Endocannabinoid Release Modulates Electrical Coupling between CCK Cells Connected via Chemical and Electrical Synapses in CA1

Electrical coupling between some subclasses of interneurons is thought to promote coordinated firing that generates rhythmic synchronous activity in cortical regions. Synaptic activity of cholecystokinin (CCK) interneurons which co-express cannabinoid type-1 (CB1) receptors are powerful modulators of network activity via the actions of endocannabinoids. We investigated the modulatory actions of endocannabinoids between chemically and electrically connected synapses of CCK cells using paired whole-cell recordings combined with biocytin and double immunofluorescence labeling in acute slices of rat hippocampus at P18–20 days. CA1 stratum radiatum CCK Schaffer collateral-associated cells were coupled electrically with each other as well as CCK basket cells and CCK cells with axonal projections expanding to dentate gyrus. Approximately 50% of electrically coupled cells received facilitating, asynchronously released inhibitory postsynaptic potential (IPSPs) that curtailed the steady-state coupling coefficient by 57%. Tonic CB1 receptor activity which reduces inhibition enhanced electrical coupling between cells that were connected via chemical and electrical synapses. Blocking CB1 receptors with antagonist, AM-251 (5 μM) resulted in the synchronized release of larger IPSPs and this enhanced inhibition further reduced the steady-state coupling coefficient by 85%. Depolarization induced suppression of inhibition (DSI), maintained the asynchronicity of IPSP latency, but reduced IPSP amplitudes by 95% and enhanced the steady-state coupling coefficient by 104% and IPSP duration by 200%. However, DSI did not did not enhance electrical coupling at purely electrical synapses. These data suggest that different morphological subclasses of CCK interneurons are interconnected via gap junctions. The synergy between the chemical and electrical coupling between CCK cells probably plays a role in activity-dependent endocannabinoid modulation of rhythmic synchronization

Dichlorido(4,7-diaza-1-azoniacyclo­nonane-κ2 N 4,N 7)palladium(II) p-toluene­sulfonate

The title compound, [PdCl2(C6H16N3)](C7H7SO3), consists of a PdII atom bonded to two N atoms of the 1,4,7-triaza­cyclo­nonane (TACN) ligand and two chloride ions, which define a distorted square-planar geometry. The third N atom of the TACN ligand is protonated and hydrogen bonds to the p-toluene­sulfonate anion. The Cl—Pd—Cl angle is larger than the N—Pd—N angle. The packing is dominated by layers, which are formed by the criss-crossing of two different hydrogen-bonded chains. One chain is composed of hydrogen-bonded Pd(TACNH)Cl2 + cations, while the second is formed through hydrogen bonding between the p-toluene­sulfonate anion and the Pd(TACNH)Cl2 + cation

GABAA receptors can initiate the formation of functional inhibitory GABAergic synapses.

The mechanisms that underlie the selection of an inhibitory GABAergic axon's postsynaptic targets and the formation of the first contacts are currently unknown. To determine whether expression of GABAA receptors (GABAA Rs) themselves - the essential functional postsynaptic components of GABAergic synapses - can be sufficient to initiate formation of synaptic contacts, a novel co-culture system was devised. In this system, the presynaptic GABAergic axons originated from embryonic rat basal ganglia medium spiny neurones, whereas their most prevalent postsynaptic targets, i.e. α1/β2/γ2-GABAA Rs, were expressed constitutively in a stably transfected human embryonic kidney 293 (HEK293) cell line. The first synapse-like contacts in these co-cultures were detected by colocalization of presynaptic and postsynaptic markers within 2 h. The number of contacts reached a plateau at 24 h. These contacts were stable, as assessed by live cell imaging; they were active, as determined by uptake of a fluorescently labelled synaptotagmin vesicle-luminal domain-specific antibody; and they supported spontaneous and action potential-driven postsynaptic GABAergic currents. Ultrastructural analysis confirmed the presence of characteristics typical of active synapses. Synapse formation was not observed with control or N-methyl-d-aspartate receptor-expressing HEK293 cells. A prominent increase in synapse formation and strength was observed when neuroligin-2 was co-expressed with GABAA Rs, suggesting a cooperative relationship between these proteins. Thus, in addition to fulfilling an essential functional role, postsynaptic GABAA Rs can promote the adhesion of inhibitory axons and the development of functional synapses

Achirality in the low temperature structure and lattice modes of tris(acetylacetonate)iron(iii)

Tris(acetylacteonate) iron(III) is a relatively ubiquitous mononuclear inorganic coordination complex. The bidentate nature of the three acetylacteonate ligands coordinating around a single centre inevitably leads to structural isomeric forms, however whether or not this relates to chirality in the solid state has been questioned in the literature. Variable temperature neutron diffraction data down to T = 3 K, highlights the dynamic nature of the ligand environment, including the motions of the hydrogen atoms. The Fourier transform of the molecular dynamics simulation based on the experimentally determined structure was shown to closely reproduce the low temperature vibrational density of states obtained using inelastic neutron scattering

Radiation dose reduction in CT-guided cryoablation of renal tumors

PURPOSEWe aimed to evaluate the effect on the radiation dose to the patient by reducing the tube current during the placement of the ablation needles (reduced dose group) compared with the patient doses delivered when scanning at the standard fully diagnostic level (full dose group) in computed tomography (CT)-guided percutaneous cryoablation.METHODSWe conducted a retrospective study of 103 patients undergoing cryoablation in a tertiary cancer center. Overall, 62 patients were scanned with standard exposure parameters (full dose group) set on a 64-slice multidetector CT scanner, while 41 patients were scanned on a reduced dose protocol. Dose levels were retrieved from the hospital picture and archiving communication system including the volumetric CT dose index (CTDIvol), total dose length product (DLP), length of cryoablation procedure, number of cryoablation needles and patient size. Wilcoxon Mann-Whitney (rank-sum) tests were used to compare the median DLP, CTDIvol and skin dose between the two groups.RESULTSMedian total DLP for the full dose group was 6025 mGy•cm (1909–13353 mGy•cm) compared with 3391 mGy•cm (1683–6820 mGy•cm) for the reduced dose group. The reduced dose group had a 44% reduction in total DLP and 42% reduction in total CTDIvol (p < 0.001). The estimated skin doses were 384 mGy for the full dose group and 224 mGy for the reduced dose group (42% reduction) (p < 0.001). At 12-month follow-up, the technical success for the full dose (n=62) was 97% with 2 patients requiring a further cryoablation treatment for residual tumor. The technical success for the reduced dose group (n=41) was 100%.CONCLUSIONCT dose reduction technique during image-guided cryoablation treatment of renal tumors can achieve significant radiation dose reduction whilst maintaining sufficient image quality

9,9-Dimethyl-9,10-dihydroanthracene

In the title compound, C16H16, the central benzene ring adopts a boat conformation, with a dihedral angle of 34.7 (9)° between the mean planes of the two fused benzene rings. The two methyl groups at the apex of the central benzene ring are in axial and equatorial conformations. The crystal packing is stabilized by weak C—H⋯π inter­molecular inter­actions

10,10-Dimethyl­anthrone

In the title compound, C16H14O, the asymmetric unit consists of three crystallographically independent mol­ecules. The anthracene units are essentially planar, with maximum deviations of 0.165 (1), 0.153 (1) and 0.045 (1) Å in the three mol­ecules. In the crystal structure, mol­ecules are linked via inter­molecular C—H⋯O hydrogen bonds. Further stabilization is provided by C—H⋯π inter­actions

An evaluation of CT radiation doses within the Yorkshire Lung Screening Trial

YesObjectives; To evaluate radiation doses for all low-dose CT scans performed during the first year of a lung screening trial. Methods; For all lung screening scans that were performed using a CT protocol that delivered image quality meeting the RSNA QIBA criteria, , radiation dose metrics, participant height, weight, gender and age were recorded. Values of CTDIvol and DLP were evaluated as a function of weight in order to assess the performance of the scan protocol across the participant cohort. Calculated effective doses were used to establish the additional lifetime attributable cancer risks arising from trial scans. Results; Median values of CTDIvol, DLP and effective dose (IQR) from the 3521 scans were 1.1mGy (0.70), 42.4mGycm (24.9) and 1.15mSv (0.67), whilst for 60-80kg participants the values were 1.0mGy (0.30), 35.8mGycm (11.4) and 0.97mSv (0.31). A statistically significant correlation between CTDIvol and weight was identified for males (r=0.9123, p<0.001) and females (r=0.9052, p<0.001), however the effect of gender on CTDIvol was not statistically significant (p=0.2328) despite notable differences existing at the extremes of the weight range. The additional lifetime attributable cancer risks from a single scan were in the range 0.001-0.006%. Conclusions; Low radiation doses can be achieved across a typical lung screening cohort using scan protocols that have been shown to deliver high levels of image quality. The observed dose levels may be considered as typical values for lung screening scans on similar types of scanner for an equivalent participant cohort. Advances in Knowledge; Presentation of typical radiation dose levels for CT lung screening examinations in a large UK trial. Effective radiation doses can be of the order of 1mSv for standard sized participants. Lifetime attributable cancer risks resulting from a single LDCT scan did not exceed 0.006%.The Yorkshire Lung Screening Trial is funded by Yorkshire Cancer Research (award reference L403)

Radiation dose reduction in thoracic and abdomen-pelvic CT using tube current modulation: A phantom study

This phantom study was designed to compare the radiation dose in thoracic and abdomen-pelvic CT scans with and without use of tube current modulation (TCM). Effective dose (ED) and size-specific dose estimation (SSDE) were calculated with the absorbed doses measured at selective radiosensitive organs using a thermoluminescence dosimeter-100 (TLD-100). When compared to protocols without TCM, the ED and SSDE were reduced significantly with use of TCM for both the thoracic and abdomen-pelvic CT. With use of TCM, the ED was 6.50 ± 0.29 mSv for thoracic and 6.01 ± 0.20 mSv for the abdomen-pelvic CT protocols. However without use of TCM, the ED was 20.07 ± 0.24 mSv and 17.30 ± 0.41 mSv for the thoracic and abdomen-pelvic CT protocols, respectively. The corresponding SSDE was 10.18 ± 0.48 mGy and 11.96 ± 0.27 mGy for the thoracic and abdomen-pelvic CT protocols with TCM and 31.56 ± 0.43 mGy and 33.23 ± 0.05 mGy, for thoracic and abdomen-pelvic CT protocols without TCM, respectively. The highest absorbed dose was measured at the breast with 8.58 ± 0.12 mGy in the TCM protocols and 51.52 ± 14.72 mGy in the protocols without TCM during thoracic CT. In the abdomen-pelvic CT, the absorbed dose was highest at the skin with 9.30 ± 1.28 mGy and 29.99 ± 2.23 mGy in protocols with and without use of TCM, respectively. In conclusion, the TCM technique results in significant dose reduction, thus it is to be highly recommended in routine thoracic and abdomen-pelvic CT