Supine MRI for regional breast radiotherapy: Imaging axillary lymph nodes before and after sentinel-node biopsy

Regional radiotherapy (RT) is increasingly used in breast cancer treatment. Conventionally, computed tomography (CT) is performed for RT planning. Lymph node (LN) target levels are delineated according to anatomical boundaries. Magnetic resonance imaging (MRI) could enable individual LN delineation. The purpose was to evaluate the applicability of MRI for LN detection in supine treatment position, before and after sentinel-node biopsy (SNB). Twenty-three female breast cancer patients (cTis-3N0M0) underwent 1.5 T MRI, before and after SNB, in addition to CT. Endurance for MRI was monitored. Axillary levels were delineated. LNs were identified and delineated on MRI from before and after SNB, and on CT, and compared by Wilcoxon signed-rank tests. LN locations and LN-based volumes were related to axillary delineations and associated volumes. Although postoperative effects were visible, LN numbers on postoperative MRI (median 26 LNs) were highly reproducible compared to preoperative MRI when adding excised sentinel nodes, and higher than on CT (median 11, p < 0.001). LN-based volumes were considerably smaller than respective axillary levels. Supine MRI of LNs is feasible and reproducible before and after SNB. This may lead to more accurate RT target definition compared to CT, with potentially lower toxicity. With the MRI techniques described here, initiation of novel MRI-guided RT strategies aiming at individual LNs could be possible

Soluble Guanylate Cyclase α1–Deficient Mice: A Novel Murine Model for Primary Open Angle Glaucoma

Primary open angle glaucoma (POAG) is a leading cause of blindness worldwide. The molecular signaling involved in the pathogenesis of POAG remains unknown. Here, we report that mice lacking the $α_1$ subunit of the nitric oxide receptor soluble guanylate cyclase represent a novel and translatable animal model of POAG, characterized by thinning of the retinal nerve fiber layer and loss of optic nerve axons in the context of an open iridocorneal angle. The optic neuropathy associated with soluble guanylate cyclase $α_1$–deficiency was accompanied by modestly increased intraocular pressure and retinal vascular dysfunction. Moreover, data from a candidate gene association study suggests that a variant in the locus containing the genes encoding for the $α_1$ and $β_1$ subunits of soluble guanylate cyclase is associated with POAG in patients presenting with initial paracentral vision loss, a disease subtype thought to be associated with vascular dysregulation. These findings provide new insights into the pathogenesis and genetics of POAG and suggest new therapeutic strategies for POAG

Impaired Vascular Contractility and Aortic Wall Degeneration in Fibulin-4 Deficient Mice: Effect of Angiotensin II Type 1 (AT1) Receptor Blockade

Medial degeneration is a key feature of aneurysm disease and aortic dissection. In a murine aneurysm model we investigated the structural and functional characteristics of aortic wall degeneration in adult fibulin-4 deficient mice and the potential therapeutic role of the angiotensin (Ang) II type 1 (AT1) receptor antagonist losartan in preventing aortic media degeneration. Adult mice with 2-fold (heterozygous Fibulin-4+/R) and 4-fold (homozygous Fibulin-4R/R) reduced expression of fibulin-4 displayed the histological features of cystic media degeneration as found in patients with aneurysm or dissection, including elastin fiber fragmentation, loss of smooth muscle cells, and deposition of ground substance in the extracellular matrix of the aortic media. The aortic contractile capacity, determined by isometric force measurements, was diminished, and was associated with dysregulation of contractile genes as shown by aortic transcriptome analysis. These structural and functional alterations were accompanied by upregulation of TGF-β signaling in aortas from fibulin-4 deficient mice, as identified by genome-scaled network analysis as well as by immunohistochemical staining for phosphorylated Smad2, an intracellular mediator of TGF-β. Tissue levels of Ang II, a regulator of TGF-β signaling, were increased. Prenatal treatment with the AT1 receptor antagonist losartan, which blunts TGF-β signaling, prevented elastic fiber fragmentation in the aortic media of newborn Fibulin-4R/R mice. Postnatal losartan treatment reduced haemodynamic stress and improved lifespan of homozygous knockdown fibulin-4 animals, but did not affect aortic vessel wall structure. In conclusion, the AT1 receptor blocker losartan can prevent aortic media degeneration in a non-Marfan syndrome aneurysm mouse model. In established aortic aneurysms, losartan does not affect aortic architecture, but does improve survival. These findings may extend the potential therapeutic application of inhibitors of the renin-angiotensin system to the preventive treatment of aneurysm disease

DNA Repair in Human Pluripotent Stem Cells Is Distinct from That in Non-Pluripotent Human Cells

The potential for human disease treatment using human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells (iPSCs), also carries the risk of added genomic instability. Genomic instability is most often linked to DNA repair deficiencies, which indicates that screening/characterization of possible repair deficiencies in pluripotent human stem cells should be a necessary step prior to their clinical and research use. In this study, a comparison of DNA repair pathways in pluripotent cells, as compared to those in non-pluripotent cells, demonstrated that DNA repair capacities of pluripotent cell lines were more heterogeneous than those of differentiated lines examined and were generally greater. Although pluripotent cells had high DNA repair capacities for nucleotide excision repair, we show that ultraviolet radiation at low fluxes induced an apoptotic response in these cells, while differentiated cells lacked response to this stimulus, and note that pluripotent cells had a similar apoptotic response to alkylating agent damage. This sensitivity of pluripotent cells to damage is notable since viable pluripotent cells exhibit less ultraviolet light-induced DNA damage than do differentiated cells that receive the same flux. In addition, the importance of screening pluripotent cells for DNA repair defects was highlighted by an iPSC line that demonstrated a normal spectral karyotype, but showed both microsatellite instability and reduced DNA repair capacities in three out of four DNA repair pathways examined. Together, these results demonstrate a need to evaluate DNA repair capacities in pluripotent cell lines, in order to characterize their genomic stability, prior to their pre-clinical and clinical use

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Contribution of the functional dyad of animal toxins acting on voltage-gated Kv1-type channels.

International audienceThe 'functional dyad', a well-defined pair of amino acid residues (basic and hydrophobic residues), is a key molecular determinant present in most animal toxins acting on voltage-gated Kv1 channels. It is increasingly used as a working concept to explain how toxins are able to recognize and block their specific ion channel targets. However, other crucial toxin determinants are emerging and the actual role of this 'functional dyad' ought to be clarified, which is the object of the present mini-review

A front- and rear-view assistant for older cyclists:evaluations on technical performance, user experience and behaviour

The older cyclist is more prone to get cycling accidents than younger cyclists. To support the older cyclist, a rear- and front-view assistant were developed that warns the cyclist of approaching traffic. User tests to evaluate system performance, user-experience and effects on behaviour were performed with 20 older cyclists (>64 years) on a predefined route outdoors with and without support from both assistants. During this route, the cyclist was confronted with two controlled scenarios with an overtaking and an oncoming cyclist. The participants’ cycling behaviour was assessed by measuring lateral distance to the other cyclist, and distance maintained to the verge. The assistants had no effect on experienced mental workload. Both assistants received positive evaluations, although the rear-view assistant was experienced as more useful. Using the front-view assistant resulted in less lateral distance to the approaching oncoming cyclist, while the use of the rear-view assistant did not have effects on lateral distance

Stereotactic 9-gauge vacuum-assisted breast biopsy, how many specimens are needed?

PURPOSE: To determine the minimum number of stereotactic 9-gauge vacuum-assisted biopsy specimens required to establish a final histopathological biopsy diagnosis of mammographically suspicious breast lesions. METHODS: This prospective single-center observational cohort study included 120 women referred for stereotactic vacuum-assisted biopsy of 129 mammographically suspicious lesions between December 2017 and October 2018. Stereotactic 9-gauge vacuum-assisted biopsy was performed, acquiring twelve specimens per lesion. Calcification retrieval was assessed with individual specimen radiography. Each specimen was histologically analyzed in chronological order and findings were compared with the final histopathological result after assessment of all twelve specimens and with results of surgical excision. Cumulative diagnostic yield per specimen was calculated. RESULTS: In total, 131 biopsy procedures were performed in 120 women (mean age 59 years). In 95% (95%CI 90%-98%) of the procedures a final histopathological diagnosis was reached after six specimens. After nine specimens the final biopsy diagnosis was established in all 131 cases. In the subgroup of 41 patients with a DCIS or invasive diagnosis at biopsy there were eight procedures (20%) where calcifications were retrieved before the diagnostic specimen was obtained. Underestimation of subsequent resection diagnosis occurred in six out of 30 excised lesions classified as DCIS (20%) and in one out of four excised high-risk lesions. CONCLUSIONS: With six stereotactic 9-gauge vacuum-assisted biopsy specimens a final histopathological biopsy diagnosis could be established in 95% (95%CI 90%-98%) of the biopsy procedures. Taking nine 9-gauge specimens seems to be optimal. Ending the stereotactic vacuum-assisted breast biopsy procedure as soon as calcifications are retrieved may cause false negative results

Stereotactic 9-gauge vacuum-assisted breast biopsy, how many specimens are needed?

PURPOSE: To determine the minimum number of stereotactic 9-gauge vacuum-assisted biopsy specimens required to establish a final histopathological biopsy diagnosis of mammographically suspicious breast lesions. METHODS: This prospective single-center observational cohort study included 120 women referred for stereotactic vacuum-assisted biopsy of 129 mammographically suspicious lesions between December 2017 and October 2018. Stereotactic 9-gauge vacuum-assisted biopsy was performed, acquiring twelve specimens per lesion. Calcification retrieval was assessed with individual specimen radiography. Each specimen was histologically analyzed in chronological order and findings were compared with the final histopathological result after assessment of all twelve specimens and with results of surgical excision. Cumulative diagnostic yield per specimen was calculated. RESULTS: In total, 131 biopsy procedures were performed in 120 women (mean age 59 years). In 95% (95%CI 90%-98%) of the procedures a final histopathological diagnosis was reached after six specimens. After nine specimens the final biopsy diagnosis was established in all 131 cases. In the subgroup of 41 patients with a DCIS or invasive diagnosis at biopsy there were eight procedures (20%) where calcifications were retrieved before the diagnostic specimen was obtained. Underestimation of subsequent resection diagnosis occurred in six out of 30 excised lesions classified as DCIS (20%) and in one out of four excised high-risk lesions. CONCLUSIONS: With six stereotactic 9-gauge vacuum-assisted biopsy specimens a final histopathological biopsy diagnosis could be established in 95% (95%CI 90%-98%) of the biopsy procedures. Taking nine 9-gauge specimens seems to be optimal. Ending the stereotactic vacuum-assisted breast biopsy procedure as soon as calcifications are retrieved may cause false negative results