共查询到20条相似文献,搜索用时 31 毫秒
1.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1986,13(6):603-609
Several bifunctional radiopharmaceuticals (BR), molecules containing a neutral 99mTc-dithiosemicarbazone (DTS) structure as a chelating site, along with a functional amino group (primary tertiary and quaternary amino group) are tested for their chemical or biological functionalities as myocardial agents. Investigation of these amino compounds is carried out in vitro and in vivo. Mice (ddY) distribution studies show a high radioactivity distribution in heart with every tested derivative, but the highest heart to blood ratio of 2.92 (1h) is achieved with the quaternary amino DTS. Also, this derivative displays low lung uptake inducing a proper target/non-target ratio for myocardial agent. The role conveyed by the various amino containing side chain in the biodistribution and validity of DTS derivative as BR are discussed. 相似文献
2.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(2):215-226
A series of 99mTc-bis(aminoethanethiol)-fatty acid (99mTc-BAT-fatty acid) analogs were synthesized and evaluated as potential tracers of myocardial metabolism. The BAT-fatty acid precursors were prepared using a new synthetic route that avoids the use of strong reducing agents such as lithium aluminum hydride. Biodistribution studies of the no-carrier-added 99mTc-complexes were conducted in rats using [125I]IPPA as an internal standard. The myocardial uptake of the 99mTc-BAT-fatty acid analogs was significantly less than that of [125I]IPPA and indicates the 99mTc analogs are not suitable candidates for SPECT-based myocardial imaging studies. 相似文献
3.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1986,13(1):75-77
Cardiac glycosides are well known to exert a specific and powerful effect on myocardial tissue, and there is a possibility that this class of compound with a 99mTc radiolabel may behave as a superior myocardial imaging agent in comparison to 201T1 which is at present used clinically. Because of the extreme chemical complexity of cardiac glycosides a simpler aglycone, strophanthidin was selected as the pilot compound for preliminary labelling and in vivo distribution studies.Strophanthidin was converted to 19-thiosemicarbazone which nicely accomodated 99mTc to produce a pure radiopharmaceutical of high specific activity. The distribution pattern in animal models was studied which is in accordance with the metabolic studies performed earlier with the ligand itself. 相似文献
4.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(6):647-654
Availability of 123I of high radionuclidic purity has encouraged the development of 123I-based radiopharmaceuticals for the assessment of myocardial fatty acid metabolism, myocardial neuronal activity, and for receptor and antibody imaging. Advances in the chemistry of technetium have resulted in the development of novel agents for myocardial and cerebral perfusion and renal function studies. Monoclonal antibodies labeled with 99mTc show promise for imaging neoplastic lesions, myocardial infarcts, and thrombus localization. Recent developments in 123I and 99mTc agents for myocardial and brain imaging studies are discussed. 相似文献
5.
Kazuma Ogawa Katsuichi Ohtsuki Tomomi Shibata Miho Aoki Morio Nakayama Yoji Kitamura Masahiro Ono Masashi Ueda Tomoki Doue Masahisa Onoguchi Kazuhiro Shiba Akira Odani 《PloS one》2013,8(12)
99mTc-HYNIC-annexin A5 can be considered as a benchmark in the field of apoptosis imaging. However, 99mTc-HYNIC-annexin A5 has characteristics of high uptake and long retention in non-target tissues such as kidney and liver. To minimize this problem, we developed a novel 99mTc-labeled annexin A5 using a bis(hydroxamamide) derivative [C3(BHam)2] as a bifunctional chelating agent, and evaluated its usefulness as an imaging agent for detecting apoptosis. The amino group of C3(BHam)2 was converted to a maleimide group, and was coupled to thiol groups of annexin A5 pretreated with 2-iminothiolane. 99mTc labeling was performed by a ligand exchange reaction with 99mTc-glucoheptonate. Biodistribution experiments for both 99mTc-C3(BHam)2-annexin A5 and 99mTc-HYNIC-annexin A5 were performed in normal mice. In addition, in tumor-bearing mice, the relationship between the therapeutic effects of chemotherapy (5-FU) and the tumor accumulation of 99mTc-C3(BHam)2-annexin A5 just after the first treatment of 5-FU was evaluated. 99mTc-C3(BHam)2-annexin A5 was prepared with a radiochemical purity of over 95%. In biodistribution experiments, 99mTc-C3(BHam)2-annexin A5 had a much lower kidney accumulation of radioactivity than 99mTc-HYNIC-annexin A5. In the organs for metabolism, such as liver and kidney, radioactivity after the injection of 99mTc-HYNIC-annexin A5 was residual for a long time. On the other hand, radioactivity after the injection of 99mTc-C3(BHam)2-annexin A5 gradually decreased. In therapeutic experiments, tumor growth in the mice treated with 5-FU was significantly inhibited. Accumulation of 99mTc-C3(BHam)2-annexin A5 in tumors significantly increased after 5-FU treatment. The accumulation of radioactivity in tumor correlated positively with the counts of TUNEL-positive cells. These findings suggest that 99mTc-C3(BHam)2-annexin A5 may contribute to the efficient detection of apoptotic tumor response after chemotherapy. 相似文献
6.
Cristina Bolzati Davide Carta Valentina Gandin Cristina Marzano Nicolò Morellato Nicola Salvarese Mariangela Cantore Nicola Antonio Colabufo 《Journal of biological inorganic chemistry》2013,18(5):523-538
[99mTc(N)(DBODC)(PNP5)]+ [DBODC is bis(N-ethoxyethyl)dithiocarbamato; PNP5 is bis(dimethoxypropylphosphinoethyl)ethoxyethylamine], abbreviated as 99mTc(N)-DBODC(5), is a lipophilic cationic mixed compound investigated as a myocardial imaging agent. The findings that this tracer accumulates in mitochondrial structures through a mechanism mediated by the negative mitochondrial membrane potential and that the rapid efflux of 99mTc(N)-DBODC(5) from nontarget tissues seems to be associated with the multidrug resistance (MDR) P-glycoprotein (P-gp) transport function open up the possibility to extend its clinical applications to tumor imaging and noninvasive MDR studies. The rate of uptake at 4 and 37 °C of 99mTc(N)-DBODC(5) was evaluated in vitro in selected human cancer cell lines and in the corresponding sublines before and after P-gp and/or MDR-associated protein (MRP) modulator/inhibitor treatment using 99mTc-sestamibi as a reference. The results indicated that (1) the uptake of both 99mTc(N)-DBODC(5) and 99mTc-sestamibi is correlated to metabolic activity of the cells and (2) the cellular accumulation is connected to the level of P-gp/MRP expression; in fact, an enhancement of uptake in resistant cells was observed after treatment with opportune MDR inhibitor/modulator, indicating that the selective blockade of P-gp/MRP prevented efflux of the tracers. This study provides a preliminary indication of the applicability of 99mTc(N)-DBODC(5) in tumor imaging and in detecting P-gp/MRP-mediated drug resistance in human cancer. In addition, the possibility to control the hydrophobicity and pharmacological activity of this heterocomplex through the variation of the substituents on the ligands backbone without affecting the P2S2 coordinating sphere makes 99mTc(N)-DBODC(5) a suitable scaffold for the preparation of a molecular probe for single photon emission computed tomography of MDR. 相似文献
7.
Renal scintigraphy is an imaging method that uses small amount of radioactive materials called radiotracers, a Gamma camera and a computer to evaluate kidney functions and its anatomy. The present work reports the comparison of the relative renal functions (RRF) calculated with technetium-99m dimercaptosuccinic acid (99mTc‑DMSA) and technetium-99m diethylenetriaminepentaacetic acid (99mTc‑DTPA) for kidney patients of ages between 5 months and 71 years. A total of 50 patients including 29 male and 21 female has been selected and studied for renography. The mean RRFs have been found to be 52.68 ± 23.63% and 47.32 ± 23.63% respectively for the left and right kidneys with 99mTc-DMSA measurement. With 99mTc-DTPA the values are 52.74 ± 23.54% and 47.26 ± 23.54% for the same. In bivariate correlation analysis, a significant positive correlation (r = 0.996, P < .001) has been found between the RRFs calculated with the two methods. Following the patients’ diagnosis, in ANOVA test, no difference has been found between the RRFs calculated for the left and right kidneys. In Bland-Altman plots, the mean difference between the two methods has been found to be 0.1 and the correlation limit lies between −4.3 and 4.2. According to the result obtained in the present work, both the 99mTc-DMSA and 99mTc-DTPA scanning methods provide almost the same RRF values. It is, therefore, always not necessary to calculate the RRFs with both the methods. This study suggests that 99mTc-DMSA may be the primary choice for the evaluation of RRF, but if the glomerular filtration rate (GFR) and renogram curve are required, 99mTc-DTPA can be the obvious selection. 相似文献
8.
R.H.J.A. Slart J.J. Bax E.E. van der Wall D.J. van Veldhuisen P.L. Jager R.A. Dierckx 《Netherlands heart journal》2005,13(11):408-415
An important aspect of the diagnostic and prognostic work-up of patients with ischaemic cardiomyopathy is the assessment of myocardial viability. Patients with left ventricular dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischaemia but at the same time benefit most from revascularisation. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy (SPECT), whether using 201thallium, 99mTc-sestamibi, or 99mTc- tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management.Metabolic and perfusion imaging with positron emission tomography radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularisation. New techniques in the nuclear cardiology field, such as attenuation corrected SPECT, dual isotope simultaneous acquisition (DISA) SPECT and gated FDG PET are promising and will further improve the detection of myocardial viability. Also the combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. 相似文献
9.
Postoperative bronchopleural fistulas may be demonstrated quickly and safely by inhalation of nebulized 99mTc-albumin, or other similar radiopharmaceuticals. Posterior scintiphotographs of the distribution of the inhaled radioactive material are obtained with the gammaray scintillation camera while the patient is in the upright and lateral decubitus positions. The observation of radioactive material in the pleural cavity indicates an abnormal communication.The radiation-absorbed doses for lung and total body are well within acceptable limits when a 99mTc tag is used. About 15 minutes are required to complete this relatively safe diagnostic test. 相似文献
10.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(5):499-502
To elucidate a factor required for tumor-imaging 99mTc-labeled radiopharmaceuticals, in vivo behaviors of 99mTc-l-cysteine (99mTc-Cys) and 99mTc-2-mercaptoethylamine (99mTc-ME) were compared with that of 99mTc-dl-homocysteine (99mTc-Hcy) which had been found to accumulate in several experimental tumors. When these three complexes were intravenously injected into mice bearing Ehrlich solid tumor, their tumor affinity was found to depend on their binding ability to serum albumin; 99mTc-Hcy, the albumin-binding ability of which was highest of the three, was the most tumor-tropic. When the albumin-bound complexes of these three were injected, their tumor distributions were enlarged. These results suggest the importance of serum albumin in serving as a carrier for the transport of 99mTc-Hcy-related compounds to tumor tissue. 相似文献
11.
Masahiro Ono Ryoichi Ikeoka Hiroyuki Watanabe Hiroyuki Kimura Takeshi Fuchigami Mamoru Haratake Hideo Saji Morio Nakayama 《Bioorganic & medicinal chemistry letters》2010,20(19):5743-5748
Two 99mTc/Re complexes based on flavone and aurone were tested as potential probes for imaging β-amyloid plaques using single photon emission computed tomography. Both 99mTc-labeled derivatives showed higher affinity for Aβ(1–42) aggregates than did 99mTc-BAT. In sections of brain tissue from an animal model of AD, the Re-flavone derivative 9 and Re-aurone derivative 19 intensely stained β-amyloid plaques. In biodistribution experiments using normal mice, 99mTc-labeled flavone and aurone displayed similar radioactivity pharmacokinetics. With additional modifications to improve their brain uptake, 99mTc complexes based on the flavone or aurone scaffold may serve as probes for imaging cerebral β-amyloid plaques. 相似文献
12.
99Tcm-pertechnetate is concentrated in the thyroid in the same way as iodide but it does not become organically bound. The uptake of 99Tcm is a measure of the thyroid trap, and this measurement is satisfactory as a routine test in the diagnosis of thyrotoxicosis. The reproducibility of the method is such that suppression tests can be carried out when necessary even when uptake is within the normal range of 0·4-3%. 99Tcm gives a low radiation dose to the thyroid and has certain other advantages over radioactive isotopes of iodine for early thyroid uptake measurements. It is particularly suitable when serial tests of thyroid function are required during treatment with an antithyroid drug. 相似文献
13.
Autoradiographic model experiments with 67Ga and 99mTc 总被引:1,自引:0,他引:1
Summary In order to evaluate the feasibility to localize correctly 67Ga citrate and 99mTc pertechnetate in tissues, the resolution of these radioactive compounds were measured in a model system using four different autoradiographic techniques, wet as well as dry.Wet autoradiographic techniques gave an almost complete loss of 67Ga. In deparaffinized sections of fixed and paraffin-embedded tissue the remaining 67Ga, which was probably bound to proteins, gave a resolution of 2.6 . 99mTc was either completely lost in wet techniques or the procedure could not be performed at all because of the very short half life of 99mTc.The resolution of 67Ga in a dry autoradiographic technique (according to Stumpf) was 6.9 and the resolution of 99mTc 22.6 .The technique in which frozen sections are thawed on dry film and consequently dryed, gave slightly better resolutions than the dry technique (according to Stumpf) with 67Ga as well as 99mTc.It is concluded that for the histological localization of 67Ga and 99mTc a dry technique is required. However, the use of a wet technique can be considered, provided a loss of the radioisotope is acceptable and the procedure is controlled by a dry technique. 相似文献
14.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1986,13(3):289-293
A series of alkyl- and halogen-substituted derivatives of ethylenediamine di[o-hydroxyphenylacetic acid] (EDDHA) and N,N′-bis[2-hydroxybenzyl]ethylenediamine N,N′-diacetic acid (HBED) were complexed with 99mTc and their biodistribution was determined in rats.All complexes displayed substantial hepatobiliary excretion; of each series, 99mTc-Br-EDDHA and 99mTc-di-Cl-HBED had the maximum amount in the gastrointestinal tract.Scintigraphic studies of 99mTc-Cl-EDDHA in dogs revealed prompt imaging of the liver followed by imaging of the gall bladder as the complex was excreted into the bile. 相似文献
15.
Bisphosphonates are widely used for treatment of osteoporosis. Recently, they have been reported to be effective anticancer agents. In this work, we designed some substituted phenyl (azanediyl) bis (methylene phosphonic acid) to be tested for their anticancer effect. Both molecular docking and dynamics studies were used to select the top ranked highly scored compounds. The selected hits showed potential in vitro anticancer effect against some cell lines. Biodistribution pattern and gamma scintigraphy were conducted to the most effective derivative (BMBP) after radiolabeling with 99mTc. Results of biodistribution and scintigraphic imaging of 99mTc-BMBP in tumor bearing mice showed a notable tumor affinity, and confirmed the targeting affinity of BMBP to the tumor tissues. As a conclusion, BMBP could act as potential anticancer agent and imaging probe. 相似文献
16.
Sweety Mittal Mohini Bhadwal Sudipta Chakraborty H.D. Sarma Sharmila Banerjee M.R.A. Pillai 《Bioorganic & medicinal chemistry letters》2013,23(6):1808-1812
Radiolabeled Arg-Gly-Asp (RGD) peptides are promising agents for non invasive imaging of αvβ3 expression in malignant tumors. The integrin αvβ3 binding affinity and consequent tumor uptake could be improved when a dimeric RGD peptide is used as the targeting moiety instead of a monomer. Towards this, a novel approach was envisaged to synthesize a 99mTc labeled dimeric RGD derivative using a RGD monomer and [99mTcN]+2 intermediate. The dithiocarbamate derivative of cyclic RGD peptide G3-c(RGDfK) (G3 = Gly-Gly-Gly, f = Phe, K = Lys) was synthesized and radiolabeled with [99mTcN]+2 intermediate to form the 99mTcN-[G3-c(RGDfK)]2 complex in high yield (~98%). Biodistribution studies carried out in C57/BL6 mice bearing melanoma tumors showed good tumor uptake [4.61 ± 0.04% IA/g at 30 min post-injection] with fast clearance of the activity from non-target organs/tissue. Scintigraphic imaging studies showed visible accumulation of activity in the tumor with appreciable target to background ratio. 相似文献
17.
Vijay Sharma Jothilingam Sivapackiam Scott E. Harpstrite Julie L. Prior Hannah Gu Nigam P. Rath David Piwnica-Worms 《PloS one》2014,9(10)
Lipophilic cationic technetium-99m-complexes are widely used for myocardial perfusion imaging (MPI). However, inherent uncertainties in the supply chain of molybdenum-99, the parent isotope required for manufacturing 99Mo/99mTc generators, intensifies the need for discovery of novel MPI agents incorporating alternative radionuclides. Recently, germanium/gallium (Ge/Ga) generators capable of producing high quality 68Ga, an isotope with excellent emission characteristics for clinical PET imaging, have emerged. Herein, we report a novel 68Ga-complex identified through mechanism-based cell screening that holds promise as a generator-produced radiopharmaceutical for PET MPI. 相似文献
18.
Waldemar G. Johanson Jr. Marina G. Kennedy Frederick J. Bonte 《Applied microbiology》1973,25(4):592-594
The suitability of technetium (99mTc), a gamma emitter, for labeling of Diplococcus pneumoniae in studies of lung bacterial clearance was examined. A killed bacterial slurry with high specific activity was obtained with a ferric ascorbate reducing system. Approximately 5.5% of radioactive counts dissociated from labeled bacteria in 6 h. Rats were exposed to a uniformly mixed aerosol of untagged, viable pneumococci and killed, 99mTc-tagged pneumococci. The aerodynamic behavior of labeled and unlabeled pneumococci was similar. Viable bacterial counts and radioactive counts were determined in lung homogenates at intervals following exposure, and rates of bacterial killing and disappearance of radioactive counts were plotted. Radioactive counts did not increase in the liver during the period of observation, suggesting that the decrease in lung radioactivity represents mucociliary clearance and not release of isotope to the systemic circulation. The use of 99mTc for bacterial labeling provides advantages of technical simplicity and personnel safety compared to the use of beta-emitting isotopes. 相似文献
19.
Joerg Kotzerke Robert Punzet Roswitha Runge Sandra Ferl Liane Oehme Gerd Wunderlich Robert Freudenberg 《PloS one》2014,9(8)
99mTc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, 99mTc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs) or double-strand breaks (DSBs); the resulting DNA fragments can be separated by gel electrophoresis and quantified by fluorescent staining. This study aimed to compare the plasmid DNA damage potential of a 99mTc-labeled HYNIC-DAPI compound with that of 99mTc pertechnetate (99mTcO4
−). pUC19 plasmid DNA was irradiated for 2 or 24 hours. Direct and radical-induced DNA damage were evaluated in the presence or absence of the radical scavenger DMSO. For both compounds, an increase in applied activity enhanced plasmid DNA damage, which was evidenced by an increase in the open circular and linear DNA fractions and a reduction in the supercoiled DNA fraction. The number of SSBs elicited by 99mTc-HYNIC-DAPI (1.03) was twice that caused by 99mTcO4
− (0.51), and the number of DSBs increased fivefold in the 99mTc-HYNIC-DAPI-treated sample compared with the 99mTcO4
− treated sample (0.02 to 0.10). In the presence of DMSO, the numbers of SSBs and DSBs decreased to 0.03 and 0.00, respectively, in the 99mTcO4
– treated samples, whereas the numbers of SSBs and DSBs were slightly reduced to 0.95 and 0.06, respectively, in the 99mTc-HYNIC-DAPI-treated samples. These results indicated that 99mTc-HYNIC-DAPI induced SSBs and DSBs via a direct interaction of the 99mTc-labeled compound with DNA. In contrast to these results, 99mTcO4
− induced SSBs via radical formation, and DSBs were formed by two nearby SSBs. The biological effectiveness of 99mTc-HYNIC-DAPI increased by approximately 4-fold in terms of inducing SSBs and by approximately 10-fold in terms of inducing DSBs. 相似文献
20.
GRAZYNA SOBAL ERNST JOHANNES MENZEL HELMUT SINZINGER 《Journal of receptor and signal transduction research》2013,33(5-6):693-707
Native (n), glycated (g), and glycoxidated (go) low-density lipoproteins (LDL) were labeled with 125I or 99mTc, and the labeling efficiency and binding were assessed for potential use of these LDL compounds in imaging analysis of atherosclerotic lesions (PPAR-γ receptors) by determining the number of specific receptors for nLDL, gLDL or goLDL on human microvascular endothelial cells as well as the KD s using either 125I-or 99mTc-labeled LDLs. The specific activity of labeled gLDL and goLDL was much higher (for goLDL 20 times higher) than that of nLDL. Gel filtration of labeled LDLs revealed, however, that 99mTc–g/goLDL is significantly degraded by the labeling reaction. No fragmentation was observed for 99mTc-nLDL and all the 125I-labeled LDL forms. Binding studies using both 125I-and 99mTc-nLDL indicated a weak binding affinity (KD 10? 7mol/L) to human microvascular endothelial cells. The binding affinity of 125I-g/goLDL to these cells was significantly higher (KD 10? 9mol/L) and could be increased further by preactivation of the endothelial cells using TNFα. Incubation with 99mTc-goLDL, however, did not result in specific binding of the ligand, possibly as a consequence of the fragmentation of the lipoprotein during the labeling. Scatchard transformation of the binding data with 99mTc-gLDL revealed the presence of only a few binding sites. This was in contrast to the results obtained with 125I-labeled gLDL, which revealed a much higher membrane density of scavenger receptors for this ligand. We conclude that for in vitro binding studies as well as for potential in vivo imaging, only 125I-labeled goLDL should be used, whereas nLDL may be applied as 125I-or 99mTc-labeled ligand. 相似文献