Measurement of the in vivo release of 3H-serotonin using a push-pull cannula implanted in selected brain structures of the cat.

Summary13 male New Zealand rabbits were injected with two different doses (25 μg/Kg and 100 μg/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 ± 0.16 and 1.76 ± 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min.The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 ± 5.9 min and 30.9 ± 2.19 min respectively.

Download Full-text

Faculty Opinions recommendation of Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725433551.793505840 ◽

2015 ◽

Author(s):

Keith Davis

Keyword(s):

Plant Immunity ◽

In Vivo Release ◽

Molecular Patterns ◽

Damage Associated Molecular Patterns

Download Full-text

Whole-brain 3D MR fingerprinting brain imaging: clinical validation and feasibility to patients with meningioma

Magnetic Resonance Materials in Physics Biology and Medicine ◽

10.1007/s10334-021-00924-1 ◽

2021 ◽

Author(s):

Thomaz R. Mostardeiro ◽

Ananya Panda ◽

Robert J. Witte ◽

Norbert G. Campeau ◽

Kiaran P. McGee ◽

...

Keyword(s):

White Matter ◽

Statistical Significance ◽

Relaxation Times ◽

Brain Structures ◽

Centrum Semiovale ◽

In Vivo Evaluation ◽

Whole Brain ◽

Mean Values ◽

Caudate Head

Abstract Purpose MR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma. Materials and methods A whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman’s ANOVA test. Results MR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001) Conclusions Phantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.

Download Full-text

The role of cochlear implant positioning on MR imaging quality: a preclinical in vivo study with a novel implant magnet system

European Archives of Oto-Rhino-Laryngology ◽

10.1007/s00405-021-07005-y ◽

2021 ◽

Author(s):

Pietro Canzi ◽

Marianna Magnetto ◽

Anna Simoncelli ◽

Marco Manfrin ◽

Federico Aprile ◽

...

Keyword(s):

Mr Imaging ◽

Cochlear Implant ◽

Occipital Lobe ◽

Brain Structures ◽

Magnet System ◽

High Positive Correlation ◽

Imaging Quality ◽

Signal Void ◽

Mri Surveillance

Abstract Purposes To investigate the effects for Ultra 3D cochlear implant (CI) positioning on MR imaging quality, looking at a comprehensive description of intracranial structures in cases of unilateral and bilateral CI placement. Methods Four CI angular positions (90°, 120°, 135° and 160°) at 9 cm distance from the outer-ear canal were explored. The 1.5 T MRI assessment included our institutional protocol for the investigation of brain pathologies without gadolinium application. Three investigators (two experienced neuroradiologists and one experienced otoneurosurgeon) independently evaluated the MR findings. A 4-point scale was adopted to describe 14 intracranial structures and to determine which CI positioning allowed the best image quality score and how bilateral CI placement modified MRI scan visibility. Results A high positive correlation was found between the three blinded observers. Structures situated contralateral from the CI showed high-quality values in all four placements. Structures situated ipsilaterally provided results suitable for diagnostic purposes for at least one position. At 90°, artifacts mainly involved brain structures located cranially and anteriorly (e.g., temporal lobe); on the contrary, at 160°, artifacts mostly influenced the posterior fossa structures (e.g., occipital lobe). For the bilateral CI condition, MR imaging examination revealed additional artifacts involving all structures located close to either CI, where there was a signal void/distortion area. Conclusions Suitable unilateral CI positioning can allow the visualization of intracranial structures with sufficient visibility for diagnostic purposes. Bilateral CI positioning significantly deteriorates the anatomical visibility. CI positioning might play a crucial role for patients who need post-operative MRI surveillance.

Download Full-text