MORTALITY, SURVIVAL, AND SEROLOGIC RESULTS FOR ELK (CERVUS CANADENSIS) IN THE CUMBERLAND MOUNTAINS OF TENNESSEE, USA.

Comprehensive disease surveillance has not been conducted in elk (Cervus canadensis) in Tennessee, US, since their reintroduction to the state 20 yr ago. We identified causes of death, estimated annual survival, and identified pathogens of concern in elk at the North Cumberland Wildlife Management Area (NCWMA), Tennessee, US. In 2019 and 2020, we captured 29 elk (21 females, eight males) using chemical immobilization and fitted individuals with GPS collars with mortality sensors. Elk that died between February 2019 and February 2022 were necropsied to identify causes of death; these included disease associated with meningeal worm (Parelaphostrongylus tenuis; n=3), poaching (n=1), vehicular collision (n=1), legal hunter harvest (n=1), and unknown due to carcass degradation (n=3). Using data from GPS collars and known-fate survival models, we estimated an average yearly survival rate of 80.2%, indicating that survival had not significantly increased from soon after elk reintroduction (79.9%). We collected blood, tissue, feces, and ectoparasites opportunistically from anesthetized elk for health surveillance. We identified lone star ticks (Amblyomma americanum; n=53, 85.5%; 95% confidence interval [CI], 73.72-92.75), American dog ticks (Dermacentor variabilis; n=8, 12.9%; 95% CI, 6.13-24.40), and black-legged ticks (Ixodes scapularis; n=1, 1.6%; 95% CI, 0.08-9.83). We detected evidence of exposure to Anaplasma marginale (100%; 95% CI, 84.50-100.00), Leptospira interrogans (70.4%; 95% CI, 49.66-85.50), Toxoplasma gondii (55.6%; 95% CI, 35.64-73.96), epizootic hemorrhagic disease virus (51.9%; 95% CI, 32.35-70.84), and Theileria cervi (25.9%; 95% CI, 11.78-46.59). Johne's disease (Mycobacterium avium subsp. paratuberculosis) is potentially established within the population, but has not been previously documented in eastern elk populations. Disease associated with P. tenuis was a primary cause of death, and more research is needed to understand its ecology and epidemiology. Research to determine population implications of other detected pathogens at the NCWMA is warranted.

Retrospective investigation of Echinococcus canadensis emergence in translocated elk (Cervus canadensis) in Tennessee, USA, and examination of canid definitive hosts.

BACKGROUND: Few reports of Echinococcus spp. have been described in the USA; however, the geographical distribution of Echinococcus spp. in wild hosts is increasing consequent to human activities. In the early 2000's, 253 elk (Cervus canadensis) originating from Alberta, Canada were released into the Great Smoky Mountains National Park and North Cumberland Wildlife Management Area in an effort to re-establish their historical range. METHODS: We investigated the prevalence of Echinococcus spp. in re-established elk populations in the North Cumberland Wildlife Management Area and the Great Smoky Mountains National Park via a retrospective analysis of banked elk tissues and helminth examinations on intestinal contents from coyotes (Canis latrans) from the North Cumberland Wildlife Management Area. RESULTS: Four elk were PCR and sequence positive for E. canadensis. Each sequence had 98% or greater coverage and identity to multiple E. canadensis genotypes on GenBank. Adult Echinococcus spp. were not detected in any of the coyotes examined in this study. CONCLUSIONS: Continued surveillance of this disease in susceptible species in these areas is warranted, and these data further underscore the risk of zoonotic pathogen introduction secondary to wildlife translocation.

Freeze-only versus fresh embryo transfer in a multicenter matched cohort study: contribution of progesterone and maternal age to success rates.

OBJECTIVE: To compare implantation and ongoing pregnancy rates in freeze-only versus fresh transfer cycles. DESIGN: Retrospective matched cohort study. SETTING: Not applicable. PATIENT(S): Women selected using a matching algorithm for similar distributions of clinical characteristics for a total of 2,910 cycles (1,455 fresh cohort and 1,455 freeze-only cohort). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Implantation and ongoing pregnancy rates. RESULT(S): Implantation and ongoing pregnancy rates were statistically significantly higher in the freeze-only transfer cohort than in the matched fresh transfer cohort: ongoing pregnancy rate for freeze-only was 52.0% (95% confidence interval [CI], 49.4-54.6) and for fresh was 45.3% (95% CI, 42.7-47.9), odds ratio (OR) 1.31 (95% CI, 1.13-1.51). In a stratified analysis, the odds of ongoing pregnancy after freeze-only transfer were statistically significantly higher for women both above and below age 35 with progesterone concentration >1.0 ng/mL (age ≤35: OR 1.38 [1.11-1.71]; age >35: OR 1.73 [1.34-2.24]). For women with progesterone concentration ≤1.0 ng/mL, no statistically significant difference in freeze-only odds of ongoing pregnancy was observed in either age group. The sensitivity analysis revealed that increasing maternal age alone (regardless of progesterone) trended toward a more beneficial effect of freeze-only cycles. A lower progesterone concentration was associated with statistically significantly higher ongoing pregnancy odds for fresh but not freeze-only cycles. CONCLUSION(S): Freeze-only transfer protocols are associated with statistically significantly higher ongoing implantation and pregnancy rates compared with fresh transfer cycles. This effect is most pronounced for cycles with progesterone >1.0 ng/mL at trigger and may also be stronger for older patients.

An Automated Motion Detection and Reward System for Animal Training.

A variety of approaches has been used to minimize head movement during functional brain imaging studies in awake laboratory animals. Many laboratories expend substantial effort and time training animals to remain essentially motionless during such studies. We could not locate an "off-the-shelf" automated training system that suited our needs.  We developed a time- and labor-saving automated system to train animals to hold still for extended periods of time. The system uses a personal computer and modest external hardware to provide stimulus cues, monitor movement using commercial video surveillance components, and dispense rewards. A custom computer program automatically increases the motionless duration required for rewards based on performance during the training session but allows changes during sessions. This system was used to train cynomolgus monkeys (Macaca fascicularis) for awake neuroimaging studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). The automated system saved the trainer substantial time, presented stimuli and rewards in a highly consistent manner, and automatically documented training sessions. We have limited data to prove the training system's success, drawn from the automated records during training sessions, but we believe others may find it useful. The system can be adapted to a range of behavioral training/recording activities for research or commercial applications, and the software is freely available for non-commercial use.

Clinically recognizable error rate after the transfer of comprehensive chromosomal screened euploid embryos is low.

OBJECTIVE: To determine the clinically recognizable error rate with the use of quantitative polymerase chain reaction (qPCR)-based comprehensive chromosomal screening (CCS). DESIGN: Retrospective study. SETTING: Multiple fertility centers. PATIENT(S): All patients receiving euploid designated embryos. INTERVENTION(S): Trophectoderm biopsy for CCS. MAIN OUTCOME MEASURE(S): Evaluation of the pregnancy outcomes following the transfer of qPCR-designated euploid embryos. Calculation of the clinically recognizable error rate. RESULT(S): A total of 3,168 transfers led to 2,354 pregnancies (74.3%). Of 4,794 CCS euploid embryos transferred, 2,976 gestational sacs developed, reflecting a clinical implantation rate of 62.1%. In the cases where a miscarriage occurred and products of conception were available for analysis, ten were ultimately found to be aneuploid. Seven were identified in the products of conception following clinical losses and three in ongoing pregnancies. The clinically recognizable error rate per embryo designated as euploid was 0.21% (95% confidence interval [CI] 0.10-0.37). The clinically recognizable error rate per transfer was 0.32% (95% CI 0.16-0.56). The clinically recognizable error rate per ongoing pregnancy was 0.13% (95% CI 0.03-0.37). Three products of conception from aneuploid losses were available to the molecular laboratory for detailed examination, and all of them demonstrated fetal mosaicism. CONCLUSION(S): The clinically recognizable error rate with qPCR-based CCS is real but quite low. Although evaluated in only a limited number of specimens, mosaicism appears to play a prominent role in misdiagnoses. Mosaic errors present a genuine limit to the effectiveness of aneuploidy screening, because they are not attributable to technical issues in the embryology or analytic laboratories.

Subdivisions and connectional networks of the lateral prefrontal cortex in the macaque monkey.

Neuroanatomical studies have long indicated that corticocortical connections are organized in networks that relate distinct sets of areas. Such networks have been emphasized by development of functional imaging methods for correlating activity across the cortex. Previously, two networks were recognized in the orbitomedial prefrontal cortex, the "orbital" and "medial" networks (OPFC and MPFC, respectively). In this study, three additional networks are proposed for the lateral prefrontal cortex: 1) a ventrolateral network (VLPFC) in and ventral to the principal sulcus; 2) a dorsal network (DPFC) in and dorsal to the principal sulcus and in the frontal pole; 3) a caudolateral network (CLPFC) in and rostral to the arcuate sulcus and the caudal principal sulcus. The connections of the first two networks are described here. Areas in each network are connected primarily with other areas in the same network, with overlaps around the principal sulcus. The VLPFC and DPFC are also connected with the OPFC and MPFC, respectively. Outside the prefrontal cortex, the VLPFC connects with specific areas related to somatic/visceral sensation and vision, in the frontoparietal operculum, insula, ventral bank/fundus of the superior temporal sulcus, inferior temporal gyrus, and inferior parietal cortex. In contrast, the DPFC connects with the rostral superior temporal gyrus, dorsal bank of the superior temporal sulcus, parahippocampal cortex, and posterior cingulate and retrosplenial cortex. Area 45a, in caudal VLPFC, is unique, having connections with all the networks. Its extrinsic connections resemble those of the DPFC. In addition, it has connections with both auditory belt/parabelt areas, and visual related areas.

Prolactin and fMRI response to SKF38393 in the baboon.

Background. This study's goal was to provide dose-response data for a dopamine agonist in the baboon using standard methods (replicate measurements at each dose, across a range of doses), as a standard against which to subsequently validate a novel pharmacological MRI (phMRI) method. Dependent variables were functional MRI (fMRI) data from brain regions selected a priori, and systemic prolactin release. Necessary first steps included estimating the magnitude and time course of prolactin response to anesthesia alone and to various doses of agonist. These first steps ("time course studies") were performed with three agonists, and the results were used to select promising agonists and to guide design details for the single-dose studies needed to generate dose-response curves. Methods. We studied 6 male baboons (Papio anubis) under low-dose isoflurane anesthesia after i.m. ketamine. Time course studies charted the changes in plasma prolactin levels over time after anesthesia alone or after an intravenous (i.v.) dose of the dopamine D 1-like agonists SKF82958 and SKF38393 or the D 2-like agonist pramipexole. In the single-dose dopamine agonist studies, one dose of SKF38393 (ranging from 0.0928-9.28 mg/kg, N = 5 animals) or pramipexole (0.00928-0.2 mg/kg, N = 1) was given i.v. during a 40-min blood oxygen level dependent (BOLD) fMRI session, to determine BOLD and plasma prolactin responses to different drug concentrations. BOLD response was quantified as the area under the time-signal curve for the first 15 min after the start of the drug infusion, compared to the linearly predicted signal from the baseline data before drug. The ED50 (estimated dose that produces 50% of the maximal possible response to drug) for SKF38393 was calculated for the serum prolactin response and for phMRI responses in hypothalamus, pituitary, striatum and midbrain. Results. Prolactin rose 2.4- to 12-fold with anesthesia alone, peaking around 50-90 min after ketamine administration and gradually tapering off but still remaining higher than baseline on isoflurane 3-5 h after ketamine. Baseline prolactin level increased with age. SKF82958 0.1 mg/kg i.v. produced no noticeable change in plasma prolactin concentration. SKF38393 produced a substantial increase in prolactin release that peaked at around 20-30 min and declined to pre-drug levels in about an hour. Pramipexole quickly reduced prolactin levels below baseline, reaching a nadir 2-3 h after infusion. SKF38393 produced clear, dose-responsive BOLD signal changes, and across the four regions, ED50 was estimated at 2.6-8.1 mg/kg. Conclusions. In the baboon, the dopamine D 1 receptor agonist SKF38393 produces clear plasma prolactin and phMRI dose-response curves. Variability in age and a modest sample size limit the precision of the conclusions.

Rapid quantitative pharmacodynamic imaging by a novel method: theory, simulation testing and proof of principle.

Pharmacological challenge imaging has mapped, but rarely quantified, the sensitivity of a biological system to a given drug. We describe a novel method called rapid quantitative pharmacodynamic imaging. This method combines pharmacokinetic-pharmacodynamic modeling, repeated small doses of a challenge drug over a short time scale, and functional imaging to rapidly provide quantitative estimates of drug sensitivity including EC 50 (the concentration of drug that produces half the maximum possible effect). We first test the method with simulated data, assuming a typical sigmoidal dose-response curve and assuming imperfect imaging that includes artifactual baseline signal drift and random error. With these few assumptions, rapid quantitative pharmacodynamic imaging reliably estimates EC 50 from the simulated data, except when noise overwhelms the drug effect or when the effect occurs only at high doses. In preliminary fMRI studies of primate brain using a dopamine agonist, the observed noise level is modest compared with observed drug effects, and a quantitative EC 50 can be obtained from some regional time-signal curves. Taken together, these results suggest that research and clinical applications for rapid quantitative pharmacodynamic imaging are realistic.

A comparison of oxygen saturation in white-tailed deer estimated by pulse oximetry and from arterial blood gases.

Physiologic monitoring is important when chemically immobilizing wildlife. Blood oxygenation is usually monitored by pulse oximetry in the field; however, there is some question whether this technique accurately reflects oxygen saturation in wild white-tailed deer (Odocoileus virginianus). We evaluated different doses of medetomidine (125, 150, 175, or 200 µg/kg) mixed with ketamine (1.5 mg/kg), and tiletamine-zolazepam (1.0 mg/kg) in 22 female white-tailed deer at the University of Georgia Whitehall Deer Research Facility in Athens, Georgia on 14-15 and 21 May 2009. Deer were hand-injected intramuscularly while physically restrained in a squeeze chute, and then they were released into a pen for monitoring. Hemoglobin saturation estimated using pulse oximetry (SpO(2)) was compared with hemoglobin saturation value from arterial blood gases (SaO(2)) at 0, 10, and 20 min postimmobilization with deer in a sternal position. We made 56 simultaneous comparisons of oxygen saturation using SpO(2) (range, 54-95%) and SaO(2) (range, 60-95%). We used a Bland-Altman analysis for determining agreement between the two methods. Hemoglobin saturation estimated using SpO(2) was generally greater than SaO(2) when the mean of the two measurements was >80%. At mean values <80% oxygen saturation, there is not sufficient agreement between the techniques. Multiple readings over time may help recognition of outliers.

Optimal medetomidine dose when combined with ketamine and tiletamine-zolazepam to immobilize white-tailed deer.

Chemical immobilization is often needed for safe and effective capture and handling of wildlife. We evaluated medetomidine (125, 150, 175, or 200 µg/kg; for synergistic effects and relaxation) mixed with ketamine (1.5 mg/kg; for relatively shorter recovery) and tiletamine-zolazepam (1.0 mg/kg; for rapid induction) in 22 female white-tailed deer (Odocoileus virginianus) at the University of Georgia Whitehall Deer Research Facility in Athens, Georgia, USA, on 14-15 and 21 May 2009. Deer were weighed before treatment, hand-injected intramuscularly (IM) while restrained in a squeeze chute, and released into a pen for monitoring. We measured rectal temperature, respiration rate, heart rate, hemoglobin saturation (using pulse oximetry), and arterial blood gases at 0, 10, and 20 min postimmobilization. We found no differences in induction time with different doses of medetomidine. Deer became laterally recumbent for all treatments combined at a median of 4.2 (2.6-21.3) min and were approachable by a median of 4.8 (3.5-21.8) min. Twelve of the 22 deer had rectal temperatures >40 C at time 0 and were treated with a cold-water enema. Hemoglobin saturation, estimated using pulse oximetry, was 79.5, 82.0, and 82.3% at times 0, 10, and 20, respectively. We injected atipamezole (0.35 mg/kg, IM) for reversal. Recovery occurred sooner and was more consistent for 125 and 150 µg/kg medetomidine whereby deer stood with minimal sedation to moderate ataxia within 60-90 min after atipamezole administration. We recommend using 150 µg of medetomidine with ketamine (1.5 mg/kg) and tiletamine-zolazepam (1.0 mg/kg) to provide effective and safe chemical immobilization of white-tailed deer.

Butorphanol-azaperone-medetomidine for immobilization of captive white-tailed deer.

Drug combinations are commonly used to immobilize white-tailed deer (Odocoileus virginianus) for capture or handling. Although efficacy of various compatible and complementary drugs has been tested in clinical trials with deer, extensive negative side effects, impractical drug volume, and slow recovery from immobilization sometimes make these combinations less than ideal for routine field use. We hypothesized that a combination of butorphanol, azaperone, and medetomidine (BAM) would provide safe and effective immobilization of captive white-tailed deer while minimizing these complicating factors. We tested two dosages of this drug combination (BAM-1 and BAM-2) and two dosages of a naltrexone, tolazoline, and atipamezole antagonist combination (NTA-1 and NTA-2) with captive white-tailed deer. We characterized efficacy of drug for immobilization, quality of drug induction, and recovery after drug reversal, and we compared our findings with those of previous drug trials. Complete immobilization and excellent induction quality was achieved with a low volume dosage of BAM-2. Time to drug induction and deer recumbency for BAM-2 compared favorably with results from previous trials involving xylaxine/ ketamine and medetomidine/ketamine but without risk of hyperthermia. We found no differences in time to deer recovery for NTA-1 and NTA-2, with deer treated with either combination standing by 30 min postinjection. Regardless of immobilizing drugs used, we suggest practitioners monitor for signs of circulatory deficiency in deer and provide supplemental oxygen when needed.

Strength of hollow hydroxyapatite microspheres prepared by a glass conversion process.

Hollow hydroxyapatite (HA) microspheres (diameter = 100-800 microm) were prepared by reacting solid Li(2)O-CaO-B(2)O(3) glass spheres in 0.25 M K(2)HPO(4) solution at 37 degrees C. The influence of subsequent heating on the microstructure, surface area, and compressive strength of the HA microspheres was evaluated using scanning electron microscopy, the BET method, and nano-mechanical testing. The surface area and rupture strength of the as-prepared microspheres were 135 m(2)/g and 1.6 +/- 0.6 MPa, respectively. On heating for 8 h at 600 degrees C, the surface area decreased to 27 m(2)/g, but there was no increase in the compressive strength (1.7 +/- 0.4 MPa). Heating to 800 degrees C (8 h) resulted in a marked decrease in the surface area (to 2.6 m(2)/g) and a sharp increase in the compressive strength (to >35 +/- 8 MPa). These hollow HA microspheres may be useful as devices for drug or protein growth factor delivery or as scaffolds for engineered tissues.

Ammonium and nitrate uptake, nitrogen productivity and biomass allocation in interior spruce families with contrasting growth rates and mineral nutrient preconditioning.

Four full-sib families of interior spruce (Picea glauca (Moench) Voss) x Picea engelmanii Parry ex Engelm.) with contrasting growth rates (two fast-growing and two slow-growing families) were grown aeroponically with either a 2% relative nitrogen addition rate or free access to nitrogen. Fast-growing families showed greater plasticity in allocating biomass to shoots at high nitrogen supply and to roots at low nitrogen supply than slow-growing families. Compared with the slow-growing families, short-term net ammonium uptake rate measured with an ion selective electrode was significantly greater in fast-growing families at high ammonium supply, but not at low supply. Net nitrate uptake showed the same trend, but differences among families were not significant. Results indicate that differences in seedling growth rate are partly a result of physiological differences in net nitrogen uptake efficiency and nitrogen productivity.

School-based use of a robotic arm system by children with disabilities.

A robotic arm system was developed for use by children who had very severe motor disabilities and varying levels of cognitive and language skills. The children used the robot in a three-task sequence routine to dig objects from a tub of dry macaroni. The robotic system was used in the child's school for 12-15 sessions over a period of four weeks. Goal attainment scaling indicated improvement in all children in operational competence of the robot, and varying levels of gain in functional skill development with the robot and in carryover to the classroom from the robot experiments. Teacher interviews revealed gains in classroom participation, expressive language (vocalizations, symbolic communication), and a high degree of interest by the children in the robot tasks. The teachers also recommended that the robot should have more color, contrast and character, as well as generating sounds and/or music for student cues. They also felt that the robotic system accuracy should be increased so that teacher assistance is not necessary to complete the task.

Effect of the iridium oxide thin film on the electrochemical activity of platinum nanoparticles.

The influence of the iridium oxide thin film on the electrocatalytic properties of platinum nanoparticles was investigated using the electro-oxidation of methanol and CO as a probe. The presence of the IrO(2) thin film leads to the homogeneous dispersion of Pt nanoparticles. For comparison, polycrystalline platinum and Pt nanoparticles dispersed on a Ti substrate in the absence of an IrO(2) layer (Ti/Pt) were also investigated in this study. Inverted and enhanced CO bipolar peaks were observed using an in situ electrochemical Fourier transform infrared technique during the methanol oxidation on the Pt nanoparticles dispersed on a Ti substrate. Electrochemical impedance studies showed that the charge transfer resistance was significantly lower for the Ti/IrO(2)/Pt electrode compared with that of the massive Pt and Ti/Pt nanoparticles. The presence of the IrO(2) thin film not only greatly increases the active surface area but also promotes CO oxidation at a much lower electrode potential, thus, significantly enhancing the electrocatalytic activity of Pt nanoparticles toward methanol electro-oxidation.

Effectiveness of antagonists for tiletamine-zolazepam/xylazine immobilization in female white-tailed deer.

A combination of tiletamine-zolazepam/xylazine (TZ/X) is effective in the chemical immobilization of white-tailed deer (Odocoileus virginianus); however, the lengthy duration of immobilization may limit its usefulness. From October to November 2002, 21 captive female deer were assigned randomly to an alpha(2) antagonist treatment to reverse xylazine-induced sedation (seven does per group). All deer were given 220 mg of TZ (4.5+/-0.4 mg/kg) and 110 mg of X (2.2+/-0.2 mg/kg) intramuscularly (IM). Antagonist treatments were either 200 mg of tolazoline (4.0+/-0.4 mg/kg), 11 mg of atipamezole (0.23+/-0.02 mg/kg), or 15 mg of yohimbine (0.30+/-0.02 mg/kg) injected, half intravenously and half subcutaneously, 45 min after the IM TZ/X injection. In addition, 10 other deer (five per group) were immobilized as before and then given tolazoline (200 mg) after 45 min, with either a carrier (dimethyl sulfoxide [DMSO]) or carrier (DMSO) plus flumazenil (5 mg) to reverse the zolazepam portion of TZ. Mean times from antagonist injection until a deer raised its head were different for alpha(2) antagonist treatments (P=0.02). Times were longer for yohimbine (62.3+/-42.7 min) than for either atipamezole (24.3+/-17.1 min) or tolazoline (21.3+/-14.3 min). Mean times from antagonist injection until standing were not different (P=0.15) among yohimbine (112.0+/-56.4 min), atipamezole (89.7+/-62.8 min), or tolazoline (52.6+/-37.2 min). A sedation score based on behavioral criteria was assigned to each deer every 30 min for 5 hr. On the basis of sedation scores, tolazoline resulted in a faster and more complete reversal of immobilization. Flumazenil treatment did not affect recovery.

Super-hydrophobic tin oxide nanoflowers.

Super-hydrophobic 3D SnO(2) flowers with nanoporous petals were produced from the 3D Sn nanoflowers using a controlled shape-preserving thermal oxidation process.

Improved molecular imaging contrast agent for detection of human thrombus.

Molecular imaging of microthrombus within fissures of unstable atherosclerotic plaques requires sensitive detection with a thrombus-specific agent. Effective molecular imaging has been previously demonstrated with fibrin-targeted Gd-DTPA-bis-oleate (BOA) nanoparticles. In this study, the relaxivity of an improved fibrin-targeted paramagnetic formulation, Gd-DTPA-phosphatidylethanolamine (PE), was compared with Gd-DTPA-BOA at 0.05-4.7 T. Ion- and particle-based r(1) relaxivities (1.5 T) for Gd-DTPA-PE (33.7 (s*mM)(-1) and 2.48 x 10(6) (s*mM)(-1), respectively) were about twofold higher than for Gd-DTPA-BOA, perhaps due to faster water exchange with surface gadolinium. Gd-DTPA-PE nanoparticles bound to thrombus surfaces via anti-fibrin antibodies (1H10) induced 72% +/- 5% higher change in R(1) values at 1.5 T (deltaR(1) = 0.77 +/- 0.02 1/s) relative to Gd-DTPA-BOA (deltaR(1) = 0.45 +/- 0.02 1/s). These studies demonstrate marked improvement in a fibrin-specific molecular imaging agent that might allow sensitive, early detection of vascular microthrombi, the antecedent to stroke and heart attack.

Clinically applicable labeling of mammalian and stem cells by combining superparamagnetic iron oxides and transfection agents.

PURPOSE: To label mammalian and stem cells by combining commercially available transfection agents (TAs) with superparamagnetic iron oxide (SPIO) magnetic resonance (MR) imaging contrast agents. MATERIALS AND METHODS: Three TAs were incubated with ferumoxides and MION-46L in cell culture medium at various concentrations. Human mesenchymal stem cells, mouse lymphocytes, rat oligodendrocyte progenitor CG-4 cells, and human cervical carcinoma cells were incubated 2-48 hours with 25 microg of iron per milliliter of combined TAs and SPIO. Cellular labeling was evaluated with T2 relaxometry, MR imaging of labeled cell suspensions, and Prussian blue staining for iron assessment. Proliferation and viability of mesenchymal stem cells and human cervical carcinoma cells labeled with a combination of TAs and ferumoxides were evaluated. RESULTS: When ferumoxides-TA or MION-46L-TA was used, intracytoplasmic particles stained with Prussian blue stain were detected for all cell lines with a labeling efficiency of nearly 100%. Limited or no uptake was observed for cells incubated with ferumoxides or MION-46L alone. For TA-SPIO-labeled cells, MR images and relaxometry findings showed a 50%-90% decrease in signal intensity and a more than 40-fold increase in T2s. Cell viability varied from 103.7% +/- 9 to 123.0% +/- 9 compared with control cell viability at 9 days, and cell proliferation was not affected by endosomal incorporation of SPIO nanoparticles. Iron concentrations varied with ferumoxides-TA combinations and cells with a maximum of 30.1 pg +/- 3.7 of iron per cell for labeled mesenchymal stem cells. CONCLUSION: Magnetic labeling of mammalian cells with use of ferumoxides and TAs is possible and may enable cellular MR imaging and tracking in experimental and clinical settings.

Glutamate receptor blockade alters the development of intracortical connections in rat barrel cortex.

We tested the hypothesis that glutamate receptor mediated activity is required for the postnatal development of intracortical connections in layers II/III of rodent barrel cortex. To block glutamate receptors, a slow release polymer (elvax) loaded with a glutamate receptor antagonist (D-AP5) was targeted subdurally over the future rat barrel cortex on P0 (day of birth). On P14-16 biotinylated dextran amine (BDA) was injected under the elvax into all layers to label neurons retrogradely. A BDA injection was made stereotactically at the mirror site of the untreated hemisphere of each animal. The animals survived to P22-24. Injection sites and retrogradely labeled cell bodies were identified in tangential sections in relation to the barrel map. D-AP5 treated and untreated hemispheres were matched according to the location of the injection site in the barrel map. Glutamate receptor blockade did not prevent the growth of intrinsic projections, but altered their organization. The normal row-like asymmetry of connections in untreated hemispheres was lacking in the D-AP5 treated cortex (ANOVA, p=0.02). Cortical activity mediated through glutamate receptors contributes to the correct development of connections between barrel columns in layers II/III.