Analysis of deoxyribonucleic acid histograms from flow cytofluorometry. Estimation of the distribution of cells within S phase.
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Biomedical subjects
Publications and source records attributed to J Fried.
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Sera from patients with a variety of infections were used to compare the sensitivity and specificity of the complement fixation (CF) and the indirect immunofluorescence (IIF) tests for schistosomiasis. Adult antigens were used in both tests. The sensitivities of the IIF and CF tests were 95% and 69%, respectively; the specificities were 98% and 100%, respectively. There was no statistical difference between the number of positive reactors among those individuals with no detectable helminth infection and those infected with helminths other than schistosomes. Infected people native to endemic areas had lower reactivity in both tests than did infected U.S. citizens who resided in endemic areas for only a few years. We concluded that the IIF test with adult antigen was more sensitive than and as specific as the CF test; therefore, the IIF test is the procedure of choice for routine diagnostic serology of schistosomiasis.
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In order to better characterize the new rapid staining method for flow cytofluorometry proposed by Krishan, we have tested its stability and several other properties, and have carried out a quantitative comparison of the fluorescence histograms obtained using propidium iodide or the acriflavine-Feulgen staining procedure. Using a human hematopoietic cell line in the logarithmic phase of growth, and analyzing the data by means of a mathematical method we have devised, we found that the fluorescence intentsity of cells stained with propidium iodide remains stable for at least 48 h; it is insensitive to dye concentration between 0.025 and 0.10 mg/ml (37-150 muM); it is not affected by incubation with ribonuclease before staining; propidium iodide in 0.1% sodium citrate remains stable for at least 20 days; and quantitative estimates of the fractions of cells in the different phases of the cell cycle are in good agreement with those obtained from acriflavine-Feulgen staining and from autoradiography after pulse labeling with tritiated thymidine. We conclude that this method is useful for the measurement of relative DNA content by flow cytofluorometry, although modifications in the technique are necessary for some cell types which grow in monolayers.
A rapid method for the laser-flow microfluorometry determination of nucleic-acid content per cell is presented. A frequency distribution of fluorescence is obtained from suspensions of living cells treated with ethidium bromide directly in their own medium (or calcium-magnesium-free Hanks' balanced solution). For a fixed number of cells, a frequency distribution of fluorescence is obtained as a function of the amount of ethidium bromide progressively added to the suspension until staturation. At any ratio of added dye per unit of DNA, histograms generated from cells stained with this method give results similar to those generated after fixation and staining by the Feulgen technique, both in terms of cell-cycle phases and ploidy-level determination. The present technique requires a minimal amount of material, is instantaneous, and is conducted directly on living cells. Furthermore, dye concentration-dependence studies of mean fluorescence per cell allow determination of association constant and binding process (primary and secondary) between the intact cell and ethidium bromide. Cells which have the same amount of DNA but vary in the amount of RNA and/or chromatin conformation (like G0 and G1) can then be distinguished.
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Meperidinic acid was converted to O-meperidinyl-glycollic acid and covalently attached to bovine serum albumin. Rabbits injected with this conjugate produced antibodies reactive with meperidine which were measured by the ammonium sulfate method. The specificities of these antisera were studied by competitive inhibition of the binding of 100 pmol/ml of 3H-meperidine to antibody by the prior addition of increasing concentrations of various unlabeled compounds. The concentrations in nanomoles per milliliter of various unlabeled opiods required to inhibit 3H-meperidine binding by 50% (I50) were: meperidine, 0.08; O-meperidinyl-glycollic acid, 1.7; methadone, 580; heroin, 1750; codeine, 2600; and morphine, 4200. Several psychopharmacologically active compounds were found to have I50 values comparable to the nonmeperidine opioids: hydroxyzine. HCl, 460; propoxyphene, 4,500; diazepam, 6,500; and cocaine, 10,800. The metabolites of meperidine exhibited the following I50 values: normeperidine, 0.7; meperidinic acid and normeperidinic acid, 210. A radioimmunoassay for meperidine which employs this antiserum was shown to be approximately 100 times more sensitive than the spectrophotometric method of Burns et al. (J. Pharmacol. Exp Ther. 114: 289-293, 1955). In this assay only normeperidine and some of the meperidine congeners might be expected to interfere with the measurement of meperidine. The degree of normeperidine interference was shown to be comparable to that present in the existing assay method.
Meperidinic acid was converted to O-meperidinyl-glycollic acid and covalently attached to bovine serum albumin. Rabbits injected with this conjugate produced antibodies reactive with meperidine which were measured by the ammonium sulfate method. The specificities of these antisera were studied by competitive inhibition of the binding of 100 pmol/ml of 3H-meperidine to antibody by the prior addition of increasing concentrations of various unlabeled compounds. The concentrations in nanomoles per milliliter of various unlabeled opiods required to inhibit 3H-meperidine binding by 50% (I50) were: meperidine, 0.08; O-meperidinyl-glycollic acid, 1.7; methadone, 580; heroin, 1750; codeine, 2600; and morphine, 4200. Several psychopharmacologically active compounds were found to have I50 values comparable to the nonmeperidine opioids: hydroxyzine-HC1, 460; propoxyphene, 4,500; diazepam, 6,500; and cocaine, 10,800. The metabolites of meperidine exhibited the following I50 values: normeperidine, 0.7; meperidinic acid and normeperidinic acid, 210. A radioimmunoassay for meperidine which employs this antiserum was shown to be approximately 100 times more sensitive than the spectrophotometric method of Burns et al. (J. Pharmacol. Exp. Ther. 114:289-293, 1955). In this assay only normeperidine and some of the meperidine congeners might be expected to interfere with the measurement of meperidine. The degree of normeperidine interference was shown to be comparable to that present in the existing assay method.
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The dissociation constants for the interactions between some prostaglandin analogues and a prostaglandin F2 receptor in bovine corpora lutea were determined. These values were compared to the antifertility potencies of these compounds in hamsters and the rates of metabolism by 15-hydro-syprostaglandin dehydrogenase. The most active analogues with regard to both affinity for the receptor and luteolytic potency were 17-phenyl-18, 19, 20-trinorprostaglandin F2alpha and 15-methylprostaglandin F2alpha. The alkyl side chain of prostaglandins could be modified considerably without altering the affinity for the receptor. In this way metabolism by 15-hydroxyprostaglandin dehydrogenase could be blocked. Some of these compounds -ad greatly increased luteolytic effects. Substitution of a phenyl group for the 3 terminal carbon units of the alkyl side chain of prostaglandins increased both the affinity for the receptor and the luteolytic activity in vivo. 7-oxa-13-prostynoic acid, an antagonist of the luteolytic effect of prostaglandin F2alpha in vivo was a weak competitive inhibitor of the interation between prostaglandin F2alpha and the receptor.
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The kinetics of cell proliferation were studied in a patient with lymphosarcoma in a leukemic phase both before treatment when the disease was very advanced and again at the earliest sign of bone marrow relapse following a drug-induced remission. During advanced disease, the pulse 3H-TdR labeling index (LI) was 11%, the mitotic index (MI) was 0.4% the growth fraction (GF) was 0.6, and the generation time (TG), as measured by the median grain count halving time, was estimated to be 160 hours. The patient went into remission for 25 days after a short course of therapy with prednisolone and arabinosylcytosine (Ara-C). During early relapsing disease, the LI was 17%; MI, 1.1%; GF, 1.0; and TG, 85 hours. The results of this study suggest that the rate of cell proliferation slows in leukemia as the tumor mass increases in volume, and that the slower growth is due to an increase in cell generation time, a decrease in the growth fraction, and an increased rate of spontaneous cell loss.
The proliferative kinetics of the leukemic cells in the cerebrospinal fluid (CSF) were studied in three adults with CNS leukemia after 18 and 8 months while receiving an intensive treatment regimen. One (J.L.) had acute myeloblastic leukemia and developed CNS disease after 5 years' treatment with arabinosylcytosine and 6-thioguanine. All were in marrow remission at the time of study. G.H. had had no therapy for CNS disease, A.K. had had intrathecal methotrexate 2 months previously, and J.L. had recently completed radiotherapy (1900 R) to the head. An Ommaya reservoir was placed in a lateral ventricle and 3H-thymidine was injected into the resrvoir every 12 hours for 10 days; samples of cells were obtained by lumbar puncture periodically for autoradiography. In all patients the flash 3H-thymidine labeling index (LI) of the leukemic cells was less than 2% (determined in vitro) and the mitotic index less than 0.1%. After 10 days of 3H-thymidine injections in vivo, the LIs of the leukemic cells were 55%, 36%, and 21% in G.H., A.K., and J.L., respectively. These findings indicate that leukemic cells may proliferate very slowly in the CNS, and stress the difficulty of eradicating CNS leukemia with chemotherapeutic agents which are only active against proliferating cells.