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At least 73 records · Page 4Linked to original sources
PubMed1997

A non-radioactive and two radioactive assays for selenophosphate synthetase activity.

Selenophosphate synthetase catalyzes the formation of monoselenophosphate (SePO3(3-)) from ATP and selenide (reaction 1). [formula: see text] In one assay frequently used, [8-14C]AMP formation from [8-14C]ATP is estimated after separation of the nucleotides by thinlayer chromatography. An alternative non-radioactive assay in which the AMP product is estimated using AMP deaminase is described. The highly oxygen-labile selenophosphate product can be estimated in an assay employing [gamma-32P]ATP. The 32P-labeled selenophosphate is converted to [32P]orthophosphate by treatment with iodine and estimated after removal of residual [32P]ATP on charcoal.

Adenosine Monophosphate↗
PubMed1975

Radioactive antigen suicide of an anti-DNP (2,4-dinitrophenyl) clone. II. Follow-up of clones relatively resistant to radioactive antigen suicide when initially selected.

After suicide of the anti-dinitrophenyl (DNP) clone E21 in a previous experiment (Eur. J. Immunol. 1975. 5:58) several new clones (S clones) appeared promptly in the recipients. There was compelling evidence that they were then resistant to suicide, relative to E21. We now report further studies on these S clones and their antibodies. The antibodies of half of the S clones had affinities ten to one hundred times higher than E21 (3 x 10(-7) M); none was lower. The four tested were also able to bind DNP on the particular conjugate used for the suicide procedure. Three of the S clones were serially propagated, they showed a very great capacity for proliferation, transferring into 510, 85 and 110 recipients each. When their cells were tested at subsequent passages, they recovered early after inhibition by radioactive antigen. Two S clones may still have been somewhat refractory to suicide but, probably in all three, rapid proliferation was largely responsible for the recovery of the few cells escaping suicide, and helped them to appear suicide resistant.

Age Factors↗
PubMed1995

Treatment with propylthiouracil before radioactive iodine therapy is associated with a higher treatment failure rate than therapy with radioactive iodine alone in Graves' disease.

Older reports have suggested that the use of antithyroid drugs with radioactive iodine-131 (RAI) results in higher rates of persistent hyperthyroidism than treatment with RAI alone. Our objective was to determine if propylthiouracil (PTU) given prior to RAI would be associated with a higher single dose RAI failure rate than treatment with RAI alone. Patients were considered treatment failures if a second dose of RAI was required to produce euthyroidism or hypothyroidism. All study patients stopped PTU at least 4 days before RAI therapy and did not receive PTU after RAI. The overall failure rate of one course of treatment in the 86 study patients was 17% (15/86). Persistent hyperthyroidism was seen in 4% of patients (2/48) treated with only RAI and in 34% of patients (13/38) receiving RAI after pretreatment with PTU (p = 0.003). Patients were treated with PTU for a mean of 151 +/- 32 days. There were no significant differences in race, gender, thyroid size, RAI dose, or days of follow-up between patients receiving RAI alone and those receiving PTU before RAI therapy. These data suggest that pretreatment with PTU leads to a higher failure rate even if PTU is discontinued at least 4 days before RAI therapy and not restarted after RAI dosing. Consideration should be given to increasing the dose of RAI in patients pretreated with PTU to ensure adequate treatment of Graves' disease.

Adult↗
PubMed2006

Comparison of gastric emptying scintigraphy based on the geometric mean of the gastric proportion of the abdominal radioactivity or on the geometric mean of the intragastric radioactivity.

PURPOSE: Using gastric emptying scintigraphy the gastric retention rate is commonly calculated within a gastric region of interest (intragastric method). This technique may have significant limitations when left oblique anterior views are acquired, due in part to attenuation resulting from intragastric redistribution. To minimize these drawbacks, it was proposed to express the intragastric content as a percentage of the abdominal radioactivity (abdominal method). Our goal was to compare these two methods when anterior-posterior scanning is used. METHODS: Antero-posterior scintigraphic data of 272 consecutive patients were analysed by both methods. Retention rates were obtained by both observation and calculation by power exponential fit. Gastric emptying parameters (half-emptying time of solids (T(50,S)) and liquids (T(50,L)), lag phase (T(lag)) time and real emptying time (T(RE))), and quality of fit were also computed and compared. RESULTS: For solids, the intragastric method resulted in weakly higher experimental retention rates, whereas retention rates were quite similar for liquids. Differences between experimental and calculated retention rates were smaller for abdominal method, for both liquids and solids. As a result, values for the quality of fit were higher for the abdominal method. Significant differences were observed only for calculated T(50,S) (122+/-46 min vs. 124+/-48 min, mean difference 2+/-2 min, P<0.00001) and T(RE) (163+/-64 min vs. 168+/-68 min, mean difference 4.5+/-3.8 min, P<0.05), respectively, for the abdominal and the intragastric methods. However, the Bland-Altman statistical method revealed good agreements (<5% outliers). CONCLUSION: Intragastric and abdominal methods can be used indifferently to treat antero-posterior data of gastric scintigraphy.

Abdomen↗
PubMed1991

Simultaneous detection of two messenger RNAs in the central nervous system: a simple two-step in situ hybridization procedure using a combination of radioactive and non-radioactive probes.

We present here a method enabling the simultaneous detection of two messenger RNAs in tissue sections by use of a two-step in situ hybridization procedure. Tissue sections were hybridized with a radioactive probe and coated with emulsion. The emulsion was processed for development, fixed, and a second hybridization was performed through the emulsion with a biotinylated probe subsequently revealed with streptavidin-alkaline phosphatase. This procedure allows the detection of two mRNAs without loss of signal, removal of the emulsion, or spurious reaction. The simultaneous detection of oxytocin and vasopressin mRNAs in the hypothalamus, and of dopamine receptor and neuropeptide mRNAs in the striatum, demonstrated the efficiency of the procedure. Such a two-step procedure provides a simple and flexible way to make possible comparative analysis of the localization of two mRNAs within the same tissue section.

Animals↗
PubMed1963

An assessment of the "radioactive renogram" using O-iodohippurate sodium (Hippuran) labelled with radioactive iodine.

A "radioactive renogram" using o-iodohippurate sodium (Hippuran)-I(131) was performed in 57 patients who had either hypertension or various renal diseases. In longstanding essential hypertension, the initial uptake and secretory phases are often reduced below normal. In five hypertensive patients who were shown to have unilateral renal disease, the renogram showed significantly abnormal tracings on the affected side. In three patients suffering from ureteral obstruction, the excretory phase was significantly prolonged.On the basis of comparative albumin and iodohippurate renograms, the initial uptake can no longer be considered as a vascular phase, as previously believed.The iodohippurate-I(131) renogram is a useful adjunct in the investigation of hypertension and renal disease, providing information about each kidney not so readily obtained by other means. Nevertheless, the test does not supplant any other investigative procedure and should not be depended upon as a screening procedure.

Essential Hypertension↗
PubMed1978

[Effect of various non-radioactive and radioactive chemical compounds on the structure of the spleen].

Dynamical changes in the spleen of mice and rats were studied morphometrically and electron microscopically when the animals were given in drinking water radionucleotides in small concentrations (137Cs, 226Ra, 89Sr, 65Zn, Pb(NO3)2, BeCl2, hexamethyleniamine, methylmercurchloride) for 1-2 years. Total doses obtained for a year were 0.3-100 rad. Reactive reconstruction of the organ under radioactive and chemical effects was stated to proceed in three directions: a) hyperplasy of lymphoid tissue; b) enhanced plasmocytogenesis; c) hyperplasy of extramedullar hemopoiesis. Sequence in the appearance of these reactions and doses which produced them were different for every compound. In 1-2 years at large doses (160-200 rad) atrophy, amyloid degeneration of the spleen or signs of leukemia were observed. Disturbance of intercellular contacts and of intracellular regeneration was demonstrated electron microscopically.

Animals↗
PubMed1995

Radioactive and non-radioactive lymphocyte proliferation assays for measuring rabies-specific cellular immunity.

We compared the radioactive lymphocyte proliferation assay for measuring rabies specific cell-mediated immunity in a group of 42 rabies vaccine recipients with a new technique using rabies-stimulated lymphocytes in a colorimetric test kit (CellTiter 96, Promega Corporation, USA). Results of both tests were good agreement (Kappa = 0.68), however, they did not show good correlation in degree (magnitude) of positivity. In addition, the conventional assay showed a higher degree of sensitivity.

Cell Division↗