Characterization of Fibrodysplasia Ossificans Progessiva relevant Acvr1/Acvr2 Activin receptors in medaka (Oryzias latipes)

Activin and Bone Morphogenetic Protein (BMP) signaling plays crucial roles in vertebrate organ formation, including osteo- and angiogenesis, and tissue homeostasis, such as neuronal maintenance. Activin and BMP signaling needs to be precisely controlled by restricted expression of shared receptors, stoichiometric composition of receptor-complexes and presence of regulatory proteins. A R206H mutation in the human (hs) BMP type I receptor hsACVR1, on the other hand, leads to excessive phosphorylation of Sons of mothers against decapentaplegic (SMAD) 1/5/8. This in turn causes increased inflammation and heterotopic ossification in soft tissues of patients suffering from Fibrodysplasia Ossificans Progressiva (FOP). Several animal models have been established to understand the spontaneous and progressive nature of FOP, but often have inherent limitations. The Japanese medaka (Oryzias latipes, ola) has recently emerged as popular model for bone research. To assess whether medaka is suitable as a potential FOP animal model, we determined the expression of Activin receptor type I (ACVR1) orthologs olaAcvr1 and olaAcvr1l with that of Activin type II receptors olaAcvr2ab, olaAcvr2ba and olaAcvr2bb in embryonic and adult medaka tissues by in situ hybridization. Further, we showed that Activin A binding properties are conserved in olaAcvr2, as are the mechanistic features in the GS-Box of both olaAcvr1 and olaAcvr1l. This consequently leads to FOP-typical elevated SMAD signaling when the medaka type I receptors carry the R206H equivalent FOP mutation. Together, this study therefore provides experimental groundwork needed to establish a unique medaka model to investigate mechanisms underlying FOP.

Enzyme self-label-bound ATTO700 in single-molecule and super-resolution microscopy

Herein, we evaluate near-infrared ATTO700 as an acceptor in SNAP- and Halo-tag protein labelling for Förster Resonance Energy Transfer (FRET) by ensemble and single molecule measurements. Microscopy of cell surface proteins in live cells is perfomed including super-resolution stimulated emission by depletion (STED) nanoscopy.

Radiological detection of extracapsular spread in head and neck squamous cell carcinoma (HNSCC) cervical metastases

BACKGROUND

Extracapsular spread of cervical lymph nodes deteriorates the prognosis of patients with head and neck squamous cell carcinoma. Postoperative radiochemotherapy is superior to postoperative radiotherapy alone in patients with histologically proven extracapsular spread. If extracapsular spread can be detected preoperatively, patients may favor primary radiochemotherapy instead of primary surgery plus postoperative radiochemotherapy.

METHODS

Computed tomography (CT) scans of nodal positive head and neck squamous cell carcinoma patients treated between 2008 and 2010 with comprehensive neck dissection as part of first line surgical treatment were retrospectively scanned for extracapsular spread by two blinded radiologists. If a positive lymph node was identified by the pathologist, CT scans were assessed for extracapsular spread retrospectively. CT criteria for Extracapsular spread were apparent fat and soft tissue infiltration or infiltration of sternocleidomastoid muscle, internal jugular vein or carotid artery. Radiologic judgment was compared with histological evidence of extracapsular spread and specificity and sensitivity of CT detection was calculated.

RESULTS

Forty-nine patients with histologically proven positive lymph nodes (pN+) were included. Extracapsular spread was histologically proven in 17 cases; the number of all affected lymph nodes was not listed. Radiologist 1 found extracapsular spread in CT scans of 15/49 patients and radiologist 2 in 16/49 patients (Cohen's kappa=0.86; p<0.01). Sensitivity of radiologic extracapsular spread detection was 73% (95% confidential index (CI): 44.0-89.7%) and specificity 91% (75.0-98.0%).

CONCLUSION

Extracapsular spread depicted on computed tomography using strict criteria has high specificity.