Abstract 1646: Synthesis of [11C]onapristone for clinical investigation

Background: Onapristone is a type I anti-progestin, which prevents the progesterone receptor (PR) monomers from dimerizing, inhibits ligand-induced phosphorylation and prevents association of the PR with its co-activators, thus preventing PR-induced transcription. Onapristone has the potential to treat patients with endometrial cancer, breast cancer, uterine sarcomas, a potential subset of ovarian cancer, prostate cancer and other tumors in which the progesterone receptor plays a role in growth, proliferation and metastasis. [11C]-radiolabeled onapristone and its visualization via PET-scan, coupled with pharmacokinetic (PK) studies, has the potential to determine tissue-specific and blood PK parameters including tumor/tissue and plasma concentrations, whole body distribution and half-life of onapristone. The aim of this study is the development of a rapid Good Manufacturing Product (GMP) synthesis of parentally administered [11C]onapristone.

Methods: The production of [11C]-labeled radiopharmaceuticals used a Tracerlab® FX c-Pro (GEMS) synthesis module. Carbon-11 was produced at Institut Curie-Hôpital René Huguenin via the 14N(p,α)11C nuclear reaction using a PETTrace cyclotron (GEMS) equipped with a carbon-11 target. Carbon-11 is delivered from the cyclotron as [11C]CO2 in the synthesis module, and reduced to [11C]CH4. Methane is halogenated to [11C]CH3I and converted to [11C]methyl triflate (CH3OTf). To prepare [11C]onapristone, the module was loaded with 1mg of N-desmethyl-onapristone (Arno Therapeutics) and 500µL of DMSO in the reaction vessel (Sigma®). [11C]CH3OTf was bubbled into the reaction vessel and heated at +50°C for 10 minutes. The reaction mixture was then diluted with 1 ml of mobile phase and purified using a semi-preparative HPLC column: Sunfire C18 5µm 250X10mm (Waters®), mobile phase: acetonitrile (Sigma®)/water (Waters®) 50/50 v/v; flow rate 4 mL/min. The product fraction was collected in 40mL of sterile water and was passed through a C18 SEP PAK (Waters®). This fraction was eluted with isotonic saline (Braun®) and ethanol (Sigma®). The resulting formulation was passed through a 0.22µm sterilizing filter into a sterile dose vial.

Results: 10 tests were performed. Time of synthesis was 50 minutes. The amount of carbon-11 delivered was 12-14GBq for the irradiation parameters as follows: 10 min; 10µA. The decay-corrected yield of reducing [11C]CO2 to [11C]CH4 was >99%. The yields of preparing [11C]CH3I were 27-29%. Time retention of [11C]onapristone was 8.5-9.5 minutes and the non-decay-corrected radiolabelling yields were 1-2%.

Conclusions: We have successfully developed a fully-automated production of [11C]onapristone ready for use in clinical trials.

Citation Format: Olivier Madar, Julien Fouque, Stefan Proniuk, Keyvan Rezai, Samuel Huguet, Alexander Zukiwski, Erard M. Gilles, Alice S. Bexon, François Lokiec. Synthesis of [11C]onapristone for clinical investigation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1646. doi:10.1158/1538-7445.AM2014-1646

A phase I pharmacokinetics study of lapatinib and tamoxifen in metastatic breast cancer (EORTC 10053 Lapatam study)

OBJECTIVE

This phase I study assessed the pharmacokinetic (PK), tolerability, safety and preliminary clinical activity of tamoxifen (T) and lapatinib (L) in patients with metastatic breast cancer (MBC).

METHODS

Patients (pts) with hormone receptor positive MBC, irrespective of HER-2 status, were randomly assigned to T → T + L group, tamoxifen in cycle 1 for 28 days then adding lapatinib on day 1 of cycle 2; or L → T + L group, lapatinib in cycle 1 for 14 days, then adding tamoxifen on day 1 of cycle 2 to evaluate the potential drug-drug PK interaction at steady-state. The dose of tamoxifen was 20 mg/day and lapatinib 1500 mg/day.

RESULTS

Twenty-five pts were enrolled of which 23 started treatment, five (22%) of them were HER-2 positive. Median age was 59 years and 96% had PS ≤1. Eleven (91.7%) pts in the T → T + L group and 10 (76.9%) in L → T + L group received at least 2 cycles of treatment. The most frequently reported drug-related adverse events (>25% of patients) were diarrhoea (62%), anaemia (56%), rash (52%), fatigue (52%), dermatology other (34%) and leukopenia (28%). Grade 3-4 drug-related toxicities were infrequent (<10%). No cardiotoxicity was observed. T plasma concentrations did not appeared to be affected by the presence of lapatinib. L steady-state plasma concentrations were 20% lower after 28 days of co-administration with T. Eight (36.4%) patients experienced stable disease and median progression free survival was 2.7 months.

CONCLUSIONS

The combination of L and T was safe and clinically active. T affected L plasma concentrations, which remained within the therapeutic index.

Abstract A72: A first-in-man Phase I study of the galectin-1 (gal-1) inhibitor OTX008 given subcutaneously as a single agent to patients with advanced solid tumors

Background: Gal-1 is a lectin with multiple biological functions including tumor progression, migration, and angiogenesis. OTX008, a small molecule downregulating gal-1 protein level, displays direct antiproliferative and anti-invasive effects in human cancer cells.

Objectives: Determine the maximum tolerated dose (MTD) of single agent OTX008 using a subcutaneous (SC) daily dosing based on dose-limiting toxicities (DLTs). Secondary objectives were safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity.

Patients and Methods: Patients (pts) with solid tumors having failed standard therapies, and given a written consent were enrolled. OTX008 was delivered as daily SC injection. In case of DLT, treatment was interrupted until recovery and resumed at the dose level (DL) below. Dose was escalated according to a 3+3 design. The MTD was defined as the highest DL, in which ≤1/6 pt experiences a DLT.

Results: 22 pts (50% with colorectal carcinoma) were treated from March 2012 to March 2013. Six were enrolled at DL1 (65mg-flat dose) without DLT. Among the 7 pts enrolled at DL2 (120-130mg), 2 experienced DLT. DL2 was therefore deemed to exceed the MTD and 9 additional pts were enrolled at DL1. No DLT was observed among the 15 patients treated at DL1. The most frequent related adverse event (AE) was G1-2 injection site reaction in 20 patients. Two pts experienced skin ulcerations, resulting in subcutaneous abscess and treatment discontinuation in one and consent withdrawal in another. Transient and fully reversible neurological AEs were observed in 12 pts (55%), and were more frequent (100% vs 33%) and more severe (G3 in 29% vs 0%) at DL2 compared to DL1 respectively. G 1-2 tremor was observed in 8 pts, perioral paresthesia in 5, dizziness in 4 and myoclonia in 2. Two patients experienced G3 ataxia (DLT), and one patient with past history of post-traumatic epilepsy experienced G3 seizure. Gastrointestinal (GI) AEs were reported by 12 pts (55%); G3 vomiting/abdominal pain and G3 diarrhea were reported in 1 pt each; 12 patients developed asymptomatic abnormal lab values (10 hypomagnesemia and 8 transient elevation of CPK without rhabdomyolysis or cardiac ischemia). OTX008 plasma concentrations were &gt;1µM over 12h after administration. PK of OTX008 is best described by a two compartment open model and showed less than proportional exposure increase, possibly due to wide inter-patient variability. The main covariate effect was related to body weight. Plasma gal-1 levels decreased proportionally with increasing OTX008 plasma concentrations. Serial tumor biopsies in 6 patients did not conclude on a PD effect. No objective response was reported.

Conclusions: OTX008 recommended flat daily sc dose is 65mg, which achieves significant systemic plasma concentrations based on in vitro models. Weight adapted dosing may optimize systemic exposure. Local tolerance of SC injection is poor.Reversible ataxia was a dose-limiting toxicity.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A72.

Citation Format: Jean-Pierre Delord, Ahmad Awada, Eric Raymond, François Lokiec, Patrice Herait, Keyvan Rezai, Nicolas Lachaux, Gabriel A. Rabinovich, Carlos Gomez-Roca, Philippe Aftimos, Sandrine Faivre, Juan Carlos Stupirski. A first-in-man Phase I study of the galectin-1 (gal-1) inhibitor OTX008 given subcutaneously as a single agent to patients with advanced solid tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A72.

Trastuzumab (T) and everolimus (E) pharmacokinetics (PK) in HER2 positive (+) primary breast cancer (BC) patients (pts): Unicancer RADHER trial results

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Background: T has greatly modified the prognosis of HER2+ BC, but few studies have analyzed its PK. The RADHER study evaluated the interest of adding E to T as preoperative therapy for primary HER2+ BC. It also aimed at describing the PK of T and studying the impact of E with T in primary BC. Methods: Eligible pts with HER2+ operable primary BC were randomized to receive T alone (loading dose 4 mg/kg, then 2 mg/kg/week (W)) or T + E (10 mg/day (D)) for a 6-W pre-operative treatment. Blood samples were collected to measure T and E concentrations. For T, plasma samples were collected in all pts before each infusion, and at Hour (H) 1, D1, D3, W1, W2, W4, W8 and W12 after the last infusion. E concentrations were determined on whole blood collected at H0, H0.5, H1, H2, H4, H6, H12 and H24 after the first T infusion, and again after the last E intake. T and E PK were described using population compartment analyses. Results: From 82 pts randomized, 79 were evaluable for T and 22 for E PK. Mean estimated PK parameters of T were (interindividual coefficient of variation %): central (Vc) and peripheral (Vp) volumes of distribution = 2 L (24%) and 1.3 L (39%), systemic (CL) and intercompartment (Q) clearances = 0.22 L/day (19%) and 0.36 L/day, respectively. Vc increased with body weight and decreased with age, while CL increased with body weight and with tumor volume. Elimination half-life was 11 days, a value lower than that previously reported in metastatic BC (28 days). E PK was best described by a two-compartment model. Mean estimated PK parameters (RSE%) of E were: CL = 3.96 L/h (22%), Q = 29.1 L/h (7%), Vc = 119 L (11%), Vp = 1530 L (24%). E did not influence T PK. E PK was similar to that previously reported in other indications. Conclusions: This is the first study describing the PK of T and E in primary BC. Notably, T CL increases with tumor volume and the elimination half-life is only 11 days, lower than expected from previous results in metastatic BC. The differences in PK between primary and metastatic BC might lead to take a second look at trastuzumab dose regimen in primary BC. Clinical trial information: NCT00674414.

Abstract 31: A population pharmacokinetic-pharmacodynamic (POP-PK/PD) modelling of EZN-3042 administered with or without docetaxel in patients with advanced solid tumors or lymphoma

Background: Survivin, a member of the apoptosis protein inhibitor family, is an essential regulator of cell division and a modulator of programmed cell death. Overexpression of survivin has been noted in multiple cancers and is associated with poor prognosis and decreased overall survival.

The survivin mRNA antagonist EZN-3042 is a locked nucleic acid (LNA)-antisense oligonucleotide (ASO) that specifically down-modulates survivin mRNA and consequently protein.

The objectives of this study are to determine the recommended dose, pharmacokinetics (PK), and pharmacodynamics (PD) and to perform a POP-PK/PD modeling of EZN3042 in patients with advanced solid tumors or lymphoma.

Materials and Methods: A phase 1, open-label, dose-escalation study evaluating the safety and tolerability of EZN-3042 given weekly as a 2-hour iv infusion was previously presented (AACR; San Francisco, CA; November 13, 2011). Dose levels ranged from 2.5 mg/Kg to 8.0 mg/Kg. For PK analysis, 10 time point blood samples were collected on D1 of cycle 1 and 1 blood sample just before administration (Cmin) was collected on D1 of each subsequent treatment cycle.

POP-PK/PD analyses were carried out using the nonlinear mixed effect modeling software program Monolix version 4.1.2. Proportional residual variability and exponential between subject variabilities (BSVs) were used. Different covariates including Body Weight (BW), and sex were investigated. The PK parameters were allometrically normalized for BW to a 70 kg individual.

Results: From 30 patients (16 males, 14 females), 479 time-plasma concentrations and 307 ANC were available for analysis. A 3-compartment open model adequately described the total EZN3042 time-concentration curve with linear elimination. The BSVs could be well estimated for all structural parameters (clearance: CL, volume of distribution: V, inter-compartmental clearances: Q) except for V2 and V3.

The main PK parameters (RSE%) estimated for EZN3042 were CL=4.2 (17%) L/h, Q2=0.26 (31%) L/h, Q3=1.22 (13%) L/h, V1=11.7 (6%) L, V2=3.7 (17%) L, and V3=640 (10%) L.

The main covariate effects were related to BW, only V1 (central volume) was influenced by BW.

Conclusions: The POP-PK modeling satisfactorily described the plasma EZN-3042 time-concentration curves in patients. The main covariate effect was related to BW and this influenced only the central volume of distribution. This indicates that the central volume of distribution of EZN-3042 increased when the body weight increased. A central volume higher than the circulating blood volume and a large volume of the deep compartment suggest that EZN-3042 has large tissue diffusion. POP-PK/PD modeling with ANC is ongoing.

Citation Format: E Baudry, Keyvan Rezai, Saik Urien, Anthony Tolcher, Amita Patnaik, Kyriakos P. Papadopoulos, James Agnew, Aby Buchbinder, Francois Lokiec. A population pharmacokinetic-pharmacodynamic (POP-PK/PD) modelling of EZN-3042 administered with or without docetaxel in patients with advanced solid tumors or lymphoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 31. doi:10.1158/1538-7445.AM2013-31

Abstract A216: Results of a phase 1, open-label, dose-escalation study evaluating the safety and tolerability of EZN-3042, a survivin mRNA antagonist, administered with docetaxel (D) in adult patients (Pts) with advanced solid tumors

Background: Survivin, the smallest member of the inhibitors of apoptosis protein gene family, functions as a key regulator of mitosis and apoptosis. Overexpression of survivin in many cancers is correlated with an increased rate of recurrence and reduced survival, and over expression of survivin has been associated with taxane resistance. EZN-3042 is a potent locked nucleic acid antisense oligonucleotide that down-modulates survivin mRNA and consequently protein in vitro. Preclinically, EZN-3042 enhances apoptotic and antitumor effects of taxanes.

Methods: This study was designed to determine the safety and tolerability, maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics, and preliminary evidence of antitumor activity of EZN-3042 as a single agent (SA) and in combination (EZN-3042 + D). The maximum tolerated dose (MTD) of SA EZN-3042 is 6.5 mg/kg. (Reported at AACR 2011, abstract LB-409). Patients with advanced tumors received EZN-3042 (qwk) + D (75 mg/m2 q3wk), either after disease progression following SA therapy (during dose escalation of SA EZN-3042), or directly (after MTD of SA EZN-3042 was determined).

Results: 16 pts (7 M / 9 F; median age = 66 y [44–75 y]) received EZN-3042 + D. 10 pts received EZN-3042 +D doses of 2.5 mg/kg (n=7) and 5 mg/kg (n=3) after progression on SA EZN-3042; 6 pts received 6.5 mg/kg of EZN-3042 + D doses directly. Tumor types included prostate cancer (n=6); breast cancer (n=3); pancreas cancer (n=2); and non-small cell lung cancer, leiomyosarcoma, gastric, tongue, and unknown primary cancer (n=1 each). Dose-limiting toxicity was observed in 1 pt at 2.5 mg/kg of EZN-3042 (Grade 3 neutropenic fever) and 1 pt at 6.5 mg/kg of EZN-3042 (Grade 3 AST & ALT). Doses higher than 6.5 mg/kg were not evaluated for EZN-3042 +D since they were found to exceed the MTD for SA EZN-3042. Drug-related AEs (in &gt;20% pts) for EZN-3042 + D were fatigue (56%), alopecia (38%), neutropenia (31%), anorexia, nausea and peripheral sensory neuropathy (25% each). Most AEs were Grade 1 or 2. Preliminary assessment of antitumor activity indicates that the best response for EZN-3042 + D was confirmed PR in 1 pt with prostate cancer (2.5 mg/kg, 27 weeks).

Conclusions: EZN-3042 + docetaxel was well tolerated in previously treated pts with advanced tumors. The MTD of EZN-3042 + D is 6.5 mg/kg. EZN-3042 is being evaluated in a window of opportunity study in combination with chemotherapy in pediatric patients with relapsed acute lymphoblastic leukemia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A216.

Abstract 5468: GEP01: A phase I pharmacokinetic study of lapatinib and iv vinorelbine in the treatment of HER2-positive locally advanced or metastatic breast cancer

Background: A novel combination of oral lapatinib (LPT), a selective dual ErbB1/ErbB2 targeted drug, + iv vinorelbine (VNR), a cell-cycle inhibiting agent, could provide a high-potential treatment for locally-advanced or metastatic HER2-overexpressing breast cancer refractory to first or second-line chemotherapy associated to trastuzumab. LPT has been shown to be a strong inhibitor of CYP3A4 which is also mainly involved in VNR metabolism.

In this study we investigated the potential pharmacokinetic (PK) interactions related to the association of VNR and LPT.

Methods: Women with HER2+ locally advanced or metastatic breast cancer progressing after ≤ 2 lines of trastuzumab-based treatment, were treated with LPT starting 7 days (D) (D-7 to D0) before adding VNR on a D1 & D8 q3w IV schedule. LPT was given orally continuously. Dose levels [DL, LPT (mg)/VNR (mg/m2)] ranged from 750/20 to 1,250/30. A total of 29 patients, 36 to 75 years old, were treated by the association of LPT + VNR. For PK analysis, 7 time point samples were collected on D1 of cycle 1 for LPT and VNR assays. For VNR and LPT respectively, whole blood and plasma concentrations were measured using UPLC coupled with tandem mass spectrometry validated methods.

Population PK was modelled using a non linear mixed effect model program (Monolix version 3.1s) by computing the maximum likelihood estimator of the parameters without any approximation of the model (no linearization).

Results: A three-compartment open model adequately described VNR time versus concentration courses. The inter-individual variabilities (ISV) could be well estimated for all stuctural parameters (clearance : CL, volume of distribution : V, inter-compartmental clearances : Q) except for Q3 and V3. The population PK parameters obtained for the structural model were: CL=40.2 L/h, V1=8.49 L, Q2=46.9 L/h, V2=1290 L, Q3=61.9 L/h and V3=60.9 L. Influence of platelet counts and LPT dose values on blood VNR CL were significant according to the Bayesian Information Criteria (BIC). A one-compartment model adequately fitted the LPT plasma concentration-time data. The population PK parameters were CL=27.9 L/h, V=61.5 L and the absorption constant, ka=0.071 h−1. The ISV were 55.7% and 81.7% for CL and V respectively. No covariate effect, including body surface area and VNR dose values on any PK parameters for LPT could be identified.

Conclusions: A PK interaction occured between VNR and LPT. When the LPT dose level increased, the VNR CL decreased significantly, probably due to CYP450-3A4 interaction. The LPT dose which should decrease VNR CL by 50% was defined as 1790 mg. No covariate effects on any LPT PK parameters had been identified. A PK/PD modelling using tumour evaluation and absolute neutrophil count (ANC) is ongoing.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5468. doi:10.1158/1538-7445.AM2011-5468

Abstract LB-409: Results of a phase 1, open-label, dose-escalation study evaluating the safety and tolerability of EZN-3042, a survivin mRNA antagonist, administered with or without docetaxel in adult patients with advanced solid tumors or lymphoma

Background: Survivin, the smallest member of the inhibitors of apoptosis protein gene family, functions as a key regulator of mitosis and apoptosis. Overexpression of survivin in many cancers is correlated with an increased rate of recurrence and reduced survival. EZN-3042 is a potent locked nucleic acid antisense oligonucleotide that down-modulates survivin mRNA and consequently protein in vitro (IC50 &lt;5 nM). Preclinically, EZN-3042 enhances apoptotic and antitumor effects of taxanes.

Methods: This study was designed to determine the safety and tolerability, maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics, and preliminary evidence of antitumor activity of EZN-3042 as a single agent (SA) and in combination with docetaxel (EZN-3042 + D). Using a novel dose-escalation design, pts with advanced tumors first received SA EZN-3042 as a 2-h IV infusion qwk. After disease progression following SA therapy, pts could receive EZN-3042 (qwk) + D (75 mg/m2 q3wk). Dose escalation (3+3) for SA and EZN-3042 + D was independently based on toxicities observed during Cycle 1 of SA EZN-3042 or EZN-3042 + D, respectively (modified Fibonacci dose-escalation design).

Results: 25 pts (14 M/11 F; median age = 61 y [44–75 y]) enrolled in the study. 24 pts received SA EZN-3042 doses of 2.5 (n=3), 5 (n=9), 6.5 (n=6), and 8 mg/kg (n=6); 1 pt did not receive SA EZN-3042 but was treated directly with EZN-3042 (6.5 mg/kg) + D. Tumor types included prostate cancer (PC) (n=9); colorectal cancer (CRC) (n=5); breast cancer (n=3); non-small cell lung cancer (n=2); and pancreatic cancer, lymphoma, mesothelioma, leiomyosarcoma, thymic carcinoma, and unknown primary cancer (n=1 each). 11 pts received EZN-3042 (2.5 mg/kg: n=7, 5 mg/kg: n=3, 6.5 mg/kg: n=1) + D. Dose-limiting toxicity was observed in 3 pts at 8 mg/kg of SA EZN-3042 (Grade 3 increased aspartate or alanine aminotransferase [AST or ALT]) and in 1 pt who had received EZN-3042 (2.5 mg/kg) + D (Grade 3 neutropenic fever).The MTD for SA EZN-3042 is 6.5 mg/kg. Drug-related adverse events (AEs) (in &gt;15% pts) for SA EZN-3042 were AST increase (42%), ALT increase (38%), fatigue (33%), and diarrhea (17%). Drug-related AEs (in &gt;20% pts) for EZN-3042 + D were fatigue (64%), neutropenia (55%), alopecia (46%), anorexia (36%), and leukopenia and nausea (27% each). Most AEs were Grade 1 or 2. PK data for all 24 patients will be presented. Preliminary assessment of antitumor activity indicates that the best response for SA EZN-3042 was stable disease in 5 pts, including 1 pt with thymic carcinoma (5 mg/kg, 16 weeks); the best response for EZN-3042 (2.5 mg/kg) + D was a confirmed partial response in 1 pt with PC (27 weeks).

Conclusions: EZN-3042 was well tolerated in previously treated pts with advanced tumors. The MTD of SA EZN-3042 is 6.5 mg/kg.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-409. doi:10.1158/1538-7445.AM2011-LB-409

Effect of ABCB1 C3435T polymorphism on docetaxel pharmacokinetics according to menopausal status in breast cancer patients

Background:

It can be hypothesised that inherited polymorphisms in the drug-transporter ABCB1 gene may interfere with interindividual variations in drug response in breast cancer patients. Docetaxel is a substrate for ABCB1 whose function has been shown to be modulated by oestrogen and progesterone.

Methods:

Whether ABCB1 polymorphisms including T-129C, A61G, C1236T, G2677T/A and C3435T polymorphisms could account for variations in the disposition of docetaxel and whether menopausal status at the time of diagnosis might interact with this effect were analysed in women receiving neoadjuvant chemotherapy for breast cancer (n=86).

Results:

A highly significant association was observed, but restricted to premenopausal women (n=53), between the pharmacokinetics of docetaxel and C3435T polymorphism, as patients with CC genotype had lower mean values of the area under the plasma concentration-time curve (AUC) of docetaxel than patients with CT and TT genotypes (P<0.0001). Comparison between pre- and postmenopausal women with the same C3435T genotype yielded a significant difference in docetaxel AUC only for CC genotype (P<0.0001).

Conclusion:

These results suggest that C3435T polymorphism genotyping and menopausal status at the time of diagnosis might be useful when considering chemotherapy regimens including docetaxel in breast cancer patients.

Population pharmacokinetics of docetaxel in elderly patients

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Background: Elderly patients (>70 years) may present different pharmacokinetic profile for many drugs , mainly because of altered elimination due to renal function or metabolic decreases. Methods: Docetaxel, 50 to 85 mg/m2, median 70 mg/m2, was infused during 1 hr to 44 patients, aged 70 to 83 years, median 76.5 years. Three blood samples per patient were obtained according to a limited sampling strategy (Baille et al. Clin Cancer Res 1997, vol. 3, 1535–38). Covariates of interest were carefully recorded, age, body weight, body surface area, gender, serum creatinine, orosomucoid, serum albumin. These data were then analysed using NONMEM V to a) obtain individual Bayesian estimates of docetaxel clearance, b) re-analyse the data in order to estimate population parameters for this elderly population, c) show possible covariate effects on the pharmacokinetic parameters. Results: Median docetaxel CL from Bayesian estimation was 29.1 (2.5–97.5% quantiles 12–49) L/h. When the population was re-analysed per se, docetaxel CL was 29.2 (2.5–97.5% quantiles 17–35) L/h. The inter- subject variability for CL was 25% (precision 32%).. No covariate effect was observed on CL. Conclusions: Docetaxel clearance in elderly patients is slightly decreased, 29 L/h versus 36.8 L/h (reported in 547 patients, mean age 56 years, 5–95% quantiles 39–71 years). The inter-subject-variability of CL in elderly patients was decreased to 25% versus 47.5% in the 547 patients population. A pharmacokinetic- pharmacodynamic modelling of neutrophil counts versus time will be performed in these elderly patients in order to point a possible different sensitivity of this population to the myelosuppressive effects of docetaxel.

No significant financial relationships to disclose.

Variations in schedules of ifosfamide administration: a better understanding of its implications on pharmacokinetics through a randomized cross-over study

PURPOSE

The metabolism of ifosfamide is a delicate balance between a minor activation pathway (4-hydroxylation) and a mainly toxification pathway (N-dechloroethylation), and there remains uncertainty as to the optimal intravenous schedule.

METHODS

This study assesses ifosfamide pharmacokinetics (PK) according to two standard schedules. Using a 1:1 randomized trial design, we prospectively evaluated ifosfamide PK on two consecutive cycles of 3 g/m2/day for 3 days (9 g/m2/cycle) given in one of two schedules either by continuous infusion (CI) or short (3 h) infusion. Highly sensitive analytical methods allowed determination of concentrations of ifosfamide and the key metabolites 4-hydroxy-ifosfamide, 2- and 3-dechloroethyl-ifosfamide.

RESULTS

Extensive PK analysis was available in 12 patients and showed equivalence between both schedules (3 h versus CI) based on area under the curves (micromol/l x h) for ifosfamide, 4-hydroxy-ifosfamide, 2- and 3-dechloroethyl-ifosfamide (9,379 +/- 2,638 versus 8,307 +/- 1,995, 152 +/- 59 versus 161 +/- 77, 1,441 +/- 405 versus 1,388 +/- 393, and 2,808 +/- 508 versus 2,634 +/- 508, respectively, all P > 0.2). The classical auto-induction of metabolism over the 3 days of infusion was confirmed for both schedules.

CONCLUSION

This study confirms similar PK for both active and toxic metabolites of ifosfamide in adult cancer patients when 9 g/m2 of ifosfamide is administered over 3 days by CI or daily 3-h infusions.

Pharmacokinetics, metabolism, and routes of excretion of intravenous irofulven in patients with advanced solid tumors

Irofulven is currently in Phase 2 clinical trials against a wide variety of solid tumors and has demonstrated activity in ovarian, prostate, gastrointestinal, and non-small cell lung cancer. The objectives of this study were to determine its pharmacokinetics and route of excretion and to characterize its metabolites in human plasma and urine samples after a 30-min i.v. infusion at a dose of 0.55 mg/kg in patients with advanced solid tumors. Three patients were administered i.v. 100 microCi of [14C]irofulven over a 30-min infusion on day 1 of cycle 1. Serial blood and plasma samples were drawn at 0 (before irofulven infusion) and up to 144 h after the start of infusion. Urine and fecal samples were collected for up to 144 h after the start of infusion. The mean urinary and fecal excretion of radioactivity up to 144 h were 71.2 and 2.9%, respectively, indicating renal excretion was the major route of elimination of [14C]irofulven. The C(max), AUC(0-infinity), and terminal half-life values for total radioactivity were 1130 ng-Eq/ml, 24,400 ng-Eq . h/ml, and 116.5 h, respectively, and the corresponding values for irofulven were 82.7 ng/ml, 65.5 ng . h/ml, and 0.3 h, respectively, suggesting that the total radioactivity in human plasma was a result of the metabolites. Twelve metabolites of irofulven were detected in human urine and plasma by electrospray ionization/tandem mass spectrometry. Among these metabolites, the cyclopropane ring-opened metabolite (M2) of irofulven was found, and seven others were proposed as glucuronide and glutathione conjugates.

Development of Daptomycin resistance in vivo in methicillin-resistant Staphylococcus aureus

Daptomycin is a new lipopeptide antibiotic that is rapidly bactericidal against Staphylococcus aureus. We report daptomycin resistance and treatment failure in 2 patients with osteomyelitis due to methicillin-resistant S. aureus. Disk diffusion susceptibility testing failed to detect resistance. Daptomycin at high concentration retained bactericidal activity against resistant isolates.

Factors Influencing Visualization of Vertebral Metastases on MR Imaging Versus Bone Scintigraphy

OBJECTIVE

The purpose of this study was to investigate whether the location and size of vertebral body metastases influence the difference in detection rates between MR imaging and bone scintigraphy.

MATERIALS AND METHODS

We retrospectively evaluated the vertebral body lesions detected on MR imaging in 74 patients with known widely disseminated metastatic disease. Three radiologists independently reviewed the MR images and bone scintigraphs. MR imaging findings included lesion size and its spatial relationship to the bony cortex (intramedullary, subcortical, and transcortical) and results were correlated with those of planar technetium 99m bone scintigraphy.

RESULTS

Findings on bone scans were negative for all intramedullary lesions without cortical involvement shown on MR imaging, regardless of their size. Findings on bone scans (71.3% for transcortical and 33.8% for subcortical) were frequently positive for lesions with cortical involvement (trans- or subcortical), and the probability of positive findings on bone scans was also influenced by the lesion size. Statistical analysis showed a positive correlation among cortical involvement, lesion size, and positive findings on bone scintigraphy (p < 0.0001).

CONCLUSION

Location (the presence of cortical bone involvement on MR imaging) and size of the vertebral body metastases appear to be important contributing factors to the difference in detection rates between MR imaging and bone scintigraphy. Cortical involvement is likely the cause of positive findings on bone scans. Early vertebral metastases tend to be small and located in the medullary cavity without cortical involvement, and therefore, findings may be positive on MR images but negative on bone scans.

Emission-based attenuation correction of myocardial perfusion studies

BACKGROUND

Nonuniform attenuation in the thorax can generate artifacts in single-photon emission computed tomographic myocardial perfusion studies that mimic coronary artery disease. In this article we present both phantom and simulation data, as well as clinical data, in support of an emission-based method that provides reliable correction for attenuation effects without the need for a transmission measurement.

METHODS AND RESULTS

The attenuation map is derived from the measured distribution of 99mTc-labeled macroaggregated albumin in the lungs and a radioactive binder wrapped about the thorax. This information is acquired as part of a dual-isotope acquisition during the rest 201Tl study. Segmentation is used to define the interiors of lung and body compartments, which are assigned a single attenuation coefficient for each of the two tissue types. The appropriateness of this approach was investigated by examining the measured attenuation coefficients in a group of 80 individuals (40 male, 40 female) from positron emission tomographic transmission studies. The correction technique was evaluated with computer simulations, a physical phantom, and clinical data acquired from 20 patients. Analysis of the positron emission tomographic data found a small SD in the mean attenuation coefficients for the body (<5%) and lungs (<15%). The application of emission-based attenuation-correction technique produced a substantial reduction in the magnitude of the attenuation artifact in images obtained from both the phantom and the simulation studies. The emission-based attenuation-correction technique was easily applied to myocardial perfusion studies, where it had a significant effect, resulting in changes in interpretation for nine of 20 patients.

CONCLUSIONS

The results of this study provide strong support for the concept that an attenuation map can be generated with fixed attenuation values in place of those that are directly measured. Thus the emission-based attenuation-correction technique can be considered an inexpensive alternative to transmission-based correction methods. Because the emission-based correction technique does not require any additional hardware, it has the major advantage of being applicable to all single-photon emission computed tomographic systems.

Effect of antipsychotics on regional cerebral blood flow measured with positron emission tomography

Positron Emission Tomography (PET) imaging of regional cerebral blood flow (rCBF) provides an in vivo method for studying brain function. We used [15O]H20 PET to assess the effect of antipsychotic medications on rCBF in 17 subjects with schizophrenia. Each subject was scanned while receiving antipsychotic medication, and after having been withdrawn from antipsychotic medication for a 3-week period. The two scans were subtracted from one another, using a within subjects design, and the areas of difference were identified using the Montreal method. Subjects treated with antipsychotic medication had significantly higher rCBF in the left basal ganglia and left fusiform gyrus compared with the "off-medication" condition. Significantly higher relative rCBF in the anterior cingulate, left dorsolateral and inferior frontal cortex, and left and right cerebellum was observed when off antipsychotic medication. Upregulation of dopamine D2 receptors may lead to a regional increase of blood flow and metabolism in the basal ganglia, which may explain recently reported anatomical enlargement in these regions.

The effect of antipsychotic medication on relative cerebral blood perfusion in schizophrenia: assessment with technetium-99m hexamethyl-propyleneamine oxime single photon emission computed tomography

Functional neuroimaging studies in schizophrenia have often been confounded by various factors including medication status. To explore the effects of antipsychotic medications on relative regional cerebral perfusion, we scanned a group of 33 persons with schizophrenia twice, while receiving a stable dose of antipsychotic and after being off antipsychotics for 3 weeks, using technetium-99m hexamethyl-propyleneamine oxime single photon emission computed tomography (Tc-99m HMPAO-SPECT. We found that antipsychotic significantly increased the mean relative cerebral perfusion in the left basal ganglia. Additionally, patients receiving thiothixene (n = 9) had a significantly greater increase in relative cerebral perfusion in the basal ganglia than patients receiving haloperidol (n = 12). These findings indicate that antipsychotics lead to regional increases in cerebral perfusion and that antipsychotic status must be controlled for in functional neuroimaging studies. Functional neuroimaging techniques such as SPECT may be useful in furthering our understanding of the mechanism of antipsychotics.

Evaluation of diabetic patients for renal and pancreas transplantation: noninvasive screening for coronary artery disease using radionuclide methods

Pharmacologic stress thallium scintigraphy is commonly performed in the risk assessment of diabetic patients with nephropathy before kidney and/or pancreas transplantation; however, controversy exists regarding the test's accuracy in detecting coronary artery disease. Our purpose was to compare pharmacologic stress thallium scintigraphy and also exercise radionuclide ventriculography with coronary angiography in diabetic patients undergoing evaluation for transplantation. In addition, we also determined the association of the test results with outcome after transplantation. The medical records of 47 patients (mean age, 37+/-9 years) without clinical evidence of coronary artery disease were reviewed. Forty-one patients had pharmacologic stress thallium scintigraphy performed during their evaluation. Sensitivity was 62% and specificity was 76% for detecting > or = 75% coronary artery stenosis (sensitivity was 53% and specificity was 73% for > or = 50% stenosis). Thirty-five patients had exercise radionuclide ventriculography performed. Sensitivity was 50% and specificity was 67% for detecting > or = 75% coronary artery stenosis (sensitivity was 44% and specificity was 63% for > or = 50% stenosis). Thirty patients had both pharmacologic stress thallium scintigraphy and exercise radionuclide ventriculography performed; when either test was abnormal, sensitivity in the detection of > or = 50% or > or = 75% stenosis tended to increase compared with pharmacologic stress thallium scintigraphy alone (0.05<P<0.10), whereas specificity decreased (P<0.01). The incidence of adverse cardiac outcomes was identical for patients with abnormal thallium scintigrams and undergoing transplantation (2/11) compared with patients with normal scintigrams and undergoing transplantation (4/22). We conclude that: (1) pharmacologic stress thallium scintigraphy and exercise radionuclide ventriculography are suboptimal screening tests for coronary artery disease in diabetic patients awaiting kidney and/or pancreas transplantation; (2) using the two radionuclide tests in combination results in a decrease in specificity; and (3) patients with abnormal thallium scintigrams can receive transplants with outcomes similar to those for patients with normal thallium scintigrams.

Four- to twenty-four-hour uptake ratio: an index of rapid iodine-131 turnover in hyperthyroidism

Rapid thyroidal iodine turnover may contribute to 131I therapy failure in patients with hyperthyroidism. The utility of a 4- to 24-hr 131I uptake ratio was evaluated as an index of thyroidal iodide retention in hyperthyroid patients.

METHODS

In 433 hyperthyroid patients, the success of 131I therapy was correlated with the following factors: gender, pretreatment with antithyroid drugs, clinical diagnosis, magnitude of early and late thyroidal 131I uptake values, and the 4- to 24-hr 131I uptake ratio.

RESULTS

Of the 433 patients, 362 patients (84%) had a successful outcome after a single therapeutic dose of 131I while 71 (16%) did not. Multiple linear regression analysis revealed that the highest statistically significant predictor of outcome was the 4- to 24-hr 131I uptake ratio (p-value < 0.001); all other factors showed a weaker association. An 131I uptake ratio of > 1 was found in 67 (15%) patients. Thirty-two of these 67 patients (48%) failed 131I therapy, whereas those patients with uptake ratios of < 1.0, only 39/366 (11%) failed 131I therapy.

CONCLUSION

The 4- to 24-hr 131I thyroidal uptake ratio is a practical substitute for exact determination of the effective half-life. It identifies patients who are likely to have a rapid 131I turnover without the need for extended thyroid uptake measurements. An 131I uptake ratio of > or = 1 was found in 15% of hyperthyroid patients and was associated with a near 50% 131I therapy failure rate.

Schizophrenia and cognitive dysmetria: a positron-emission tomography study of dysfunctional prefrontal-thalamic-cerebellar circuitry

Patients suffering from schizophrenia display subtle cognitive abnormalities that may reflect a difficulty in rapidly coordinating the steps that occur in a variety of mental activities. Working interactively with the prefrontal cortex, the cerebellum may play a role in coordinating both motor and cognitive performance. This positron-emission tomography study suggests the presence of a prefrontal-thalamic-cerebellar network that is activated when normal subjects recall complex narrative material, but is dysfunctional in schizophrenic patients when they perform the same task. These results support a role for the cerebellum in cognitive functions and suggest that patients with schizophrenia may suffer from a "cognitive dysmetria" due to dysfunctional prefrontal-thalamic-cerebellar circuitry.

Effects of leflunomide and other immunosuppressive agents on T cell proliferation in vitro

Leflunomide and its active metabolite, A771726, are structurally unrelated to immunosuppressive agents currently under investigation. Previous in vitro studies have revealed that leflunomide primarily inhibits interleukin-2-stimulated T cell proliferation. In the current study, we have extended our previous work and demonstrate that leflunomide prevents T cell progression induced by phytohemagglutinin into the S phase of the cell cycle. To discriminate further the action on T cells of leflunomide from other immunosuppressive agents, we performed kinetic studies where leflunomide was added either after the initiation of mixed lymphocyte cultures (MLC) or after interleukin-2 stimulation of CTLL-4 cell proliferation. These studies revealed that leflunomide acted comparably to rapamycin, but was distinct from brequinar sodium in the MLC, and from cyclosporine and mycophenolic acid in both MLC and CTLL-4. Although previous biochemical studies indicated that leflunomide can inhibit src-family tyrosine kinase activity, more recent studies have suggested that leflunomide can also inhibit pyrimidine synthesis. Our data demonstrate that the ability of leflunomide (25-100 microM) to inhibit MLC and CTLL-4 cell proliferation is partially antagonized by uridine (25-100 microM), and support the hypothesis that leflunomide inhibits pyrimidine synthesis in T cells. Unique molecular mechanisms of immunosuppression suggest that drug combinations may result in synergistic immunosuppression. Our in vitro studies revealed synergistic inhibition of T cell proliferation with the combinations of leflunomide with cyclosporine or with rapamycin. We have extended those studies to quantitate inhibition of MLC by the combinations of leflunomide and brequinar sodium or mycophenolic acid.

Neural substrates of facial recognition

Seventeen healthy normal volunteers performed three facial recognition tasks while their cerebral blood flow was measured with PET: categorizing faces according to gender, recognizing new faces, and recognizing familiar faces. These tasks activated three different pathways: respectively, the left inferior temporal lobe and left frontal cortex; a predominantly right frontal-right parietal-left cerebellar network; and left lingual and left and right fusiform gyri. These results suggest that humans use different brain regions in performing these three routine daily activities. The results are consistent with previous observations concerning organization of extrastriate visual cortex in human and nonhuman primate lesion studies, including studies of the unusual syndrome of prosopagnosia (loss of the ability to recognize familiar faces with intact ability to recognize a face as a face).

I. PET studies of memory: novel and practiced free recall of complex narratives

Positron Emission Tomography (PET) with the tracer H215O was used to measure regional cerebral blood flow in 13 healthy volunteers during two experimental memory tasks, one of which was well-practiced and the other of which was novel. The materials used for the memory tasks consisted of two complex narratives (Story A and Story B from the Wechsler Memory Scale). Natural language materials were chosen because they similate experimentally the natural learning situation and permit study of the neural mechanisms by which recall memory becomes more fluid, automatic, or "rote." One week before the PET study, subjects were trained to perfect recall of Story A, while they were exposed to Story B only 60 s prior to PET data acquisition. Despite the substantial differences in level of familiarity (and in free recall performance), patterns of activation were quite similar; activations presumed to reflect recall in both tasks included frontal, inferior temporal, thalamic, anterior cingulate, and cerebellar regions. Many regions were smaller during recall of the familiar story, however, presumably reflecting greater neural efficiency due to practice. In addition, the novel task activated an additional left frontal region that is presumed to reflect more active encoding. The similarity and multiplicity of the activations in the two tasks suggest that the brain uses a multinodal general network for memory tasks such as free recall, while the differences suggest that some nodes in the network may be used for specific components of memory such as encoding and retrieval.

II. PET studies of memory: novel versus practiced free recall of word lists

Positron emission tomography (PET) with the tracer H215O was used to measure regional cerebral blood flow in 13 healthy volunteers while they engaged in free recall of 15-item word lists from the Rey Auditory Verbal Learning task. The study was designed so that recall of well-practiced versus novel material could be compared. One week before the PET study, subjects were trained to perfect recall of List A, while they were exposed to list B only 60 s prior to PET data acquisition. As in the companion study of free recall of complex narratives, we observed that practice tended to decrease the size of activations in regions involved in the memory component of the task; we also observed that the novel recall task produced greater activation in left frontal regions, probably due to active encoding. A commonality of other regions observed in this pair of studies, as well as other studies of memory in the literature, suggests that the human brain may contain a distributed multinodal general memory system. Nodes on this network include the frontal, parietal, and temporal cortices, the thalamus, the anterior and posterior cingulate, the precuneus, and the cerebellum. There appears to be a commonality of components across tasks (e.g., retrieval, encoding) that is independent of content, as well as differentiation of some components that may be content-specific or tasks-specific. In addition, these results support a significant role for the cerebellum in cognitive functions such as memory.

Remembering the past: two facets of episodic memory explored with positron emission tomography

OBJECTIVE

This study used positron emission tomography to examine two kinds of personal memory that are used in psychiatric evaluation: focused episodic memory (recall of past experience, employed in "taking a history") and random episodic memory (uncensored thinking about experience, examined during analytic therapy using free association). For comparison, a third memory task was used to tap impersonal memory that represents general information about the world ("semantic memory").

METHOD

Thirteen subjects were studied using the [15O]H2O method to obtain quantitative measurements of cerebral blood flow. The three conditions were subtracted and their relative relationships examined.

RESULTS

The random episodic condition produced activations in widely distributed association cortex (right and left frontal, parietal, angular/supramarginal, and posterior inferior temporal regions). Focused episodic memory engaged a network that included the medial inferior frontal regions, precuneus/retrosplenial cingulate, anterior cingulate, thalamus, and cerebellum. The use of medial frontal regions and the precuneus/retrosplenial cingulate was common to both focused and random episodic memory. The major difference between semantic and episodic memory was activation of Broca's area and the left frontal operculum by semantic memory.

CONCLUSIONS

These results indicate that free-ranging mental activity (random episodic memory) produces large activations in association cortex and may reflect both active retrieval of past experiences and planning of future experiences. Focused episodic memory shares some components of this circuit (inferior frontal and precuneus), which may reflect the time-linked components of both aspects of episodic memory, and which permit human beings to experience personal identity, consciousness, and self-awareness.

Cranial osteomyelitis: diagnosis and follow-up with In-111 white blood cell and Tc-99m methylene diphosphonate bone SPECT, CT, and MR imaging

PURPOSE

To assess the usefulness of indium-111 white blood cell and technetium-99m methylene diphosphonate bone single photon emission computed tomography (SPECT), computed tomography (CT), and magnetic resonance (MR) imaging in cranial osteomyelitis.

MATERIALS AND METHODS

Twenty-six cases (25 patients: 13 male, 12 female; mean age, 55 years) of suspected osteomyelitis were evaluated. Sixteen were postoperative. Final diagnosis was established by means of bone culture in 18 cases and clinical follow-up in eight.

RESULTS

Of 35 CT scans, 10 were true-positive (TP); three false-negative (FN); 13, true-negative (TN); one, false-positive (FP); and eight, equivocal. Of 36 SPECT scans, 19 were TP; 13, TN; one, FP; one, FN; and two, equivocal. Of 11 MR images four were TP; five, TN; and two, FN.

CONCLUSION

CT is best for differentiation between soft-tissue and bone infection. MR imaging is best for assessment of the calvaria and skull base. SPECT is best for assessment of altered bone and may be the best technique for follow-up.

Short-term and long-term verbal memory: a positron emission tomography study

Short-term and long-term retention of experimentally presented words were compared in a sample of 33 healthy normal volunteers by the [15O]H2O method with positron emission tomography (PET). The design included three conditions. For the long-term condition, subjects thoroughly studied 18 words 1 week before the PET study. For the short-term condition, subjects were shown another set of 18 words 60 sec before imaging, with instructions to remember them. For the baseline condition, subtracted from the two memory conditions, subjects read a third set of words that they had not previously seen in the experiment. Similar regions were activated in both short-term and long-term conditions: large right frontal areas, biparietal areas, and the left cerebellum. In addition, the short-term condition also activated a relatively large region in the left prefrontal region. These complex distributed circuits appear to represent the neural substrates for aspects of memory such as encoding, retrieval, and storage. They indicate that circuitry involved in episodic memory has much larger cortical and cerebellar components than has been emphasized in earlier lesion studies.

Forskolin and methylxanthines block the increase in intracellular pH during meiosis in Xenopus laevis oocytes

Xenopus oocytes, arrested in late prophase of the meiotic cell cycle, undergo nuclear membrane breakdown (Germinal Vesicle Breakdown, GVBD) in response to progesterone stimulation. During this prophase/M-phase transition the oocytes undergo an increase in their intracellular pH (pHi) from 7.3 to 7.7 in response to the steroid. This increase in pHi appears to be due to the activation of Na+/H+ antiporters in the oocyte plasma membrane. Several studies have shown that the pathway leading to GVBD is blocked by forskolin or methylxanthines which elevate cAMP levels within the oocyte. We have found that these same compounds also blocked the up-regulation of the Na+/H+ exchangers during oocyte meiotic maturation.

Protooncogene product, c-mos kinase, is involved in upregulating Na+/H+ antiporter in Xenopus oocytes

Progesterone-stimulated Xenopus laevis oocytes undergo an increase in their intracellular pH from 7.3 to 7.7 because of the activation of Na+/H+ antiporters in their plasma membrane. Activation of Na+/H+ exchangers (NHE) in other cell systems appears to be regulated by phosphorylation of the NHE protein. In the current study we demonstrated that cytoplasm taken from steroid-stimulated oocytes rapidly induced an increase in intracellular pH when microinjected into full-grown stage VI recipient oocytes. The protein within the cytoplasm that appears to be responsible for this activity is c-mos kinase. Microinjected pure mosxe kinase protein rapidly activated the Na+/H+ exchangers in full-grown recipient oocytes. Furthermore, injected mosxe protein rapidly activated the Na+/H+ exchangers in smaller progesterone-insensitive stage IV oocytes. Therefore, it appears that the protooncogene product, p39 c-mos kinase, which is normally synthesized in full-grown stage VI oocytes in response to progesterone stimulation, is involved in the upregulation of the Na+/H+ antiporters during oocyte meiotic maturation.

Quantification of left ventricular function with an automated border detection system and comparison with radionuclide ventriculography

Quantification of 2-dimensional echocardiograms with a recently developed automated border detection (ABD) system provides on-line estimation of left ventricular (LV) function. Previous studies showed that short-axis cavity area measurements with the ABD system approximate manually traced cavity areas obtained with conventional 2-dimensional echocardiography. Further clinical validation needs a comparison of LV function between the ABD system and established methods. Fractional area change and ejection fraction measured by the ABD system were compared with ejection fraction measured by radionuclide ventriculography. Echocardiographic measurements were obtained from LV short-axis views at the level of the papillary muscles. Calculation of ejection fraction by the ABD system was based on an algorithm using a modified ellipsoid model. Forty-six patients underwent echocardiography on the same day as radionuclide ventriculography. Patients were included in the study if > or = 75% of the endocardium was visualized with conventional 2-dimensional echocardiography. Twenty-seven of 46 patients (59%) had a technically adequate, conventional echocardiogram. Fractional area change with the ABD system was highly correlated with ejection fraction from radionuclide ventriculography (r = 0.92; SEE 8.4%). Ejection fraction determined by the ABD system and radionuclide ventriculography also showed a strong linear relation in the 23 patients without severe wall motion abnormality (r = 0.90; SEE 9.5%). It is concluded that LV function measurements by the ABD system and radionuclide ventriculography have a strong linear relation.

A scintigraphic sign for detection of right-to-left shunts

We evaluated the usefulness of a new scintigraphic sign, a quantum mottling pattern, in diagnosing right-to-left shunt using 99mTc-MAA particles. The quantum mottling pattern is characterized by random distribution of discrete clumps of radioactivity that are more intense than the general body background. Forty-nine 99mTc-MAA scintigrams were analyzed retrospectively for presence of a quantum mottling pattern in extrapulmonary soft tissues and brain. This distinctive pattern was observed in every patient (18/18) in whom a right-to-left shunt was confirmed by nonscintigraphic means and was noted only in one patient in whom independent proof of a right-to-left shunt was not available. In contrast, application of conventional criteria yielded a true-positive interpretation for 15/18 patients with right-to-left shunts and a false-positive interpretation for another four patients. Presence of a quantum mottling pattern on 99mTc-MAA images appears to be a reliable aid for detecting a right-to-left shunt. Use of this sign is likely to improve accuracy of the scintigraphic test in patients with small shunts.

The neuropsychology of the prefrontal cortex

Single photon emission computed tomography with the xenon inhalation technique is used to compare activation of regional cerebral blood flow in frontal brain regions during the performance of four widely used neuropsychological tests: the Continuous Performance Test, the Wisconsin Card Sorting Test, the Tower of London, and Porteus Mazes. Healthy normal volunteers performing these tasks show significant increases in frontal regions during the Continuous Performance Test, the Wisconsin Card Sorting Test, and the Tower of London, but not the Porteus Mazes. Activation produced by the Continuous Performance Test and the Tower of London are mesial and bilateral and may reflect stimulation of midline attentional circuits. The Wisconsin Card Sorting Test produces a left dorsolateral area of prefrontal activation. These findings indicate that regional activation of the frontal lobes occurs in response to cognitive challenges produced through performance of standard neuropsychological tests.

Dual isotope brain SPECT imaging for monitoring cognitive activation: initial studies in humans

A dual isotope, single photon emission tomography (SPECT) technique using 99Tcm-hexamethylpropyleneamine oxime (HMPAO) and 123I-iodoamphetamine (IMP) was investigated to determine its suitability for assessing regional cerebral blood flow (rCBF) changes resulting from cognitive activation. The similarity of the 123I-IMP and 99Tcm-HMPAO distributions under the same physiological conditions was first investigated by administering the two agents to human subjects (n = 8) either simultaneously or at different times but during the performance of the same task. Normalized ratio images generated from the 99Tcm and 123I data showed that the two tracers distributed similarly in the left and right cerebral hemispheres when administered under similar physiological conditions. There was, however, a significant anterior/posterior gradient that appears to be the result of partial volume effects due to small differences in spatial resolution of the two agents. In two subjects, 99Tcm-HMPAO was administered during a resting period with eyes-closed and 123I-IMP was injected later during visual checkerboard stimulation. Ratio images showed a localized increase in the occipital lobes during the visual stimulation consistent with the expected increase in rCBF. The dual isotope strategy appears promising for study of changes in rCBF due to cognitive activation.

Incidental lymph node visualization on bone scan due to subcutaneous infiltration of Tc-99m MDP. A potential for false positive interpretation

Soft tissue localization of radiotracer on bone scintigraphy may result in false-positive interpretations, if the activity overlies a bony structure. A case is presented in which special views and follow-up clarified the soft tissue nature of focal uptake in arm and axilla.

Hypofrontality in neuroleptic-naive patients and in patients with chronic schizophrenia. Assessment with xenon 133 single-photon emission computed tomography and the Tower of London

The "hypofrontality hypothesis" has been supported by many neuroimaging studies, but not all, perhaps because of heterogeneity of samples. The present study examined three different samples that permitted assessment of a variety of confounders, such as effects of long-term treatment, chronicity of illness, and presenting phenomenology: (1) 13 neuroleptic-naive schizophrenic patients, (2) 23 nonnaive schizophrenic patients who had been relatively chronically ill but were medication free for at least 3 weeks, and (3) 15 healthy normal volunteers. Regional cerebral blood flow was measured using single-photon emission computed tomography with xenon 133 as the tracer. The control condition consisted of looking at undulating colored shapes on a video monitor, while the experimental task was the Tower of London. We observed the Tower of London to be a relatively specific stimulant of the left mesial frontal cortex (probably including parts of the cingulate gyrus) in healthy normal volunteers. Both the neuroleptic-naive and the nonnaive patients lacked this area of activation, as well as a related one in the right parietal cortex (representing the circuitry specifically activated by the Tower of London). Decreased activation occurred only in the patients with high scores for negative symptoms. These results suggest that hypofrontality is related to negative symptoms and is not a long-term effect of neuroleptic treatment or of chronicity of illness.

MR imaging and HMPAO scintigraphy in conjunction with balloon test occlusion: value in predicting sequelae after permanent carotid occlusion

OBJECTIVE

Permanent occlusion of the internal carotid artery may be required for en bloc resection of a neck tumor or to treat certain aneurysms. The risk of ischemic infarct is usually assessed with carotid balloon test occlusion and concurrent distal arterial pressure measurement. However, up to 20% of patients who tolerate the test occlusion have delayed neurologic sequelae. We propose enhanced MR imaging and hexamethylpropyleneamine oxime (HMPAO) scintigraphy to detect subclinical signs of ischemia and hypoperfusion as adjuncts to the balloon test occlusion to identify patients at risk for delayed sequelae.

SUBJECTS AND METHODS

We prospectively examined 12 patients referred for balloon test occlusion of the carotid artery. Serial measurements of distal occluded internal carotid pressure were recorded. 99mTc-HMPAO was injected IV after 2 min of asymptomatic test occlusion, and single-photon emission computed tomographic (SPECT) data acquisition was done 1-6 hr later. Contrast-enhanced MR imaging was performed 1-8 hr after completion of the 30-min test occlusion. Signs of decreased perfusion or ischemia on these tests were compared with the mean distal arterial pressure and neurologic status of the patient during test occlusion.

RESULTS

Seven (58%) of 12 patients had abnormal findings on HMPAO scintigraphy or contrast-enhanced MR imaging. Only one patient had neurologic deficits that corresponded to abnormal MR enhancement. The other 11 patients (92%) remained asymptomatic during the 30-min test occlusion. Of these 11 asymptomatic patients, five (45%) had areas of decreased perfusion on scintigraphy and three (27%) had abnormal MR contrast enhancement suggesting residual focal ischemia as a result of the test occlusion. Mean arterial pressures in the distal occluded artery did not correlate well with the imaging results.

CONCLUSION

HMPAO scintigraphy can show clinically silent areas of decreased perfusion, while enhanced MR shows signs of acute ischemia (i.e., significant hypoperfusion) associated with asymptomatic balloon test occlusion. Theoretically, such patients would be at increased risk for permanent sequelae after permanent carotid occlusion.

Intraperitoneal bleeding demonstrated by Tc-99m labeled red blood cell scintigraphy

Tc-99m RBC scintigraphy is known to be useful for the evaluation of gastrointestinal bleeding. The authors describe a patient with a posttraumatic peritoneal tap in whom Tc-99m RBC imaging showed bleeding into the gastrointestinal wall and into the ascitic fluid.

Coronary artery disease and cardiac events with asymptomatic and symptomatic cerebrovascular disease

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the prevalence of coronary artery disease and coronary events during follow-up in patients with asymptomatic carotid stenosis, transient ischemic attacks, or small strokes.

METHODS

We prospectively studied 60 consecutive patients with thallium-201 scintigraphy followed by coronary arteriography according to an established protocol.

RESULTS

The 201Tl testing was abnormal in seven of 15 patients (47%) with asymptomatic carotid stenosis and in 19 of 44 patients (43%) with transient ischemic attacks or small strokes (p greater than 0.05). In 33 patients with no history of coronary artery disease, 11 (33%) had reversible 201Tl defects. In 26 patients with a history of coronary artery disease, 15 (58%) had reversible and/or fixed defects (p = 0.054 compared with patients with no history). A history of peripheral vascular disease was the only risk factor significantly associated with an abnormal 201Tl test (p = 0.032). Coronary artery stenosis of greater than 50% was identified in one or more vessels in 14 of 15 patients undergoing coronary arteriography. Over a mean follow-up period of 311 days, four patients (7%) developed new onset of angina. There were four coronary events among 14 patients (29%) with both a reversible area on the 201Tl and abnormal coronary arteriography. In comparison, there were only four coronary events among 46 patients (9%) without reversible defects on the 201Tl studies (p = 0.055).

CONCLUSIONS

Our study demonstrates that one third of patients with no history of coronary artery disease had an abnormal 201Tl test and that nearly one half of patients with either symptomatic or asymptomatic cerebrovascular disease had abnormal 201Tl tests. Patients with a reversible 201Tl defect and significant stenosis by coronary arteriography were at higher risk for subsequent cardiac events. These findings demonstrate the utility of screening patients with asymptomatic and symptomatic cerebrovascular disease for cardiac disease.

Abnormal captopril renogram in a patient without renovascular hypertension

Captopril renal scintigraphy is a well-known noninvasive tool in the diagnosis of renovascular hypertension. The authors present a case of a patient with malignant hypertension whose captopril renal scintigraphy suggested bilateral and equal renovascular hypertension. His renal angiogram, however, demonstrated no renal artery stenosis or abdominal aortic atherosclerotic disease. False-positive captopril renal scintigraphy has been reported but can usually be attributed to the patient's hypotensive episode after captopril administration, volume or salt depletion, or chronic glomerulonephropathy. This patient demonstrated mild blood pressure changes after captopril administration and was not volume or salt depleted. His creatinine was 1.6 mg/dl on admission but demonstrated appropriate renal function on subsequent noncaptopril renal scintigraphy.

Image processing for the study of brain structure and function: problems and programs

Fundamental problems in the analysis of functional and structural imaging data include data transport, boundary identification (including manual tracing, edge detection, and tissue segmentation), volume estimation, three-dimensional reconstruction and display, surface and volume rendering, shape analysis, and image overlay. These problems require that research investigators have access to suitable methods of image analysis, implemented on a set of software programs, in order to conduct neuroimaging research. The authors describe a group of software programs designed to provide a comprehensive solution for these problems.

Physiological assessment of sensitivity of noninvasive testing for coronary artery disease

The sensitivity of three noninvasive tests for coronary artery disease was assessed by means of quantitative indexes of disease severity in three different groups of patients. The overall population consisted of 110 subjects with limited coronary artery disease and no myocardial infarction. Planar dipyridamole-201Tl scintigraphy was evaluated in 31 patients, computer-assisted exercise treadmill in 28, and high-dose dipyridamole echocardiography testing in 51. Sensitivity was assessed by rigorous gold standards to define disease severity, such as measurement of minimum cross-sectional area and percent area of stenosis, by quantitative computerized coronary angiography (Brown/Dodge method). On the basis of the results of previous studies, the presence of physiologically significant coronary artery disease was indicated by a stenotic minimum cross-sectional area (MCSA) of less than 2.0 mm2 or a greater than 75% area of stenosis. With MCSA as the gold standard, dipyridamole-201Tl scintigraphy, computerized exercise treadmill, and dipyridamole echocardiography testing showed sensitivities of 52%, 54%, and 61%, respectively, in the three different patient cohorts enrolled. With percent area of stenosis as the gold standard, the sensitivity figures obtained for dipyridamole-201Tl, computerized exercise treadmill, and dipyridamole echocardiography testing were 64%, 54%, and 69%, respectively. For each of the three tests, sensitivity increased with increasing lesion severity. Sensitivity was also better in patients with left anterior descending coronary (LAD) disease when compared with patients with left circumflex or right coronary artery disease. Results of these studies, which were obtained with more strict patient selection criteria and by more rigorous gold standards than previous studies, demonstrate that in patients with limited coronary artery disease none of the tests evaluated is definitely superior in sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative accuracy of three scintigraphic methods for determination of right ventricular ejection fraction: a correlative study with ultrafast computed tomography

The accuracy of three scintigraphic methods for determination of right ventricular ejection fraction (RVEF) was tested in 29 patients using ultrafast computed tomography (UFCT) as the gold standard. RVEF measurements by the ECG-gated first-pass approach showed excellent correlation with the UFCT results (r = 0.96, y = 0.06 + 0.91x), while both the standard gated acquisition blood-pool imaging (r = 0.71, y = 0.14 + 0.59x) and the nongated first-pass curve approach (r = 0.63, y = 0.18 + 0.37x) significantly underestimated RVEF. The error can be ascribed to partial inclusion of the atrial activity in the region assigned to the right ventricle. The tricuspid valve plane was found to move by a distance equal to 9%-33% (mean = 20%) of the right ventricular long-axis between systole and diastole. This translational motion was more pronounced with higher EFs.