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Migrations between different habitats are key events in the lives of many organisms. Such movements involve annually recurring travel over long distances usually triggered by seasonal changes in the environment. Often, the migration is associated with travel to or from reproduction areas to regions of growth. Young anadromous Atlantic salmon ( Salmo salar) emigrate from freshwater nursery areas during spring and early summer to feed and grow in the North Atlantic Ocean. The transition from the freshwater ('parr') stage to the migratory stage where they descend streams and enter salt water ('smolt') is characterized by morphological, physiological and behavioural changes where the timing of this parr-smolt transition is cued by photoperiod and water temperature. Environmental conditions in the freshwater habitat control the downstream migration and contribute to within- and among-river variation in migratory timing. Moreover, the timing of the freshwater emigration has likely evolved to meet environmental conditions in the ocean as these affect growth and survival of the post-smolts. Using generalized additive mixed-effects modelling, we analysed spatio-temporal variations in the dates of downstream smolt migration in 67 rivers throughout the North Atlantic during the last five decades and found that migrations were earlier in populations in the east than the west. After accounting for this spatial effect, the initiation of the downstream migration among rivers was positively associated with freshwater temperatures, up to about 10 °C and levelling off at higher values, and with sea-surface temperatures. Earlier migration occurred when river discharge levels were low but increasing. On average, the initiation of the smolt seaward migration has occurred 2.5 days earlier per decade throughout the basin of the North Atlantic. This shift in phenology matches changes in air, river, and ocean temperatures, suggesting that Atlantic salmon emigration is responding to the current global climate changes. [ABSTRACT FROM AUTHOR]

Purpose: The characteristics of the radionuclide 57Co make it interesting for use as a brachytherapy source. 57Co combines a possible high specific activity with the emission of relatively low-energy photons and a half-life (272 days) suitable for regular source exchanges in an afterloader. 57Co decays by electron capture to the stable 57Fe with emission of 136 and 122 keV photons. Methods: A hypothetical 57Co source based on the Flexisource brachytherapy encapsulation with the active core set as a pure cobalt cylinder (length 3.5 mm and diameter 0.6 mm) covered with a cylindrical stainless-steel capsule (length 5 mm and thickness 0.125 mm) was simulated using Geant4 Monte Carlo (MC) code version 9.4. The radial dose function, g(r), and anisotropy function F(r,θ), for the line source approximation were calculated following the TG-43U1 formalism. The results were compared to well-known 192Ir and 125I radionuclides, representing the higher and the lower energy end of brachytherapy, respectively. Results: The mean energy of photons in water, after passing through the core and the encapsulation material was 123 keV. This hypothetical 57Co source has an increasing g(r) due to multiple scatter of low-energy photons, which results in a more uniform dose distribution than 192Ir. Conclusions: 57Co has many advantages compared to 192Ir due to its low-energy gamma emissions without any electron contamination. 57Co has an increasing g(r) that results in a more uniform dose distribution than 192Ir due to its multiple scattered photons. The anisotropy of the 57Co source is comparable to that of 192Ir. Furthermore, 57Co has lower shielding requirements than 192Ir. [ABSTRACT FROM AUTHOR]

Summary Purpose: Abdominal oedema is common in sepsis. A technique for the study of such oedema may guide in the fluid regime of these patients. Procedures: We modified a double-isotope technique to evaluate abdominal organ oedema and fluid extravasation in 24 healthy or endotoxin-exposed ('septic') piglets. Two different markers were used: red blood cells (RBC) labelled with Technetium-99m (99mTc) and Transferrin labelled with Indium111 (111In). Images were acquired on a dual-head gamma camera. Microscopic evaluation of tissue biopsies was performed to compare data with the isotope technique. Results: No 99mTc activity was measured in the plasma fraction in blood sampled after labelling. Similarly, after molecular size gel chromatography, 111In activity was exclusively found in the high molecular fraction of the plasma. Extravasation of transferrin, indicating the degree of abdominal oedema, was 4·06 times higher in the LPS group compared to the healthy controls ( P<0·0001). Abdominal free fluid, studied in 3 animals, had as high 111In activity as in plasma, but no 99mTc activity. Intestinal lymphatic vessel size was higher in LPS (3·7 ± 1·1 μm) compared to control animals (0·6 + 0·2 μm; P<0·001) and oedema correlated to villus diameter ( R2 = 0·918) and lymphatic diameter ( R2 = 0·758). A correlation between a normalized index of oedema formation (NI) and intra-abdominal pressure (IAP) was also found: NI = 0·46*IAP−3·3 ( R2 = 0·56). Conclusions: The technique enables almost continuous recording of abdominal oedema formation and may be a valuable tool in experimental research, with the potential to be applied in the clinic. [ABSTRACT FROM AUTHOR]

Simulation-driven design with computational fluid dynamics has been used to evaluate the flow downstream of a hydropower plant with regards to upstream migrating fish. Field measurements with an Acoustic Doppler Current Profiler were performed, and the measurements were used to validate the simulations. The measurements indicate a more unstable flow than the simulations, and the tailrace jet from the turbines is stronger in the simulations. A fishway entrance was included in the simulations, and the subsequent attraction water was evaluated for two positions and two angles of the entrance at different turbine discharges. Results show that both positions are viable and that a position where the flow from the fishway does not have to compete with the flow from the power plant will generate superior attraction water. Simulations were also performed for further downstream where the flow from the turbines meets the old river bed which is the current fish passage for upstream migrating fish. A modification of the old river bed was made in the model as one scenario to generate better attraction water. This considerably increases the attraction water although it cannot compete with the flow from the tailrace tunnel. [ABSTRACT FROM AUTHOR]

Targeted cancer therapies rely on bifunctional molecules, typically a protein that specifically recognizes tumor cells and a toxic component which is linked to the protein. Therefore, development of such therapies includes detailed characterizations of protein-cell interactions in order to find a good targeting agent. Knowledge of factors such as antibody-antigen specificity, as well as cellular uptake, retention and affinity of the antibody are necessary in order to be successful. In this paper, we have used a novel instrument, LigandTracer® Yellow, to characterize the interactions of 111In and 177Lu-labeled monoclonal antibodies (MAbs) with CD44v6. Uptake studies with varying specific radioactivity of the chimeric MAb U36 and with an irrelevant antibody for the CD44v6 receptor verified the reliability of the method, as well as the specificity of the antibody-receptor binding. Uptake, retention, and affinity were very similar for the 111In and 177Lu-labeled conjugate, and were in line with earlier studies using manual methods. The fact that no adverse effects from labeling were seen, together with the high retention, could make these conjugates promising candidates for imaging and therapy of certain cancer types in the future. The novel LigandTracer technology reduced the workload and reagent spending while providing data with superior time resolution. The obtained results were in agreement with previously reported findings. In addition the real-time detection and higher time resolution made more detailed studies of the interactions possible. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

1. The keystone piscivore northern pike Esox lucius can structure fish communities, and models predicting pike-focused connectivity will be important for management of many waters. 2. We explored the ability of pike to colonize upstream locations and modelled presence–absence in lakes based on landscape features derived from maps. An upstream connectivity model (UC model) was generated using data from 87 lakes. We validated the UC model with retrospective whole-lake experiments involving introductions ( n = 49) and extirpations (by rotenone) of pike ( n = 96), as well as with the natural distribution of pike in lakes ( n = 1365) within 26 drainage basin networks in northern Sweden. 3. The UC model predicted the incidence of pike in lakes with stream-connections with 95·4% accuracy, based mainly on a single variable, SV5max, that measures the minimum distance found between 5 m elevation intervals (= maximum stream slope) along watercourses from nearest downstream source of potential immigrants. Recolonizations of pike in rotenone lakes generated a near-identical classification tree, as in the UC model. The classification accuracy of pike presence in the external validation procedure ranged from 88·7 to 98·7% between different drainage basins. Predictions of pike absence were not as accurate, due possibly to undetected introductions, but still lead to 86·6% overall accuracy of the external validation. Most lakes lacking pike, but misclassified as having pike based on low SV5max, were isolated from downstream sources of pike by subsurface streamflow through bouldery areas (SSB). 4. Synthesis and applications. The variable SV5max provide managers with a tool for revealing the location and severity of natural dispersal barriers to pike (and logically also barriers to other species with equivalent or less dispersal capacity). Because presented models only require map-based information, and have high predictive power, they may have the potential to be of fundamental use in predicting distribution of freshwater fish. These predictions may provide the means for prioritizing in risk assessment and control programmes to combat pike invasions, as well as contribute to determining a reference state of species incidence in specific lakes. Our results also point towards a possibility that, even where stream slope is low, long-term effective barriers may be designed that mimic natural SSB. [ABSTRACT FROM AUTHOR]

Summary. Parenteral iron–polysaccharide complexes are increasingly applied. The pharmacokinetics of iron sucrose have been assessed by our group using positron emission tomography (PET). A single intravenous injection of 100 mg iron as iron (III) hydroxide–polymaltose complex, labelled with a tracer in the form of 52 Fe/59 Fe, was similarly assessed in six patients using PET for about 8 h. Red cell utilization was followed for 4 weeks. Iron polymaltose was similarly distributed to the liver, spleen and bone marrow. However, a larger proportion of this complex was rapidly distributed to the bone marrow. The shorter equilibration phase for the liver, about 25 min, indicates the minimal role of the liver for direct distribution. Splenic uptake also reflected the reticuloendothelial handling of this complex. Red cell utilization ranged from 61% to 99%. Despite the relatively higher uptake by the bone marrow, there was no saturation of marrow transport systems at this dose level. In conclusion, high red cell utilization of iron polymaltose occurred in anaemic patients. The major portion of the injected dose was rapidly distributed to the bone marrow. In addition, the reticuloendothelial uptake of this complex may reflect the safety of polysaccharide complexes. Non-saturation of transport systems to the bone marrow indicated the presence of a large interstitial transport pool, which might possibly be transferrin. [ABSTRACT FROM AUTHOR]

Kinetic analysis of a single intravenous injection of 100 mg iron(III) hydroxide–sucrose complex (Venofer®) mixed with 52Fe(III) hydroxide–sucrose as a tracer was followed for 3–6 h in four generally anaesthetized, artificially ventilated minipigs using positron emission tomography (PET). The amount of injected radioactivity ranged from 30 to 200 MBq. Blood radioactivity, measured by PET in the left ventricle of the heart, displayed a fast clearance phase followed by a slow one. In the liver and bone marrow a fast radioactivity uptake occurred during the first 30 min, followed by a slower steady increase. In the liver a slight decrease in radioactivity uptake was noted by the end of the study. A kinetic analysis using a three-compartment (namely blood pool, reversible and irreversible tissue pools) model showed a fairly high distribution volume in the liver as compared with the bone marrow. In conclusion, the pharmacokinetics of the injected complex was clearly visualized with the PET technique. The organs of particular interest, namely the heart (for blood kinetics), liver and bone marrow could all be viewed by a single setting of a PET tomograph with an axial field of view of 10 cm. The half-life (T1/2) of 52Fe (8.3 h) enables a detailed kinetic study up to 24 h. A novel method was introduced to verify the actual 52Fe contribution to the PET images by removing the interfering radioactive daughter 52mMn positron emissions. The kinetic data fitted the three-compartment model, from which rate constants could be obtained for iron transfer from the blood to a pool of iron in bone marrow or liver to which it was bound during the study period. In addition, there was a reversible tissue pool of iron, which in the liver slowly equilibrated with the blood, to give a net efflux from the liver some hours after i.v. administration. The liver uptake showed a relatively long... [ABSTRACT FROM AUTHOR]

The pharmacokinetics of a single intravenous injection of 100 mg iron hydroxide–sucrose complex labelled with a tracer in the form of 52Fe/59Fe was followed in six anaemic patients for a period ranging from 6 to 8.3 h using positron emission tomography (PET). Red cell utilization of the labelled iron was followed for 4 weeks. PET data showed radioactive uptake by the liver, spleen and bone marrow. The uptake by the macrophage-rich spleen demonstrated the reticuloendothelial uptake of this iron preparation, with subsequent effective release of that iron for marrow utilization. Red cell utilization, followed for 4 weeks, ranged from 59% to 97%. The bone marrow influx rate constant was independent of blood iron concentration, indicating non-saturation of the transport system in bone marrow. This implied that higher doses of the iron complex can probably be used in the same setting. A higher influx rate into the marrow compared with the liver seemed to be consistent with higher red cell utilization. This would indicate that early distribution of the injected iron complex may predict the long-term utilization. [ABSTRACT FROM AUTHOR]

5-[76Br]Bromo-3-[[2(S)-azetidinyl]methoxy]-pyridine ([76Br]BAP), a novel nicotinic acetylcholine receptor ligand, was synthesized using [76Br]bromide in an oxidative bromodestannylation of the corresponding trimethylstannyl compound. The radiochemical yield was 25%, and the specific radioactivity was on the order of 1 Ci/μmol. The binding properties of [76Br]BAP were characterized in vitro and in vivo in rat brain, and positron emission tomography (PET) experiments were performed in two rhesus monkeys. In association experiments on membranes of the cortex and thalamus, >90% of maximal specific [76Br]BAP binding was obtained after 60 min. The dissociation half-life of [76Br]BAP was 51 ± 6 min in cortical membranes and 56 ± 3 min in thalamic membranes. Saturation experiments with [76Br]BAP revealed one population of binding sites with dissociation constant (KD) values of 36 ± 9 and 30 ± 9 pM in membranes of cortex and thalamus, respectively. The maximal binding site density (Bmax) values were 90 ± 17 and 207 ± 33 fmol/mg in membranes of cortex and thalamus, respectively. Scatchard plots were nonlinear, and the Hill coefficients were <1, suggesting the presence of a lower-affinity binding site. In vitro autoradiography studies showed that binding of [76Br]BAP was high in the thalamus and presubiculum, moderate in the cortex and striatum, and low in the cerebellum and hippocampus. A similar pattern of [76Br]BAP accumulation was observed by ex vivo autoradiography. In vivo, binding of [76Br]BAP in whole rat brain was blocked by preinjection of (S)(-)-nicotine (0.3 mg/kg) by 27, 52, 68, and 91% at survival times of 10, 25, 40, 120, and 300 min, respectively. In a preliminary PET study in rhesus monkeys, the highest [76Br]BAP uptake was found in the thalamus, and radioactivity was displaceable by ~60% with cytisine and by 50% with (S)(-)-nicotine. The data of this study indicate that [76Br]BAP is a promising radioligand for the characterization of nicotinic acetylcholine receptors in vivo. [ABSTRACT FROM AUTHOR]

Use of the passive integrated transponder (PIT) as a fish identification and monitoring system for behavioral study of Arctic char Salvelinus alpinus was evaluated. The system was developed in order to track individual differences, mainly in rheotactic behavior. In a preliminary experimental setup, Arctic char ( N = 20, 9-140 g each) were PIT-tagged and their movements were recorded at regular intervals in a circular stream channel. Two PIT tag loop detectors, placed on a narrow part of the channel, automatically recorded identity and swimming direction of tagged fish. We demonstrate some of the applications in behavioral research, such as individual, general, and diel locomotor activity patterns, rheotactic behavior, and sociograms showing activity relationships among individuals within a group. [ABSTRACT FROM AUTHOR]

The regional distribution and kinetics in the brain of Rhesus monkeys of N-(methyl-11C)-pethidine have been studied by positron emission tomography, PET. 11C-Pethidine reached the brain with peak radioactivities appearing within 6-10 min. after administration. Highest radioactivities were measured in areas corresponding to the thalamus, the striatal area and also the lowest transection of the temporal lobes, with an uptake of 2.7-3.1 times the homogenous dilution of the radioactive dose. Low radioactivities were seen in the cerebellum and the occipital lobes. This distribution corresponds to the regional density of opioid receptors using in vitro binding techniques. The 11C-pethidine derived radioactivity left the brain with an initial half-life of 40-60 min., followed by an elimination which paralleled the plasma elimination of unlabelled pethidine. After pretreatment of the monkey with a small dose of naloxone, the radioactivities decreased about 40% in areas corresponding to the thalamus, striatum and lowest section of the temporal lobes, indicating competition for the same binding sites. By the use of a three-compartment model, it was possible to get an estimate of 11C-pethidine receptor binding characteristics in the brain. The ratio of Kon/Koff, equal to Bmax./Kd, was 0.06-0.1. This indicates that pethidine is bound with low affinity to the opioid receptors and is a poor ligand for studies of opioid receptor function with PET. Brain kinetics of 11C-pethidine is mainly determined by its blood kinetics. [ABSTRACT FROM AUTHOR]

Parenteral iron-polysaccharide complexes are increasingly applied. The pharmacokinetics of iron sucrose have been assessed by our group using positron emission tomography (PET). A single intravenous injection of 100 mg iron as iron (III) hydroxide-polymaltose complex, labelled with a tracer in the form of 52Fe/59Fe, was similarly assessed in six patients using PET for about 8 h. Red cell utilization was followed for 4 weeks. Iron polymaltose was similarly distributed to the liver, spleen and bone marrow. However, a larger proportion of this complex was rapidly distributed to the bone marrow. The shorter equilibration phase for the liver, about 25 min, indicates the minimal role of the liver for direct distribution. Splenic uptake also reflected the reticuloendothelial handling of this complex. Red cell utilization ranged from 61% to 99%. Despite the relatively higher uptake by the bone marrow, there was no saturation of marrow transport systems at this dose level. In conclusion, high red cell utilization of iron polymaltose occurred in anaemic patients. The major portion of the injected dose was rapidly distributed to the bone marrow. In addition, the reticuloendothelial uptake of this complex may reflect the safety of polysaccharide complexes. Non-saturation of transport systems to the bone marrow indicated the presence of a large interstitial transport pool, which might possibly be transferrin.