Changes in reflectin protein phosphorylation are associated with dynamic iridescence in squid

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of The Royal Society for personal use, not for redistribution. The definitive version was published in Journal of The Royal Society Interface 6 (2010): 549-560, doi:10.1098/rsif.2009.0299.Many cephalopods exhibit remarkable dermal iridescence, a component of their complex, dynamic camouflage and communication. In the species Euprymna scolopes, the light-organ iridescence is static and is due to reflectin protein-based platelets assembled into lamellar thin-film reflectors called iridosomes, contained within iridescent cells called iridocytes. Squid in the family Loliginidae appear to be unique in that the dermis possesses a dynamic iridescent component, with reflective, colored structures that are assembled and disassembled under the control of the muscarinic cholinergic system and the associated neurotransmitter acetylcholine (Mathger et al. 2004). Here we present the sequences and characterization of three new members of the reflectin family associated with the dynamically changeable iridescence in Loligo and not found in static Euprymna iridophores. In addition, we show that application of genistein, a protein tyrosine kinase inhibitor, suppresses acetylcholine- and calcium-induced iridescence in Loligo. We further demonstrate that two of these novel reflectins are extensively phosphorylated in concert with the activation of iridescence by exogenous acetylcholine. This phosphorylation and the correlated iridescence can be blocked with genistein. Our results suggest that tyrosine phosphorylation of reflectin proteins is involved in the regulation of dynamic iridescence in Loligo.We gratefully acknowledge support from Anteon contract F33615-03-D-5408 to the Marine Biological Laboratory, Woods Hole, MA and grant # W911NF-06-1-0285 from the Army Research Office to D.E.M

Chromatophore Activity during Natural Pattern Expression by the Squid Sepioteuthis lessoniana: Contributions of Miniature Oscillation

Squid can rapidly change the chromatic patterns on their body. The patterns are created by the expansion and retraction of chromatophores. The chromatophore consists of a central pigment-containing cell surrounded by radial muscles that are controlled by motor neurons located in the central nervous system (CNS). In this study we used semi-intact squid (Sepioteuthis lessoniana) displaying centrally controlled natural patterns to analyze spatial and temporal activities of chromatophores located on the dorsal mantle skin. We found that chromatophores oscillated with miniature expansions/retractions at various frequencies, even when the chromatic patterns appear macroscopically stable. The frequencies of this miniature oscillation differed between “feature” and “background” areas of chromatic patterns. Higher frequencies occurred in feature areas, whereas lower frequencies were detected in background areas. We also observed synchronization of the oscillation during chromatic pattern expression. The expansion size of chromatophores oscillating at high frequency correlated with the number of synchronized chromatophores but not the oscillation frequency. Miniature oscillations were not observed in denervated chromatophores. These results suggest that miniature oscillations of chromatophores are driven by motor neuronal activities in the CNS and that frequency and synchrony of this oscillation determine the chromatic pattern and the expansion size, respectively

Robotic Living Donor Right Hepatectomy: A Systematic Review and Meta-Analysis

The introduction of robotics in living donor liver transplantation has been revolutionary. We aimed to examine the safety of robotic living donor right hepatectomy (RLDRH) compared to open (ODRH) and laparoscopic (LADRH) approaches. A systematic review was carried out in Medline and six additional databases following PRISMA guidelines. Data on morbidity, postoperative liver function, and pain in donors and recipients were extracted from studies comparing RLDRH, ODRH, and LADRH published up to September 2020; PROSPERO (CRD42020214313). Dichotomous variables were pooled as risk ratios and continuous variables as weighted mean differences. Four studies with a total of 517 patients were included. In living donors, the postoperative total bilirubin level (MD: −0.7 95%CI −1.0, −0.4), length of hospital stay (MD: −0.8 95%CI −1.4, −0.3), Clavien–Dindo complications I–II (RR: 0.5 95%CI 0.2, 0.9), and pain score at day > 3 (MD: −0.6 95%CI −1.6, 0.4) were lower following RLDRH compared to ODRH. Furthermore, the pain score at day > 3 (MD: −0.4 95%CI −0.8, −0.09) was lower after RLDRH when compared to LADRH. In recipients, the postoperative AST level was lower (MD: −0.5 95%CI −0.9, −0.1) following RLDRH compared to ODRH. Moreover, the length of stay (MD: −6.4 95%CI −11.3, −1.5) was lower after RLDRH when compared to LADRH. In summary, we identified low- to unclear-quality evidence that RLDRH seems to be safe and feasible for adult living donor liver transplantation compared to the conventional approaches. No postoperative deaths were reported

Quantitative appraisal of bilateral sagittal split osteotomy impact on the loading of temporomandibular joint

Bilateral sagittal split osteotomy is one of the most frequently performed operations in orthognathic surgery. The health of the temporomandibular joint (TMJ) is an important prerequisite for its functionality. The aim of this finite element study was to assess the developed stresses during mouth opening after bilateral sagittal split osteotomy. Different osteotomy gap widths and disc positions were evaluated. Computed tomography and magnetic resonance data of a dentulous cadaver head were used in order to create two finite element models simulating split distances of 5 and 10 mm, respectively. The fixation of the distal and proximal segments was made by a four- or a six-hole titanium mini plate and four monocortical screws respectively. For both models, three different situations of the articular disc were created: a physiological disc position, anterior disc displacement and posterior disc displacement. The mandible was vertically displaced in the midline in order to simulate a mouth opening of 20 mm. The simulation showed high stresses in the area of the titanium plates (up to 850 MPa), implying an increased risk of material failure. High stresses were found within the discs in the models with normal disc position and anterior disc displacement as well (up to 8 MPa), indicating a higher risk of developing craniomandibular disorders. Regarding the stresses within the fixation screws, the highest values were recorded in the area of the upper thread. The degree of mandibular advancement after a bilateral sagittal split osteotomy affects the stress balance in the mandible and the articular discs during mouth opening. © 2020 Elsevier Lt