Search

Here, we tested whether rapid changes in carbohydrate transport and partitioning to storage organs would be induced by jasmonic acid (JA), a plant-produced signal of herbivore attack known to induce resistance. Carbon-11, introduced as (11)CO(2), was used to track real-time carbohydrate transport and partitioning nondestructively in Populus species before and 12 h after application of JA to a single leaf. Jasmonic acid resulted in more rapid [(11)C]-photosynthate export from both local and systemic leaves, as well as greater partitioning of [(11)C]-photosynthate to the stem and roots. In Populus tremuloides, following JA treatment, leaf starch decreased, but there was no change in photosynthetic rates or leaf soluble sugar concentration, indicating that recent photosynthate was diverted from starch accumulation in the leaf to other plant organs. Increasing the supply of photosynthate to roots and stems may shield resources from folivorous predators, and may also facilitate both storage and nutrient uptake, and ultimately lead to greater tolerance, either by enhancing regrowth capacity or by replacing nutrients consumed by herbivores.

Background (2S,3S)-2-(3-Chlorophenyl)-3,5,5,-trimethyl-2-morpholinol hydrochloride (radafaxine) is a new antidepressant that blocks dopamine transporters (DAT). A concern with drugs that block (DAT) is their potential reinforcing effects and abuse liability. Using positron emission tomography (PET) we have shown that for DAT-blocking drugs to produce reinforcing effects they must induce >50% DAT blockade and the blockade has to be fast (within 15 minutes). This study measures the potency and kinetics for DAT blockade by radafaxine in human brain. Methods PET and [ 11 C]cocaine were used to estimate DAT blockade at 1, 4, 8, and 24 hours after radafaxine (40 mg p.o) in 8 controls. Plasma pharmacokinetics and behavioral and cardiovascular effects were measured in parallel. Results DAT blockade by radafaxine was slow, and at 1 hour, it was 11%. Peak blockade occurred at about 4 hours and was 22%. Blockade was long lasting: at 8 hours 17%, and at 24 hours 15%. Peak plasma concentration occurred about 4 to 8 hours. No behavioral or cardiovascular effects were observed. Conclusions The relatively low potency of radafaxine in blocking DAT and its slow blockade suggests that it is unlikely to have reinforcing effects. This is consistent with preclinical studies showing no self-administration. This is the first utilization of PET to predict abuse liability of a new antidepressant in humans based on DAT occupancy and pharmacokinetics.

This study examined the striatal dopamine system integrity and associated behavior in 5- to 7-year-old rhesus monkeys born from mothers that experienced stress and/or consumed moderate levels of alcohol during pregnancy. Thirty-one young adult rhesus monkeys were derived from females randomly assigned to one of four groups: (1) control group that consumed isocaloric sucrose solution throughout gestation; (2) stress group that experienced prenatal stress (10-min removal from home cage and exposure to three random loud noise bursts, gestational days 90 through 145); (3) alcohol group that consumed alcohol (0.6 g/kg/day) throughout gestation; or (4) combined alcohol plus stress group that received both treatments. The subjects were assessed for striatal dopamine system function using positron emission tomography (PET), in which the dopamine (DA)-rich striatum was evaluated in separate scans for the trapping of [(18)F]-Fallypride (FAL) and 6-[(18)F]fluoro-m-tyrosine (FMT) to assess dopamine D2 receptor binding potential (BP) and DA synthesis via dopa decarboxylase activity, respectively. Subjects were previously assessed for non-matching-to-sample (NMS) task acquisition, with ratings of behavioral inhibition, stereotypies, and activity made after each NMS testing session. Subjects from prenatal stress conditions (Groups 2 and 4) showed an increase in the ratio of striatal dopamine D2 receptor BP and DA synthesis compared to controls (Group 1). An increase in the radiotracer distribution volume ratios (DVRs), which is used to evaluate the balance between striatal DA synthesis and receptor availability, respectively, was significantly correlated with less behavioral inhibition. The latter supports a hypothesis linking striatal function to behavioral inhibitory control.

A search for the Doppler broadening following the beta decay of oxygen-14 was conducted with high resolution gamma spectroscopy on the 2313 keV gamma ray. Such a broadening should signal the mass of the labeled molecule and the nature of the stopping medium. Oxygen-14 labeled H2O, O2 and CO2 trapped on solid soda lime were investigated. No broadening was observed beyond the 1.65 keV instrumental resolution of the Ge detector, monitored by the unbroadened 2319 keV isomeric transition in 90Nb decay.

Fractionated cisplatin-containing regimens are routinely used for chemotherapy in certain types of cancer. Dolasetron has been shown to be effective in preventing acute emesis related to high-dose cisplatin chemotherapy over 24 h; its effectiveness has not been evaluated in fractionated cisplatin-containing chemotherapy. This trial was designed to assess the efficacy of dolasetron alone or dolasetron plus dexamethasone in preventing nausea and vomiting related to fractionated cisplatin chemotherapy. The patients were 210 cancer in-patients, who were randomised to receive 100 mg dolasetron i.v. or 100 mg dolasetron i.v. plus 20 mg dexamethasone before chemotherapy primarily with cisplatin (15-50 mg/m2) infused overor =4 h for at least 2 but not more than 5 consecutive days. Dolasetron was administered to all patients 30 min before cisplatin. Dexamethasone was administered in double-blind fashion 5 min before cisplatin. Efficacy was measured at hour 24 of each study day using complete response (no vomiting and no rescue medication) and maximum severity of nausea, self-assessed by patients using a 100mm visual analogue scale. Most (198) of the patients completed the study and were evaluable. Overall complete response rates were significantly higher in the dolasetron plus dexamethasone group than in the dolasetron only group (72.9% vs. 40.8%, respectively; P0.0001). Complete response rates on each study day were also significantly higher with dolasetron plus dexamethasone than with dolasetron alone (P0.029), with an attenuated efficacy in the delayed phase in both groups. Chi-square test and logistic regression applied to daily response rates indicated a significant influence of treatment (day 1: P = 0.0002, day 2: P0.0001, day 3: P = 0.0007, day 4: P = 0.0007, day 5: P = 0.029). Treatment and duration of chemotherapy exerted the only statistically significant subgroup effects on complete response (P0.0001). Both treatments were administered safely. As seen with other 5-HT3 receptor antagonist antiemetics, the addition of dexamethasone to dolasetron significantly increases effectiveness in preventing nausea and vomiting related to fractionated cisplatin chemotherapy. Both dolasetron and dolasetron plus dexamethasone were well tolerated.

Agents capable of reversing P-glycoprotein-associated multidrug resistance have usually failed to enhance chemotherapy activity in patients with solid tumours. Based on its toxicity profile and experimental potency, dexverapamil, the R-enantiomer of verapamil, is considered to be promising for clinical use as a chemosensitizer. The purpose of this early phase II trial was to evaluate the effects of dexverapamil on epirubicin toxicity, activity and pharmacokinetics in patients with metastatic breast cancer. A two-stage design was applied. Patients first received epirubicin alone at 120 mg m(-2) i.v. over 15 min, repeated every 21 days. Patients with refractory disease continued to receive epirubicin at the same dose and schedule but supplemented with oral dexverapamil 300 mg every 6 h x 13 doses. The Gehan design was applied to the dexverapamil/epirubicin cohort of patients. Thirty-nine patients were entered on study, 25 proceeded to receive epirubicin plus dexverapamil. Dexverapamil did not increase epirubicin toxicity. The dose intensity of epirubicin was similar when used alone or with dexverapamil. In nine intrapatient comparisons, the area under the plasma concentration-time curve (AUC) of epirubicin was significantly reduced by dexverapamil (mean 2968 vs 1901 microg ml[-1] h[-1], P= 0.02). The mean trough plasma levels of dexverapamil and its major metabolite nor-dexverapamil were 1.2 and 1.5 microM respectively. The addition of dexverapamil to epirubicin induced partial responses in 4 of 23 patients evaluable for tumour response (17%, CI 5-39%, s.e.P 0.079). The remissions lasted 3, 8, 11 and 11+ months. These data suggest that the concept of enhancing chemotherapy activity by adding chemosensitizers may function not only in haematological malignancies but also in selected solid tumours. An increase in the AUC and toxicity of cytotoxic agents does not seem to be a prerequisite for chemosensitizers to enhance anti-tumour activity.

A thick beryllium target has been developed for installation onto a small proton cyclotron (CTI RDS 112), providing an intense source of fast neutrons for activation purposes. Careful attention was paid to cooling and irradiation geometry, allowing cubic centimeter scale samples to approach the proton beam strike surface to within 5 mm. This proximity assures approximately equal to 10(11) neutron/s passing through the irradiated sample when 20 microgramsA of 11 MeV protons are incident on the beryllium primary target.

An improved production procedure and formulation method for the carbon-11 radiolabeled phytohormone, 3-indolyl-[l-(11)C]acetic acid ([(11)C]IAA), was developed by modifying selected original reaction parameters. This updated procedure both doubled the yield (from 25.9±6.7% (n=12) to 61.0±0.3% (n=10)) and increased the concentration (0.2-0.4 GBq/0.15-0.3 mL), enabling us to provide the radiotracer [(11)C]IAA suitable for in vivo phyto-PET-imaging studies. The specific activity was improved by more than a factor of three (26.7±5.6 GBq/µmol to 82.5±36.1 GBq/µmol). The total synthesis time for both production and formulation was 81.8±3.0 min (n=10). In addition, a streamlined semi-remote controlled production system, containing five processing modules, was designed and built for routine [(11)C]IAA production. This integrated system facilitated routine high radiation level production of [(11)C]IAA while minimizing radiation exposure to the production chemists.

Upon attack by leaf herbivores, many plants reallocate photoassimilates below ground. However, little is known about how plants respond when the roots themselves come under attack. We investigated induced resource allocation in maize plants that are infested by the larvae Western corn rootworm Diabrotica virgifera virgifera. Using radioactive (11) CO(2), we demonstrate that root-attacked maize plants allocate more new (11) C carbon from source leaves to stems, but not to roots. Reduced meristematic activity and reduced invertase activity in attacked maize root systems are identified as possible drivers of this shoot reallocation response. The increased allocation of photoassimilates to stems is shown to be associated with a marked thickening of these tissues and increased growth of stem-borne crown roots. A strong quantitative correlation between stem thickness and root regrowth across different watering levels suggests that retaining photoassimilates in the shoots may help root-attacked plants to compensate for the loss of belowground tissues. Taken together, our results indicate that induced tolerance may be an important strategy of plants to withstand belowground attack. Furthermore, root herbivore-induced carbon reallocation needs to be taken into account when studying plant-mediated interactions between herbivores.

PET brings the promise of quantitative imaging of the in-vivo distribution of any positron emitting nuclide, a list with hundreds of candidates. All but a few of these, the "pure positron" emitters, have isotropic, coincident gamma rays that give rise to misrepresented events in the sinogram and in the resulting reconstructed image. Of particular interest are /sup 10/C, /sup 14/O, /sup 38/K, /sup 52m/Mn, /sup 60/Cu, /sup 61/Cu, /sup 94m/Tc, and /sup 124/I, each having high-energy gammas that are Compton-scattered down into the 511 keV window. The problems arising from the "third gamma," and its accommodation by standard scatter correction algorithms, were studied empirically, employing three scanner models (CTI 933/04, CTI HR+, and GE Advance), imaging three phantoms (line source, NEMA scatter, and contrast/detail), with /sup 18/F or /sup 38/K and /sup 72/As mimicking /sup 14/O and /sup 10/C, respectively, in 2D and 3D modes. Five findings emerge directly from the image analysis. The third gamma: (1) does, obviously, tax the single event rate of the PET scanners, particularly in the absence of septa, from activity outside of the axial field of view; (2) does, therefore, tax the random rate, which is second order in singles, although the gamma is a prompt coincidence partner; (3) does enter the sinogram as an additional flat background, like randoms, but unlike scatter; (4) is not seriously misrepresented by the scatter algorithm which fits the correction to the wings of the sinogram and (5) does introduce additional statistical noise from the subsequent subtraction, but does not seriously compromise the detectability of lesions as seen in the contrast/detail phantom. As a safeguard against the loss of accuracy in image quantitation, fiducial sources of known activity are included in the field of view alongside of the subject. With this precaution, a much wider selection o f imaging agents can enjoy the advantages of positron emission tomography.

Biotransformation of irinotecan (CPT-11) into its pharmacologic active metabolite SN-38 was investigated in patients treated for advanced colorectal cancer. A dose of 180 mg/m(2) CPT-11 was administered to 6 patients by 60 min hepatic intra-arterial infusion (HAI) via a surgically implanted Port-a-Cath® system. Blood samples were collected from 0 to 360 min after start of HAI, and CPT-11 plus metabolites were analysed by a selective reversed phase HPLC method. The objective of this study was to evaluate the extent to which SN-38 is generated after HAI of irinotecan given at a low dose of 180 mg/m(2). In a second investigation, CPT-11 was administered via conventional intravenous infusion (dose 180 mg/m(2), 60 min infusion time, 11 patients) and CPT-11 plus metabolites were quantified using identical analytical procedure. Compared to i.v. infusion, the pharmacokinetics of CPT-11 and SN-38 were altered by HAI. The mean c(max) of CPT-11 after HAI was reduced by 37%, whereas the mean c(max) of SN-38 increased by 60%. HAI resulted in a desired, increased metabolic conversion of CPT-11 into SN-38 and might improve the regional availability of the pharmacologic active metabolite SN-38 at the site of tumor. Plasma concentrations of the metabolites SN-38 glucuronide and APC remained unaffected by the route of administration.

Introduction PET imaging in plants is receiving increased interest as a new strategy to measure plant responses to environmental stimuli and as a tool for phenotyping genetically engineered plants. PET imaging in plants, however, poses new challenges. In particular, the leaves of most plants are so thin that a large fraction of positrons emitted from PET isotopes ( 18 F, 11 C, 13 N) escape while even state-of-the-art PET cameras have significant partial-volume errors for such thin objects. Although these limitations are acknowledged by researchers, little data have been published on them. Methods Here we measured the magnitude and distribution of escaping positrons from the leaf of Nicotiana tabacum for the radionuclides 18 F, 11 C and 13 N using a commercial small-animal PET scanner. Imaging results were compared to radionuclide concentrations measured from dissection and counting and to a Monte Carlo simulation using GATE (Geant4 Application for Tomographic Emission). Results Simulated and experimentally determined escape fractions were consistent. The fractions of positrons (mean±S.D.) escaping the leaf parenchyma were measured to be 59±1.1%, 64±4.4% and 67±1.9% for 18 F, 11 C and 13 N, respectively. Escape fractions were lower in thicker leaf areas like the midrib. Partial-volume averaging underestimated activity concentrations in the leaf blade by a factor of 10 to 15. Conclusions The foregoing effects combine to yield PET images whose contrast does not reflect the actual activity concentrations. These errors can be largely corrected by integrating activity along the PET axis perpendicular to the leaf surface, including detection of escaped positrons, and calculating concentration using a measured leaf thickness.

Reversible inhibitors of monoamine oxidase-A (RIMA) inhibit the breakdown of three major neurotransmitters, serotonin, norepinephrine and dopamine, offering a multi-neurotransmitter strategy for the treatment of depression. CX157 (3-fluoro-7-(2,2,2-trifluoroethoxy)phenoxathiin-10,10-dioxide) is a RIMA, which is currently in development for the treatment of major depressive disorder. We examined the degree and reversibility of the inhibition of brain monoamine oxidase-A (MAO-A) and plasma CX157 levels at different times after oral dosing to establish a dosing paradigm for future clinical efficacy studies, and to determine whether plasma CX157 levels reflect the degree of brain MAO-A inhibition. Brain MAO-A levels were measured with positron emission tomography (PET) imaging and [(11)C]clorgyline in 15 normal men after oral dosing of CX157 (20-80 mg). PET imaging was conducted after single and repeated doses of CX157 over a 24-h time course. We found that 60 and 80 mg doses of CX157 produced a robust dose-related inhibition (47-72%) of [(11)C]clorgyline binding to brain MAO-A at 2 h after administration and that brain MAO-A recovered completely by 24 h post drug. Plasma CX157 concentration was highly correlated with the inhibition of brain MAO-A (EC(50): 19.3 ng/ml). Thus, CX157 is the first agent in the RIMA class with documented reversible inhibition of human brain MAO-A, supporting its classification as a RIMA, and the first RIMA with observed plasma levels that can serve as a biomarker for the degree of brain MAO-A inhibition. These data were used to establish the dosing regimen for a current clinical efficacy trial with CX157.

Why beat about the bush? An operationally simple and mild reaction based on the direct fixation of (11)CO(2) with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) has been developed for the synthesis of (11)C-labeled carbamates at 75 degrees C within 10 minutes in radiochemical yields above 70% (see scheme). This strategy should be immediately useful for the construction of new radiotracers for positron emission tomography and other applications.

Introduction Aromatase, a member of the cytochrome P 450 family, converts androgens such as androstenedione and testosterone into estrone and estradiol, respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1 H -1,2,4-triazole; Femara) is a high-affinity aromatase inhibitor ( K i =11.5 nM) that has Food and Drug Administration approval for breast cancer treatment. Here we report the synthesis of carbon-11-labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Methods Letrozole and its precursor (4-[(4-bromophenyl)-1 H -1,2,4-triazol-1-ylmethyl]benzonitrile) were prepared in a two-step synthesis from 4-cyanobenzyl bromide and 4-bromobenzyl bromide, respectively. The [ 11 C]cyano group was introduced via tetrakis(triphenylphosphine)palladium(0)-catalyzed coupling of [ 11 C]cyanide with the bromo precursor. Positron emission tomography (PET) studies in the baboon brain were carried out to assess regional distribution and kinetics, reproducibility of repeated measures and saturability. Log D , the free fraction of letrozole in plasma and the [ 11 C-cyano]letrozole fraction in arterial plasma were also measured. Results [ 11 C-cyano]Letrozole was synthesized in 60 min with a radiochemical yield of 79–80%, with a radiochemical purity greater than 98% and a specific activity of 4.16±2.21 Ci/μmol at the end of bombardment ( n =4). PET studies in the baboon revealed initial rapid and high uptake and initial rapid clearance, followed by slow clearance of carbon-11 from the brain, with no difference between brain regions. Brain kinetics was not affected by coinjection of unlabeled letrozole (0.1 mg/kg). The free fraction of letrozole in plasma was 48.9%, and log D was 1.84. Conclusion [ 11 C-cyano]Letrozole is readily synthesized via a palladium-catalyzed coupling reaction with [ 11 C]cyanide. Although it is unsuitable as a PET radiotracer for brain aromatase, as revealed by the absence of regional specificity and saturability in brain regions such as amygdala, which are known to contain aromatase, it may be useful in measuring letrozole distribution and pharmacokinetics in the brain and peripheral organs.

Over a hundred proton-induced reactions have been studied at the University of Wisconsin Medical Physics department since the installation of the first CTI RDS 112 in 1985. The focus has been to measure thick target yields at 11 MeV, in an effort to concentrate on the practical production of positron emitting radionuclides that have favorable decay characteristics, high yields and the potential for labeling pivotal biological tracers. This review covers our recent advances to scale-up the production of the heavy halogens and transition metals as feed-stock for non-conventional PET tracers that are currently attracting increased attention in oncology.

Production of 17F (t1/2=65 s) in the form of [17F] F2 has been achieved using both the 20Ne(p,alpha)17F and 16O(d,n)17F reactions with 11 MeV protons and 6 MeV deuterons, respectively. Yields have proven suitable for subsequent radiosynthesis of the blood flow tracer, [17F]CH3F (60 mCi in saline), currently in use for fast repetition human studies of regional cerebral blood flow with positron emission tomography. Thick target yields of 15 mCi /microA for protons and 44 mCi/microA for deuterons have been measured for [17F]F2.

This work describes the production of 10C (t12 = 19 s) from an enriched 10B2O3 target using a CTI RDS‐112 11 MeV proton cyclotron. Proton beam heating is used to raise the target to a molten state (∼ 1300 °C), enabling the activity to diffuse to the surface of the melt. An infrared thermocouple monitors the melt temperature. Helium sweep gas then transports the activity to flow‐through chemistry processing for human inhalation of 10CO2 for blood flow imaging with Positron Emission Tomography. The temperature‐related diffusion of activity out of the white‐hot molten glass target is discussed.

Cytoprotection of healthy cells represents a new approach in cancer chemotherapy, but a pharmacokinetic drug interaction between the cytostatic and the cytoprotectant is undesired.The purpose was to evaluate the clinical pharmacokinetics (PHK) of paclitaxel (PACLI) and its metabolites under cytoprotection in patients suffering from breast cancer. PACLI was administered alone and in a second cycle in combination with amifostine (AMI) as a paired cross over.In both treatment schedules the steady state of PACLI occurred after 3 hours, the tmax of metabolites between 3 and 4 hours. The mean steady-state concentration was cmax = 5432 +/- 1238 ng/ml in the control group and cmax = 5140 +/- 2407 ng/ml in the AMI group. For the serum metabolites, the findings were very similar: 6-OH-PACLI: cmax 413 +/- 153 ng/ml versus 432 +/- 304 ng/ml, 3"-OH-PACLI: cmax 99 +/- 103 ng/ml versus 123 +/- 98 ng/ml, 3",6-DiOH-PACLI: cmax 43 +/- 55 ng/ml versus 75 +/- 85 ng/ml. AUC values of metabolites were slightly higher in the AMI group, but PHK seemed equal.The results gave evidence, that cytoprotection with AMI has no clinical consequences on PACLI pharmacokinetics and biotransformation.

Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft-lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics-derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.

Dual-modality imaging, using Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) simultaneously, is a powerful tool to gain valuable information correlating structure with function in biomedicine. The advantage of this dual approach is that the strengths of one modality can balance the weaknesses of the other. However, success of this technique requires developing imaging probes suitable for both. Here, we report on the development of a nanoparticle labeling procedure via covalent bonding with carbon-11 PET isotope. Carbon-11 in the form of [(11)C]methyl iodide was used as a methylation agent to react with carboxylic acid (-COOH) and amine (-NH2) functional groups of ligands bound to the nanoparticles (NPs). The surface coating ligands present on superparamagnetic iron-oxide nanoparticles (SPIO NPs) were radiolabeled to achieve dual-modality PET/MR imaging capabilities. The proof-of-concept dual-modality PET/MR imaging using the radiolabeled SPIO NPs was demonstrated in an in vivo experiment.

LBA4010 Background: While G is a widely accepted treatment for pts with advanced pancreatic cancer, C has shown single agent activity and promising efficacy in combination with G in phase II studie...

3737 Background: The improved safety profile of the oral fluoropyrimidine X (Xeloda) versus bolus 5-FU/LV has been demonstrated in over 3000 pts in 3 large randomized trials in 1st line metastatic and adjuvant colon cancer (Twelves EJC 2002, Scheithauer Ann Oncol 2003). In addition, the safety advantage over 5-FU/LV in the adjuvant setting was maintained in older pts (≥65 years) and also in terms of less early severe toxicity with X. The median age of pts at diagnosis of colon cancer is increasing in developed countries. Therefore we examined whether there is enough evidence to support the safe use of X in an elderly population, i.e. pts 70 years and older. Methods: We performed retrospective analyses on the safety database of the X-ACT adjuvant colon cancer trial, which compared X (993 pts) to 5-FU/LV Mayo Clinic Regimen (974 pts) in Dukes' C colon cancer pts. Adverse events (AEs) in the two arms were analyzed by age

Objective: To evaluate the visible and quantitative anatomic distribution of fluorine-18–labeled l-DOPA in the healthy human brain, to thereby expand the understanding of extrastriatal sites of levodopa function, and to provide a broader foundation for clinical and research studies of fluoroDOPA accumulation in patients. Methods: The authors performed dynamic three-dimensional fluoroDOPA PET imaging in 10 healthy volunteers and analyzed the images visually and quantitatively. Twenty-eight regions of interest were applied to parametric images of the uptake rate constant (using the multiple-time graphic plot method with cortical input function) and also were used to quantitate regional radioactivity at 80 to 90 minutes. The authors correlated the uptake constants with published human regional neurotransmitter and decarboxylation data. Results: PET imaging with fluoroDOPA demonstrates trapping of labeled dopamine or its metabolites in substantial quantities in many areas of the brain other than the mesostriatal pathways, including considerable uptake in the serotonergic and noradrenergic areas of the hypothalamus and brainstem as well as in extrastriatal cerebral sites. Total fluoroDOPA uptake correlates best with the sum of catecholamine and indolamine concentrations in the brain and moderately well with regional activity of aromatic l-amino acid decarboxylase, but correlates poorly with extrastriatal dopamine concentration. Conclusion: Neither l-DOPA nor its radiolabeled analog fluoroDOPA is metabolized or accumulates specifically in dopaminergic or even catecholaminergic neurons. Substantial dopamine production within serotonin and norepinephrine neurons may play a role in either therapeutic effects or adverse effects of therapy with l-DOPA.

De tres nombreuses etudes ont ete effectuees sur le Meleze, concernant son temperament, ses origines, sa repartition, ses relations avec le sol. Mais un aspect seulement retiendra ici notre attention : celui de sa nutrition minerale. Les elements etudies sont : l'azote, le phosphore, le soufre, le potassium, le calcium et le magnesium, le manganese et le zinc. Ces elements ont ete choisis non seulement en raison de leur importance dans la nutrition minerale du Meleze mais aussi parce qu'ils ont ete etudies chez de nombreux genres resineux et feuillus ; ainsi nos resultats pourront etre confrontes avec ceux qui ont ete publies par ailleurs.

Background Although important aspects of whole-plant carbon allocation in crop plants (e.g., to grain) occur late in development when the plants are large, techniques to study carbon transport and allocation processes have not been adapted for large plants. Positron emission tomography (PET), developed for dynamic imaging in medicine, has been applied in plant studies to measure the transport and allocation patterns of carbohydrates, nutrients, and phytohormones labeled with positron-emitting radioisotopes. However, the cost of PET and its limitation to smaller plants has restricted its use in plant biology. Here we describe the adaptation and optimization of a commercial clinical PET scanner to measure transport dynamics and allocation patterns of 11C-photoassimilates in large crops. Results Based on measurements of a phantom, we optimized instrument settings, including use of 3-D mode and attenuation correction to maximize the accuracy of measurements. To demonstrate the utility of PET, we measured 11C-photoassimilate transport and allocation in Sorghum bicolor, an important staple crop, at vegetative and reproductive stages (40 and 70 days after planting; DAP). The 11C-photoassimilate transport speed did not change over the two developmental stages. However, within a stem, transport speeds were reduced across nodes, likely due to higher 11C-photoassimilate unloading in the nodes. Photosynthesis in leaves and the amount of 11C that was exported to the rest of the plant decreased as plants matured. In young plants, exported 11C was allocated mostly (88 %) to the roots and stem, but in flowering plants (70 DAP) the majority of the exported 11C (64 %) was allocated to the apex. Conclusions Our results show that commercial PET scanners can be used reliably to measure whole-plant C-allocation in large plants nondestructively including, importantly, allocation to roots in soil. This capability revealed extreme changes in carbon allocation in sorghum plants, as they advanced to maturity. Further, our results suggest that nodes may be important control points for photoassimilate distribution in crops of the family Poaceae. Quantifying real-time carbon allocation and photoassimilate transport dynamics, as demonstrated here, will be important for functional genomic studies to unravel the mechanisms controlling phloem transport in large crop plants, which will provide crucial insights for improving yields. Electronic supplementary material The online version of this article (doi:10.1186/s12870-015-0658-3) contains supplementary material, which is available to authorized users.

Primary insertion of a large caliber catheter into the renal pelvis would provide the most favorable drainage in all cases in which urinary diversion by nephropyelostomy is indicated. Therefore, the puncture technique of Guenther and associates was modified. A specially designed balloon catheter was used to prevent dislocation.