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At least 163 records · Page 9Linked to original sources

PubMed2000

[Radioisotopic synoviorthesis in rheumatoid arthritis. A study of 108 cases].

There are several therapeutic alternatives in the local treatment of rheumatoid arthritis (RA): intraarticular corticosteroids, chemical synoviorthesis, surgical synovectomy and synoviorthesis with radioisotopes. We present the results of an observational study on radioisotopic synoviorthesis carried out in the Valencian health care area from January 1989 to May 1997 which included 108 synoviortheses performed in 51 patients. This study aimed to assess the efficacy and safety of radiosynoviorthesis in the treatment of RA which had not responded to conventional treatment. Good and moderate results were obtained in 76.2% of the cases, there being significant differences in the efficacy of synoviorthesis in patients with and without advanced radiographic alterations. There were few side effects (3.7%). We conclude that radiosynoviortesis is a useful and safe therapeutic tool in RA that does not respond to conventional treatment, that it is more effective in large joints with little cartilaginous deterioration and that its repeated use does not decrease the expected therapeutic effect.

Adolescent↗

PubMed1978

Cobalamin analogues are present in human plasma and can mask cobalamin deficiency because current radioisotope dilution assays are not specific for true cobalamin.

Since R protein binds cobalamin (vitamin B12) and cobalamin analogues, whereas intrinsic factor is highly specific for true cobalamin, we compared the serum cobalamin values obtained with these proteins in radioisotope dilution assays. With R protein, eight of 21 patients with cobalamin deficiency had serum cobalamin levels (mean, 204, range, 85 to 355 pg per milliliter) that overlapped with values for 74 normal subjects (mean, 576, range, 220 to 1230). With intrinsic factor, no patient values (mean, 36, range, less than 10 to 78 pg per milliliter) overlapped with the normal values (mean, 322, range, 130 to 785). Paper chromatography showed that these differences were due to the presence of cobalamin analogues. R protein constituted 51 to 85 per cent of the cobalamin-binding protein in 10 commercial serum cobalamin assay kits, which were said to contain "intrinsic factor". Human plasma contains cobalamin analogues that can mask cobalamin deficiency with current radioisotope dilution assays.

Adult↗

PubMed2003

Guidance on individual monitoring programmes for radioisotopic techniques in molecular and cellular biology.

The radioisotope techniques used in molecular and cellular biology involve external and internal irradiation risk. The personal dosemeter may be a reasonable indicator for external irradiation. However, it is necessary to control the possible internal contamination associated with the development of these techniques. The aim of this project is to analyse the most usual techniques and to establish programmes of internal monitoring for specific radionuclides (32P, 35S, 14C, 3H, 125I and 131I). To elaborate these programmes it was necessary to analyse the radioisotope techniques. Two models have been applied (NRPB and IAEA) to the more significant techniques, according to the physical and chemical nature of the radionuclides, their potential importance in occupational exposure and the possible injury to the genetic material of the cell. The results allowed the identification of the techniques with possible risk of internal contamination. It was necessary to identify groups of workers that require individual monitoring. The risk groups have been established among the professionals exposed, according to different parameters: the general characteristics of receptor, the radionuclides used (the same user can work with one, two or three radionuclides at the same time) and the results of the models applied. Also a control group was established. The study of possible intakes in these groups has been made by urinalysis and whole-body counter. The theoretical results are coherent with the experimental results. They have allowed guidance to individual monitoring to be proposed. Basically, the document shows: (1) the analysis of the radiosotopic techniques, taking into account the special containment equipment; (2) the establishment of the need of individual monitoring; and (3) the required frequency of measurements in a routine programme.

Cell Biology↗

PubMed1975

[Dynamic radioisotope studies of the regional functions of the lung (a preliminary report)].

A critical analysis on the non-isotope method potentiallities is presented in the paper as well as the radioisotope xenon mode for examinations of gas ventilation and diffusion. The advantages of 133xenon are listed, the main being as follows: regional investigation parallelly in four zones, completely safe for the patient without loading procedures, precision and availability for mass investigations. The authors recommend its wider application in practive, based on a great many radioisotope investigations of healthy and sick individuals.

Bronchial Spasm↗

PubMed1990

[Diagnostic value of radioisotope clearance in patients with a single kidney].

In a group of patients with solitar kidney a radioisotope clearance was performed to determine exactly the renal functional status and to reduce the blind area of standard diagnostical parameters. In 41 percent of these patients a restriction of the glomerular or tubular value was found. In the same way the function-diminishing effect of hypertension on renal plasma flow and tubular-secretory function was determine. In the present study of dynamic radioisotope investigations in patients with solitar kidney could be verified.

Glomerular Filtration Rate↗

PubMed1974

[A study of renal function using radioisotope methods in patients with diabetic nephropathy].

An earlier and more manifested affect of glomerular function was established during the examination of 35 patients with diabetic nephropathy, 14 of them in a stage of renal insufficiency, with the help of radioisotope clearance methods (of EDTA, labelled with 169Yb for the determination of glomerular function and of hippuran, labelled with 131J for the determination of the renal plasma flow). The renal plasma flow is affected to a considerably more restricted extent. The combination of diabetic nephropathy with chronic pyelonephritis, found in 10 patients, does not affect substantially the mentioned functions of the kidney, but additional investigations were considered necessary in that field. Bilateral symmetric alterations are more frequently the secretory and excretory segmentsmthe establishment of unilateral alterations may speak of the presence of chronic pyelonephritis of uropathic character. The radioisotope methods, because of their accessibility and less possibilities for errors are recommended for renal functional investigations.

Adolescent↗

PubMed1981

[Comparison of conventional renal clearance values with differently evaluated results of radioisotope nephrography (author's transl)].

81 patients with renal abnormalities or renal disorders of different genesis and severity with and without restricted renal function were investigated by means of the classical PAH- and inulin-clearance. Furthermore a radioisotope nephrography was carried out after application of I 131-Hippuran followed by Cr 51-EDTA. In addition the activity reduction was measured above the shoulder, as well as the activity in serum samples and urine samples gained 30 min after application. A comparison of the clearance values found with those of conventional clearance resulted in poor correlation for I 131-Hippuran (r = 0.54) and no correlation for Cr51-EDTA. Of the many parameters of the radioisotope nephrogram curves only the following are able to give sufficient quantitative functional results: The parameters connected with the rise of the curve between the 48rh and 120rh s and those connected with the slope of the secant. This is also true for the values of activity measured in the urine.

Adolescent↗

PubMedDate not supplied

Radioisotope x-ray fluorescence analysis of ancient pottery from Tel Kouzama site in Damascus, Syria.

The radioisotope X-ray fluorescence method has been utilized in the analysis of thirty nine archaeological pottery fragment samples from Tel Kouzama site, Damascus city, Syria. The samples were irradiated by a 109Cd radioisotope source (-9 10(8) Bq) for 1000 s. 17 chemical elements were determined. These elemental concentrations have been processed using two multivariate statistical methods, cluster and factor analysis in order to determine similarities and correlation between the various samples. Factor analysis confirms that samples were correctly classified by cluster analysis. These two methods suggest that samples can be considered to be manufactured using four different sources of raw material.

Archaeology↗

PubMed1993

Two cases of Graves' disease with presentation of unilateral diffuse uptake of radioisotopes.

We present two cases of Graves' disease whose initial thyroidal scintiscan with 99mTcO4- (Case 1) and 123I (Case 2) showed unilateral diffuse uptake of radioisotopes. Initial diagnosis was possibility of malignancy in Case 1 and Graves' disease or Plummer's disease in Case 2. Both cases underwent right hemithyroidectomy. Histopathology of the resected thyroid gland in both showed hyperplastic columnar epithelium and infiltrative lymphocytes which was compatible with Graves' disease. Twenty seven (Case 1) and eight months (Case 2) after operation, both presented with thyrotoxic symptoms associated with enlarged left lobe, increased serum free thyroid hormone concentrations, suppressed TSH concentration, increased thyroidal 123I uptake in the remaining left lobe, and positive thyrotropin receptor antibodies. Both cases were successfully treated with methimazole. It was concluded that initial radioisotope uptake as well as scintigram in rare subgroup of patients with Graves' disease could be similar with that of non-autoimmune autonomous goiter (Plummer's disease).

Animals↗

PubMed1975

Comparison of results of microbiologic and radioisotopic assays for serum vitamin B12 during pregnancy.

The serum vitamin B12 level falls progressively during pregnancy, when measured either by microbiologic assay or by a radioisotope dilution technique. The concentration of the vitamin assayed by radioisotope dilution was consistently higher than the value obtained by microbiologic assay. This discrepancy was greatest in early pregnancy and decreased as the duration of pregnancy increased. These results add further evidence to the hypothesis that changes in serum binders for vitamin B12 are of major significance in the pathogenesis of the observed fall in serum levels of the vitamin during pregnancy.

Biological Assay↗

PubMed1990

Combination of 31P-NMR magnetization transfer and radioisotope exchange methods for assessment of an enzyme reaction mechanism: rate-determining steps of the creatine kinase reaction.

The theoretical analysis of a reversible enzyme reaction performed in this work shows that the 31P-NMR magnetization (saturation) transfer technique combined with a radioisotope exchange method may potentially provide information on the position of rate-determining step(s). It depends on chemical shifts of NMR signals of nuclei of interest in free and enzyme-bound forms of substrate(s) and product(s) of the reaction. The creatine kinase reaction (MgATP + creatine----MgADP + P-creatine) has been used as a model. Chemical shifts of 31P in binary, ternary and transitional state substrate-enzyme complexes have been estimated by the variable frequency saturation transfer (VFST) method. This method is based on selective irradiation of numerous points in the spectrum and observation of changes in the intensity of visible line(s) which occur due to chemical exchange between it and lines which are not visible in the routine spectrum. Also, dissociation rate constants of MgADP-containing complexes were determined. Magnetization exchange rates, P-creatine----[gamma-P]MgATP and [beta-P]MgADP----[beta-P]MgATP, were compared with radioisotope exchange rates, [gamma-32P-MgATP----P-creatine and [3H]MgADP----MgATP at different [P-creatine]/[creatine] ratios and at different temperatures. All these exchange rates were close to each other at 30-37 degrees C and [PCr]/[Cr] ratios lower than 2. It is concluded that phosphoryl group transfer is the rate-determining step of the overall creatine kinase reaction under these conditions. However, at lower temperatures (below 25 degrees C) or at high [PCr]/[Cr] ratios ([ADP] less than 20 microM) the rate-determining step seems to be shifted toward dissociation of nucleotide substrates from enzyme-substrate complexes, since exchange rates became significantly different. This approach is useful for analysis of mechanism of enzymatic reactions and also can be applied to non-enzymatic reactions and evaluation of small rapidly exchangeable metabolite pools.

Adenosine Diphosphate↗

PubMed1989

Radioisotopic assay for erythrocyte adenosine 5'-monophosphate deaminase.

Adenosine-5'-monophosphate deaminase is a critical enzyme in the regulation of adenine nucleotide levels in the erythrocyte. The routine examination of this enzyme in crude hemolysates is difficult with the commonly used assay which monitors ammonia generated by the deamination reaction. This report details a radioisotopic assay for AMP deaminase which allows separation of the [14C]inosine 5'-monophosphate product from the [14C]adenosine 5'-monophosphate substrate by ion-exchange chromatography at pH 2.2. The radioisotopic assay is linear with respect to time and enzyme concentration over a considerable range and thereby significantly simplifies the monitoring of crude or dilute enzyme preparations.

AMP Deaminase↗

PubMed1986

Creatine kinase-catalyzed ATP-phosphocreatine exchange: comparison of 31P-NMR saturation transfer technique and radioisotope tracer methods.

Unidirectional fluxes from ATP to phosphocreatine, catalyzed by the MM isoenzyme of creatine kinase, were measured by both the 31P-NMR saturation transfer technique and radioisotope tracer ([gamma-32P]ATP) method. It was found that at 30-37 degrees C and pH 7.4, over a wide range of [phosphocreatine]/[creatine] (from 0.2 to 5.0) ratios, both methods gave the same results, showing that magnetization transfer allows determination of real fluxes under 'physiological' conditions. However, at [PCr]/[Cr] ratios higher than 5 ([ADP]free less than 30 microM) or at lower temperatures (t less than 15 degrees C, [PCr]/[Cr] approximately 1), the fluxes assessed by saturation transfer were somewhat faster than those detected by the radioisotope tracer method. These data imply that under physiological conditions phosphoryl group transfer is actually the rate-determining step of the creatine kinase reaction. In contrast, at high [PCr]/[Cr] ratios or at lower temperatures, control may be shifted from phosphoryl group transfer or distributed among other steps of the reaction.

Adenosine Triphosphate↗

PubMed1990

Radioisotopic measurement of femtomolar amounts of NAD(P)H in the assay of enzymatic activity at a single cell level.

A radioisotopic method for the assay of reduced or oxidized pyridine nucleotides, based on the interconversion of 2-[U-14C]ketoglutarate or 2-keto[3,4-3H]glutarate and labelled L-glutamate in the reaction catalyzed by glutamate dehydrogenase, was applied to the measurement of lactate dehydrogenase activity in rat pancreatic islet homogenates. Using the tritiated tracer, the limit of sensitivity of the procedure for NAD(P)H assay was close to 1.0 fmol/sample, and lactate dehydrogenase activity could be measured in as little as 0.0005 islet/sample i.e., at a single cell level. This radioisotopic procedure, which can be used for the assay of various metabolites and enzymic activities, thus provides a tool for investigating the heterogeneity in metabolic behaviour of individual cells.

Animals↗

PubMed1996

In situ 19F MRS measurement of RIF-1 tumor blood volume: corroboration by radioisotope-labeled [125I]-albumin and correlation to tumor size.

Tumor blood volume (TBV) is an important factor in the metabolism of a tumor and in its response to therapy. Until recently, the only methods to determine TBV were highly invasive and many involved radioisotopes. In this study, a perfluorocarbon (PFC) emulsion, Oxypherol, was monitored by 19F magnetic resonance spectroscopy (MRS). TBVs as determined by 19F MRS of in situ and excised radiation-induced fibrosarcoma (RIF-1) tumors (n = 9), were strongly correlated with the TBV measured by a radioisotope labeled albumin method (slopes of 1.1 and 0.8 with R = 0.86 and 0.91, respectively, by linear regression). In general, the TBV as calculated from the in situ MRS measurements (n = 24) decreased from 28 to 5 ml/100 g tumor mass for tumors ranging in mass from 0.15 to 2 g. However, there was an indication of an initial increase of TBV in tumors smaller than 0.5 g.

Albumins↗

PubMed2003

Intradermal radioisotope injection optimises sentinel lymph node identification in breast cancer.

AIM: Currently there is no consensus on the optimal technique for sentinel lymph node (SLN) identification in patients with breast cancer. The aim was to compare the efficacy of intraparenchymal and intradermal isotope injection in sentinel lymph node mapping for breast cancer. METHODS: One hundred and twenty-five patients with histologically confirmed invasive breast cancer underwent SLN mapping using radioisotope and isosulphan blue dye followed by a back-up axillary dissection. The first 80 patients had intraparenchymal (IP) injection of radioisotope given in four portions around the tumor. The remaining 45 patients had an intradermal (ID) injection given at a single site over the tumour. Both groups had isosulphan blue dye injected around the tumour. Sentinel node(s) were identified using a combination of lymphoscintigraphy, blue dye and an intra-operative hand held gamma probe. RESULTS: The preoperative lymphoscintigram (LSG) demonstrated a SLN significantly more often in the ID isotope group compared to the IP isotope group (P=0.002). A combination of blue dye and isotope successfully located the SLN in 96% of the intraparenchymal group and 100% of the intradermal group. CONCLUSION: Our results suggest that intradermal isotope injection in combination with intraparenchymal blue dye optimises the localization of the sentinel lymph node in breast cancer.

Axilla↗

PubMed2006

Non-radioisotope detection of pol sequences of HTLV-1 proviral DNA: Standardisation and sensitivity analysis.

Proviral DNA amplification methods may be used for identification of HTLV-1 infection or in basic virology research. Published standardised methods in this regard usually depend on hybridisation of PCR products with radioisotope-labelled probes. However, this procedure has limited use in routine testing, due to environmental and health risks. The aim was to assess the feasibility of routine use and the accuracy of an alternative detection system that employs an HTLV-1-specific enzyme-labelled probe. For this purpose DNA was extracted from MT-2 cells, quantified and submitted to serial dilution (1:10), starting from 1.2 microg of genomic DNA. Primary and nested PCR amplifications of pol sequences of the HTLV-1 genome were carried out with standardised primers (SK110/111 and POL1.1/3.1). After Southern blotting, two different detection systems were compared, consisting of hybridisation with either 32P- or alkaline phosphatase-labelled SK112 probes. Both detection systems yielded similar results, detecting PCR products generated from 120 pg of DNA (genomic DNA amount equivalent to 20 diploid human cells) after primary and nested PCR. The alkaline phosphatase-labelled detection technique was feasible for the diagnosis of HTLV-1 with the advantage of precluding the handling of radioisotopes.

Alkaline Phosphatase↗

PubMed1992

Dual radioisotopic study: a technique for the evaluation of vasculogenic impotence.

Arterial and venous systems are the main points for the evaluation of vasculogenic impotence. To evaluate both of these systems in the same study we propose a dual radioisotopic study in which 99mtechnetium (99mTc) and 133xenon (133Xe) were used. The changes in 99mTc and 133Xe radioactivities administered intravenously and intracavernously, respectively, were monitored before and after intracavernous papaverine injection. These changes were determined as time activity curves, which were generated from the region of interest over the penis. A 99mTc penogram index derived from the 99mTc time activity curve was significantly different in the control and arteriogenic impotence groups (131.67 +/- 74.6 versus 62.94 +/- 51.6, p less than 0.01). A meaningful correlation between 99mTc penogram index results and duplex ultrasonographic findings were observed (r = 0.905). 133Xe penogram index, derived from the 133Xe washout curve was significantly different in the control and venogenic impotence groups (-25.65 +/- 24.9 versus -56.09 +/- 13.4, p less than 0.01). Also, a meaningful correlation was obtained between pharmacocavernosometry and 133Xe penogram index results of venogenic impotent patients (r = 0.86). These findings suggest that the dual radioisotopic study will be a useful technique in the evaluation of the entire vascular system of the penis, since it is a noninvasive method.

Adult↗