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Serum sulfhydryl levels in rheumatoid patients treated with haloperidol.

Six months of haloperidol treatment significantly increased the serum sulfhydryl (SH) levels in all 12 rheumatoid arthritis (RA) patients studied and significantly decreased the PIP joints technetium index (Tc-index), erythrocyte sedimentation rate (ESR) and joint count. These findings suggest a specific antirheumatic activity of haloperidol in the RA patients.

Adult↗

New tacrine-hydrazinonicotinamide hybrids as acetylcholinesterase inhibitors of potential interest for the early diagnostics of Alzheimer's disease.

The syntheses and the preliminary results of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by an affinity series of tacrine-hydrazinonicotinamide hybrids are described. These molecules were prepared by condensation of tacrine analogues with the hydrazine nicotinate moiety (HYNIC). Derivatives 6a and 6b showed lower activity than the model tacrine, while compounds 6c and 6d showed the strongest affinity to AChE. All the tested compounds exhibited lower affinity for BChE than tacrine. Alzheimer disease (AD) is characterised by a deficit of acetylcholinesterase, and these new compounds, as ligands for 99mTc complexes, are potential radiopharmaceuticals for an early diagnosis of Alzheimer's disease.

Acetylcholinesterase↗

Assessment of antioxidative ability in brain: technetium-99m-meso-HMPAO as an imaging agent for glutathione localization.

UNLABELLED: To visualize the regional localization of glutathione (GSH) in the brain, the relationship between the concentrations of tissue GSH and uptake of [99mTc]meso-hexamethyl propyleneamine oxime ([99mTc] meso-HMPAO) or [99mTc]d,l-hexamethyl propyleneamine oxime ([99mTc]d,l-HMPAO) was studied in mice. METHODS: The uptake of [99mTc]meso-HMPAO in the mouse brain was decreased to 35% of control paralleling the decrease in GSH content by pre-loading of diethyl maleate (DEM), an agent to reduce GSH. In contrast, pre-treatment with DEM scarcely affected the 99mTc-d,l-HMPAO uptake in the brain. RESULTS: The DEM treatment decreased the GSH content in liver, kidney, spleen, fat and lung but did not affect the uptake of [99mTc]meso-HMPAO in those tissues except lung. The images of rat brain acquired with a gamma camera showed a significant reduction of [99mTc]meso-HMPAO uptake by DEM treatment. CONCLUSION: Technetium-99m-meso-HMPAO may be a potential tool to assess GSH content and to estimate antioxidative ability in the brain.

Animals↗

Simultaneous assessment of left ventricular wall motion and myocardial perfusion with technetium-99m-methoxy isobutyl isonitrile at stress and rest in patients with angina: comparison with thallium-201 SPECT.

The newly developed technetium-99m (99mTc) isonitriles can be used for the simultaneous evaluation of ventricular function and myocardial perfusion. We compared technetium-99m hexakis-2-methoxy isobutyl isonitrile [( 99mTc] MIBI) derived first-pass left ventricular wall motion at stress and rest with simultaneous myocardial perfusion defined by [99mTc]MIBI SPECT. These results were then compared with 201TI SPECT. We examined 28 patients with coronary artery disease; 25 had a previous myocardial infarction. We found concordance between segmental wall motion and myocardial perfusion imaging in defining normal, ischemic, and infarcted myocardium in 68% and 69% of segments using [99mTc]MIBI and 201TI respectively. The best agreement between wall motion and myocardial perfusion was seen in the inferior wall, while most of the discrepancies were found at the apex. Agreement between [99mTc]MIBI and 201TI SPECT myocardial perfusion was seen in 93% of segments. Technetium-99m-MIBI appears to be an ideal radiopharmaceutical for the simultaneous evaluation of ventricular function and myocardial perfusion during stress and at rest.

Angina Pectoris↗

Technetium-99m (V) DMSA uptake in amyloidosis.

Technetium-99m(V) DMSA scintigraphy was performed in two patients with pathologically confirmed amyloidosis associated with plasmacytoma. Significant uptake of the tracer was found in the deposition of amyloid. Technetium-99m(V) DMSA scintigraphy could be useful in determining the appropriate region of biopsy and in forecasting the prognosis of patient with plasmacytoma.

Aged↗

Stability studies on (99m)technetium(III) complexes with tridentate/monodentate thiol ligands and phosphine ('3 + 1 + 1' complexes).

The preparation and characterisation of 3 + 1 + 1 technetium complexes of the general formula [Tc(SES)(RS)(PMe2Ph)] (SES = tridentate dithiol ligand, E = S, O, NMe; RSH = monothiol ligand) at the n.c.a. level is described. The Tc(III) complexes are prepared in a one-step procedure starting from pertechnetate in yields of 85-95% of radiochemical purity. A comparison of their chromatographic data with the fully characterised 99Tc complexes indicate the identity of the investigated compounds. Stability studies show that the 99mTc complexes undergo some alteration in solution. They are oxidised to the 3 + 1 oxotechnetium (V) complexes and/or decompose in aqueous solution. In challenge experiments performed with glutathione, exchange of the monothiolato ligand occurs in the same manner as known for the 3 + 1 complexes.

Chromatography, High Pressure Liquid↗

Hepatobiliary scanning in hemobilia-induced acute cholecystitis.

Radionuclide scanning of the hepatobiliary tree is highly accurate for the detection of patients with acute cholecystitis. Hemobilia, a rare complication of percutaneous liver biopsy, may result in blood clots within the biliary canaliculi. Such clots, like gallstones, may occlude the ducts and produce a clinical syndrome indistinguishable from acute cholecystitis. A patient with acute cholecystitis resulting from hemobilia following percutaneous biopsy of the liver is described. The diagnosis of acute cholecystitis secondary to blood clots was made with technetium 99mTc Iprofenin (Pipida [Sn]) scintigraphy. The patient was treated conservatively, and follow-up Pipida scan 6 weeks later demonstrated normal hepatobiliary function.

Adult↗

Synthesis, characterization and biodistribution of a new hexadentate aminethiol ligand labeled with Tc-99m.

A new hexadentate aminethiol ligand (TACNS) derived from triazacyclononane was synthesized and characterized for the development of technetium radiopharmaceuticals. The ligand formed a neutral, lipophilic and stable complex with [99mTc]pertechnetate in the presence of tin(II)tartarate as a reducing agent. The biodistribution of [99mTc]TACNS indicates slight uptake in brain (0.23% ID/organ at 5 min) with a washout at 30 min to 0.14% ID/organ. A small uptake in heart (0.48% ID at 5 min) was also observed. The characterization of [99mTc]TACNS complex using single crystal x-ray analysis and mass spectroscopy has shown that an Sn-N3S3 complex was formed in which tin is oxidized from Sn(II) to Sn(IV). Pertechnetate was incorporated into the complex as counter anion. The nature of the species formed with Tc-99 and "no-carrier-added" [99mTc]pertechnetate is different as confirmed by ratio TLC. From these results, it is demonstrated that sometimes it may be difficult to predict the structure of new technetium radiopharmaceuticals, especially when stannous ion is used as a reducing agent. Moreover, the nature of the chemical species may not be the same at millimolar and at nanomolar levels.

Animals↗

Identity confirmation of 99mTc-MAG3, 99mTc-sestamibi and 99mTc-ECD using radio-LC-MS.

Due to the low concentrations in which 99mTc-radiopharmaceuticals are obtained (4-40 ng/ml), confirmation of the identity of these tracer agents in the European Pharmacopoeia is generally performed only indirectly by assessment of their retention times on RP-HPLC. We have investigated whether it is possible to obtain more direct proof of the identity of technetium-99m labelled radiopharmaceuticals using radio-LC-MS. As representative examples, negatively charged 99mTc-MAG3, positively charged 99mTc-Sestamibi and neutral 99mTc-ECD were used. The three technetium-99m radiopharmaceuticals were prepared in several conditions to obtain variable relative amounts of radiochemical impurities and variable concentrations of the complexes (pico- to nanomolar). The preparations were analyzed on a reversed phase C18 HPLC column using a radio-LC-MS system equipped with a time of flight mass spectrometer with electrospray ionization in positive (99mTc-Sestamibi, 99mTc-ECD) or negative (99mTc-MAG3, 99mTc-ECD) mode. For each of the studied complexes, the main peak in the radiometric channel coincided with the expected molecular ion mass of the corresponding technetium complex in the mass spectrometer channel. The relative error on the measured accurate mass was in the range of 10 ppm. The identity of several radiochemical impurities of the three technetium complexes was also confirmed or established. It is concluded that radio-LC-MS can be a sensitive aid in quality control of 'no carrier added' radiopharmaceuticals.

Chromatography, Liquid↗

The design of a pentavalent 99mTc-dimercaptosuccinate complex as a tumor imaging agent.

In our search for a technetium-tumor seeking agent, the chemical characteristic of polynuclear Ga-citrate attracted our attention. On this basis, we selected the ligand dimercaptosuccinic acid (DMS) and appropriate labeling conditions in the design of 99mTc(V)-DMS. Chemical characterization was performed by thin layer chromatography, electrophoresis, Sephadex column chromatography and spectrophotometric studies at the chemical concentration (99Tc). Biodistribution in mice bearing Ehrlich ascites tumor and scintigraphic images in VX-2 tumor-bearing rabbit, indicated the great applicability of 99mTc(V)-DMS as a new tumor imaging agent. Its distinctive characteristic, different from the kidney imaging agent (99mTc-DMSA) is demonstrated and the biological implication of hydrolytic polynucleation of pentavalent technetium, through an anionic specie Tc(V)O3-(4), in the tumor cell is discussed.

Animals↗

Oxorhenium(V) and oxotechnetium(V) [NN][S]3 complexes of 2-phenylbenzothiazole derivatives.

The reaction of 2-(2'-pyridyl)benzothiazole, [NN], with the ReO(V)(3+) and TcO(V)(3+) cores in the presence of thiophenols, [S] (RC(6)H(4)SH, R = H, 4-CH(3), 4-OCH(3)), as coligands led to the isolation of hexacoordinated complexes of the MO[NN][S](3) type (M = Re, Tc). In all cases, two geometric mer isomers were formed, as evidenced by NMR spectroscopy and confirmed by X-ray crystallography. In both isomers, the coordination geometry about the metal ion is a distorted octahedral defined by the two nitrogen atoms of the bidentate ligand, the three sulfur atoms of the monodentate thiols, and the oxygen atom of the oxo group. The apical positions of the octahedron are occupied by the oxygen of the oxo group and, in one of the isomers, the nitrogen of the pyridyl moiety of 2-(2'-pyridyl)benzothiazole, while, in the second isomer, the imine nitrogen of 2-(2'-pyridyl)benzothiazole. The complexes are stable, neutral, and lipophilic. Complete (1)H and (13)C NMR assignments are reported for all complexes. The synthetic reaction was also successfully transferred at the technetium-99m tracer level by ligand exchange reaction using (99m)Tc-glucoheptonate as precursor in the presence of 2-(2'-pyridyl)benzothiazole and 4-CH(3)C(6)H(4)SH. The structure of the technetium-99m complex was established by high-performance liquid chromatographic comparison with the analogous oxotechnetium and oxorhenium complexes. The 2-(2'-pyridyl)benzothiazole ligand serves as a preliminary model for 2-(4-aminophenyl)benzothiazole, which possesses interesting properties for the development of technetium and rhenium radiopharmaceuticals for tumor imaging and/or radiotherapy as well as in vivo diagnosis of Alzheimer's disease.

Alzheimer Disease↗

SPECT images using 99mTc(V)-DMS in lung metastasis of osteosarcoma.

Color images of single-photon emission computed tomography (SPECT) using technetium-99m(V) dimercaptosuccinic acid (99mTc(V)-DMS) were demonstrated in a patient with lung metastases from osteosarcoma. SPECT image using 99mTc(V)-DMS could be useful for the detection of lung metastasis from osteosarcoma.

Adult↗