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At least 19 recordsLinked to original sources
PubMed1979

Quantitation of antibody binding to cell surface antigens by x-ray fluorescence spectrometry.

An X-ray spectrometric method has been developed to quantitate antibody bindng to whole cell surfaces in order to obtain a distribution of binding within a population of cells. The method involves incubation of target cells with ferritin-labeled antibody. Analysis of prepared samples in a modified transmission electron microscope with an X-ray detector and data analysis equipment, yields quantitative results on the binding of labeled antibody to individual cells. The binding of anti-2,4-dinitrophenol serum to Chinese hamster ovary cells with attached 2,4-dinitrophenol haptens was measured by X-ray spectrometry. Measurements of attached hapten by a radioisotopic marker correlated with the X-ray spectrometric determination of bound antibody. The use of synchronized cells in metaphase and G1 phases of the cell cycle permitted investigations into the binding per unit surface area. The distribution of antibody binding among a given population of cells was related to the surface area of the cells.

Animals↗
PubMed1977

[Simultaneous analyses of gaseeous and particulate sulfur in the atmosphere by X-ray fluorescence spectrometry--results of observation and discussion-- (author's transl)].

Concentrations of gaseous and particulate sulfur in the atmosphere were simultaneously measured for 24 hours at a time interval of one hour by the use of the method described in the previous report (this journal, 24, 312 (1975)). Such measurements were made sixteen times in the period from April to September, 1975. As the result of the measurements, it was found that the method used can be applied to practical observation with sufficient reliability. The concentration of gaseous sulfur showed always a larger variation coefficient than that of particulate sulfur. Both the concentrations of gaseous and particulate sulfur were found strongly dependent on the wind direction and velocity and other meteorological conditions. After hot and fine days continued, the concentration of particulate sulfur rose considerably reaching 20 microgramS/m3.

Air Pollution↗
PubMed1977

[Simultaneous analyses of gaseous and particulate sulfur in the atmosphere by X-ray fluorescence spectrometry--discussion on the results of observation and presentation of the problems involved in the methods of sampling and analysis (author's transl)].

Following the previous article, the results of observation are discussed in relation to meteorological conditions. The frequency distribution of gaseous sulfur concentrations (1 hr mean values) was bimodal as the result of the alternation of land and sea winds. The frequency distribution of particulate sulfur concentrations was also bimodal, but this can be rather ascribed to the variation of weather. The correlation between the concentrations of gaseous and particulate sulfur was not so great as was expected. Autocorrelations of the concentrations of gaseous and particulate sulfur were respectively investigated, and it was found that the variation of gaseous sulfur concentration showed daily cycle, and, against this, the variation of particulate sulfur concentration did not show appreciable daily cycle, but had weather correlation. Some discussions are presented concerning the selection of sampling points suitable for clarifying the behavior of sulfur in the atmosphere as well as the improvement of the methods of sampling and analysis.

Air Pollution↗
PubMed1979

Localization and chemical characterization of a partially purified bovine pineal antigonadotropin.

An antigonadotropic substance was partially purified from aqueous extracts of bovine pineal glands by methods of gel filtration, ultrafiltration and ion exchange chromatography. Two biological tests, viz. inhibition of compensatory ovarian hypertrophy and reduction of ventral prostate weight, were used to guide the purification. The partially purified antigonadotropin was characterized chemically using techniques of UV and fluorescence spectrometry, thin layer and paper chromatography, paper electrophoresis and amino acid analysis. The results reveal a diversity of ninhydrin-positive components present in the preparations, including free and peptide-bound amino acids, as well as other unidentified components, but not including any of the commonly occurring indoles, indoleamines or catecholeamines. One peptide, oxidized glutathione, was identified in the most purified material containing the biologically active principle yet pure, synthetric glutathione has no antigonadotropic activity in the biological tests utilized. Although the chemical nature of the bovine pineal antigonadotropin remains in question it may be purified by the methods described. The activity is thought to reside in the extremely small, perhaps trace quantities of residues derived. It is believed that large scale, preparative studies will be required for structural determination.

Amino Acids↗
PubMed1977

High-performance liquid-chromatographic analysis for tryptophan in serum.

Concentrations of total tryptophan were determined rapidly and sensitively in 50 microliter of serum by a reversed-phase partition version of high-performance liquid chromatography. For determination of total tryptophan, sample preparation requires only precipitation of the serum protein with trichloroacetic acid and removing excess trichloroacetic acid with a 1,1,2-trichlorotrifluoroethane(Freon)/tri-N-octylamine solution. Tryptophan in serum samples was detected by ultraviolet and fluorescence spectrometry. No interferences from the naturally occurring constituents of serum were observed. Elution time for tryptophan is 15 min, the limit of detection is 1 pmol.

Chromatography, High Pressure Liquid↗
PubMed1978

Serum copper and zinc measurement in patients with osteogenic sarcoma.

Serum copper level (SCL), serum zinc level (SZL), and SCL/SZL ratio were measured in 18 patients with biopsy-proven osteogenic sarcoma. Measurements were made on sequentially collected serum samples beginning prior to the institution of therapy and continuing periodically until documented relapse. All patients were treated by curative resection and adjuvant therapy consisting of high dose methotrexate (with leucovorin rescue) with or without BCG immunotherapy. The SCL, SZI, and SCL/SZL determinations were made using proton-induced x-ray fluorescence spectrometry. SCL was significantly elevated (p less than .0001) in the 18 patients with primary untreated osteogenic sarcoma )173 +/- 30 microgram/dl) compared with a sex and age-matched normal group (115 +/- 16 microgram/dl). A significantly different SZL was not found, however, so that an elevated SCL/SZL ratio in the osteogenic sarcoma patients was primarily due to the altered SCL. SCL and SCL/SZL did not change significantly following curative surgery or become more abnormal in those patients who developed recurrent disease. The SCL and SCL/SZL were noted to be markedly elevated in those patients receiving BCG therapy, raising concern regarding the specificity of these tests as markers of tumor activity. SCL, SZL, and SCL/SZL did not appear useful as markers of tumor activity in patients with osteogenic sarcoma.

Adolescent↗
PubMed1979

Fluorescence analysis of cells using a laser light source.

A quantitative microfluorometric instrument is described that employs a helium cadmium laser (442 nm) as the illumination source. The instrument consists of a double grating monochromator in front of a gallium arsenide photomultiplier that is interfaced with a desktop computer. The versatility of the instrument in making quantitative nucleic acid measurements on acridine orange and Feulgen-Schiff stained cells is demonstrated. The ploidy levels of several populations are easily determined, and the Feulgen fluorescent emissions are considerably greater than those obtained with a standard mercury lamp.

Animals↗
PubMed1978

Antibody-mediated targeting of liposomes. Binding to lymphocytes does not ensure incorporation of vesicle contents into the cells.

Small sonicated lipid vesicles containing the water-souble fluorescent dye 6-carboxyfluorescein were formed from dioleoyl phosphatidylcholine and the antigenic lipid N-dinitrophenylaminocaproyl phosphatidylethanolamine. When these vesicles were incubated with trinitrophenyl-modified human lymphocytes and divalent anti-trinitrophenyl antibody, the antibody bound 5000 to 15 000 vesicles to each cell. Binding was detected by fluorescence microscopy and quantitated by fluorometry and flow microfluorometry. Binding was three times greater with F(ab')2 fragments than with the whole antibody and, as expected, was almost absent with the monovalent F(ab') fragments. It was also absent or greatly reduced, (i) with control immunoglobulin G, (ii) in the presence of excess soluble trintrophenyl hapten, or (iii) if hapten was omitted from either cells or vesicles. It was unaffected by sodium azide and 2-deoxy-D-glucose but was markedly decreased at 3 degrees C. It was not reversed by incubation at 3 degrees C with excess trinitrophenyl lysine. Self-quenching of the fluorescence of 6-carboxyfluorescein was used to distinguish between release of vesicle contents into the cells and simple binding of intact vesicles (Weinstein, J.N., Yoshikami, S., Henkart, P., Blumenthal, R. and Gagins, W.A. (1977) Science 195, 489--491). Antibody-mediated binding led to little or no increase over spontaneous background levels in the amount of vesicle contents released into the lymphocytes.

Antibodies↗
PubMed1979

Sex-related and cyclic variation of trace elements in rat hypothalamus and pituitary.

The concentrations of 7 trace elements--iron, copper, zinc, arsenic, selenium, bromine, and rubidium--in rat hypothalami and anterior pituitaries were measured by X-ray fluorescence spectrometry. Male, cycling female, and oophorectomized animals were studied under different conditions of reproductive function. Hypothalamic zinc and copper concentrations both rose between proestrus and estrus days and fell again at diestrus. After castration, concentrations of iron, copper, and arsenic were decreased in both pituitary and hypothalamus, while zinc concentrations rose. Male rats had lower pituitary concentrations of iron, copper, zinc, arsenic, and rubidium than cycling females. Under these hormonal manipulations, hypothalamus zinc concentration and gonadotropin secretion appear to be correlated. While injections of copper salts into the hypothalamus can also stimulate gonadotropin release, we did not observe any consistent relation between endogenous hypothalamic copper concentrations and gonadotropins.

Animals↗
PubMed2026

Differentiated extraction strategies for selenium speciation in hyperaccumulator and non-hyperaccumulator plants via orthogonal LC-AFS.

The growing demand for selenium (Se)-enriched products highlights the need for accurate and accessible Se speciation analysis. In this study, a cost-effective orthogonal liquid chromatography-atomic fluorescence spectrometry (LC-AFS) method was developed for the determination of seven Se species (SeO3 2-, SeO4 2-, SeLan, SeMet, SeCys2, MeSeCys, and γ-GluMeSeCys), providing an alternative to ICP-MS-based approaches. Differences in Se accumulation mechanisms between hyperaccumulator Cardamine hupingshanensis and non-hyperaccumulator wheat significantly affected extraction efficiency. The sequential aqueous-enzymatic extraction increased SeLan recovery in C. hupingshanensis from 5.06 to 143.74 μg Se g-1, a 28.41-fold increase, while anaerobic extraction enhanced SeMet recovery in wheat from 98.73 to 112.17 μg Se g-1. Consequently, matrix-specific strategies improved Se recoveries from 20.82% to 80.65% in C. hupingshanensis and from 34.11% to 90.02% in wheat. These findings highlight the importance of matrix-specific extraction for accurate Se speciation analysis.

Cardamine hupingshanensis↗