Sources of error in tissue and tumor measurements of 5-[18F]fluorouracil

Central to the assessment of variability of pharmacokinetic parameters is knowledge of bias and variability of the measurement technique, preventing observed differences from being ascribed inappropriate significance. This article presents an evaluation of sources of error in the measurement of normal tissue and tumor pharmacokinetics using 18F-labeled 5-fluorouracil (FU) and PET. METHODS: A standard approach to data acquisition, processing and analysis was developed using a PET scanner, filtered backprojection reconstruction and region of interest analysis. Fourteen tracer 5-[18F]FU patient studies and a phantom study were completed, with 4 of the patient studies repeated 1 wk later. These data allowed evaluation of the overall reproducibility of the technique and the components of measurement variability due to tissue sampling. The effect of reconstruction technique and sampling region size on quantification was assessed using phantom data. RESULTS: All measured radioactivity versus time curves were tissue specific. Week-to-week variability in the area under this curve (representing combined physiological and measurement difference) was -3% to +15% for liver and -9% to -16% for spleen and kidney. Metastasis variability was greatest at -20%. Visual and computer realignment of the second paired study produced similar results. Interobserver effects were small compared to differences between studies. CONCLUSION: These results confirm the feasibility of using PET as a pharmacokinetic tool for 5-[18F]FU studies. Although overall experimental error (i.e., random variation in data acquisition, processing and analysis) was low, constraints in data interpretation emerged.     

Whole-body 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for accurate staging of Hodgkin's disease

BACKGROUND: Staging of Hodgkin's disease (HD) is accomplished by a variety of invasive and non-invasive modalities. This prospective study was undertaken to investigate the value of whole-body positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in defining regions involved by lymphoma compared with conventional staging methods in patients with HD. PATIENTS AND METHODS: Fourty-four newly diagnosed patients with HD underwent FDG-PET as part of their initial staging work-up. PET findings were correlated with findings of conventional staging including computed tomography, ultrasound, bone scanning, bone marrow biopsy, liver biopsy and laparotomy. When results of FDG-PET differed to those obtained by conventional methods reevaluation was performed by biopsy, if possible, or magnetic resonance imaging. RESULTS: The results of FDG-PET were compared with three hundred twenty-one conventional staging procedures performed in 44 patients. FDG-PET was positive in 38 of 44 (86%) patients at sites of documented disease. PET detected additional lesions in five cases previously not identified by conventional staging methods. In another case a nodal lesion suspect on CT was negative at FDG-PET and was settled as true negative by biopsy. As a consequence of PET findings five patients had to be upstaged and one patient had to be downstaged, resulting in changes in treatment strategy in all six cases (14%). FDG-PET failed to visualize sites of HD in four patients. In two of our patients a false positive PET result was obtained. CONCLUSIONS: Our data indicate that FDG-PET provides an imaging technique that appears to visualize involved lesions in most patients with HD and is useful in the management of these patients.     

Comparison of high specific activity (-) and (+)-6-[18F]fluoronorepinephrine and 6-[18F]fluorodopamine in baboons: heart uptake, metabolism and the effect of desipramine

(-)-Norepinephrine is the principal neurotransmitter of the mammalian sympathetic nervous system and a major CNS neurotransmitter. The simple ring fluorinated derivatives of (-)- and (+)-norepinephrine [(-)- and (+)6-fluoronorepinephrine] and dopamine (6-fluorodopamine) have been labeled with 18F in high specific activity (2-5 Ci/mumol) and evaluated as tracers for (-)-norepinephrine. Comparative PET studies of (-) and (+)-6-[18F]fluoronorepinephrine [(-)-6-[18F]FNE and (+)-6-[18F]FNE] and 6-[18F]fluorodopamine (6-[18F]FDA) in the same baboon showed strikingly different kinetics in the heart. Analysis of plasma showed more rapid metabolism of 6-[18F]FDA with only 1%-2% of 18F remaining as parent tracer at 10 min after injection of 6-[18F]FDA, in contrast to 28% and 17% remaining after injection of (-) and (+)-6-[18F]FNE. No changes in vital signs were observed at any time during the study. Pretreatment with desipramine (0.5 mg/kg), a tricyclic antidepressant drug which interacts with a binding site associated with norepinephrine reuptake, markedly decreased cardiac uptake of 6-[18F]FDA and (-)-6-[18F]FNE. However, a greater blocking effect was observed for (-)-6-[18F]FNE. These studies show that (-) and (+)-6-[18F]FNE are similar to (-)- and (+)-norepinephrine in their patterns of metabolism and clearance in the heart and that (-)-6-[18F]FNE is a promising tracer for endogenous (-)-norepinephrine.     

Synthesis and antitumor activity of 4-[p-[bis(2-chloroethyl)amino]phenyl]butyrates

Ten 4-[p-[bis(2-chloroethyl)amino]phenyl]butyrates were synthesized and evaluated for antitumor activity. The 2-phenoxyethyl ester exhibited activity against P-388 lymphocytic leukemia, and the n-butyl and n-pentyl esters exhibited activity against L-1210 lymphoid leukemia in initial screening tests.     

Synthesis of allyl O-[sodium(alpha-D-glycero-D-talo-2- octulopyranosyl)onate]-(2-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosi de, a core constituent of the lipopolysaccharide from Acinetobacter calcoaceticus NCTC 10305

Reaction of methyl 2,6-anhydro-2,3-dideoxy-D-manno-2-octenoate 1 with 3-chloroperoxybenzoic acid gave the 2,3-anhydro derivative 2, which was converted into the per-O-acetylated anomeric methyl glycosides of D-glycero-D-galacto-2-octulopyranosylonic acid in good yield. Subsequent inversion of the configuration at C-3 and deprotection afforded sodium (methyl beta-D-glycero-D-talo-2-octulopyranosid)onate. Alternatively, 2 was transformed into methyl (alpha-D-glycero-D-talo-2- octulopyranosyl bromide(onate derivatives. Reaction with methanol or allyl 2-acetamido-2-deoxy- 3,4-O-(1,1,3,3-tetraisopropyldisiloxan-1,3-diyl)-beta-D-g lycopyranoside, promoted by silver triflate, gave good yields of the corresponding orthoester derivatives. Me3Si triflate-catalyzed orthoester rearrangement and removal of the protecting groups afforded sodium O-(methyl alpha-D-glycero- D-talo-2-octulopyranosid)onate and the disacchanide, allyl O-[sodium(alpha-D-glycero-D-talo-2- octulopyranosyl)onate]-(2-->6)-2-acetamido-2-deoxy-beta-D-gl ucopyranoside in high yield.     

Synthesis and beta-adrenoreceptor blocking activity of [[3-(alkylamine)-2-hydroxypropyl]oximino]pyridines and O[3-(alkylamine)-2-hydroxypropyl]methylpyridine ketone oximes derivatives

[[3-(alkylamine)-2-hydroxypropyl]-2-oximino]pyridines and O-[3-(alkylamine)-2-hydroxypropyl]methylpyridine ketone oximes 5a-o were synthesized by a solid-liquid phase-transfer reaction, and their beta-adrenoreceptor blocking activity was evaluated in vitro and in vivo. The replacement of the aryl linked to the oximic carbon of the (methylenaminoxy)methyl moiety with the bioisoster pyridine ring produced a decrease of the beta-adrenergic blocking activity. The polarization of the oximic group, derived from the electron-withdrawing action of the nitrogen atom, is more evident for the 2-oxyminopyridine derivative 5d. But also conformational parameters may play an important role in the variation of activity of the compounds 5d, 5l and 5n. The replacement of the hydrogen linked to the oximic carbon with a methyl group increased the activity of the compounds 5a, 5i, 5m and 5o. The methyl could allow a delocalization of the partial positive charge present on the oximic carbon, but also its lipophilicity contributed to the increment of binding to the receptor site. None of the compounds showed high beta 1 or beta 2 selectivity in vitro. The (R) and (S) isomers of the compound 5a were synthesized and obtained with enantiomeric ratio 7:3 and 6:4, respectively. The binding tests and the pharmacological in vivo results confirmed the in vitro data.     

Synthesis and biological activities of optically active 6-[3-(3,4-dimethoxybenzylamino)-2-hydroxypropoxy]-2(1H)-quinolinone (OPC-18790)

The enantiomers of 6-[3-(3,4-dimethoxybenzylamino)-2-hydroxypropoxy]-2(1H)-quinolinon e (OPC-18790), a novel cardiotonic agent, were synthesized and evaluated for positive inotropic activity. The key intermediates, 2,3-epoxypropoxy derivatives, were obtained by the alkylation of 6-hydroxy-2(1H)-quinolinone with optically active epichlorohydrin and subsequent ring closure. In an in vitro study, the (R)-(+)-isomer was about 10-fold more potent than the (S)-(-)-isomer.     

Positron emission tomography with 2-[18F]Fluoro-2-deoxy-D-glucose and 16alpha-[18F]fluoro-17beta-estradiol in breast cancer: correlation with estrogen receptor status and response to systemic therapy

We assessed the value of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and 16alpha-[18F]fluoro-17beta-estradiol (FES) in women with breast cancer for predicting response to systemic therapy. Results of FES-PET were correlated with estrogen receptor (ER) status. Forty-three women with locally advanced or metastatic breast cancer underwent FDG-PET and FES-PET prior to institution of systemic therapy. All patients had measurable disease and had tumors submitted for ER determination. Cancers were considered functionally hormone sensitive if the standardized uptake value of the lesion on FES-PET was >/=1.0 (FES+) and hormone resistant if the standardized uptake value was <1.0 (FES-). Information obtained by FES-PET was compared with the results of ER assays. The tumor response to chemotherapy and hormonal therapy was correlated with intensity of uptake by both FDG-PET and FES-PET. The ER status of the breast cancers was negative (ER-) in 20 patients, positive (ER+) in 21 patients, and unknown in 2 patients. All 20 of the ER- tumors were also FES-. However, of the 21 ER+ tumors, 16 were FES+ and 5 were FES-. Thirty patients were treated initially with chemotherapy, and 21 (70%) demonstrated objective responses. We were unable to correlate the response to chemotherapy with information obtained by FDG-PET or FES-PET. Thirteen patients were treated with hormone therapy, and 8 (61%) responded to that therapy. Only 1 of the 5 patients whose tumors were ER+ but FES- received hormone therapy, and this treatment resulted in disease stabilization only. Multiple sites of disease were assessed by FES-PET in 17 patients with metastatic breast cancer. Functional hormone sensitivity, defined by FES-PET, was concordant with multiple lesions in 13 (76%). Ten patients with locally advanced breast cancer developed recurrent disease. The initial site of recurrence was the breast in 5 patients. Of the 5 patients with systemic recurrence, 4 had disease detected at the site of recurrence on the pretreatment FDG-PET study but not detected on pretreatment computed tomography. In our experience, FDG-PET imaging is more sensitive than conventional imaging methods, including computed tomography, in staging women with breast cancer. When compared with the in vitro assay of ER status, FES-PET has an apparent sensitivity of 76% and specificity of 100%. Our finding of a subset of patients who have tumors that are ER+ and FES- suggests that the functional assessment of hormone sensitivity by PET imaging can identify patients with ER+ disease whose tumors are likely to be hormone refractory.     

Validation of S-1'-[18F]fluorocarazolol for in vivo imaging and quantification of cerebral beta-adrenoceptors

S-1'-[18F]fluorocarazolol (S-(-)-4-(2-hydroxy-3-(1'-[18F]fluoroisopropyl)-aminopropoxy)carba zole, a non-subtype-selective beta-adrenoceptor antagonist) has been investigated for in vivo studies of beta-adrenoceptors. Previous results indicated that uptake of this radioligand in heart and lung can be inhibited by beta-adrenoceptor agonists and antagonists. In the present study, blocking, displacement and saturation experiments were performed in rats, in combination with metabolite analysis to investigate the suitability of this radioligand for in vivo positron emission tomography (PET) imaging and quantification of beta-adrenoceptors in the brain. The results demonstrate that, (i) the uptake of S-1'-[18F]fluorocarazolol reflects specific binding to beta-adrenoceptors, (ii) binding of S-1'-[18F]fluorocarazolol to atypical or non-beta-adrenergic sites is negligible, (iii) uptake of radioactive metabolites in the brain is less than 25% of total radioactivity, 60 min after injection, (iv) in vivo measurements of receptor densities (Bmax) in cortex, cerebellum, heart, lung and erythrocytes are within range of densities determined from in vitro assays, (v) binding of S-1'-[18F]fluorocarazolol can be displaced. In conclusion, S-1'-[18F]fluorocarazolol seems to possess the appropriate characteristics to visualize and quantify beta-adrenoceptors in vivo in the central nervous system using PET.     

Heteroaromatic analogs of 1-[2-(diphenylmethoxy)ethyl]- and 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazines (GBR 12935 and GBR 12909) as high-affinity dopamine reuptake inhibitors

A new series of heteroaromatic GBR 12935 [1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)-piperazine] (I) and GBR 12909 [1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine] (2) analogs was synthesized and evaluated as dopamine transporter (DAT) ligands. Analogs 5-16, in which the benzene ring in the phenylpropyl side chain of the GBR molecule had been replaced with a thiophene, furan, or pyridine ring, exhibited high affinity and selectivity for the DAT vs serotonin transporter (SERT) and stimulated locomotor activity in rats in a manner similar to the parent compound 2. In cocaine and food self-administration studies in rhesus monkeys, both thiophene-containing (6 and 8) and pyridine-containing (14 and 16) derivatives displayed potency comparable to 2 in decreasing the cocaine-maintained responding at the doses tested (0.8, 1.7, and 3 mg/kg). However, these compounds did not produce the degree of separation between food- and cocaine-maintained responding that was seen with 2. Among the bicyclic fused-ring congeners 17-38, the indole-containing analog of 2, 22, showed the greatest affinity for binding to the DAT, with IC50 = 0.7 nM, whereas the corresponding indole-containing derivative of 1, 21, displayed the highest selectivity (over 600-fold) at this site vs the SERT site.     

Reliability of a simple non-invasive method for the evaluation of 5-HT2 receptors using [18F]-setoperone PET imaging

This study was designed to determine the effects of oral administration of the copper(II) complex of amino acids, on gastric lesions induced by ethanol in rats and the possible mechanism(s) of protection. The copper(II) complex of L-tryptophan and L-phenylalanine is reported as the most effective in reducing ulcer numbers as well as ulcer severity of the many amino acid complexes studied. We investigated the role of PGE2 and nitric oxide (NO) in the protection afforded by Cu(II)(L-Trp)(L-Phe) against ethanol-induced damage. The involvement of endogenous eicosanoids and NO was evaluated with the respective inhibitors of prostaglandin and NO synthesis, indomethacin and NG-nitro-L-arginine (L-NNA). Ex vivo PGE2 accumulation in the rat gastric mucosa has also been determined. Pretreatment with indomethacin only partially counteracted the protective activity of Cu(II)(L-Trp)(L-Phe). L-NNA did not attenuate the protection by Cu(II)(L-Trp)(L-Phe), which was reduced but not prevented by indomethacin, suggesting that prostanoids contribute to the Cu(II)(L-Trp)(L-Phe) protective effect, together with some mechanism(s) other than NO synthesis.     

新显色剂2-苯并噻唑偶氮-7-(4-羧基苯偶氮)-变色酸的合成及与铁(Ⅲ)显色反应研究

合成了一种新的杂环不对称双偶氮变色酸试剂2-苯并噻唑偶氮-7-(4-羧基苯偶氮)-变色酸(简称BTACPACA).研究了试剂的结构和光度性质,结果表明在pH6.0～6.4的缓冲介质中,Fe(Ⅲ)与BTACPACA及CTMAB形成1∶2∶1的三元络合物,其最大吸收波长为685nm,表观摩尔吸光系数ε＝1.13×105,在25mL溶液中0～6μg范围内Fe(Ⅲ)符合比尔定律.建立了测定石灰石和高炉渣中铁的新方法,结果满意.     

20-[18F]fluoroarachidonic acid: tissue biodistribution and incorporation into phospholipids

The in vivo behavior of 20-[18F]fluoroarachidonic acid (18F-FAA) was investigated to evaluate its potential use as a radiotracer for studying the regional brain and heart lipid metabolism by positron emission tomography (PET). Tissue biodistribution studies in rats have revealed that 18F-FAA has a high uptake in the liver and lung, thus probably reflecting the metabolism, and is accompanied by both low in vivo defluorination and low blood levels. At 30 min postinjection, the uptake in the brain and heart reached values of 0.26 +/- 0.02 and 1.22 +/- 0.58% dose/g, respectively, with ratios to the blood radioactivity of 1.04 and 4.88, respectively. Lipid extraction at 30 min postinjection showed that 39% of the brain radioactivity was in the organic phase whereas the organic phase from heart tissue contained 73% of the total radioactivity. A TLC analysis demonstrated that 18F-FAA was mainly bound to phospholipids in the brain and heart tissue as expected. Based on the findings of this study, the utility of 18F-FAA as an in vivo tracer for cerebral phospholipid studies appears to be limited because of its relatively high radioactivity in the aqueous brain fraction. However, our findings do suggest that this agent might be useful as a tool for studies of cardiac phospholipid turnover, even though it demonstrated a poor heart-to-lung and heart-to-liver contrast.     

Synthesis and calcium antagonistic activity of 8-[N-[2-(3,4-dimethoxy- phenyl)ethyl]-beta-alanyl]-5,6,7,8-tetrahydrothieno[3,2-b][1,4]thiazepi ne fumarate

KT-362 is an antiarrhythmic and antihypertensive agent with vasodilating activity. Since it carries a homoveratryl group in the side chain, an obvious relation exists to the verapamil-type calcium antagonists. Replacement of the fused aromatic moiety in KT-362 with thiophene provided 8-[N-[2-(3,4-dimethoxyphenyl) ethyl]-beta-alanyl]-5,6,7,8-tetrahydrothieno[3,2-b][1,4] thiazepine (1). Compound 1 shows a negative chronotropic activity in spontaneously beating right atria (IC50 = 23 microM, n = 7), and a negative inotropic effect in papillary muscles (IC50 = 2.7 microM, n = 7) and left atria (IC50 = 4 microM, n = 6) of the guinea-pig heart. The decrease of contractility in papillary muscles could be antagonized by increasing the extracellular calcium concentration. Compound 1 was found to affect high (IC50: 70 +/- 5 microM) and low (IC50: 129 +/- 34 microM) voltage-activated calcium channel currents as well as voltage-activated sodium channel currents (IC50: 80 +/- 13 microM) in chick dorsal root ganglion neurons. In addition nicotine-induced currents were potently inhibited (IC50: 6 +/- 0.7 microM) in bovine chromaffin cells.     

Synthesis and preliminary pharmacological investigation of some 2-[4-(dialkylaminoalkoxy)phenyl]benzotriazoles and their N-oxides

A set of 2-[4-(dialkylaminoalkoxy)phenyl]benzotriazoles and corresponding N-oxides was prepared. In a preliminary pharmacological investigation concerning some of these compounds, several in vitro and in vivo activities were shown. At concentrations in the range of 3-10 microM all tested compounds strongly inhibited (50-100%) the guinea pig ileum contractions induced either electrically or by means of several agonists; of particular interest was the antagonism to leukotriene D4. Compound 5b inhibited platelet aggregation induced by thromboxane A2, PAF and ADF (but not by arachidonic acid) and increased the bleeding time in mice. Compounds 5b and 6b protected mice from potassium cyanide hypoxia and exerted anti-hypercholesterolemic action; the first compound produced a ratio between HPL and total serum cholesterol concentrations below 0.92, thus indicating a potential anti-atherogenic activity.     

新显色剂2-苯并噻唑偶氮-7-(4-羧基苯偶氮)-变色酸的合成及与铁显色反应研究

合成了一种新的杂环不对称双偶氮变色酸试剂 2-苯并噻唑偶氮-7-( 4-羧基苯偶氮 )-变色酸 (简称BTACPACA)。研究了试剂的结构和光度性质 ,结果表明 :在 pH6.0～ 6.4的缓冲介质中 ,Fe 与BTACPACA及CTMAB形成 1∶2∶1的三元络合物 ,其最大吸收波长为 685nm ,表观摩尔吸光系数ε =1.13× 10 5,在 2 5mL溶液中 0～ 6μg范围内Fe 符合比尔定律。建立了测定石灰石和高炉渣中铁的新方法 ,结果满意。     

Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.     

5-[2-(5-乙基-1,3,4-噻二唑)偶氮]-8-羟基喹啉的合成及其与铜(Ⅱ)的显色反应

合成了新型偶氮显色剂5-[2-(5-乙基-1,3,4-噻二唑)偶氮]-8-羟基喹啉(ETADQ),研究了它与铜的显色反应。结果表明:在pH 5.0~7.0的KH2PO4-NaOH缓冲溶液中试剂与铜离子迅速形成一种稳定的黄色络合物,10 min后吸光度达到最大值,络合物的摩尔比组成为1∶1,最大吸收波长位于540 nm处,表观摩尔吸光系数ε=8.1×104L.mol-1.cm-1。铜离子在3.0×10-6~2.2×10-5mol/L范围内服从比尔定律,相关系数r=0.9985。用于测定矿石和合金样品中的微量铜,相对标准偏差为0.79%~4.52%,结果与认定值相吻合。