A novel role for the extraembryonic area opaca in positioning the primitive streak of the early chick embryo

Classical studies have established that the marginal zone, a ring of extraembryonic epiblast immediately surrounding the embryonic epiblast (area pellucida) of the chick embryo is important in setting embryonic polarity by positioning the primitive streak, the site of gastrulation. The more external extraembryonic region (area opaca) was only thought to have nutritive and support functions. Using experimental embryology approaches, this study reveals three separable functions for this outer region: first, juxtaposition of the area opaca directly onto the area pellucida induces a new marginal zone from the latter; this induced domain is entirely posterior in character. Second, ablation and grafting experiments using an isolated anterior half of the blastoderm and pieces of area opaca suggest that the area opaca can influence the polarity of the adjacent marginal zone. Finally, we show that the loss of the ability of such isolated anterior half-embryos to regulate (re-establish polarity spontaneously) at the early primitive streak stage can be rescued by replacing the area opaca by one from a younger stage. These results uncover new roles of chick extraembryonic tissues in early development.

Postcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria)

Beipiaosaurus inexpectus, from the Lower Cretaceous Yixian Formation (Sihetun locality, near Beipiao), Liaoning, China, is a key taxon for understanding the early evolution of therizinosaurians. Since initial publication in 1999, only the cranial elements of this taxon have been described in detail. Here we present a detailed description of the postcranial skeletal anatomy of the holotype specimen of B. inexpectus, including two never before described dorsal vertebrae from the anterior half of the series. Based on these observations, and comparisons with the postcranial skeleton of therizinosaurian taxa named since the most recent diagnosis, we revised the diagnostic features for B. inexpectus adding three new possible autapomorphies (PII-3 shorter than PIII-4, subequal length of the pre- and postacetabular portions of the ilium, and equidimensional pubic peduncle of ilium). Additionally, we also propose three possible synapomorphies for more inclusive taxa (Therizinosauroidea and Therizinosauridae) and discuss implications for evolutionary trends within Therizinosauria. The newly acquired data from the postcranial osteology of the holotype specimen of B. inexpectus sheds light on our understanding of postcranial skeletal evolution and identification of therizinosaurians.

High-Dose Irradiation Inhibits Motility and Induces Autophagy in Caenorhabditis elegans

Radiation damages many cellular components and disrupts cellular functions, and was previously reported to impair locomotion in the model organism Caenorhabditis elegans. However, the response to even higher doses is not clear. First, to investigate the effects of high-dose radiation on the locomotion of C. elegans, we investigated the dose range that reduces whole-body locomotion or leads to death. Irradiation was performed in the range of 0–6 kGy. In the crawling analysis, motility decreased after irradiation in a dose-dependent manner. Exposure to 6 kGy of radiation affected crawling on agar immediately and caused the complete loss of motility. Both γ-rays and carbon-ion beams significantly reduced crawling motility at 3 kGy. Next, swimming in buffer was measured as a motility index to assess the response over time after irradiation and motility similarly decreased. However, swimming partially recovered 6 hours after irradiation with 3 kGy of γ-rays. To examine the possibility of a recovery mechanism, in situ GFP reporter assay of the autophagy-related gene lgg-1 was performed. The fluorescence intensity was stronger in the anterior half of the body 7 h after irradiation with 3 kGy of γ-rays. GFP::LGG-1 induction was observed in the pharynx, neurons along the body, and the intestine. Furthermore, worms were exposed to region-specific radiation with carbon-ion microbeams and the trajectory of crawling was measured by image processing. Motility was lower after anterior-half body irradiation than after posterior-half body irradiation. This further supported that the anterior half of the body is important in the locomotory response to radiation.

Ultrasound evaluation shows increase in laxity after partial common extensor origin detachment but not after additional lesion of the radial band of the lateral collateral ligament

Purpose The lateral elbow musculature conveys a dynamic valgus moment to the elbow, increasing joint stability. Muscular or tendinous lesions to the anterior half of the common extensor origin (CEO) may provoke a deficiency in the elbow dynamic stabilizers, regardless of their traumatic, degenerative, or iatrogenic aetiology. Furthermore, a role for the radial band of the lateral collateral ligament (R-LCL) has been postulated in the aetiology of lateral elbow pain. This study aimed to evaluate the effects of sequential lateral releases with dynamic ultrasound, evaluating its capability to detect lesions of the CEO and of the R-LCL. Methods Ultrasound investigation of the lateral compartment of the elbow was performed on nine cadaveric specimens with a 10 MHz linear probe in basal conditions, after the release of the anterior half of the CEO and after complete R-LCL release. The lateral joint line widening (λ) was the primary outcome parameter, measured as the linear distance between the humeral and radial articular surfaces. Results The release of the anterior half of the CEO significantly increased λ by 200% compared to the starting position (p = 0.0008) and the previously loaded position (p = 0.0015). Conversely, further release of the R-LCL caused only a marginal, non-significant increase in λ. Conclusions Ultrasound evaluation can detect changes related to tendon tears or muscular avulsions of the CEO and can depict lateral elbow compartmental patholaxity by assessing articular space widening while scanning under dynamic stress. However, it cannot reliably define if the R-LCL is injured. Iatrogenic damage to the CEO should be carefully avoided, since it causes a massive increase in compartmental laxity.

Anterior Half of the Peroneus Longus Tendon Combined with Semitendinosus and Gracilis Tendons for Anterior Cruciate Ligament Reconstruction: An Athlete Case Report

In clinical practice, it is observed that the hamstring tendon graft, despite being first choice in knee ligament reconstruction, may not present adequate size. Therefore, it becomes necessary to search for other graft alternatives. In this context, the peroneus longus tendon arises as an option to replace or complement other grafts. The surgeon can opt to use the tendon in its totality or only its anterior half, presenting adequate length, diameter, and biomechanics, without major repercussions for the donor site. In this study, we report a case of an athlete in which the autologous hamstring tendon graft did not present the adequate diameter for anterior cruciate ligament reconstruction. It was, then, necessary to use the anterior half of the peroneus longus tendon.

A new chameleon of the Trioceros affinis species complex (Squamata, Chamaeleonidae) from Ethiopia

A new species of chameleon, Trioceros wolfgangboehmeisp. nov., inhabiting the northern slopes of the Bale Mountains in Ethiopia, is described. It differs from its Ethiopian congeners by a combination of the following features: presence of a prominent dorsal crest with a low number of enlarged conical scales reaching along the anterior half of the tail as a prominent tail crest, a casque raised above the dorsal crest, heterogeneous body scalation, long canthus parietalis, rugose head scalation, high number of flank scales at midbody and unique hemipenial morphology. Based on morphological characteristics, phylogenetic discordances of previous studies and biogeographical patterns, this new species is assigned to the Trioceros affinis (Rüppell, 1845) species complex. An updated comprehensive key to the Trioceros found in Ethiopia is provided.

A new species of the genus Cryptarcha (Coleoptera: Nitidulidae) from Solomon Islands

Cryptarcha solomonensis sp. nov. from Solomon Islands is described. This new species belongs to the strigata-group and is similar to C. australis Reitter, 1873, but distinct from it in the somewhat slenderer body with the yellow colouration on the elytra not reaching presutural parts in their anterior half, the longer and narrower aedeagus having one brush of hairs on the apex of the tegmen and in the different structure of its ovipositor. The diagnosis of the new species is compiled on the basis of comparison with other members of the strigata-group from Australia and adjacent islands.

Efficacy Study of Medial Patellofemoral Ligament Single-bundle Reconstruction with Anterior Half of the Peroneus Longus Tendon Autograft for Treatment of Recurrent Patellar Dislocation

Background To report the clinical outcomes of a longitudinal patellar tunnel technique in reconstruction of the medial patellofemoral ligament(MPFL) with anterior half of the peroneus longus tendon autograft treatment of recurrent patellar dislocation.Methods From May 2010 to January 2019, we performed MPFL reconstruction with anterior half of the peroneus longus tendon autograft by using a longitudinal patellar tunnel technique on 48 knees in 45 patients(26 female, 19 male) with the median age was 24 (17 ~ 44) years old with recurrent patellar dislocation. We made one 4. 5 mm channel from the medial upper edge of the patella to the surface (medial half) of the patella so that to introduce autograft into the medial femoral channel. The autograft was fixed with absorbable screws with the knee bent at 30°. CT and X-rays were used to assess the correction of the tibia tuberosity- trochlear groove (TT-TG) distance, patellar tilt angle, Caton-Deschamps index, femoral anteversion angle, tibial extorsion angle, and the presence or absence of knee valgus. Subjective scores, such as Kujala score and Lysholm score, were used to evaluate knee function preoperatively and postoperatively.Results No recurrence of patellar dislocation occurred in these patients during an average of 25 ± 7.6 months (range, 6 to 54 months) of follow-up. Preoperative TT-TG distance, patellar tilt angles, and Caton-Deschamps index was (18.9 ± 5.7)mm(10.2mm ~ 32.4 mm),31.5°±13.7° (20.3°~58.4°),1.1 ± 0.2 (1.0 ~ 1.5), respectively, which were corrected by (10.8 ± 4.3) mm (4.5 mm ~ 17.1 mm), 10.7°±2.6° (5.6°~15.3°), and 1.07 ± 0.06 (1.02 ~ 1.15) postoperatively(P < 0.05). 28 knees were treated with lateral release + MPFL reconstruction; 11 knees were treated with lateral release + tibial tubercle ingression + MPFL reconstruction; 9 knees were treated with lateral release + tibial tubercle ingression and depression + MPFL reconstruction. At the last follow-up, Lysholm score was (89.7 ± 2.3), which significantly improved (P < 0.05) compared with the pre-operational score of (54.4 ± 5.9); Kujala score was (91.5 ± 4.4) points, which significantly improved (P < 0.05) compared with the pre-operational score of (60.6 ± 5.8).Conclusion One patellar tunnels in reconstruction of the medial patellofemoral ligament (MPFL) with anterior half of the peroneus longus tendon autograft is a safe, effective, and economic method for recurrent patellar dislocation.