Intestinal uptake and metabolism of auranofin, a new oral gold-based antiarthritis drug.

Auranofin, 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranosato-S-(triethy lphosphine)- gold(I), an experimental antiarthritis pharmaceutical, metabolized in contact with hamster or rat gut wall to yield the deacetylated form of the drug. This product, 1-thio-beta-D-glucopyranosato-S-(triethylphosphine)gold(I), passed through hamster or rat intestinal wall in an everted gut experiment. The metabolite was separated by high-performance liquid chromatography and characterized by retention time, chemical reactivity to yield a known product, and comparison to a synthetic sample of the metabolite.

Heart imaging with cationic complexes of technetium.

The cationic technetium-99 complex trans-[99TC(dmpe)2Cl2]+, where dmpe is bis(1,2-dimethylphosphino)ethane or (CH3)2P-CH2-P(CH3)2, has been prepared and characterized by single-crystal, x-ray structural analysis. The technetium-99m analog, trans-(99mTc(dmpe) 2Cl2]+, has also been prepared and shown to yield excellent gamma-ray images of the heart. The purposeful design, characterization, and synthesis of this technetium-99m radiopharmaceutical represents a striking application of fundamental inorganic chemistry to a problem in applied nuclear medicine.

Myocardial uptake and kinetic properties of technetium-99m-Q3 in dogs.

UNLABELLED: We postulated that 99mTc-Q3, a cationic imaging agent, produces myocardial activity related to myocardial blood flow during myocardial ischemia and pharmacologic coronary artery vasodilation, and shows little or no myocardial redistribution over 4 hr after intravenous injection. METHODS: In six Group 1 dogs, the chest was opened, the left circumflex coronary artery was acutely ligated, and dipyridamole (0.32, 0.56 or 0.84 mg/kg) was infused into the right atrium, followed by 10 mCi of 99mTc-Q3. Myocardial blood flow was measured by radiolabeled microspheres. The animals were euthanized and 357 myocardial samples were assayed in a well counter for 99mTc activity. One week later, radiolabeled microsphere activity was counted and myocardial blood flow calculated. In nine Group 2 dogs, a variable occluder was placed around the left circumflex coronary artery and an ischemic level of circumflex blood flow was maintained constant over 4 hr as measured by an ultrasonic flow meter. Dipyridamole (0.56 mg/kg) was then infused into the right atrium followed by 10 mCi of 99mTc-Q3. Gamma camera images were acquired at 5, 15, 30, 60, 120 and 240 min following 99mTc-Q3 injection. Microsphere blood flow and endocardial biopsies (n = 6 dogs) were performed at 30, 60, 120 and 240 min following 99mTc-Q3 injection. RESULTS: In the Group 1 animals, 99mTc activity (y) was related to myocardial blood flow (x) from 0 to 6.1 ml/min/g by the relationship y = 0.83X + 0.18, r = 0.95, p = 0.0001. The scintigraphic ratio of myocardial perfusion defect zone counts-to-normal myocardial zone counts (0.54 +/- 0.05 at 30 min) remained constant over 4 hr, as did technetium counts from direct endocardial sampling. Scintigraphic count ratios allowed discrimination between perfusion defect and normal myocardial regions beginning at 5 min following 99mTc-Q3 injection. CONCLUSIONS: Over a range of myocardial blood flows from 0 to 6.1 ml/min/g, 99mTc-Q3 myocardial activity is related to myocardial flow at the time of tracer injection. Technetium-99m-Q3 shows no evidence of myocardial redistribution over a 4-hr period.

Comparison of technetium-99m-Q3 and thallium-201 for detection of coronary artery disease in humans.

UNLABELLED: Technetium-99m-Q3 is a myocardial imaging agent that produces prompt myocardial visualization in humans. METHODS: In 19 patients with angiographic coronary artery disease, 2 patients with no angiographic coronary artery stenosis greater than 50% of the luminal diameter and 6 healthy volunteers, exercise and resting myocardial imaging were performed with 99mTc-Q3 and also with 201Tl. Technetium-99m-Q3 imaging began 15 min after injection at rest and with exercise, in a complete imaging sequence that required less than 100 min. RESULTS: Overall accuracy for coronary disease detection was 78% (21 true-positive or true-negative studies among 27 study participants) by tomographic thallium imaging versus 89% for 99mTc-Q3 tomographic imaging (p = ns). Accuracy for detection of individual coronary stenoses was 75% (61 true-positive or true-negative coronary segment classifications among 81 total coronary segments) for 201Tl imaging and 83% for 99mTc-Q3 imaging (p = ns). CONCLUSIONS: Technetium-99m-Q3 when used in a rest-exercise sequence that can be completed in 100 min appears to provide comparable diagnostic accuracy to 201Tl for overall coronary disease detection and detection of individual coronary artery stenoses.

Erythrocytosis associated with a placental-site trophoblastic tumor.

We present a case of placental-site trophoblastic tumor associated with erythrocytosis. This 42-year-old woman had persistent amenorrhea and low elevations of her hCG titer after term delivery of a healthy female infant. The woman was noted to have polycythemia of uncertain etiology and was treated with serial phlebotomy. Placental-site trophoblastic tumor was diagnosed and hysterectomy was performed, with subsequent resolution of the polycythemia. Although erythrocytosis has been reported with other gynecologic tumors, this is the first reported association with a placental-site trophoblastic tumor. A role has been suggested for placental lactogen in erythropoiesis during pregnancy based on previous animal studies. Diffuse positive staining for hPL is characteristic of placental-site trophoblastic tumors. We postulate that hPL may have played an ancillary role to erythropoietin in the erythrocytosis demonstrated in this case. Spider angiomata and splenomegaly are interesting clinical features previously described in association with placental-site trophoblastic tumors, and were demonstrated in this patient.

Studies of the Structure and Composition of Rhenium-1,1-Hydroxyethylidenediphosphonate (HEDP) Analogues of the Radiotherapeutic Agent (186)ReHEDP.

Complexes of technetium with diphosphonate ligands are widely used for the imaging and diagnosis of bone disease and most especially metastatic bone cancer. Analogous complexes of radioactive rhenium ((186)Re) with the ligand H(4)HEDP, 1,1-hydroxyethylidenediphosphonate, have been shown to be effective palliatives for the treatment of the intense pain associated with metastatic bone cancer. We have synthesized several of these analogs using nonradioactive Re and have structurally characterized them using EXAFS (extended X-ray absorption fine structure) spectroscopy. One complex synthesized via the substitution reaction of HEDP with trans-[(py)(4)(O)(2)Re]Cl in absolute ethanol appears to be the 1:1 salt of the tris-HEDP complex anion with the starting Re cation, [(py)(4)(O)(2)Re][Re(H(2)HEDP)(3)]. Three other materials, all synthesized via reduction of perrhenate by stannous chloride in the presence of excess H(4)HEDP ligand, are quite different in structure from the material formed by substitution. The principal difference is that each of these contains Re-Re bonds and is formulated as oligomers. The material with a large excess of reductant has Re-Re bonds of ca. 2.4 Å and is best modeled as a linear tetramer of rhenium atoms bridged by HEDP ligands which also bind an equivalent number of tin atoms with additional HEDP ligands. It is formulated as Li(x)()[Re(4)(OH)(2)Sn(4)(HEDP)(12)]. The material formed with the least amount of reducing agent is best modeled as a triangular cluster of rhenium atoms bicapped by two HEDP ligands and bridged to three tin atoms by HEDP to form a complex Li(x)()[Re(3)Sn(3)(HEDP)(8)]. It also has Re-Re bonds but of a significantly longer distance, ca. 2.8 Å. A material with an intermediate amount of reducing agent, prepared in a manner most closely resembling the medically effective palliative agent, appears to contain a mixture of these, and perhaps other, oligomers.

Determination of gold-based antiarthritis drugs and their metabolites in urine by reversed-phase ion-pair chromatography with ICP-MS detection.

A sensitive method for the determination of gold-based drugs auranofin, myochrysine, and their metabolites has been developed. These gold-containing compounds were separated by reversed-phase ion-pair chromatography with tetrabutylammonium chloride as the ion-pairing agent. Gold-specific on-line detection utilized inductively coupled plasma mass spectrometry (ICP-MS). The separation conditions of pH, methanol content, concentration of the ion-pairing agent and ionic strength have been investigated. The detection limit for auranofin, the last peak in the chromatogram, was 0.3 ng. These methods were applied to the analysis of gold-containing species in urine from arthritis patients on auranofin, myochrysine or solganol therapy. The recovery of the total gold-containing species from urine was greater than 90%. Dicyanogold(I) anion, [Au(CN)2]-, was detected in the urine of several patients.

Gold sodium thiomalate toxicity in cadmium-sensitive and cadmium-resistant Chinese hamster ovary cells.

Gold sodium thiomalate was incubated with one cadmium-sensitive cell line and two cadmium-resistant variants. The resistant lines have been reported to synthesize metallothionein (MT) in response to both cadmium and zinc, whereas the sensitive line does not. All cell lines showed a dose-dependent inhibition of growth as a result of gold sodium thiomalate treatment. However, daily comparisons of cell numbers indicate that the cadmium-resistant lines actually increase in number at the highest gold concentrations, whereas numbers of cells in the nonresistant line decrease. MT biosynthesis was measured by monitoring the incorporation of [35S )cysteine into low molecular weight protein. None of the cells synthesized MT in response to gold. When incubated with both zinc and gold, MT was synthesized by both of the cadmium resistant lines; however, the amount of MT synthesized was reduced in the presence of gold which appears to inhibit the uptake of [35S]cysteine by all the cell lines. Although MT is synthesized in the presence of zinc and gold sodium thiomalate, the MT does not have a significant effect on the ability of these cells to withstand high concentrations of gold.

Determination of cisplatin and some possible metabolites by ion-pairing chromatography with inductively coupled plasma mass spectrometric detection.

A sensitive method is described for measuring cisplatin and some possible metabolites. The method combines reversed-phase ion-pairing liquid chromatography (LC) with inductively coupled plasma mass spectrometry (ICP-MS) for platinum-specific detection. Separation conditions for cisplatin hydrolysis products and the reaction products of cisplatin with methionine, cysteine, and glutathione have been investigated with sodium dodecylsulfate or heptanesulfonate as the ion-pairing agent. The detection limit for cisplatin was found to be 0.1 ng, corresponding to a concentration detection limit of 1 ng/ml when using an injection volume of 100 microliters. This study has demonstrated the usefulness of LC-ICP-MS for cisplatin metabolism studies.

Myochrysine solution structure and reactivity.

We have determined the framework structure of Myochrysine (disodium gold(I)thiomalate) in the solid state and extremely concentrated aqueous solution, previously. It consists of an open chain polymer with linear gold coordination to two thiolates from the thiomalic acid moieties which bridge between pairs of gold atoms providing an Au-S-Au angle of 95 degrees . The question remained: was this structure relevant to the dilute solutions of drugs administered and the still lower concentrations of gold found in the bodies of patients (typically 1 ppm Au in blood and urine or 5 muM in Au). We have provided an answer to that question using extended X-ray absorption spectroscopy (EXAFS) and capillary zone electrophoresis (CZE). EXAFS studies confirm that the polymeric structure with two sulfur atoms per gold atom persists from molar concentrations down to millimolar concentrations. CZE is able to separate and detect Myochrysine at millimolar levels. More importantly, at micromolar levels Myochrysine solutions exhibit identical CZE behavior to that measured at millimolar levels. Thus, aqueous solutions of the drug remain oligomeric at concentrations commensurate with those found in patient blood and urine.The reactivity of Myochrysine with cyanide, a species especially prevalent in smoking patients, was explored using CZE. Cyanide freely replaces thiomalic acid to form [Au(CN)(2)](-) and thiomalic acid via a mixed ligand intermediate. The overall apparent equilibrium constant (K(app)) for the reaction is 6x10(-4)M(-1). Further reaction of [Au(CN)(2)](-) with a large excess of L, where L is cysteine, N-acetylcysteine, or glutathione, shows that these amino acids readily replace cyanide to form [AuL(2)](-). These species are thus potential metabolites and could possibly be active forms of gold in vivo. That all of these species are readily separated and quantified using CZE demonstrates that capillary electrophoresis is an accessible and powerful tool to add to those used for the study of gold-based antiarthritis drugs.

Vasculitis in the antiphospholipid syndrome. A cause of ischemia responding to corticosteroids.

A 63-year-old woman with atherosclerotic peripheral vascular disease and the lupus anticoagulant developed ischemia of the right lower extremity, requiring progressive amputations. Pathologic specimens revealed inflammatory vasculitis in multiple arteries. Her serum showed anticardiolipin antibodies in high titer. Treatment with high-dose corticosteroids reversed the ischemic process. In patients with antiphospholipid antibodies, thrombosis is the most common pathologic finding associated with cutaneous lesions and/or gangrene. Vasculitis, although uncommon, is known to occur and may respond to corticosteroid therapy.

Granulocytic sarcoma of the uterine cervix--literature review of granulocytic sarcoma of the female genital tract.

Granulocytic sarcoma is an extramedullary tumor of malignant granulocytic progenitor cells that accompanies, heralds, or signals relapse of acute myelogenous leukemia (AML), or indicates blastic transformation of a chronic myeloproliferative disorder. We describe a case involving the uterine cervix of a 51-year-old woman that led to the diagnosis of AML. Granulocytic sarcoma can occur in the female genital tract and may be the first clinically significant manifestation of a hematologic malignancy. The salient findings in 28 reported cases from 12 different countries are reviewed. Awareness of this lesion is important for all medical personnel involved in the health care of women.

Emission energy correlates with inverse of gold-gold distance for various [Au(SCN)2]- salts.

A series of bis(thiocyanato)gold(I) complexes with Au-Au interactions show luminescence in the range from 500 to 670 nm. The series of salts correlates emission energy with the reciprocal of the Au-Au distance. As the Au-Au distance increases, the emission energy decreases. The ligand system provides no framework for the Au-Au interaction. The emission energy seems totally determined by the Au-Au distance.

Structural characterization of a bridged 99Tc-Sn-dimethylglyoxime complex: implications for the chemistry of 99mTc-radiopharmaceuticals prepared by the Sn (II) reduction of pertechnetate.

Reduction of pertechnetate by tin(II) in the presence of dimethylglyoxime is shown, by single crystal x-ray analysis, to yield a technetium-tin-dimethylglyoxime complex in which tin and technetium are intimately connected by a triple bridging arrangement. One bridge consists of a single oxygen atom and it is hypothesized that this bridge arises from the inner sphere reduction of technetium by tin(II), the electrons being transferred through a technetium "yl" oxygen which eventually becomes the bridging atom. Two additional bridges arise from two dimethylglyoxime ligands that function as bidentate nitrogen donors towards Tc and monodentate oxygen donors towards Sn. The tin atom can thus be viewed as providing a three-pronged "cap" on one end of the Tc-dimethylglyoxime complex. The additional coordination sites around Tc are occupied by the two nitrogens of a third dimethylglyoxime ligand, making the Tc seven-coordinate. The additional coordination sites around Sn are occupied by three chloride anions, giving the Sn a fac octahedral coordination environment. From indirect evidence the oxidation states of tin and technetium are tentatively assigned to be IV and V, respectively. Since most 99mTc-radiopharmaceuticals are synthesized by the tin(II) reduction of pertechnetate, it is likely that the Sn-O-Tc linkage described in this work is an important feature of the chemistry of these species. This linkage also provides a ready rationale for the close association of tin and technetium observed in many 99mTc-radiopharmaceuticals.

Dicyanogold effects on lymphokine production.

Having identified dicyanogold(I) as a common metabolite of gold-based antiarthritis drugs, we are investigating the effects of the compound on the production of lymphokines. Handel, et al. 1 suggested that the transcription factor AP-1, critical to the production of a number of cytokines, might be the target for gold compounds because of a critical cysteine within its DNA binding region. Using Jurkat cells, an established cell line as a model for CD4(+) lymphocytes, we have shown that dicyanogold inhibits the binding of AP-1 to DNA and inhibits the synthesis of IL-2 mRNA and protein. In a macrophage line, THP-1, which synthesizes IL-1beta in response to mitogen, we have shown that dicyanogold inhibits the binding of a second transcription factor, CREB to DNA. Incubation of THP-1 cells with dicyanogold inhibits the production of IL-1beta mRNA. These results suggest that the mechanism of action of gold drugs may be through their interaction with transcription factors necessary for the immune activation seen in Rheumatoid Arthritis.

Formation and characterization of aurothioneins: Au,Zn,Cd-thionein, Au,Cd-thionein, and (thiomalato-Au)chi-thionein.

Three gold-containing thioneins (Au,Zn,Cd-Th, Au,Cd-Th, and (TmSAu)chi Th, where Th = thionein and TmS = thiomalate) have been prepared by the reactions of horse kidney Zn,Cd-thionein with gold thiomalate (AuSTm). When thionein was present in excess, the thiomalate ligand was displaced and the protein chelated the gold in a bidentate fashion. Primarily zinc but also some cadmium was displaced to form Au,Zn,Cd-Th or Au,Cd-Th. Excess AuSTm reacted to form (TmSAu)chi-thionein with monodentate coordination of the protein to each bound gold, retention of the thiomalate, loss of zinc and cadmium, and an increase in the Stokes radius of the product. EXAFS/XANES studies of Au,Zn,Cd-Th and (TmSAu)chi Th established that the oxidation states and coordination environments of gold were Au(I)S2 and that the gold-sulfur bond distances were 229 and 230 pm, respectively. Radioimmunoassay established that the aurothioneins retained their antigenicity to native metallothionein antibodies. Metal exchange reactions with gold were complete within 5-10 min when Zincon or 4-(2-pyridylazo) resorcinol was used to monitor Cd2+ and Zn2+ displacement.

Transport of the dicyanogold(i) anion.

We have shown that dicyanogold(I), [Au(CN)(2)](-) is a common metabolite found in blood and urine samples of patients treated with different gold based drugs. Some patients have high levels of gold within their red blood cells (RBCs). Size exclusion and C18 reversed phase chromatography show that the majority of the gold in RBC lysates is bound to protein, but small molecules such as dicyanogold(I) and gold-glutathione complexes are also present. Dicyanogold incubation with red blood cells in vitro leads to a rapid and complete uptake of gold. This uptake is unaffected by DIDS, an inhibitor of the anion channel, but is blocked by the addition of external cyanide. Dicyanogold is also readily taken up by H9 cells, a continuous CD(4+) cell line. This uptake is significantly inhibited by N-ethylmaleimide, suggesting a requirement for sulfhydryl groups. Dicyanogold inhibits the replication of the AIDS virus, HIV, in a cell culture model.

Determination of biotransformation products of platinum drugs in rat and human urine.

Cisplatin is an extremely effective cancer chemotherapeutic agent, but its use is often accompanied by toxicity. Second generation drugs such as carboplatin are becoming more widely used because of reduced toxicity. Since biotransformation products have been implicated in the toxic responses, we have begun to investigate the reactions of cisplatin and carboplatin with potential biological ligands. Reaction products were characterized using HPLC with inductively coupled plasma - mass spectrometry (HPLC-ICP-MS), (1)H and (13)C NMR and fast atom bombardment - mass spectrometry (FAB-MS). Three Pt-creatinine complexes, cis-[Pt(NH(3))(2)Cl(Creat)](+), cis-[Pt(NH(3))(2)(H(2)O)(Creat)](2+) and cis-[Pt(NH(3))(2)(Creat)(2)](2+), were synthesized and the platinum was shown to coordinate to the ring nitrogen, N(3). Human urine samples from patients on cisplatin chemotherapy were shown to contain cisplatin, its hydrolysis product and biotransformation products containing Pt-creatinine, Pt-urea and Pt-uric acid complexes. Urine from carboplatin patients shows fewer biotransformation products. Studies with control and diabetic (protected against cisplatin toxicity) rats showed systematic differences in the biotransformation products formed on administration of cisplatin.

Dicyanogold (I) is a common human metabolite of different gold drugs.

Gold based drugs and their metabolites have been characterized using reversed phase, ion pairing chromatography with an inductively coupled plasma mass spectrometer as an element specific detector. For a patient receiving gold sodium thiomalate the principal gold species in the urine is [Au(CN)2]-, which is also seen in a low molecular weight infiltrate of the blood. The same compound is also identified in the urine and blood of a patient taking auranofin and in patients taking solganol. This represents the first identification of a specific gold metabolite in biological fluids taken from patients undergoing gold therapy and the first evidence that different gold drugs have common metabolites.

Kinetic properties of 99mTc-Q12 in canine myocardium.

BACKGROUND: 99mTc-Q12 is a new Tc(III) perfusion imaging agent that permits prompt myocardial visualization in humans. We postulated that 99mTc-Q12 myocardial activity is related to actual myocardial blood flow during conditions of myocardial ischemia and pharmacological coronary artery vasodilation and that 99mTc-Q12 shows little or no myocardial redistribution as long as 4 hours after intravenous injection. METHODS AND RESULTS: In seven anesthetized, open chest dogs, the left circumflex coronary artery was occluded, and dipyridamole (0.32 or 0.56 mg/kg) was infused into the right atrium, followed by 10 mCi of 99mTc-Q12. Myocardial blood flow was measured by radiolabeled microspheres. The animals were euthanized, and a total of 315 myocardial samples were assayed in a well counter for 99mTc activity. One week later, radiolabeled microsphere activity was determined, and myocardial blood flow was calculated. 99mTc activity (y) was related to myocardial blood flow (x) from 0 to 2 mL.g-1 x min-1 by the relation y = 0.64x + 0.35 (r = .88, P = .0001). In 14 additional anesthetized, open chest dogs, an occluder was placed around the left circumflex coronary artery, and an ischemic level of circumflex blood flow was maintained constant over 4 hours as measured by an ultrasonic flowmeter. Dipyridamole (0.56 mg/kg) was infused intravenously beginning 15 minutes after coronary occlusion and then followed by 10 mCi of 99mTc-Q12. Gamma camera images, hemodynamics, microsphere blood flow, and endocardial biopsies (latter in six dogs) were performed at 30, 60, 120, and 240 minutes after 99mTc-Q12 injection. Myocardial blood flow in the distribution of the left anterior descending artery decreased by 29.6% from 30 to 240 minutes (P < .05), whereas left circumflex blood flow increased by 40.4% from 30 to 120 minutes (P < .05) as the dipyridamole hemodynamic effects dissipated. Nevertheless, the ratio of myocardial perfusion defect zone counts to normal myocardial zone counts remained constant over 4 hours, as did the technetium counts from the needle biopsy endocardial samples. CONCLUSIONS: Over a limited range of myocardial blood flows from 0 to approximately 2 mL.g-1 x min-1, 99mTc-Q12 myocardial activity is related to actual myocardial flow at the time of tracer injection. 99mTc-Q12 shows no evidence of myocardial redistribution.