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At least 613 records · Page 34Linked to original sources
PubMed1981

A method of measuring the radio-opacity of catheters.

Two methods for measuring the radio-opacity of catheters are described. An analysis of the physical quantities that are important for the satisfactory detection of a catheter inside a patient shows that an intrinsic index of radio-opacity can be defined and measured using a radiograph of a step wedge. Quantitative comparisons between catheters of different compositions may then be made, and results are presented of measurements made on several commercially available devices. It is suggested that the methods described are more satisfactory than previous techniques used to define standards, and that they highlight some anomalies in current catheter design and usage.

Catheterization↗
PubMed1998

Radio-opaque markers for stereotactic imaging of uveal melanoma.

In in vitro and in vivo studies, episclerally sutured radio-opaque markers were evaluated as localizers for better determination of the clinical tumour volume prior to stereotactic radio-therapy of uveal melanoma. Four different types of markers were studied in vitro: tantalum marker, 2.5 mm in diameter; ring-shaped markers custom-designed in polymethyl methacrylate (PMMA), 2.6 mm and 3.0 mm in diameter; and barium-impregnated silicone rubber spheres, 2 mm in diameter. In vivo PMMA markers 3.0 mm in diameter and barium-impregnated silicone rubber spheres 2 mm in diameter were used. The best results were obtained with the barium-impregnated silicone rubber spheres both in vitro and in vivo. For the CT-delineation of selected uveal melanomas with either a flat discoid shape or flat tumour extensions or when adjacent serous retinal detachment is present, small episclerally sutured barium-impregnated silicone rubber spheres are useful as localizers for determining the clinical tumour volume.

Humans↗
PubMed1999

Improving the visibility of radio-opaque markers in mammography.

Owing to the high mean film optical densities used in breast screening mammography, and the very high maximum optical densities that can be obtained using modern mammographic film, it is often found that for larger exposures the nominally radio-opaque markers used to identify views, left and right etc., cannot be seen using a normal illuminator. A simple solution to this problem is to back the radio-opaque markers with a thin metal filter chosen to keep the marker information visible over a wide range of exposures. A convenient material for this is copper foil in the form of self-adhesive tape. The improvement in marker contrast produced by this modification is illustrated using point optical density measurements on marked test films produced at the extremes of the mammographic exposure range.

Breast Neoplasms↗
PubMed2005

Radio-sensitivity of the cells from amyotrophic lateral sclerosis model mice transfected with human mutant SOD1.

In order to clarify the possible involvement of oxidative damage induced by ionizing radiation in the onset and/or progression of familial amyotrophic lateral sclerosis (ALS), we studied radio-sensitivity in primary cells derived from ALS model mice expressing human mutant SOD1. The primary mouse cells expressed both mouse and the mutant human SOD1. The cell survival of the transgenic mice (with mutant SOD1), determined by counting cell numbers at a scheduled time after X-irradiation, is very similar to that of cells from wild type animals. The induction and repair of DNA damage in the transgenic cells, measured by single cell gel electrophoresis and pulsed field gel electrophoresis, are also similar to those of wild type cells. These results indicate that the human mutant SOD1 gene does not seem to contribute to the alteration of radio-sensitivity, at least in the fibroblastic cells used here. Although it is necessary to consider the difference in cell types between fibroblastic and neuronal cells, the present results may suggest that ionizing radiation is not primarily responsible for the onset of familial ALS with the SOD1 mutation, and that the excess risks are probably not a concern for radiation diagnosis and therapy in familial ALS patients.

Amyotrophic Lateral Sclerosis↗
PubMed1997

Radio-opaque agents in bone cement increase bone resorption.

A heavy infiltrate of foreign-body macrophages is commonly seen in the fibrous membrane which surrounds an aseptically loose cemented implant. This is in response to particles of polymethylmethacrylate (PMMA) bone cement and other biomaterials. We have previously shown that monocytes and macrophages responding to particles of bone cement are capable of differentiating into osteoclastic cells which resorb bone. To determine whether the radio-opaque additives barium sulphate (BaSO4) and zirconium dioxide (ZrO2) influence this process, particles of PMMA with and without these agents were added to mouse monocytes and cocultured with osteoblast-like cells on bone slices. Osteoclast differentiation, as shown by the presence of the osteoclast-associated enzyme tartrate-resistant acid phosphatase (TRAP) and lacunar bone resorption, was observed in all cocultures. The addition of PMMA alone to these cocultures caused no increase in TRAP expression or bone resorption relative to control cocultures. Adding PMMA particles containing BaSO4 or ZrO2, however, caused an increase in TRAP expression and a highly significant increase in bone resorption. Particles containing BaSO4 were associated with 50% more bone resorption than those containing ZrO2. Our results suggest that radio-opaque agents in bone cement may contribute to the bone resorption of aseptic loosening by enhancing macrophage-osteoclast differentiation, and that PMMA containing BaSO4 is likely to be associated with more osteolysis than that containing ZrO2.

Acid Phosphatase↗
PubMed2006

Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser.

We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.

Journal Article↗
PubMed1984

A radio-immunoassay of 19-nortestosterone using Celite column chromatography.

In order to measure plasma or serum concentrations of 19-nortestosterone (nandrolone), a radio-immunoassay has been developed using C7-tritium labelled nandrolone and antisera raised against nandrolone 3-(O-carboxymethyl)oxime-albumin. Because these antisera displayed considerable cross-reactions towards testosterone, 5 alpha-dihydrotestosterone and 5 alpha-dihydronandrolone, it proved to be necessary to separate nandrolone from these cross-reacting steroids prior to the radio-immunoassay. Using Celite/ethylene glycol columns a complete separation could be achieved between nandrolone and these cross-reacting steroids. The assay procedure involved extraction with ethyl acetate, chromatography on Celite/ethylene glycol columns, overnight incubation of samples and standards with antiserum and labelled compound, bound/free separation with dextran-coated charcoal and counting of the supernatant in a liquid scintillation counter. Recoveries for the total assay procedure (expressed as fractions) were between 0.85 and 1.01. The assay displayed a sensitivity of 0.7 nmol/l (at 50% binding) or 0.2 nmol/l (at 80% binding), while the within-assay and from day to day coefficients of variation were 9.8% (n = 114) and 12.9% (n = 13) respectively for duplicate measurements.

Animals↗
PubMed1989

Discrepancy between serum concentrations of 1,25-dihydroxyvitamin D metabolites measured by radio-immunoassay and thymus radioreceptor assay during vitamin D2 treatment.

A radio-immunoassay (RIA) for determination of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 1,25-dihydroxyergocalciferol (1,25(OH)2D2) in serum was compared with a competitive protein binding assay using calf thymus receptor to clarify the comparability of measurements in subjects treated with either vitamin D2 or vitamin D3 (4000 IU per day for 8 weeks). Before and during treatment with vitamin D3 the two assay techniques were concordant, but during vitamin D2 treatment the serum concentrations of 1,25(OH)2D2 and 1,25(OH)2D3 were higher when measured by RIA. The study demonstrates that during vitamin D2 treatment unknown compounds, recognized only by the antiserum, co-elute with 1,25(OH)2D2 and 1,25(OH)2D3 in high pressure liquid chromatography. It can be concluded that the radio-immunoassay used here cannot replace the calf thymus receptor assay.

Adult↗
PubMed1989

Radio-immunoassay of somatostatin from isolated rat pancreatic islets.

Certain aspects of radio-immunoassay of somatostatin from isolated rat pancreatic islets are described. Somatostatin-14, and not somatostatin-28, is secreted from isolated rat pancreatic islets. Less somatostatin secretion is measured per islet owing to purity of tracer in the radio-immunoassay. Theophylline apparently cross-reacts with somatostatin in the assay described, and this has to be taken into consideration when studying somatostatin release induced by theophylline in isolated islets.

Animals↗
PubMedDate not supplied

Radio frequency ablation in the rabbit lung using wet electrodes: comparison of monopolar and dual bipolar electrode mode.

OBJECTIVE: To compare the effect of radio frequency ablation (RFA) on the dimensions of radio frequency coagulation necrosis in a rabbit lung using a wet electrode in monopolar mode with that in dual electrode bipolar mode at different infusion rates (15 mm/hr versus 30 ml/hr) and saline concentrations (0.9% normal versus 5.8% hypertonic saline). MATERIALS AND METHODS: Fifty ablation zones (one ablation zone in each rabbit) were produced in 50 rabbits using one or two 16-gauge wet electrodes with a 1-cm active tip. The RFA system used in the monopolar and dual electrode wet bipolar RFA consisted of a 375-kHz generator (Elektrotom HiTT 106, Berchtold, Medizinelektronik, Germany). The power used was 30 watts and the exposure time was 5 minutes. The rabbits were assigned to one of five groups. Group A (n = 10) was infused with 0.9% NaCl used at a rate of 30 ml/hr in a monopolar mode. Groups B (n = 10) and C (n = 10) were infused with 0.9% NaCl at a rate of 15 and 30 ml/hr, respectively in dual electrode bipolar mode; groups D (n = 10) and E (n = 10) were infused with 5.8% NaCl at a rate of 15 and 30 ml/hr, respectively in a dual electrode bipolar mode. The dimensions of the ablation zones in the gross specimens from the groups were compared using one-way analysis of variance by means of the Scheffe test (post-hoc testing). RESULTS: The mean largest diameter of the ablation zones was larger in dual electrode bipolar mode (30.9+/-4.4 mm) than in monopolar mode (22.5+/-3.5 mm). The mean smallest diameter of the ablation zones was larger in dual electrode bipolar mode (22.3+/-2.5 mm) than in monopolar mode (19.5+/-3.5 mm). There were significant differences in the largest and smallest dimension between the monopolar (group A) and dual electrode wet bipolar mode (groups B-E). In dual electrode bipolar mode, the mean largest diameter of the ablation zones was larger at an infusion rate of 15 ml/hr (34.2+/-4.0 mm) than at 30 ml/hr (27.6+/-0.1 mm), and the mean smallest diameter of the ablation zones was larger at an infusion rate of 15 ml/hr (27.2+/-7.5 mm) than at an infusion rate of 30 ml/hr (24+/-2.9 mm). CONCLUSION: Using a wet electrode, dual electrode bipolar RFA can create a larger ablation zone more efficiently than monopolar RFA.

Animals↗
PubMed1975

Enhanced uptake by guinea-pig macrophages of radio-iodinated human aggregated immunoglobulin G in the presence of sera from rheumatoid patients with cutaneous vasculitis.

A competitive radiobioassay method for soluble immune complexes in sera has been used to study sera from patients with rheumatoid arthritis. Twenty-eight out of sixty-two sera from selected seropositive rheumatoid patients were found to produce enhanced uptake of radio-iodinated human aggregated IgG by guinea-pig macrophages in contrast with the inhibition of uptake seen with SLE sera. Twenty-two out of the twenty-eight enhancing sera belonged to patients with cutaneous vasculitis. None of the twenty-two sera from seronegative rheumatoid patients possessed enhancing properties and none of these patients had clinical evidence of vasculitis. Three patients with seropositive SLE had sera with enhancing properties and had cutaneous vasculitis. We have shown that the enhancement is probably due to the presence in sera of immune complexes or altered IgG bound to rheumatoid factor. The possible mechanism has been investigated and it appears that there is increased binding of radio-iodinated aggregated IgG to free valencies on rheumatoid factor already bound to immune complexes.

Animals↗
PubMed2000

[Autonomic nerve-sparing surgery combined with preoperative radio-chemotherapy in advanced lower rectal cancer patients].

Since 1985, we have studied autonomic nerve-sparing surgery combined with preoperative radiochemotherapy in patients with advanced rectal cancer to preserve genitourinary function without compromising radicality. The aim of this study was to evaluate postoperative genitourinary function and prognosis. A total of 84 patients with advanced rectal cancer underwent curative surgery combined with preoperative radio-chemotherapy. Of them, 76 underwent curative nerve-sparing surgery using radiation (42.6 Gy) and tegafur suppository. Postoperative genitourinary function, survival, and pelvic recurrence were investigated in these patients. The 5-year and 10-year disease-free survival rate was 80.7%, and the pelvic recurrence rate was 7.9% in patients receiving curative nerve-sparing surgery combined with radio-chemotherapy. All of these patients could micturate spontaneously, but preservation of sexual function was not as successful. Although this combined therapy is useful for curability and good postoperative quality of life, a new approach is needed to preserve sexual function.

Autonomic Nervous System↗
PubMed1975

Comparative determination of total serum thyroxine. Radio-immunoassay and protein-binding assay.

The precision, accuracy, sensitivity and clinical results of a radio-immunological method for the determination of total serum thyroxine are compared with similar criteria of a competitive protein-binding assay. Application of both methods in the assay of thyroxine in 150 serum samples gave good agreement between the two techniques. The radio-immunoassay offers certain methodological advantages and is considerably less costly than thyroxine determinations in which commercially available kits are used.

Costs and Cost Analysis↗
PubMed1997

Cardiovascular adaptations to parabolic flight in rats: a radio-telemetry feasibility study.

This experiment was a feasibility study which consisted in investigating arterial blood pressure and heart rate to transient and repeated exposure to microgravity in eight unrestrained rats previously implanted with radio-telemetry transmitter. The aim was to perform such recordings throughout all the phases of a parabola during parabolic flights. This study revealed that it was possible to collect the radio-signal without any interference with electronic or magnetic environment. We observed in microgravity a significant reduction in heart rate (6%) and a significant increase in arterial blood pressure (7%). In conclusion, such a study seems to be feasible during longer exposure to microgravity (space flight) in order to study the cardiovascular adaptation in rat.

Adaptation, Physiological↗
PubMed1975

[A proposal to improve radioactive waste disposal following metabolic radio-iodine therapy].

After metabolic radio-iodine treatments of carcinomas of the thyroid, increased activities of I 131 are secreted from the patient's body by the renal route. The highly radioactive urine represents a serious danger of contamination for the nursing staff and third persons. The ideal conditions for the isolation of treated patients in a department disposing of a sewage disposal system of its own are not fulfilled at our hospital. Collection of radioactive urine of the patients for the purpose of annihilating radioactivity over several half-lifes of I 131 is extremely intricate. For this reason, we developed a filter system by means of which we were able to free the radioactive urine of the first five female patients treated from more than 99% of radioactivity. The contaminated locked filter patterns can be stored as "closed radio-sources" essentially more securely and space saving. The advantages of this system and their practical possibilities of use are discussed.

Female↗
PubMed2001

[Hematologic and cytochemical effects in specialists working with radiolocalization and radio navigation means].

Examination of workers servicing radio location, radio navigation and communication means proved electromagnetic radiofrequency waves to induce some peripheral blood changes: cytopenia, Hb decrease, lower RBC and WBC counts, increased RBC with basophilic granularity, WBC metabolism alteration (higher acid phosphatase and myeloperoxidase activity), disordered lymphocytes subunits (T-helpers, T-suppressors) ratio and T- and B-cells numbers.

Adult↗
PubMed1999

[Clinical observation on radio- or chemotherapy plus Traditional Chinese medicine in treating brain metastatic tumor].

OBJECTIVE: To observe the clinical efficacy of radio- or chemotherapy plus traditional Chinese medicine (TCM) by Syndrome Differentiation in treating brain metastatic tumor. METHODS: Forty-one patients were randomized into four groups: Group A treated with chemotherapy plus TCM, Group B with radiotherapy plus TCM, Group C with chemotherapy alone and Group D with radiotherapy alone. The efficacies of the four groups were compared. RESULTS: The short-term response rate, living quality, 1-, 2-, 3- and 4-year survival rate, median survival period and immunity of the Group A and B were significantly higher than those of the Group C and D (P < 0.05). CONCLUSION: Radio- or chemotherapy plus TCM by Syndrome Differentiation has the effect of tumor growth inhibition, survival period extension and living quality enhancement in treating brain metastases.

Adult↗