Steroid-associated hip joint collapse in bipedal emus

In this study we established a bipedal animal model of steroid-associated hip joint collapse in emus for testing potential treatment protocols to be developed for prevention of steroid-associated joint collapse in preclinical settings. Five adult male emus were treated with a steroid-associated osteonecrosis (SAON) induction protocol using combination of pulsed lipopolysaccharide (LPS) and methylprednisolone (MPS). Additional three emus were used as normal control. Post-induction, emu gait was observed, magnetic resonance imaging (MRI) was performed, and blood was collected for routine examination, including testing blood coagulation and lipid metabolism. Emus were sacrificed at week 24 post-induction, bilateral femora were collected for micro-computed tomography (micro-CT) and histological analysis. Asymmetric limping gait and abnormal MRI signals were found in steroid-treated emus. SAON was found in all emus with a joint collapse incidence of 70%. The percentage of neutrophils (Neut %) and parameters on lipid metabolism significantly increased after induction. Micro-CT revealed structure deterioration of subchondral trabecular bone. Histomorphometry showed larger fat cell fraction and size, thinning of subchondral plate and cartilage layer, smaller osteoblast perimeter percentage and less blood vessels distributed at collapsed region in SAON group as compared with the normal controls. Scanning electron microscope (SEM) showed poor mineral matrix and more osteo-lacunae outline in the collapsed region in SAON group. The combination of pulsed LPS and MPS developed in the current study was safe and effective to induce SAON and deterioration of subchondral bone in bipedal emus with subsequent femoral head collapse, a typical clinical feature observed in patients under pulsed steroid treatment. In conclusion, bipedal emus could be used as an effective preclinical experimental model to evaluate potential treatment protocols to be developed for prevention of ON-induced hip joint collapse in patients

Triplet–Triplet Annihilation Photon Upconversion in Polymer Thin Film: Sensitizer Design

Efficient visible-to-UV photon upconversion via triplet–triplet annihilation (TTA) is accomplished in polyurethane (PU) films by developing new, powerful photosensitizers fully functional in the solid-state matrix. These rationally designed triplet sensitizers feature a bichromophoric scaffold comprising a tris-cyclometalated iridium­(III) complex covalently tethered to a suitable organic small molecule. The very rapid intramolecular triplet energy transfer from the former to the latter is pivotal for achieving the potent sensitizing ability, because this process out-competes the radiative and nonradiative decays inherent to the metal complex and produces long-lived triplet excitons localized with the acceptor moiety readily available for intermolecular transfer and TTA. Nonetheless, compared to the solution state, the molecular diffusion is greatly limited in solid matrices, which even creates difficulty for the Dexter-type intramolecular energy transfer. This is proven by the experimental results showing that the sensitizing performance of the bichromophoric molecules strongly depends on the spatial distance separating the donor (D) and acceptor (A) units and that incorporating a longer linker between the D and A evidently curbs the TTA upconversion efficiency in PU films. Using a rationally optimized sensitizer structure in combination with 2,7-di-<i>tert</i>-butylpyrene as the annihilator/emitter, the doped polyurethane (PU) films demonstrate effective visible-to-UV upconverted emission signal under noncoherent-light irradiation, attaining an upconversion quantum yield of 2.6%. Such quantum efficiency is the highest value so far reported for the visible-to-UV TTA systems in solid matrices

Iridium-Based High-Sensitivity Oxygen Sensors and Photosensitizers with Ultralong Triplet Lifetimes

The photophysics of a series of bichromophoric molecules featuring an intramolecular triplet energy transfer between a triscyclometalated iridium­(III) complex and covalently linked organic group are studied. By systematically varying the energy gap (0.1–0.3 eV) between the donor (metal complex) and acceptor (pyrene unit), reversible triplet energy transfer processes with equilibrium constant <i>K</i> ranging from ca. 500 to 40 000 are established. Unique photophysical consequences of such large <i>K</i> values are observed. Because of the highly imbalanced forward and backward energy transfer rates, triplet excitons dominantly populate the acceptor moiety in the steady state, giving rise to ultralong luminescence lifetimes up to 1–4 ms. Because the triscyclometalated Ir and triplet pyrene groups both impart relatively small nonradiative energy loss, decent phosphorescence quantum yields (Φ = 0.1–0.6) are attained in spite of the exceptionally prolonged excited states. By virtue of such precious combination of long-lived triplet state and high Φ, these bichromophoric molecules can serve as highly sensitive luminescent sensors for detecting trace amount of O₂ and as potent photosensitizers for producing singlet oxygen even under low-oxygen content conditions

Alkaloids from the Deep-Sea-Derived Fungus <i>Aspergillus westerdijkiae</i> DFFSCS013

Two new benzodiazepine alkaloids, circumdatins K and L (<b>1</b>, <b>2</b>), two new prenylated indole alkaloids, 5-chlorosclerotiamide (<b>3</b>) and 10-<i>epi</i>-sclerotiamide (<b>4</b>), and one novel amide, aspergilliamide B (<b>5</b>), together with six known alkaloids were isolated from the deep-sea-derived fungus <i>Aspergillus westerdijkiae</i> DFFSCS013. Their structures were elucidated by extensive spectroscopic analysis. All of the compounds were tested for cytotoxicity toward human carcinoma A549, HL-60, K562, and MCF-7 cell lines

The Scaphoid Safe Zone: A Radiographic Simulation Study to Prevent Cortical Perforation Arising from Different Views

<div><p>Purpose</p><p>The purpose of this study was to simulate and calculate the probability of iatrogenic perforation of the scaphoid cortical bone when internal fixation appeared to be safe on radiographs. The results will assist surgeons in determining proper screw placement.</p><p>Methods</p><p>Thirty scaphoids were reconstructed using computed tomography data and image-processing software. Different central axes were determined by the software to simulate the surgical views. The safe zone (SZ) and risk zone (RZ) were identified on the axial projection radiographs by comparing the scaphoid bone stenosis measured by the fluoroscopic radiographs with a three-dimensional reconstruction of the scaphoid stenosis. Each original axial projection radiograph was zoomed and compiled to match a calculated average image. The RZ, SZ, and probability of perforations in various quadrants were calculated.</p><p>Results</p><p>Using a volar view (approach), the mean risks of cortical perforation were 25% with screws and 36% with k-wires. Using a dorsal view (approach), the mean risks of cortical perforation were 18% with screws and 30% with k-wires. A high risk of perforation was detected at the ulnar–dorsal zone.</p><p>Conclusion</p><p>Surgeons should be wary of screws that appear to lie close to the scaphoid cortex on both anteroposterior (AP) and lateral radiographs, particularly in the ulnar–dorsal and radial–dorsal quadrants, because such screws are likely to perforate the cortex. The position of the internal fixator should be assessed using a diagram outlining the various SZs. Therapeutic, Level III.</p></div

Mean ratio of different risk zones (RZs).

<p>(a): Mean ratio of different risk zones (RZs) with screw arising from the screw axis within the scaphoid was maximized (MSL)/cylinder (MSL/CYL) axis. (b): Mean ratio of different RZs with K-wire arising from the MSL/CYL axis.</p

Proportions of perforation.

<p>Proportions of perforation.</p

Simulated radiographs views and three-dimensional simulation of the reconstruction.

<p>(a), (b): Simulated radiographs anteroposterior (AP) and lateral views, Boundary radial–volar (Brv) line was parallel to the screw axis within the scaphoid was maximized (MSL)/cylinder (MSL/CYL) and lateral view, tangential to the mid- scaphoid curve. The radial–dorsal boundary (Brd), the ulnar–volar boundary (Buv), and the ulnar–dorsal boundary (Bud) were constructed and simulated using the same method. (c): Three-dimensional simulation of the reconstruction.</p

Projection views.

<p>(a) Axillary view. Original radial boundary (dotted line) was translated toward the ulnar side (yellow arrow). Red dot shows the axis point. (b) Axis projection view. Figure shows the risk zone (RZ), including the RD, UD, RV, and UV quadrants. The safe zone (SZ) is denoted by the green area. Blue lines mark the boundaries. (c) Screw cross-section view. Circles represent the cross-section of the screw, and purple areas represent the trajectory of the screw. We could not accurately identify the screw’s position when it was perpendicular on AP radiographs.</p

Wrist coordinate system.

<p>Horizontal plane(red), sagittal plane(green) and coronal plane(blue).</p