First-in-human phase I study of copanlisib (BAY 80-6946), an intravenous pan-class I phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors and non-Hodgkin's lymphomas.

BACKGROUND: To evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of copanlisib, a phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors or non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Phase I dose-escalation study including patients with advanced solid tumors or NHL, and a cohort of patients with type 2 diabetes mellitus. Patients received three weekly intravenous infusions of copanlisib per 28-day cycle over the dose range 0.1-1.2 mg/kg. Plasma copanlisib levels were analyzed for pharmacokinetics. Biomarker analysis included PIK3CA, KRAS, BRAF, and PTEN mutational status and PTEN immunohistochemistry. Whole-body [(18)F]-fluorodeoxyglucose positron emission tomography ((18)FDG-PET) was carried out at baseline and following the first dose to assess early pharmacodynamic effects. Plasma glucose and insulin levels were evaluated serially. RESULTS: Fifty-seven patients received treatment. The MTD was 0.8 mg/kg copanlisib. The most frequent treatment-related adverse events were nausea and transient hyperglycemia. Copanlisib exposure was dose-proportional with no accumulation; peak exposure positively correlated with transient hyperglycemia post-infusion. Sixteen of 20 patients treated at the MTD had reduced (18)FDG-PET uptake; 7 (33%) had a reduction >25%. One patient achieved a complete response (CR; endometrial carcinoma exhibiting both PIK3CA and PTEN mutations and complete PTEN loss) and two had a partial response (PR; both metastatic breast cancer). Among the nine NHL patients, all six with follicular lymphoma (FL) responded (one CR and five PRs) and one patient with diffuse large B-cell lymphoma had a PR by investigator assessment; two patients with FL who achieved CR (per post hoc independent radiologic review) were on treatment >3 years. CONCLUSION: Copanlisib, dosed intermittently on days 1, 8, and 15 of a 28-day cycle, was well tolerated and the MTD was determined to be 0.8 mg/kg. Copanlisib exhibited dose-proportional pharmacokinetics and promising anti-tumor activity, particularly in patients with NHL. CLINICALTRIALSGOV: NCT00962611; https://clinicaltrials.gov/ct2/show/NCT00962611.

Evaluation of a commercial radiochromatography module as an arterial blood activity monitor.

Input functions required for positron emission tomography (PET) tracer kinetic modeling are often obtained from arterial blood. In some situations, using short-lived radiotracers, e.g. [(15)O]water, rapid sample handling is required. A method used at several facilities is to pump blood through a detector system at a constant rate. We investigate the suitability of a commercial radiochromatography module (IN/US Posi-RAM) for this new use. The Posi-RAM consists of two 2.5 cm (length) x 2.5 cm (diameter) cylindrical bismuth germanate (BGO) detectors that can operate in coincidence mode. Arterial blood is transported through the system via a length of tubing with flow rate controlled by a peristalsis pump. A custom-counting loop and support frame were designed for the Posi-RAM for PET studies. System sensitivity was determined to be 1.1 x 10(4) cps/(MBq ml(-1)). Dead time as a function of count-rate was found to be less than 1% for concentrations below 3.5 MBq ml(-1), a range encompassing all human-study values. In a human study, the performance of the device was found to be similar to that of the facility's current blood monitor (Siemens Fluid Monitor). We conclude that the Posi-RAM has the necessary sensitivity and count-rate capabilities to be used as a real-time blood activity monitor.

Registration-based method for determining relative PET/MR left-right image orientation.

A quality control method is described for verifying that the coordinate systems of a PET and MR image from the same subject have the same relative left-right orientation. Such ambiguities can arise, for example, at the coordinating center receiving data from many institutions in large multisite studies. In this study, image registration was performed on the PET/MR image pair. The MR image was then reflected (left/right reversed) and the image registration was performed again. A comparison of the values of the cost function describing the accuracy of the registration was used to identify the correct relative orientation. In 122 studies using data with known orientations, 100% accuracy of the method was observed.

Nuclear medicine in the rehabilitative treatment evaluation in stroke recovery. Role of diaschisis resolution and cerebral reorganization.

There has recently been a tremendous increase in imaging technology and imaging methodology enabling noninvasive exploration of brain function to such an intricate degree as to enable measurements of very small spatial and short temporal cerebral operations responsible for neurological and functional recovery after stroke. This has allowed conceptualization of rehabilitation strategies designed to maximally enhance rehabilitation protocols tailored to the individual patient's deficits. Rehabilitation strategies may now be designed and optimized by employing methods to synchronize functional training of brain regions ascribed to those areas innately undergoing neuronal plasticity change responsible for stroke recovery. In order to effectively apply these noninvasive imaging methods, one must have a clear understanding of the physics and technique of the imaging methodologies and how these are best applied to understand brain physiology during the stroke recovery process to provide a solid rationale for development of rehabilitation protocols. Nuclear medicine imaging is first presented as a diagnostic method to assess the stroke process. The initial brain damage and resulting neurological disability can be primarily assessed in terms of changes in the vascular and hemodynamic status of the cerebral circulation in addition to alterations in the metabolic status around the infarction region. Techniques for assessing perfusion and metabolism include regional cerebral blood flow (rCBF), single photon emission computed tomography (SPECT), and F-18 2-Fluoro-2-deoxy-D-glucose (F-18 FDG) positron emission tomography (PET). In addition, hemodynamic vascular insufficiency can be assessed using O-15 O2 oxygen extraction PET and rest and Diamox rCBF SPECT. The status of the peri-infarction region can be characterized in terms of components of diaschisis and ischemia using proton magnetic resonance spectroscopy imaging ((1)H MRSI) and rest/stress rCBF assessment of cerebral vascular reserve. As the brain recovers from cerebral infarction, areas of reorganization and energy utilization by the brain can be measured using oxygen extraction methods with PET, F-18 FDG glucose utilization by PET, and functional magnetic resonance imaging (fMRI) measures using the blood oxygenation level dependent (BOLD) technique. In addition, high field MRI imaging of the brain is now able to provide detailed fractional anisotropy (FA) maps to characterize changes in white matter by fiber tracking mapping using diffusion tensor imaging. Imaging of the stroke recovery process focuses on the physiologic model of stroke characterized by rCBF, metabolism, 1H spectroscopic measures of N-acetyl aspartate (NAA), choline (Ch) and creatine (Cr) in the peri-infarction zone as well as in the extended stroke penumbra including areas of distant ''pure'' diaschisis unencumbered with the confound of cerebral ischemia. Data is presented describing the results of application of imaging methodologies as the patient undergoes rehabilitation that demonstrates the importance of blood flow and metabolic changes in the contralesional frontal lobe both during the resting state and during motor and speech activation paradigms. The results of advanced imaging technologies on cerebral damage and cerebral reorganization during rehabilitation are presented in the context of furthering designs of rehabilitation strategies. Success can be monitored to assess the optimization of rehabilitation strategy design to maximize neurological recovery from stroke by employing facilitatory methods to maximally synchronize rehabilitation techniques with recovery of functionally counterpart areas of viable brain.

Effect of dietary intake before F-18 FDG positron emission tomographic scanning on the evaluation of a solitary pulmonary nodule.

The uptake of fluorine-18 fluorodeoxyglucose (F-18 FDG) by a malignant tumor depends on the blood glucose level. The authors present a striking case that illustrates the importance of blood glucose measurement in F-18 FDG positron emission tomographic (PET) imaging in a patient with a solitary pulmonary nodule. With the emergence of freestanding imaging centers, this case emphasizes the importance of using an objective method, such as a glucometer, to measure blood glucose levels before F-18 FDG PET imaging. Results of the initial scan were equivocal (the patient had eaten before the scan), whereas a hypermetabolic focus was clearly identified on a second scan obtained 2 days later.

A noninvasive reporter system to image adenoviral-mediated gene transfer to ovarian cancer xenografts.

OBJECTIVE: Gene therapy trials for ovarian cancer would benefit from a noninvasive imaging modality to detect the location and extent of gene transfer. The human type 2 somatostatin receptor gene (hSSTr2) was evaluated as a reporter gene for imaging adenoviral (Ad) gene transfer to ovarian cancer. METHODS: A replication-incompetent Ad vector encoding hSSTr2 (Ad-hSSTr2) was used to infect SKOV3.ip1 cells in vitro and tumors growing in nude mice. Gamma camera imaging detected uptake of 99m-Tc-P2045 (a somatostatin analogue) due to expressed hSSTr2. RESULTS: Specific uptake of 99m-Tc-P2045 was imaged in Ad-hSSTr2-infected cells in vitro. Noninvasive in vivo imaging detected gene transfer to intraperitoneal tumors. Uptake of 99m-Tc-P2045 (percentage dose per gram of tumor) averaged 2.2 and 0.18 for Ad-hSSTr2-injected mice and controls, respectively. CONCLUSION: This study reports the first noninvasive imaging method for imaging gene transfer to ovarian cancer. A human gene therapy trial is planned.

Normal T-cell response and in vivo magnetic resonance imaging of T cells loaded with HIV transactivator-peptide-derived superparamagnetic nanoparticles.

The present study analyzed the feasibility of using magnetic resonance imaging (MRI) to monitor T-cell homing in vivo after loading T cells with superparamagnetic iron oxide (CLIO) nanoparticles derivatized with a peptide sequence from the transactivator protein (Tat) of HIV-1. T cells were isolated from C57BL/6 (B6) mice and loaded with 0, 400, 800, 1600, or 8000 ng/ml of FITC conjugated CLIO-Tat (FITC-CLIO-Tat). There was a dose-dependent uptake of FITC-CLIO-Tat by T cells. Stimulation of FITC-CLIO-Tat loaded T cells with anti-CD3 (0.1 microg/ml) plus IL-2 (5 ng/ml) elicited normal activation and activation-induced cell death (AICD) responses, and normal upregulation of CD69, ICAM-1 (CD54), L-selectin (CD62L), and Fas. The FITC-CLIO-Tat loaded T cells (3 x 10(7)) were transferred intravenously (i.v.) into B6 mice and the in vivo MRI of mice was acquired using a spin-echo pulse sequence at 4.7 T with a Bruker Biospec system. Homing of T cells into the spleen was observed by a decrease in MRI signal intensity within 1 h after the transfer, which remained decreased for 2-24 h after transfer. These homing data were confirmed by FACS analysis and biodistribution analysis using 125I-CLIO-Tat. Thus, T cells can be efficiently loaded with FITC-CLIO-Tat without interfering with their normal activation and AICD, or homing to the spleen, and the biodistribution of FITC-CLIO-Tat loaded T cells can be monitored in vivo over time by MRI.

Light-based imaging of green fluorescent protein-positive ovarian cancer xenografts during therapy.

OBJECTIVE: The purpose of the study was to develop a sensitive, noninvasive imaging method for monitoring ovarian xenografts during therapeutic intervention. METHODS: Human ovarian tumor cells (SKOV3.ip1) were infected with a replication-deficient adenoviral (Ad) vector encoding green fluorescent protein (GFP). The GFP-positive tumor cells were imaged in vitro and in vivo with a fluorescence stereomicroscope. Using appropriate filters, both GFP fluorescence and adriamycin were simultaneously detected. Nude mice implanted with GFP-positive cells were imaged repeatedly, in a noninvasive manner. RESULTS: SKOV3.ip1 cells infected with Ad-GFP showed high GFP fluorescence, which was eliminated after treatment with adriamycin. Loss of GFP fluorescence was confirmed to be dead cells. For in vivo imaging, intraperitoneal tumors as small as 0.2 mm in diameter were detected externally. Adriamycin uptake was detected in tumors by in vivo imaging, and reduction in tumor size was concurrent with decrease in GFP fluorescence. These findings were confirmed at necropsy. CONCLUSIONS: Fluorescence stereomicroscopy monitored the response of ovarian xenografts to adriamycin therapy. For the first time, GFP and adriamycin were imaged simultaneously.

Detection and measurement of in vitro gene transfer by gamma camera imaging.

The purpose of this work was to develop a high capacity method to image gene transfer to cancer cells growing as monolayers in cell culture plates. A sensitive and high capacity nuclear-imaging method for detection of gene transfer in vitro will allow rapid validation of vectors in different cell lines under various conditions. Human cancer cell lines (A-427 non-small cell lung, SKOV3.ip1 ovarian, MDA-MB-468 breast, and BxPC-3 pancreatic) were infected with a replication-incompetent adenoviral vector encoding the human type 2 somatostatin receptor (Ad-hSSTr2). Expression of the hSSTr2 reporter protein in cells was detected by imaging an internalized 99mTc-labeled, hSSTr2 binding peptide (P2045, Diatide, Inc.). Imaging provided an accurate measure of internally bound 99mTc as evidenced by equivalence of results for imaging region of interest (ROI) analyses and gamma counter measurements. Internally bound 99mTc-P2045 was linearly correlated (R2 = 0.98) with the percentage of hSSTr2-positive cells following gene transfer. Excess P2045 blocked binding and internalization of the 99mTc-P2045, indicating the specificity of the technique. Up to four 96-well plates could be imaged simultaneously, thereby demonstrating the high capacity of the system. This novel in vitro approach provides a new method to test enhanced gene transfer as new vectors are developed.

Simultaneous evaluation of dual gene transfer to adherent cells by gamma-ray imaging.

A gamma camera imaging method was developed to detect dual gene transfer to adherent cells growing as monolayers in cell culture plates. Human cancer cells were infected with replication-incompetent adenoviral vectors encoding the human type 2 somatostatin receptor (Ad-hSSTr2) and/or herpes virus thymidine kinase (Ad-TK). The hSSTr2 and TK reporter proteins were detected by imaging internally bound (99m)Tc-P2045 peptide (Diatide, Inc.) and radioiodinated 2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl-5-iodouracil (FIAU), respectively. Following gene transfer, expression of hSSTr2 and TK were accurately imaged in vitro.

Large carotid sheath parathyroid adenoma localized by Tc-99m sestamibi.

The use of Tc-99m sestamibi to localize parathyroid adenomas is well established. Its greatest value is in the detection of adenomas in presurgical candidates to localize one or more adenomas in the parathyroid glands or to identify ectopic parathyroid adenomas. The authors describe a patient who had long-standing hyperparathyroidism with a history of end-stage renal disease, hypertension, and peptic ulcers with gastrointestinal bleeding. The scan showed a large ectopic parathyroid adenoma in the left retrosternocleidomastoid region. At surgery, the adenoma was located between the jugular vein and the carotid artery, within the carotid sheath.

Use of neuroimaging to understand abnormal pain sensitivity in fibromyalgia.

This paper examines the use of neuroimaging to measure change in regional cerebral blood flow (rCBF) produced by pain in patients with fibromyalgia and in healthy individuals. Fibromyalgia patients differ from healthy persons in rCBF distribution in several brain structures involved in pain processing and pain modulation both at rest and during experimental pain induction. These abnormalities may contribute to abnormal pain sensitivity as well as the maladaptive pain behaviors that characterize many patients with fibromyalgia. We anticipate that future neuroimaging studies will enhance our understanding of abnormal pain sensitivity and of pain management interventions aimed at altering central nervous system function in patients with fibromyalgia.

Imaging Tc-99m-labeled FGF-1 targeting in rats.

Recombinant human acidic fibroblast growth factor (FGF-1) was radiolabeled with (99m)Tc by the HYNIC method. The (99m)Tc-FGF-1 retained its representative molecular mass, heparin affinity, cellular binding to both low (Kd = 9.5 nM) and high (Kd = 125 pM) affinity sites, and mitogenic activity. Gamma camera imaging after intravenous dosing in rats confirmed high liver and kidney binding. Heparin significantly decreased (99m)Tc-FGF-1 liver uptake and increased urinary excretion. These studies illustrate a new method for imaging FGF-1 targeting under various conditions.

Noninvasive monitoring of gene transfer using a reporter receptor imaged with a high-affinity peptide radiolabeled with 99mTc or 188Re.

UNLABELLED: Gene therapy protocols require better modalities to monitor the location and level of transferred gene expression. One potential in vivo mechanism to assess gene expression would be to image the binding of a radiolabeled peptide to a reporter receptor that is expressed in targeted tissues. This concept was tested in a tumor model using a replication-incompetent adenoviral vector encoding the human type 2 somatostatin receptor (Ad5-CMVhSSTr2). Expression of the hSSTr2 reporter was imaged using a radiolabeled, somatostatin-avid peptide (P829). METHODS: Bilateral subcutaneous A427 tumor xenografts were established on the flanks of athymic nude mice. These human-origin, non-small cell lung tumors are normally negative for hSSTr2 expression. One tumor was injected directly with Ad5-CMVhSSTr2, whereas the second tumor was injected directly with a control Ad5 vector. The mice were injected intravenously 48 h later with P829 peptide that was radiolabeled to high specific activity with 99mTc (half-life, 6 h) or 188Re (half-life, 17 h). Tumors were frozen and evaluated for somatostatin receptor expression using fluorescein-labeled somatostatin. RESULTS: The accumulation of radiolabeled P829 in hSSTr2-expressing tumors was easily visualized by gamma camera imaging 3 h after injection. Imaging region of interest analyses and biodistribution studies confirmed a 5- to 10-fold greater accumulation of both radiolabeled P829 peptides in the Ad5-CMVhSSTr2-injected tumors versus control tumors injected with control Ad5 vectors. Ad5-CMVhSSTr2-injected tumors accumulated 2.5-3.8 percentage injected dose per gram 3 h after injection. Only Ad5-CMVhSSTr2-injected tumors expressed somatostatin receptors, as determined by immunohistochemistry. CONCLUSION: These studies show the feasibility of imaging a 99mTc-labeled peptide's binding to a reporter receptor after in vivo gene transfer to tumor cells. The 188Re-labeled peptide worked equally well for this imaging approach and offers the additional advantage of energetic beta decay with potential therapeutic efficacy. 99mTc and 188Re are generator produced, an advantage for widespread availability and low cost, and both radioisotopes can be imaged with existing, high-resolution modalities. There is great potential for using 99mTc-labeled peptides for imaging gene transfer with the hSSTr2 reporter receptor, especially when the reporter correlates with the expression of therapeutic genes that can be included simultaneously in the gene therapy vector.

Anterior cingulate gyrus epilepsy: the role of ictal rCBF SPECT in seizure localization.

PURPOSE: The goal of this report is to demonstrate the utility of ictal brain single photon emission tomography (SPECT) in a 39-year-old man with complex partial seizures arising from the anterior cingulate gyrus. Seizures originating from the anterior cingulate gyrus are difficult to localize because they have variable ictal semiology, are usually brief, and have rapid cortical propagation. METHODS: Clinical neurologic examination, electroencephalography, extended video-electroencephalography with scalp and sphenoidal electrodes, magnetic resonance imaging, computed tomography, and ictal brain SPECT with Tc-99m HMPAO were performed to identify the seizure focus. The patient's regional cerebral blood flow (rCBF) findings were compared with those of eight normal controls, and changes in rCBF were assessed by comparing the patient's ictal scan with those of normal controls at rest by using statistical parametric mapping (SPM). RESULTS: Clinical and neurologic evaluations failed to demonstrate the epileptogenic focus. Ictal rCBF brain SPECT showed a focal region of hyperperfusion in the anterior cingulate gyrus. By using SPM, the ictal blood flow increase in the right anterior cingulate gyrus (x, y, z, -6, 42, 24 mm) was found to be statistically significant when compared with normal controls (z score, 4.88, p < 0.001). Subdural EEG recordings with intracranial electrodes positioned over this location confirmed that the cingulate gyrus was the origin of the seizures, and surgical resection resulted in >90% seizure reduction. CONCLUSIONS: We concluded that ictal brain SPECT localization in conjunction with subdural electrode confirmation is a useful test in the presurgical evaluation of difficult to localize cingulate epilepsy.

Anterior choroidal artery infarction presenting as a progressive cognitive deficit.

PURPOSE: The authors describe a patient in whom neuroimaging using Tc-99m HMPAO SPECT, F-18 fluorodeoxyglucose (F-18 FDG) coincidence imaging, and magnetic resonance imaging (MRI) identified an anterior choroidal artery infarction. Neuroimaging played a critical role in confirming this diagnosis, because the patient had symptoms of progressive cognitive decline and satisfied the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). METHODS: Tc-99m HMPAO brain SPECT was performed using a triple-head gamma camera. F-18 FDG scanning was obtained 40 minutes after intravenous injection of 5 mCi F-18 FDG using a coincidence camera. A brain MRI scan was performed using a 1.5-Tesla scanner. RESULTS: Tc-99m HMPAO SPECT showed focal hypoperfusion to the right parahippocampal cortex. F-18 FDG coincidence imaging showed a more extensive reduction in glucose metabolism compared with SPECT. The MRI scan confirmed the presence of a small segmental choroidal artery infarction. The Tc-99m HMPAO and F-18 FDG scans were not consistent with AD. CONCLUSIONS: This case illustrates the value of the regional cerebral blood flow SPECT for evaluating memory impairment in the elderly. Decreased regional cerebral blood flow to the posterior temporoparietal region is consistent with AD, whereas regional cerebral blood flow diminution in a vascular territory is consistent with vascular dementia. In this case, the patient was clinically diagnosed with AD, and SPECT was performed to establish the baseline regional cerebral blood flow before the cholinesterase inhibitor donepezil was administered. An infarction was diagnosed on the regional cerebral blood flow brain SPECT scan, which was later confirmed by MRI. Infarctions of the parahippocampal cortex may resuft in memory impairment, which can appear clinically similar to AD.

Frontotemporal decreases in rCBF correlate with degree of dysnomia in primary progressive aphasia.

UNLABELLED: Primary progressive aphasia (PPA) is an uncommon degenerative dementia characterized by gradual impairment of language function with initial sparing of the memory domain. Using semiquantitative 99mTc-hexamethyl propyleneamine oxime (HMPAO) brain SPECT as a measure of regional cerebral blood flow (rCBF), we investigated the relationship between reduced 99mTc-HMPAO uptake and the severity of dysnomia in PPA. METHODS: Seven right-handed patients with PPA had their dysnomia assessed by the Boston Naming Test (BNT), a subtest of the Boston Diagnostic Aphasia Examination. Neuroimaging studies, including 99mTc-HMPAO brain SPECT, CT, and MRI, were performed. Correlational analysis between reduced rCBF and BNT was performed. RESULTS: Brain SPECT showed a reduction in 99mTc-HMPAO uptake involving the frontal and temporal lobes in all 7 patients. CT and MRI showed mild to moderate cerebral atrophy in 4 patients. Low scores on the BNT correlated with low frontotemporal 99mTc-HMPAO (Spearman r = 0.97, P = 0.004) in the 5 patients with left-hemisphere involvement. CONCLUSION: Decreased rCBF to the frontotemporal region characterized the cerebral abnormalities associated with PPA. The finding of focal rCBF abnormalities in the right hemisphere of 2 right-handed women corroborates that PPA symptoms may arise from a "non-left-dominant"-hemisphere degenerative process. Our results support the usefulness of rCBF SPECT imaging as a diagnostic aid in PPA.

A new semiquantitative method for comparing brain tumor uptake of Tc-99m sestamibi and TI-201.

PURPOSE: We describe a new method for measuring brain tumor uptake of TI-201 and Tc-99m sestamibi (MIBI) that permits the semiquantitative comparison of tracer uptake to yield comparable "tumor bulk" ratios. We tested this method in patients treated recently and remotely with chemotherapy to determine if this method could identify differences between these two patient groups. METHODS: Eleven patients with high-grade astrocytoma underwent TI-201 and Tc-99m MIBI SPECT. Each patient received 5 mCi TI-201 intravenously followed by SPECT using a dual-head gamma camera. This was immediately followed by an intravenous injection of 20 mCi Tc-99m MIBI and repeated SPECT. Four patients had recent therapy (from 1 day to 6 weeks before SPECT) and seven had remote treatment (>1 year before SPECT). Regions of interest were outlined in the tumor area using a computer-automated program to include all counts above background activity. Tumor activity counts were obtained from this region of interest. The tumor region of interest was mirrored to the contralateral uninvolved cerebral hemisphere to obtain background control count activity. A hypothetical volume of the number of pixels with background count activity necessary to constitute the tumor count activity (tumor bulk) was calculated using the ratio of total tumor counts (Ct), subtracting background (Cb), and dividing by the average counts per pixel in the control region (Cab). This was multiplied by the number of pixels (P), the pixel volume (Vp), and summed over all sections (i) involved with tumor. This method yields the equation tumor bulk = RESULTS: The mean Tc-99m MIBI to TI-201 tumor bulk ratio was 1.03 (range, 0.81 to 1.12) in four patients who had recently received chemotherapy. The mean Tc-99m MIBI to TI-201 tumor bulk ratio was 1.55 (range, 1.46 to 1.64) in seven patients who had remote therapy. The difference in the Tc-99m MIBI to TI-201 tumor bulk ratio between the two groups was significant (P = 0.0001). Patients who received recent chemotherapy had relatively lower Tc-99m MIBI uptake compared with TI-201. In remotely treated patients, uptake of the Tc-99m MIBI was greater compared with TI-201. CONCLUSION: This method allows semiquantitative comparison of different tracer uptake values independent of tracer dose and reduces the variability in drawing a region of interest when measuring tumor uptake. Among the patients studied, those who had recent chemotherapy showed a low Tc-99m MIBI to TI-201 ratio. This method of measuring "tumor bulk" can provide a useful index of viable tumor size in evaluating early tumor response and during ongoing chemotherapy.

Specific targeting of activated endothelium in rat adjuvant arthritis with a 99mTc-radiolabeled E-selectin-binding peptide.

OBJECTIVE: To determine the potential of an E-selectin-binding peptide (ESbp) to specifically bind activated endothelium in rheumatoid arthritis (RA) animal models. METHODS: ESbp (KYDGDITWDQLWDLMK; 2,027 daltons) was labeled with biotin and 99mTc. The affinity of ESbp derivatives for E-selectin was measured by enzyme-linked immunosorbent assay. The binding of biotin-ESbp was compared with that of an anti-E-selectin antibody, by immunohistochemical analyses of human synovial sections and sections from the Mycoplasma pulmonis MRL-lpr/lpr mouse arthritis model. 99mTc-ESbp was sequentially imaged in vivo with a gamma camera in the rat adjuvant-induced arthritis model. RESULTS: E-selectin expression was detected in human RA synovium and mouse arthritic synovium using biotin-ESbp. Both biotin-ESbp and 99mTc-labeled ESbp had high affinity for E-selectin (dissociation constant 2-5 nM). In vivo imaging showed specific binding of 99mTc-ESbp to the rat ankle joint prior to clinical manifestations of inflammation. CONCLUSION: These results demonstrate that activated endothelium can be targeted with 99mTc-ESbp. The specificity of targeting can be used to evaluate up-regulation of E-selectin in RA models, and to follow changes in this up-regulation during treatment trials.

59Fe is retained from an elemental 59Fe powder supplement without effects on 65Zinc, 47Calcium and 67Copper in young pigs.

In vivo counting with the use of a germanium detector evaluated the retention of an elemental 59Fe powder supplement while measuring potential interactions with zinc, calcium and copper. Effects of dietary iron and zinc on in vivo retentions of 59Fe, 65Zn, 67Cu and 47Ca were studied in young pigs. In Experiment 1, 4-d-old piglets fed a cereal-based diet were randomly assigned to one of four treatment groups (2 x 2 factorial arrangement, n = 5 per group). Variables were dietary iron source (either elemental iron or FeSO4, each at 100 mg iron/kg diet) and the dosage form of radioactive iron (either elemental 59Fe powder or 59FeSO4). Experiment 2 (2 x 3 factorial arrangement) was performed using two levels of iron (100 and 200 mg/kg, as elemental iron) and three levels of zinc (25, 50 and 100 mg/kg). Piglets were also dosed with 47Ca, 65Zn and 67Cu; all radioisotopes were measured for 8 d. Apparent absorption of elemental 59Fe powder was 13 +/- 1%, whereas 59Fe sulfate was significantly (P < 0.05) higher at 26 +/- 1%. The FeSO4 diet decreased 65Zn retention in Experiment 1, in contrast to the elemental iron diet, which did not have this effect in either experiment. Apparent 65Zn absorption averaged 44 +/- 2, 35 +/- 1 and 27 +/- 2% for the three levels of zinc (25, 50 and 100 mg/kg), respectively. Retention of 47Ca was not affected by dietary iron or zinc; retention of 67Cu was not affected by dietary iron. The data demonstrate good bioavailability of elemental iron without effects on zinc, copper and calcium.