, however, it decreased markedly. As venous outflow pressure was increased step by step, both the laser Doppler flow value and the laser photometry value fell proportionally; thus, the greater the increase in pressure the lower were the steady state levels of both variables. Stepwise reductions of arterial inflow pressure were followed by proportional decreases in both mean blood volume flow, recorded using electromagnetic flowmetry, and in laser Doppler flowmetric values. However, laser photometric values varied only minimally. Laser Doppler flowmetry thus might be a useful clinical aid in detecting decreased blood flow in transferred flaps, and laser photometry may determine whether the decreased flow is due to arterial or venous causes.

Animals↗
PubMed1981

Adaptation and heterochromatic matching.

This study is a follow-up of a previous study of the effect of adaptation on heterochromatic matching by flicker photometry and direct comparison. In flicker photometry, two patches of color are applied alternately to a region of the retina adapted to a mixture of the two colors. In direct comparison, the two halves of the pattern are usually applied to regions of the retina adapted to the separate colors. Two additional methods of equalizing the state of adaptation in the two halves of the retina in direct comparison matching have been tested. In both cases, equalizing the states of adaptation reduces the discrepancy between flicker photometry and direct comparison for two of the three subjects tested. For the third subject, the discrepancies are small but one can still demonstrate effects produced by equalizing the states of adaptation. Further study is needed to delineate the specific mechanisms of adaptation involved.

Adaptation, Ocular↗
PubMed1978

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

1. Measurements of cytoplasmic and nuclear Na, K and Cl have been made by electron microprobe analysis on freeze-dried sections of oocytes of Bufo bufo, using standards of bovine plasma albumin and gamma-globulin. Concentrations were obtained per kilogram of dry mass, were converted to concentrations per litre of water content using known figures for water and solid concentration of nucleus and cytoplasm, and were then compared with measurements on cells from the same animal obtained by flame photometry. 2. In fresh oocytes concentrations were (mean +/- S.E. of mean in m-mole/l. H2O) in cytoplasm Na 10.9 +/- 1.95, K 70.2 +/- 3.22, Cl 98.8 +/- 11.0, and in nucleus Na 10.4 +/- 1.79, K 266.4 +/- 22.8, Cl 91.3 +/- 9.0. 3. After treatment with Na-free Ringer (Li substituted for Na) for 5 hr, concentrations were in cytoplasm Na 11.1 +/- 2.44, K 64.4 +/- 5.7, Cl 88.7 +/- 8.8, and in nucleus Na 2.4 +/- 0.73, K 141 +/- 13.9, Cl 75.0 +/- 6.7. Na inexchangeable with Li therefore lay in the cytoplasm but not in the nucleus as previously shown by autoradiography. 4. For K electron microscopic analysis measurements agreed well with those obtained by flame photometry but the former measured only 35% of Na measured by flame photometry. This discrepancy may be due either to technical difficulties with the electron microprobe analysis or to localization of Na in the cytoplasm.

Animals↗
PubMed1985

A comparison of reference method values for sodium, potassium and chloride with method-dependent assigned values.

The concentrations of sodium, potassium, and chloride in various control sera were determined by reference methods. The reference method values were compared with the corresponding method-dependent assigned values. Sodium: Measurements by flame photometry and ion selective electrodes differed on the whole by less than 1% from the reference method value; determinations by photometry differed, however, by -4.7%. Potassium: The mean bias was -1.2% with flame photometry and -0.4% with ion selective electrodes, whereas nephelometric procedures differed by -1.9 or -4.8%. Chloride: Satisfactory agreement was obtained with values given for ion selective electrodes (-0.3%), for some coulometric procedures (-0.7 and 0.4%), and photometric determinations using mercury rhodanide (-0.5 and +0.7%). Values for mercurimetric titration and for photometric determinations using mercury 2,4,6-tri-(2-pyridyl)-s-triazine differed by + 2.5 and + 1.8%. Proposals concerning the allowable deviation from reference method values are discussed.

Chlorides↗
PubMed2004

Measures of bone mineral content in mature dairy cows.

The objectives of this investigation were to assess the relationship between chemical measures and imaging estimates (radiographic photometry and dual-energy x-ray absorptiometry) of bone mineral content in dairy cows and to evaluate the effects of parity, stage of lactation, and site of measurement (fused third and fourth metacarpal bone vs. caudal vertebrae 14 and 15) on bone mineral content. In a preliminary study, the caudal vertebrae were excised from 33 cows following slaughter. Samples were analyzed by radiographic photometry and then analyzed for mineral content chemically. In a second experiment, the caudal vertebrae and right front metacarpal (sample pairs) were excised from 107 Holstein cull cows following slaughter. Parity and days in milk (DIM) of the donor animals were obtained for 43 pairs of samples. Samples were grouped by parity (1, 2, 3, and >or=4) stage of lactation (Stage 1: <90 DIM, Stage 2: 90 to 150 DIM, Stage 3: 151 to 250 DIM, and Stage 4: >250 DIM). Samples were analyzed by radiographic photometry and dual-energy x-ray absorptiometry and then analyzed for mineral content chemically. In both experiments, the relationship between mineral content estimated via the imaging techniques and mineral content measured chemically was poor, likely because of the relative maturity of animals in the sample set and lack of variation in mineral content. Ash content was higher in the metacarpal than in the caudal vertebrae, as were concentrations of Mg (expressed as a proportion of bone ash). No effects of stage of lactation were observed on bone mineral in the caudal vertebrae, but in the metacarpal, P content (proportion of total mineral) was highest in second lactation cows. Total bone mineral content (ash) was not affected by parity in the metacarpal or caudal vertebra, but Ca and P content of the metacarpal increased with parity. Noninvasive imaging techniques are not sufficiently sensitive to detect changes in mineral content or composition of mature cows, and only modest changes in bone mineral were observed with stage of lactation and parity.

Abattoirs↗
PubMed1990

[A photometric method of determining the activity of antithrombin III using a peptide coumarylamide substrate].

Toz-Gly-Pro-Arg-4-methylcoumaryl-7-amide is recommended for antithrombin-III (AT-III) photometry as a substrate. This substrate is cleaved by thrombin at 366 nm. AT-III photometry with this substrate is in accord with the requirements to methods used in clinical laboratory diagnosis, and the results of such measurement are in good correlation with the data of AT-III analysis with Chromozym-TH substrate. Use of photometry with methylcoumaryl substrates for measuring protease activities is more available than the traditional fluorometry.

Antithrombin III↗