The effect of the shape of a clip on the magnetic field during magnetic resonance imaging examinations

Aim Plastic clips are a diamagnetic material and produce fewer artefacts in the MR field than titanium clips, which are standard in neurosurgery. However, alongside their physical properties, the shape of the clips, and their very geometry subtlety affects their behaviour in the magnetic field. Therefore, we performed a simulation in order to establish which clips cause less disturbance in the magnetic field from the point of view of the geometry of the body. Methods The simulation tool used for the research was the software package COMSOL Mph version 4.3. Since it was a question of magnetics, the models were prepared in the AC/DC module within the option Magnetic Fields, No Currents (mfnc). Within this module we were able to analyse electro-magnetic fields for a specific geometrical structure, using the Finite Element Method in order to resolve the two-dimensional electromagnetic problems. Results The value of the magnetic field with titanium clips with their specific geometric reference lines reached the value of c. (A/m). The simpler geometry of the plastic clips resulted in a less intensive magnetic field, amounting to c. (A/m), which is an entire order of magnitude less than the field with the titanium clips. Conclusion The simpler geometry of the plastic clips and the type of material from which they are made causes less disturbance to the magnetic field, which was precisely confirmed with the simulation model. The use of plastic clips in neurosurgery and neuroradiology will facilitate the interpretation of MR images

CT advantages of potential use of polymer plastic clips in neurocranium

Aim Clips in neurosurgery are made of titanium alloys, which reduce artifacts on computed tomography (CT). The radiological advantage of plastic clips on the CT image was demonstrated when they were placed in an inter-hemispherical position at an angle of 90º. The aim of this study was to investigate the behaviour of the clip placed at different angles. Methods Sixty heads of domestic pigs were divided into two groups, in group 1 a titanium clip was placed to the interhemispheric position at an angle of 90º, 45º, 0º, ten heads for each angle. In group 2 a plastic clip was placed in the same way. CT scan of the brain was performed for each angle. The size of the density and possible artifact were measured on CT. Results The size of the titanium clip ranged from 17.05 mm at an angle of 0º in the axial plane to 91.47 mm at an angle of 0º in the sagittal plane. The average size of the plastic clip ranged from 6.4 mm at an angle of 0º in the axial plane to 23.22 mm in an angle of 90º in the sagittal plane. Artifacts were observed only in the titanium clip. Conclusion Plastic clips have shown radiological advantages over titanium clips in the CT image. The average density size of the plastic clip in all planes and all angles was smaller than the titanium clip

Ablation of Bscl2/Seipin in hepatocytes does not cause metabolic dysfunction in congenital generalised lipodystrophy

Funding Work was supported by the Medical Research Council (GDM/JJR; MR/L002620/1, MC/PC/15077), the Biotechnology and Biological Sciences Research Council (JJR; BB/K017772/1), Diabetes UK (GDM/JJR; 18/0005884), the British Heart Foundation (MD;PG/14/43/30889) and the Wellcome Trust and the University of Aberdeen ISSF Fund (GDM; ISSF Fellowship Support Fund).Peer reviewedPublisher PD

Volatile organic compounds for the detection of hepatocellular carcinoma : A scoping review

Funding Information: This study is partially funded by the endowment fund NHS Grampian as part of the project (IRAS 250335).Peer reviewe

Gene therapy restores adipose tissue and metabolic health in a pre-clinical mouse model of lipodystrophy

The authors are extremely grateful to Dr Donna MacCallum (University of Aberdeen) for assistance with AAV vector i.v. tail vein injections and Pat Bain (University of Aberdeen) for design and generation of the graphical abstract. The authors would also like to thank the staff at the University of Aberdeen’s Microscopy and Histology Core Facility and the Medical Research Facility for support with animal breeding and maintenance. This research was supported by funding from the EFSD/Lilly Young Investigator Research Award Programme, Wellcome Trust ISSF Fellowship Support Fund, and Diabetes UK RD Lawrence Fellowship (21/0006280) awarded to G.D.M. and Diabetes UK (18/0005884) awarded to J.J.R.Peer reviewedPublisher PD

Bscl2 Deficiency Does Not Directly Impair the Innate Immune Response in a Murine Model of Generalized Lipodystrophy

Funding: Work was supported by Diabetes UK (JJR;18/0005884, MD;17/0005621) the Medical Research Council (JJR; MR/L002620/1, MC/PC/15077), the British Heart Foundation (MD; PG/14/43/30889), The Agency for Science, Technology and Research, Singapore (A*STAR) (WH), The Wellcome Trust (ISSF Funding to GDM) and the European Union’s Horizon 2020 ERC consolidator award (MB:2016-726152-TYPHI).Peer reviewedPublisher PD

Fenretinide mediated retinoic acid receptor signalling and inhibition of ceramide biosynthesis regulates adipogenesis, lipid accumulation, mitochondrial function and nutrient stress signalling in adipocytes and adipose tissue

Fenretinide (FEN) is a synthetic retinoid that inhibits obesity and insulin resistance in high-fat diet (HFD)-fed mice and completely prevents 3T3-L1 pre-adipocyte differentiation. The aim of this study was to determine the mechanism(s) of FEN action in 3T3-L1 adipocytes and in mice. We used the 3T3-L1 model of adipogenesis, fully differentiated 3T3-L1 adipocytes and adipose tissue from HFD-induced obese mice to investigate the mechanisms of FEN action. We measured expression of adipogenic and retinoid genes by qPCR and activation of nutrient-signalling pathways by western blotting. Global lipid and metabolite analysis was performed and specific ceramide lipid species measured by liquid chromatography-mass spectrometry. We provide direct evidence that FEN inhibits 3T3-L1 adipogenesis via RA-receptor (RAR)-dependent signaling. However, RARα antagonism did not prevent FEN-induced decreases in lipid levels in mature 3T3-L1 adipocytes, suggesting an RAR-independent mechanism. Lipidomics analysis revealed that FEN increased dihydroceramide lipid species 5- to 16-fold in adipocytes, indicating an inhibition of the final step of ceramide biosynthesis. A similar blockade in adipose tissue from FEN-treated obese mice was associated with a complete normalisation of impaired mitochondrial β-oxidation and tricarboxylic acid cycle flux. The FEN catabolite, 4-oxo-N-(4-hydroxyphenyl)retinamide (4-OXO), also decreased lipid accumulation without affecting adipogenesis. FEN and 4-OXO (but not RA) treatment additionally led to the activation of p38-MAPK, peIF2α and autophagy markers in adipocytes. Overall our data reveals FEN utilises both RAR-dependent and -independent pathways to regulate adipocyte biology, both of which may be required for FEN to prevent obesity and insulin resistance in vivo

Deficiency in Protein Tyrosine Phosphatase PTP1B shortens lifespan and leads to development of acute leukemia

This work was performed with the funds from the Wellcome Trust ISSF grant to M. Delibegovic and BHF project grant to M. Delibegovic (PG/11/8/28703). S. Le Sommer is a recipient of the University of Aberdeen Institute of Medical Sciences PhD studentship. Conflict of interest: Authors declare there are no conflicts of interests.Peer reviewedPostprin

Adipocyte-specific protein tyrosine phosphatase 1B deletion increases lipogenesis, adipocyte cell size and is a minor regulator of glucose homeostasis

Peer reviewedPublisher PD

Liver-specific deletion of protein tyrosine phosphatase (PTP) 1B improves obesity- and pharmacologically induced endoplasmic reticulum stress

Peer reviewedPostprin