Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RADIOACTIVITY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources
PubMed2000

First non-radioactive assay for in vitro screening of histone deacetylase inhibitors.

Inhibitors of histone deacetylase (HD) are of great potential as new drugs due to their ability to influence transcriptional regulation and to induce apoptosis or differentiation in cancer cells. So far only radioactive enzyme activity assays or in-vivo assays with subsequent electrophoresis and immunoblotting existed to study the activity of HD and potential inhibitors. To aid in the search of new inhibitors, a non-radioactive screening assay was sought and we have previously succeeded in establishing this for the first time. The assay uses an aminocoumarin derivative of an omega-acetylated lysine as substrate for the enzyme. Here we report full experimental details, the evaluation of other potential substrates, and comparative analysis of various inhibitors. This advantageous method should have an impact on further developments in the field.

Aminocaproic Acid↗
PubMed2001

Study of quantitative oral radioactivity in salivary gland scintigraphy and determination of the clinical stage of Sjögren's syndrome.

UNLABELLED: In this study, the oral radioactivity seen in salivary gland scintigraphy, which was established entirely on the basis of radioactive saliva secreted by the parotid and submandibular glands, was evaluated quantitatively in healthy volunteers and in patients with Sjögren's syndrome. METHODS: Salivary gland scintigraphy and labial biopsy were performed on 70 patients with Sjögren's syndrome. After intravenous administration of 99mTc-sodium pertechnetate, dynamic scintigraphy was performed and time-activity curves for the oral cavity and four major salivary glands were generated. Lemon juice stimulation was delivered at 40 min. The prestimulatory oral activity index, poststimulatory oral activity index, and time interval between the vascular perfusion peak and the prestimulated maximum oral activity point were calculated to quantify the oral activity. Other glandular functional parameters-namely, maximum accumulation (MA), maximum secretion, secretion velocity, time at maximum count, time interval from stimulation to minimum count, and uptake ratio (UR) of the parotid and submandibular glands-were also calculated. Salivary gland scintigraphy was also performed on 21 healthy subjects with no evidence of salivary gland malfunction. RESULTS: Histopathologic grade 1 or 2 was found in 29 patients and grade 3 or 4 was found in 41 patients, and they were regarded as being in the early and advanced stages of Sjögren's syndrome, respectively. After overall analysis, all of the oral activity indices and the MA and UR of the submandibular gland clearly decreased as clinical severity progressed, and statistically significant differences were observed. CONCLUSION: New oral activity indices correlated with the stage of Sjögren's syndrome, and these quantitative oral indices together with certain glandular parameters (mainly MA and UR of the submandibular gland) were found to be sensitive enough to distinguish the disease severity of Sjögren's syndrome.

Biopsy↗
PubMed2001

3D localization of implanted radioactive sources in the prostate using trans-urethral ultrasound.

Prostate cancer is the most common cancer diagnosed in men in the United States. Many techniques have been developed to diagnose and treat prostate cancer. 3D Trans-Urethral Ultrasound (TUUS) is a new technique for the diagnosis and treatment of prostate disease. This research focuses on the potential of TUUS for therapy-guidance during and after transperineal interstitial permanent prostate brachytherapy (TIPPB). Computed tomography (CT) is currently used to determine the source locations and the effective radiation dose distribution throughout the tissue after the completion of the procedure. TUUS may be a viable alternative to CT for determining source locations within the prostate. Placement of the TUUS catheter into the urethra provides excellent 2D images of the prostate. In addition, the catheter can be used to acquire 3D volumetric data for 3D analysis of the prostate, associated tissue, and radioactive sources. Initial work on source localization was conducted on an ultrasound-equivalent prostate phantom. Cylindrical dummy radiation sources with diameter of .8 mm and length of 4.5 mm were placed into the prostate phantom for assessment with TUUS. The TUUS imaging device is a 10 fr catheter with a linear array of ultrasonic crystals at one end. The ultrasound catheter operates at 10 MHz and is controlled by the Acuson Sequoia ultrasound workstation. The catheter was placed in the phantom urethra and 3D scans were acquired. A corresponding CT was acquired for comparative purposes. Segmentation of the prostate capsule was done semi-automatically. Dummy radiation seed segmentation was conducted manually. Additional processing was necessary to account for image artifact and correctly reconstruct the seeds. The prostate shell and radioactive source reconstructions provide an excellent 3D representation. Comparison to the CT data suggests that the TUUS data provided: 1) greater resolution and 2) better soft tissue differentiation. The reconstructed sources were measured and corresponded to the physical dimensions of those placed in the phantoms. The method is now being evaluated on cadavers and patients.

Brachytherapy↗
PubMed1975

Localization of radioactive lead in ocular and skin melanoma.

The ability of radioactive lead to localize melanomas was studied. The Greene melanoma in the Syrian Golden hamster served as a model for both skin and ocular melanoma. The affinity of heavy metals for neoplasms has been studied but previous reports have been inconsistent as to tumor specificity. For this investigation the radioactive lead (203-Pb,) was studied as the chemical complex 203-Pb-Tris. Significant tumor:nontumor ratios were found in ocular melanoma and the concentration in the lens was minimal. The ratio of per cent uptake per gram of tumor: per cent uptake per gram in control tissue with skin melanoma was 9.4 at 24 hours and for the eye melanoma the ratio was 26.3 at 24 hours. The affinity of 203-Pb-Tris for melanomas appears to be as promising as other compounds presently being evaluated for ocular scintigraphy, namely, labeled quinoline analogs. Therefore, further preclinical evaluation is warranted.

Animals↗
PubMed1975

[Analog computer analysis of radioactivity kinetics in man following oral administration of tilidine HCl-14C].

Models for studying the absorption and elimination kinetics of 14-C labelled DL-Ethyl-trans-2-dimethylamino-1-phenyl-cyclohex-3-ene-trans-1-carboxylate-hydrochloride (Tilidine - HCl, Valoron) are developed, based on the concentration vs. time of radioactivity in the plasma following a single oral administration in man. For this purpose, the average concentration values in the plasma of 3 healthy adults, as given by Vollmer and Poisson [12] were employed. 1. Two three-compartment-models were developed which simulate with sufficient accuracy the 14-C-Valoron concentration curve in the plasma. 2. Computer analysis enables one to determine the distribution of 14-C-Valoron among the intra- and extravasal compartments and the half life for absorption t1/2 equals 0.57 h, for transport from plasma into the extravasal compartment t1/2 equals 3.31 h, for resorption t1/2 equals 4.11 h, for elimination with feces t1/2 equals 29.5 h and for elimination in urine t1/2 equals 8.75 h. 3. The use of two different models allows one to draw conclusions concerning the participation of parenchymatous organs in storage and elimination. 4. The probable radioactivity curve is calculated for repeated oral application of 14-C-Valoron in 8 hours intervals.

Administration, Oral↗
PubMed1975

Continuous monitoring of radioactivity of effluent from a high-speed amino acid analyzer, with a new system of sample segmentation.

Radioactivity in the effluents from high-speed liquid chromatographic analyzers was continuously measured by use of a new sample segmentation system. To achieve highest counting efficiency, the column effluents were mixed with scintillation fluid carrying small segments of semisolid, resillient spacer. After passing through a mixer, the mixture was passed through a hollow-tube flow cell mounted in a liquid scintillation spectrometer. Because the added spacer acts like a continuous series of pistons, it unifies flow rate at center and walls of the conduit and so decreases sample carryover. This system was applied to measurement of radioactivity in the effluent of a high-speed amino acid analyzer, in which some amino acids emerge at 30-s intervals. The resulting profiles were as well resolved as were the ninhydrin-color profiles. Counting efficiencies for tritium and carbon- 14 were comparable to those obtained by static counting in vials.

Amino Acids↗
PubMed1975

Metabolism of lithocholate in healthy man. III. Plasma disappearance of radioactivity after intravenous injection of labeled lithocholate and its derivatives.

The plasma disappearance of intravenously injected radiolabeled lithocholate, lithocholylglycine, and their respective 3alpha-sulfates was defined in healthy subjects. Binding of these bile acids to serum protein in vitro was measured by ultrafiltration. Lithocholate and lithocholylglycine rapidly disappeared from plasma (t1/2 less than 3 min), showing a behavior similar to that of the other major primary bile acids present in man. However, after 15 min, when 99% of the radioactivity had been cleared, the disappearance curve flattened, and chromatography suggested that the chemical form of circulating radioactivity had become sulfolithocholylglycine, the end product of hepatic metabolism of lithocholate in man. Injected sulfolithocholate and sulfolithocholylglycine were cleared about one-fourth as rapidly. Lithocholate and its derivatives were tightly bound to serum proteins (87 to 99%); for a given steroid moiety and mode of conjugation, binding was altered slightly by sulfation, but all sulfated derivatives were tightly bound (greater than 95%) to serum protein. The results indicate that lithocholate, which enters the plasma compartment, whether unconjugated, conjugated, or conjugated and sulfated, will be protein-bound but nonetheless will be rapidly cleared from plasma.

Adult↗
PubMed1999

Dr. Nobuo Yamada's whole life, dead due to his radioactive studies at the Radium Institute (Part 2): in celebration of the 100-year anniversary of the discovering radium, 1898-1998.

On the occasion of the 100th anniversary of the discovery of radium by M. & Mme. Curie, commemorative lecture meetings were held in Japan in 1998 as follows. 1) The 42nd Symposium on Radiochemistry was held in Sendai on September 18. Dr. M. Sakanoue, Professor Emeritus Kanazawa University, presented a commemorative lecture entitled "Collaborative Research done by Irene Curie and Nobuo Yamada." He explained an outline of the studies on the measurement of long-range particles emitted by various radioactive substances such as polonium, radium and thorium. In addition to his lecture, I made a comment on the curriculum vitae of Dr. N. Yamada. 2) On October 24, another commemorative lecture meeting was held in Tokyo. At this meeting, Helene Langevin-Joliot, daughter of Irene Joliot-Curie presented a lecture on whole life of M. & Mme. Curie as a guest speaker. After meeting ended, I had the opportunity to talk with her personally. I have been investigating references describing the cause of death of Dr. Nobuo Yamada and found the following. The inadequacy of an apparatus for protection from radioactivity in the 1920s and reference to the death of Dr. Nobuo Yamada specifically were described in an article written by Dr. S. Iimori and in a nonograph written by Dr. M. Furukawa. The tragedy of scientists who suffered severe radiation syndrome during experiments at the Radium Institute was described in a biography of Marie Curie written by Susan Quinn.

Academies and Institutes↗
PubMed2002

[Estimation by static SPECT of the radioactivity remaining after the first dose of two-fractionated 123I-IMP administration: the rate of increase in cerebral blood flow by ARG and the rate of increase in SPECT count].

We devised a method for estimating the radioactivity remaining after the first dose of two-fractionated tracer administration in the acetazolamide activation study in a facility where static SPECT is used for 123I-IMP cerebral blood flow scintigraphy. Three static SPECT scans were obtained over 9-min periods beginning 10 min after the first 123I-IMP administration, to estimate the remaining activity until after 60 min. In 72 patients at rest, 9-min SPECT was performed 6 times, and 11 different patterns of distribution and the fitting coefficient were obtained. The correlation between the actual measurement and the estimation at the mid scan time of 59.5 min could be expressed as y = 1.0064x - 1.9656, and r = 0.9972 (p < 0.01). The correlation between the first and second measurements of cerebral blood flow in 5 patients given two-fractionated administration at rest could be expressed as y = 0.9919x + 0.2978, r = 0.9976 (p < 0.01), indicating the usefulness of this method for estimating the radioactivity remaining after the first dose. In 57 patients with unilateral cerebrovascular disease, the cerebral blood flow on the unaffected side increased by 55.4 +/- 13.1%, whereas the blood flow in 19 regions exhibiting severe stenosis on the affected side was increased only 1.4 +/- 10.5% (p < 0.01). In addition, the correlation between the rate of increase in cerebral blood flow and the rate of increase in SPECT count could be expressed as y = 0.8415x + 0.291, and r = 0.9979 (p < 0.01). Thus, with this method, the cerebral hemodynamic reserve test using the rate of increase in cerebral blood flow by the ARG method or the rate of increase in SPECT count can be completed within a day while maintaining the image quality of static SPECT.

Adult↗
PubMed1998

[Detection of Cryptosporidium parvum in fecal samples using polymerase chain reaction combined with non-radioactive labeled DNA probe hybridization].

AIM: To develop a non-radioactive labeled probe hybridization technique for the detection of the PCR products of Cryptosporidium parvum DNA in fecal samples and evaluate its specificity and sensitivity. METHODS: DNA of C. parvum was prepared directly from C. parvum infected patients' fecal samples by the direct lysis method, and was used as the template for PCR. A pair of oligonucleotide primers was synthesized and used to prime the amplification of a 452 bp target fragment specific for C. parvum. The PCR products were directly spotted or transferred on to NC membrane. Then, the PCR products were hybridized with the biotin-labeled oligonucleotide probe and coloured by a substrate BCIP (5-bromo-4-chloro-3-indolyl-phosphate). RESULTS: Positive hybridized signals were only showed in the PCR products of DNA extracted from the fecal samples of C. parvum infected patients, but not in the other DNA of P. yoelii, L. donovani, G. lamblia, C. albicans, E. coli and human leucocytes. The lowest detectable amount of both dot or Southern blotting hybridization was 0.1 pg of C. parvum DNA. CONCLUSION: A combination of PCR and non-radioactive biotin-labeled probe hybridization assay is highly sensitive, specific, and relatively simple and safe for the detection of the PCR products of C. parvum in fecal samples.

Animals↗
PubMed2002

Calculating the absorbed dose from radioactive patients: the line-source versus point-source model.

UNLABELLED: In calculations of absorbed doses from radioactive patients, the activity distribution in such patients is generally assumed to be an unattenuated point source and the dose to exposed individuals at a given distance is therefore calculated using the inverse square law. In many nuclear medicine patients, the activity distribution is widely dispersed and does not simulate a point source. In these cases, a line-source model is proposed to more accurately reflect this extended activity distribution. METHODS: Calculations of dose rate per unit activity were performed for a point source and for line sources of lengths of 20, 50, 70, 100, and 174 cm, and the ratios of line-source values to point-source values were calculated. In addition, radionuclide-independent conversion factors, to convert exposure rate constants to dose rates per unit activity, for these line-source lengths at various distances were determined. RESULTS: The calculated values, substantiated by published data, indicate that the inverse square law approximation is not valid for a line source until a certain distance is reached, dependent on the length of the line source. For the 20-, 50-, 70-, 100-, and 174-cm line sources, the dose rate values estimated by the inverse square law approximation are within approximately 10% of the values estimated using the line-source approach at distances of 20, 45, 60, 85, and 145 cm, respectively. At closer distances, use of the point-source model for a patient with an extended activity distribution will overestimate the radiation absorbed dose to exposed individuals, sometimes by a very significant amount. CONCLUSION: The line-source model is a more realistic and practical approach than the traditional point-source model for determining the dose to individuals exposed to radioactive patients with widespread activity distributions.

Environmental Exposure↗
PubMed1975

[Study of anemia in spirochetosis of poultry by means of radioactive iron].

Radioactive iron was used to follow up some hematologic indices in birds infected with irradiated spirochetes of the Borrelia anderina species. Used were a total of 90 cockerels, aged two months, divided into three groups. Ist group - cockerels inoculated with spirochetes that had been gamma-irradiated at the rate of 40000 R; IInd group-cockerels inoculated with untreated spirochetes; and IIIrd group - normal cockerels. The infective material consisted of strain Rouen spirochetes of the Pamoukchii serotype. Radiometric studies were also carried out to find out to what extent radioactive iron was incorporated in the erythrocytes and was deposited in the liver, spleen, and marrow of the investigated birds. Classical methods of investigation were employed to determine the erythrocyte, leukocyte, and thrombocyte counts, the hemoglobin content (after Sahli) as well as the erythrocyte pack after the method of Todorov. It was found that the inoculation of gamma-treated spirochetes led to sub-clinical changes in the hemopoiesis of the cockerels. Such changes, however, were negligible and were rapidly overcome by the birds. So they could successively be referred to in the specific immunoprophylaxis of spirochetosis. 59FeCl3 can be successfully applied in the study of anemia in birds caused by sbirochetosis.

Anemia↗
PubMed1975

Deposition and clearance of inhaled fibrous minerals in the rat. Studies using radioactive tracer techniques.

The deposition and clearance of various fibrous materials have been investigated in the rat using radioactive tracer techniques. The materials used include the U.I.C.C. standard reference samples and synthetic mineral fibres. Measurements of total and alveolar deposition were correlated with the AMADs of the radioactive dust samples which ranged from 1 to 2.5 micron. Although total deposition increases steeply over this range, alveolar deposition is relatively constant only increasing from about 10 to 13%. Alveolar deposition is lower than in man, but the maximum in alveolar deposition appears to occur at a similar aerodynamic diameter. Half times of alveolar clearance, measured over a period of several months following single inhalation exposures, were in the range 60-90 days and no significant difference was observed between amphibole and chrysotile asbestos. Autoradiographs of lung sections indicate that alveolar deposition is relatively uniform and occurs right up to the periphery of the lung. Over a period of several months the uniform distribution alters to one in which fibres accumulate in foci which are mainly subpleural. These foci act as centres for the development of nodular fibrosis.

Animals↗
PubMed2000

[The development of a new version of multifunctional radioactive nuclide diagnostic instrument].

A new kind of multifunctional radioactive nuclide diagnostic instrument is described here, which can make noninvasive measurements on the metabolic functions of five most important inner organs which are kidney, liver, heart and thyroid. The design of the hardware and software of the new instrument embodies many advanced advantages such as multifunctional integration, high accuracy and high reliability, computer controlled, automatic data-processing, easy to use and manage, and so on. Applications show that this is an advanced and efficient radioactive medical diagnostic instrument.

Equipment Design↗
PubMedDate not supplied

Confirmation of dialysate leakage by intraperitoneal administration of radioactive colloid.

A 29-year-old man who had been on continuous ambulatory peritoneal dialysis (CAPD) was admitted to our hospital because of pleural effusion. Radioactive colloid studies with intraperitoneal administration revealed a pleuroperitoneal communication. After pleurodesis by the administration of fibrin glue and antiplasmin into the thoracic cavity, the pleural effusion did not reaccumulate and there was no evidence of pleuroperitoneal communication by radioactive colloid study.

Adult↗
PubMedDate not supplied

Interpretation of atmospheric pollution phenomena in relationship with the vertical atmospheric remixing by means of natural radioactivity measurements (radon) of particulate matter.

In this paper the results of seasonal monitoring campaign for primary (benzene and carbon monoxide) and secondary (nitrogen dioxide and ozone) pollutants and for the natural radioactivity of the particulate matter in the urban area of Rome, are reported to investigate acute atmospheric pollution episodes. Comparing the daily concentration trends of primary and secondary pollutants with those of the natural radioactivity, considered as index of the vertical diffusion in the low boundary layer, it has been evidenced that the acute pollution episodes in Rome occur in the winter period for the high atmospheric stability (primary pollution) and in the summer period for the strong diurnal atmospheric remixing (secondary pollution).

Air Movements↗
PubMed1954

Therapeutic studies in hyperthyroidism; use of radioactive iodine.

Of 112 patients with hyperthyroidism who were treated with radioactive iodine, 110 were relieved of the disease. Nine had transient hypothyroidism. Twelve had permanent hypothyroidism. No other adverse effects that could be attributed to radioactive iodine were noted.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1954

Use of radioactive chromic phosphate in pleural effusions.

Radioactive chromic phosphate was chosen in place of radioactive gold for control of pleural effusions and ascites. The chromic phosphate has no gamma radiation to complicate the health physics. Its 14.3 day half-life in contrast to that of 2.69 days for gold makes possible the use of much smaller total dosages. There were no untoward results from the use of this material. The results in the series here reported upon compare favorably with those reported for gold(198).

Ascites↗