Posterior Section Research Articles

The influence of gravity on respiratory kinematics during phonation measured by dynamic magnetic resonance imaging

Respiratory kinematics are important for the regulation of voice production. Dynamic MRI is an excellent tool to study respiratory motion providing high-resolution cross-sectional images. Unfortunately, in clinical MRI systems images can only be acquired in a horizontal subject position, which does not take into account gravitational effects on the respiratory apparatus. To study the effect of body posture on respiratory kinematics during phonation, 8 singers were examined both in an open-configuration MRI with a rotatable gantry and a conventional horizontal MRI system. During dynamic MRI the subjects sang sustained tones at different pitches in both supine and upright body positions. Sagittal images of the respiratory system were obtained at 1–3 images per second, from which 6 anatomically defined distances were extracted to characterize its movements in the anterior, medium and posterior section of the diaphragm as well as the rip cage (diameter at the height of the 3rd and 5th rip) and the anterior–posterior position of the diaphragm cupola. Regardless of body position, singers maintained their general principles of respiratory kinematics with combined diaphragm and thorax muscle activation for breath support. This was achieved by expanding their chest an additional 20% during inspiration when singing in the supine position but not for sole breathing. The diaphragm was cranially displaced in supine position for both singing and breathing and its motion range increased. These results facilitate a more realistic extrapolation of research data obtained in a supine position.

Protein and Water Distribution Across Visual Axis in Mouse Lens: A Confocal Raman MicroSpectroscopic Study for Cold Cataract.

Purpose: The aims of the study were to investigate cellular mechanisms of cold cataract in young lenses of wild-type C57BL/6J (B6WT) mice treated at different temperatures and to test a hypothesis that cold cataract formation is associated with the changes in lens protein and water distribution at different regions across lens fiber cells by Raman spectroscopy (RS). Methods: RS was utilized to scan the mouse lens at different regions with/without cold cataract. Three regions with various opacification along the equatorial axis in the anterior–posterior lens section were scanned. The intensity ratio of Raman bands at 2,935 and 3,390 cm−1 (Ip/Iw) were used to evaluate lens protein and water distribution. We further determined water molecular changes through Gaussian profiles of water Raman spectra. Results: Three specific regions 1, 2, and 3, located at 790–809, 515–534, and 415–434 μm away from the lens center, of postnatal day 14 B6WT lenses, were subjected to RS analysis. At 37°C, all three regions were transparent. At 25°C, only region 3 became opaque, while at 4°C, both regions 2 and 3 showed opacity. The sum of the difference between Ip/Iw and the value of linear fitting line from scattered-line at each scanning point was considered as fluctuation degree (FD) in each region. Among different temperatures, opaque regions showed relatively higher FD values (0.63 and 0.79 for regions 2 and 3, respectively, at 4°C, and 0.53 for region 3 at 25°C), while transparent regions provided lower FD values (less than 0.27). In addition, the decrease in Gaussian peak II and the rising of Gaussian peak III and IV from water Raman spectra indicated the instability of water molecule structure in the regions with cold cataract. Conclusion: Fluctuation degrees of RS data reveal new mechanistic information about cold cataract formation, which is associated with uneven distribution of lens proteins and water across lens fiber cells. It is possible that RS data partly reveals cold temperature-induced redistribution of lens proteins such as intermediate filaments in inner fiber cells. This lens protein redistribution might be related to unstable structure of water molecules according to Gaussian profiles of water RS.

Infant EEG Band Power Analysis at 6 Months and 18 Months.

Neural development of infants has drawn increasing research interests from the community. In this paper, we investigated the frequency band power of 112 infants who participated in an auditory oddball experiment, and the visual expectation (VE) score of 177 infants who went through a visual expectation paradigm test. Analysis found that the frequency band power decreases in the delta and theta bands, and increases in the alpha and beta bands when the infants grow up from 6 months old to 18 months old. We also proposed a sustainability index to measure the capability of a subject to maintain their band power in the auditory oddball experiment when infants grow up from 6 months old to 18 months old. Analysis shows that the sustainability index increased significantly in the alpha and beta band, decreased in the delta and theta bands. Correlation between the VE score and frequency band power was investigated on 47 infants who participated in both auditory oddball experiment and visual expectation paradigm test. Analysis shows that the reaction speed to stimulus have statistical a significant correlation with the changes of band power and sustainability index in posterior and temporal section, and in the higher frequency bands.

Distinct representation of ipsilateral hand movements in sensorimotor areas

There is ample evidence that the contralateral sensorimotor areas play an important role in movement generation, with the primary motor cortex and the primary somatosensory cortex showing a detailed spatial organization of the representation of contralateral body parts. Interestingly, there are also indications for a role of the motor cortex in controlling the ipsilateral side of the body. However, the precise function of ipsilateral sensorimotor cortex in unilateral movement control is still unclear. Here, we show hand movement representation in the ipsilateral sensorimotor hand area, in which hand gestures can be distinguished from each other and from contralateral hand gestures. High‐field functional magnetic resonance imaging (fMRI) data acquired during the execution of six left‐ and six right‐hand gestures by healthy volunteers showed ipsilateral activation mainly in the anterior section of precentral gyrus and the posterior section of the postcentral gyrus. Despite the lower activation in ipsilateral areas closer to the central sulcus, activity patterns for the 12 hand gestures could be mutually distinguished in these areas. The existence of a unique representation of ipsilateral hand movements in the human sensorimotor cortex favours the notion of transcallosal integrative processes that support optimal coordination of hand movements.

Two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the tropical monsoon forest in southern China.

Two new species of the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the tropical monsoon forest in southern China are described on the basis of an integrative taxonomic study involving morphology, karyology, histology, and molecular analyses. The new species Dugesiacircumcisa Chen & Dong, sp. nov. is characterised by asymmetrical openings of the oviducts; right vas deferens opening at anterior portion of the seminal vesicle and the left one opening at mid-lateral portion of the seminal vesicle; two diaphragms in ejaculatory duct, the latter being ventrally displaced and opening at the tip of the penis papilla, which is provided with a nozzle; wide duct connecting male atrium and common atrium; chromosome complement triploid with 24 metacentric chromosomes. The other new species, Dugesiaverrucula Chen & Dong, sp. nov., is characterised by the large size of the living worm, usually exceeding 3.5 cm in length; asymmetrical openings of the oviducts; subterminal opening of ventrally displaced ejaculatory duct; vasa deferentia symmetrically opening into the postero-lateral portion of the seminal vesicle; well-developed duct between the seminal vesicle and diaphragm; single dorsal bump near the root of the penis papilla; bursal canal with pleated wall and spacious posterior section; unstalked cocoons; chromosome complement diploid with 16 metacentric chromosomes. Inter-specific molecular distances and their positions in the phylogenetic tree reveal that D.circumcisa and D.verrucula are clearly separated from their congeners.

Consequences of Peri-Implant Bone Loss in the Occlusal Load Transfer to the Supporting Bone in terms of Magnitude of Stress, Strain, and Stress Distribution: A Finite Element Analysis.

Methods Three models of a single internal connection bone level-type implant inserted into a posterior mandible bone section were constructed using a 3D finite element software: one control model without marginal bone loss and two test models, both with a circumferential peri-implant bone defect, one with a 3 mm high defect and the other one 6 mm high. A 150 N static load was tested on the central fossa at 6° relative to the axial axis of the implant. Results The results showed differences in the magnitude of strain and stress transferred to the bone between models, being the higher strain found in the trabecular bone around the implant with greater marginal bone loss. Stress distribution differed between models, being concentrated at the cortical bone in the control model and at the trabecular bone in the test models. Conclusion Marginal bone loss around dental implants under occlusal loading influences the magnitude and distribution of the stress transferred and the deformation of peri-implant bone, being higher as the bone loss increases.

New information on the Jurassic lepidosauromorph Marmoretta oxoniensis

AbstractThe earliest known crown‐group lepidosaurs are known from the Middle Triassic; however, their stem group is poorly sampled, with only a few representative fossils found. This is partly due to the small size and delicate bones of early stem‐lepidosaurs (= non‐lepidosaurian lepidosauromorphs), which make both preservation in the fossil record and subsequent discovery less likely. The Middle Jurassic lepidosauromorph Marmoretta oxoniensis is re‐examined using high‐resolution micro‐computed tomography to reveal parts of the skull anatomy that were previously unknown. These include a squamosal, postorbital, more complete parietal, pterygoids, and an articulated posterior section of the mandible. Some differences between this and other Marmoretta specimens were identified as a result, such as the arrangement of palatal teeth and the shape of the parabasisphenoid. The status of Marmoretta as a stem‐lepidosaur or stem‐squamate has been debated. To evaluate this, we tested the phylogenetic position of Marmoretta by including our new data in an adapted phylogenetic character matrix. We recover Marmoretta as a stem‐lepidosaur and sister to Fraxinisaura rozynekae. Our findings support the hypothesis that both taxa belonged to a clade of non‐lepidosaurian lepidosauromorphs that co‐existed with lepidosaurs into the Middle Jurassic.

Surgical Techniques and Outcomes of Pure Laparoscopic Donor Right Posterior Sectionectomy for Living Donor Liver Transplantation.

Right posterior section (RPS) graft for living donor liver transplantation (LDLT) is an alternative graft in a live liver donor with insufficient remnant left lobe volume and portal vein anomaly.(1,2) In recent decades, laparoscopic liver resection (LLR) has been widely adopted by hepatobiliary surgeons, and the indication for LLR have expanded to donor hepatectomy.(3,4) Laparoscopic-approach donor surgery would be ideal for liver donation in healthy individuals, due to the fast return to normal life and satisfaction with the incisional scar. However, there have been no reports regarding laparoscopic donor hepatectomy for RPS graft. Herein, we report surgical outcomes and techniques of pure laparoscopic donor right posterior sectionectomy (PLDRPS) for LDLT. The institutional review boards of our center (number 2019-03-080) approved this study.

Pure Laparoscopic Donor Hepatectomy: Right Posterior Section Graft

BackgroundThe use of laparoscopic liver resection (LLR) is widespread owing to its several advantages, especially smaller incision (Kaneko et al., Ann Gastroenterol Surg 1:33–43, 1; Ciria et al., Surg Endosc 34:349–360, 2). However, both posterior sectionectomy and donor hepatectomy are extremely difficult procedures to perform in LLR (Hasegawa et al., Ann Gastroenterol Surg 2:376–382, 3; Soubrane and Kwon, J Hepatobiliary Pancreat Sci 24:E1–E5, 4; Takahara et al., Transplantation 101:1628–1636, 5; Lee et al., Clin Transplant 33:e13683, 6; Hong et al., Surg Endosc 33:3741–3748, 7; Rhu et al., J Hepatobiliary Pancreat Sci 27:16–25, 8). Moreover, the right posterior section graft procurement is also difficult even in open laparotomy procedure (Sugawara et al., Transplantation 73:111–114, 9; Hwang et al., Liver Transpl 10:1150–1155, 10; Hori, Kirino, and Uemoto, Hepatol Res 45:1076–1082, 11; Kusakabe et al., Liver Transpl 26:299–303, 12). The pure laparoscopic donor posterior sectionectomy has not been reported yet. Therefore, we aimed to introduce a novel procedure through a video clip. MethodsThe donor was placed in the semi-left lateral decubitus position with the reverse Trendelenburg position using a bean bag device. The right liver was mobilized, and the right hepatic vein was exposed. To adopt the liver hanging maneuver, a tape was inserted between the middle and right hepatic veins along the inferior vena cava. The posterior Glissonean pedicle was encircled and controlled, and the liver parenchyma was completely transected using the liver hanging maneuver. The vessels to the posterior section were respectively isolated. The posterior branches of the hepatic duct, hepatic artery, and portal vein were cut. The right hepatic vein was divided, and the graft liver was retrieved via a suprapubic incision. This study was approved by institutional ethics board (No. MH2019-119), and informed consent was taken from the patient. ResultsThe overall surgical time was 503 min, and the blood loss was 400 mL. No complications were observed, and the donor was discharged from the hospital on postoperative day 11. ConclusionThis is the first report of pure laparoscopic donor hepatectomy of the posterior section graft. This procedure is more difficult than other laparoscopic donor hepatectomies because it involves parenchymal transection in the right intersectional plane and dissection of the posterior branches of hilar vessels.

Deficiency of interleukin-17 receptor A1 induces microbiota disruption in the intestine of Japanese medaka, Oryzias latipes

The mutual relationship between the intestinal immune system and the gut microbiota has received a great deal of attention. In mammals, interleukin-17A and F (IL-17A/F) are inflammatory cytokines and key regulators of the gut microbiota. However, in teleosts, the function of IL-17A/F in controlling the gut microbiota is poorly understood. We attempted to elucidate the importance of teleost IL-17 signaling in controlling gut microbiota. We previously established a knockout (KO) of IL-17 receptor A (RA) 1, a receptor for IL-17A/F, in the Japanese medaka (Oryzias latipes) using the CRISPR-Cas9 system and performed 16S rRNA-based metagenomic analyses using the anterior and posterior sections of the intestinal tract. The number of observed OTUs in the anterior intestine was significantly decreased in IL-17RA1 KO medaka compared to that in the wild-type (WT). Furthermore, β-diversity analysis (weighted UniFrac) revealed considerably different bacterial composition in the anterior intestine of IL-17RA1 KO compared to WT, with similar findings in α-diversity. Notably, the pathogen Plesiomonas shigelloides was significantly increased in the posterior intestine of IL-17RA1 KO medaka. These findings indicate that signaling via IL-17RA1 is required to maintain a healthy gut microbiota in teleosts and mammals. The involvement of IL-17RA1 in controlling the gut microbiota has been demonstrated, resulting in microbiome dysbiosis in IL-17RA1 KO medaka.

Design and Implementation of Two 16-Element Antisymmetric Transceiver Coil Arrays for Parallel Transmission Human Cardiac MRI at 7 T

Two 16-element radio frequency (RF) transceiver antisymmetric coil arrays with two different implementation designs aiming for improved characteristics for static phase $B_{1}^{+}$ shimming and parallel receive were developed for human cardiac MRI at 7 T. Both cardiac arrays consist of a weakly curved lightweight housing fit to an average human thorax shape as an anterior array in combination with a flat posterior array. The first array (Design 1) comprised eight identical antisymmetric loops for both anterior and posterior sections. Based on initial testing and to improve parallel imaging capabilities and $B_{1}^{+}$ field homogeneity, the second array (Design 2) was composed of 12-loops for the anterior section and four antisymmetric loops of larger size for the posterior section. Electromagnetic-field (EMF) simulations were carried out for both antisymmetric arrays loaded with an elliptical-shaped thorax phantom and two human voxel models (Duke and Ella). Static phase $B_{1}^{+}$ shimming has been carried out within Duke and Ella models using two optimization cost functions aiming to maximize the transmit efficiency and weighted combination of both $B_{1}^{+}$ field homogeneity and efficiency. The hardware and imaging performance of the two developed antisymmetric cardiac arrays was validated through EMF simulations, benchtop measurements, and MR measurements in a thorax phantom. Both antisymmetric arrays were compared to two commercial 16-element transceiver arrays (a 1Tx/16Rx in single transmit mode and an 8Tx/16Rx in parallel transmit mode). MRI measurements were performed with Design 2 using a 70-kg fresh pig cadaver (10–15 min postmortem). Parallel imaging with an acceleration factor up to $R = 6$ was possible using Design 2 while maintaining a mean g-factor of 1.47 within the pig heart. $T_{2}^{\ast }$ -weighted images of the pig heart were acquired using up to $R = 5$ with a spatial resolution of $0.35 \times 0.35 \times 4$ mm3.

Laparoscopic right posterior sectionectomy (LRPS) in semi prone position: surgical aspects and results

Laparoscopic hepatectomy has been accepted widely due to its advantages as a minimally invasive surgery, but laparoscopic right posterior sectionectomy (LRPS) has rarely been reported. Tumors located over the right posterior section are considered to be difficult for laparoscopic resection. The Glissonean approach is our technique of choice. The aim of this work is to present our experience in LRPS in semi prone position and to show surgical technical aspects. For six years period we were performed 12 LRPS procedures. Patient's data were prospectively collected. Demographics data, tumor characteristics, operative data, and postoperative outcome were collected and analyzed. There were 8 patients with colorectal liver metastasis, 2 HCC, one melanoma metastasis and one breast cancer liver metastasis. During the period of 2014-2020, we performed 12 LRPS. Median operative time was 200 minutes, median blood loss was 300 ml. Significant bleeding occurred in 1 cirrhotic liver patients. The median size of the tumor resected was 3.5 cm, and the median resection margin was 7 mm. Nine patients show single tumor nodule, 2 patients had two metastases and 1 with 3 metastases. There was no postoperative mortality. Median hospital stay was 6 days. LRPS is a technically demanding procedure. LRPS in semi prone position is feasible and safe. Semi prone position offers a maximum amount of working space. A proper inflow control is mandatory for excellence of anatomical resection. The Glissonean approach allows safe and masse control of the portal structures of the posterior sector and resulting in less blood loss during transection.

Hepatic resection for hepaticolithiasis: A single-centre experience of 8 cases

Hepaticolithiasis is frequently not amenable to endotherapy, and surgery forms the mainstay of treatment. This study highlights the outcomes of major liver resection for this benign pathology. Our tertiary hepatobiliary centre performed 8 liver resections for hepaticolithiasis between January 2010 and December 2019. Demographic data, clinicoradiological data, surgical details, and outcomes were recorded. Out of 8 patients, 6 were females. Median age was 54 years. 6 patients underwent left hepatectomy, and 1 each underwent right hepatectomy and right trisectionectomy. Trisectionectomy was done after liver volumetry showed a future liver remnant volume of 48% with right posterior section atrophy. Mean intra-operative blood loss was 226 mL, median hospital stay was 11.2 days. 1 patient had Clavien-Dindo grade 3 complication in the form of intra-abdominal collection requiring percutaneous drain placement. Six patients had significant elevation of transaminases that resolved by a median duration of 8 days. No patient had post-hepatectomy liver failure. None of the patients developed recurrent hepaticolithiasis or biliary stricture, with follow-up duration of 11 to 64 months. Major hepatic resection is a safe and recommended procedure for hepaticolithiasis, especially in presence of hepatic lobar atrophy. It carries acceptable morbidity and good outcomes when performed by an experienced hepatobiliary surgical team. A tertiary care centre with good imaging and liver volumetry facilities is best suited for this line of management.

Optimizing Graft Extraction From the Femoral Condyle for Fresh Osteochondral Allograft Transplantation in Treating Osteochondritis Dissecans of the Capitellum: Best Fit Based on Radius of Curvature.

Osteochondritis dissecans (OCD) of the capitellum is a common cause of pain and dysfunction in adolescents that engage in repetitive elbow loading. For large, unstable lesions fresh osteochondral allograft transplantation (FOCAT) from the femoral condyle has been described as an effective treatment. Current practice involves significant guesswork in obtaining an appropriately sized graft, with anatomic variations resulting in poor graft fit. No studies currently exist that analyze and identify the best distal femur FOCAT graft site to repair OCD lesions of the capitellum based on the radius of curvature (ROC) and simulated matching. Computed tomography scans of the elbow were used to estimate the subchondral bone ROC of capitella in adolescents aged 11 to 21 years. The capitellar location used corresponds to the most commonly reported site of OCD lesions in the elbow. Computed tomography scans of the lower extremity were used to estimate the subchondral bone ROC of 4 potential donor femoral condyle grafts. ROC from distinct regions at the posterior section of both the medial and lateral femoral condyles were measured: 2 areas representing 10 mm grafts from the center (MC1 and LC1), and 2 areas estimating 10 mm grafts posterior and adjacent to the physeal scar (MC2 and LC2). Intraobserver and interobserver reliability measurements were preformed to corroborate precision and validate the method. The mean ROC of healthy subchondral bone at the region of the capitellum were OCD lesions most commonly occur was 9.79±1.39 mm. The mean ROC of MC1 was 18.61±2.26 mm. The average ROC of the MC2 was 15.23±1.43 mm. The average ROC of LC1 was 16.47±1.34 mm. The average ROC of LC2 was 18.19±3.09 mm. After 15,000 simulated condyle-to-capitellar site matchings based on these measurements, a good fit graft was achieved at a frequency of 15%. No site measured from the femoral condyle demonstrated a subchondral ROC that exactly matched the subchondral ROC of the capitellum at the center location where OCD lesions most commonly occur; of the locations measured, a 10 mm section from MC2 demonstrated the closest match. On the basis of this analysis, extracting a graft from MC2 has the potential to further optimize FOCAT fit to the capitellum. Level III.

Patellar Tendon Imbrication

Background: Patella alta is a common cause of patellar instability. Patellar tendon imbrication is a successful surgery addressing the deformity by shortening the patellar tendon without necessitating an osteotomy. Indications: Symptomatic patella alta causing patellar instability in both skeletally immature and adult patients. Technique Description: The patellar tendon is exposed, and levels of imbrication as determined preoperatively by radiographic measurements are outlined on the tendon with a marking pen. A third line is then made proximal to the level of dissection that is half the distance of the lengthening. From the distal marking, a flap of tendon, the anterior half, is elevated by sharp dissection using a fresh No. 15 blade proximal to the predetermined level. Next, “redundancy-reducing” 2-0 vicryl sutures are placed and left untied by entering at the proximal marking, passing deep to the tendon, and emerging at the middle of the intact posterior section of tendon, followed by placement of 3 structural #2 Ethibond/Ti-Cron horizontal sutures into the patellar tendon that will create and maintain the imbrication. These sutures are then tied proximally while applying downward pressure to the patella to avoid tying under tension. Next, the “redundancy-reducing” sutures are tied thus imbricating the redundant posterior section of tendon. In a “pants over vest” fashion, the distal end of the anterior section of isolated tendon is repaired with ‘‘0’’ absorbable suture. The knee is then flexed beyond 90° to assess competence of the suture lines and to assess the need for quadriceps lengthening. Results: Radiographic shortening is maintained at a minimum of 2 years on 27 patients/32 knees. There were no complications directly related to the technique. Discussion/Conclusion: Patellar tendon imbrication is a safe and effective procedure to correct patella alta in the setting of lateral patellar instability. On average, the technique allowed 1 cm of patellar tendon shortening and maintained the correction at a minimum 2-year follow-up. In the skeletally immature patient, this technique allows correction of patella alta by avoidance of a tibial tuberosity osteotomy.

Salvage surgery improves the treatment outcome of patients with residual/recurrent maxillary sinus cancer after superselective intra-arterial cisplatin infusion with concomitant radiation therapy.

We have performed superselective intra-arterial cisplatin infusion with concomitant radiotherapy (RADPLAT) for patients with maxillary sinus cancer. The promising treatment outcomes of this non-surgical treatment were reported in past studies. However, few clinical studies have been conducted to evaluate the outcome of salvage surgery following RADPLAT. The purpose of this study was to analyze the treatment outcomes of salvage surgery for patients with recurrent maxillary sinus cancer after RADPLAT. We assessed 45 patients who had recurrence following RADPLAT between 1999 and 2017, and conducted a retrospective analysis. We excluded patients who did not complete RADPLAT. Patients were not considered to have completed RADPLAT if they underwent intra-arterial cisplatin less than three times or received a total radiation dose of less than 60Gy. The primary endpoint was overall survival. The median follow-up period for surviving patients after recurrence was 5.1years. Twenty-five of the 45 (56%) patients underwent salvage surgery. The 5-year overall survival rate was 68% in patients who underwent salvage surgery, while all patients who did not undergo salvage surgery died during the observation period. Fifteen of 24 (63%) patients with local recurrence underwent salvage surgery. Eight patients did not undergo salvage surgery because of unresectable disease; five of the eight patients had unresectable posterior extension. All nine patients with nodal recurrence underwent neck dissection. Treatment outcomes of salvage surgery following RADPLAT were favorable enough for it to be generally recommended. To reduce unresectable recurrence, the posterior section should be eradicated by RADPLAT.

Integrative descriptions of two new species of Dugesia from Hainan Island, China (Platyhelminthes, Tricladida, Dugesiidae).

Two new species of the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Hainan Island of China are described on the basis of morphological, karyological and molecular data. Dugesia semiglobosa Chen & Dong, sp. nov. is mainly characterized by a hemispherical, asymmetrical penis papilla with ventrally displaced ejaculatory duct opening terminally at tip of penis papilla; vasa deferentia separately opening into mid-dorsal portion of intrabulbar seminal vesicle; two diaphragms in the ejaculatory duct; copulatory bursa formed by expansion of bursal canal, lined with complex stratified epithelium, which projects through opening in bursa towards intestine, without having open communication with the gut; mixoploid chromosome complement diploid (2n = 16) and triploid (3n = 24), with metacentric chromosomes. Dugesia majuscula Chen & Dong, sp. nov. is mainly characterized by oviducts opening asymmetrically into female reproductive system; hyperplasic ovaries; expanded posterior section of bursal canal; vasa deferentia separately opening into mid-dorsal portion of seminal vesicle; asymmetrical penis papilla due to ventral course of ejaculatory duct, which has subterminal and dorsal opening at tip papilla; mixoploid chromosome complement diploid (2n = 16) and triploid (3n = 24); chromosomes metacentric. Apart from their anatomy, separate species status of the two new species is supported also by their genetic distances and by their positions in the phylogenetic tree. The sexualization process may have been induced by the lower temperatures, in comparison with their natural habitat, under which the worms were cultured in the laboratory.

BITE MARKS ON AN AETOSAUR (ARCHOSAURIA, SUCHIA) OSTEODERM: ASSESSING LATE TRIASSIC PREDATOR-PREY ECOLOGY THROUGH ICHNOLOGY AND TOOTH MORPHOLOGY

ABSTRACTTrace fossils such as bite marks provide rare, direct evidence of animal behavior, including predator-prey interactions. We present an osteoderm of the aetosaur Typothorax coccinarum from the Late Triassic Chinle Formation of Arizona with several punctures and scores, interpreted here as bite marks, preserved as evidence of predation/scavenging by a large carnivore. The marks include a single bite producing four subparallel fusiform pits on the ventral surface and several additional marks, including striated scores, on the dorsal surface. These traces are described and compared with known contemporaneous carnivorous taxa to determine the source of the bite marks. Some Triassic carnivores, including theropod dinosaurs can be ruled out because of tooth shape and serration densities. Phytosaurs and large paracrocodylomorphs remain as likely candidates based on tooth morphology. Although some phytosaur teeth are too rounded to produce the marks seen in this specimen, we demonstrate that the more lingually flattened teeth typically found in the posterior section of the snout are sufficiently mediolaterally compressed to produce a fusiform pit. A protective function for aetosaur osteoderms cannot be confirmed presently, but the extensive carapace these bones formed would have been a major barrier to both scavengers and active predators and may preserve more feeding/predation traces than previously thought. The bite marks described herein support the hypothesis that aetosaurs were prey items of large archosauromorphs, expanding our understanding of the complex, and seemingly carnivore dominated Late Triassic terrestrial ecosystems of North America.

Control of drop attacks with selective posterior callosotomy: Anatomical and prognostic data

ObjectiveIn a previous proof of concept study, selective posterior callosotomy achieved similar degree of control of drop attacks as total callosotomy, while sparing prefrontal interconnectivity. The present study aims to confirm this finding in a larger cohort and to provide anatomical and prognostic data. MethodsFifty-one patients with refractory drop attacks had selective posterior callosotomy and prospective follow up for a mean of 6.4 years. Twenty-seven patients had post-operative magnetic resonance imaging (MRI) and 18 had tractography (DTI) of remaining callosal fibers. Pre and postoperative falls were quantified and correlated with demographic, clinical and imaging data. ResultsMean monthly frequency of drop attacks had a 95 % reduction, from 297 before to 16 after the procedure. Forty- one patients (80 %) had either complete or greater than 90 % control of the epileptic falls. Age and duration of epilepsy at surgery correlated with outcome (p values, respectively, 0.042 and 0.005). Mean index of callosal section along the posterior-to-anterior axis was 53.5 %. Extending the posterior section anterior to the midbody of the corpus callosum did not correlate with seizure control (p 0.91), providing fibers interconnecting the primary motor (M1) and caudal supplementary motor areas (SMA) were sectioned. Only one patient had a notable surgical complication which resolved in two days. ConclusionsThis level III cohort study with objective outcome assessment confirms that selective posterior callosotomy is safe and effective to control epileptic falls. Younger patients with smaller duration of epilepsy have better results. A posterior section contemplating the splenium, isthmus and posterior half of the body (posterior midbody) seems sufficient to achieve complete or almost complete control of drop attacks.

КОМПЛЕКСНАЯ ЛУЧЕВАЯ ДИАГНОСТИКА У ПАЦИЕНТОВ С ДИСФУНКЦИЕЙ ВИСОЧНО-НИЖНЕЧЕЛЮСТНОГО СУСТАВА (ВНЧС)

Purpose. Сonducting a comprehensive analysis of clinical and radiological data in patients with temporomandibular joint (TMJ) dysfunction at the stages before and after conservative and dental types of treatment using multislice computed tomography (MSCT) and magnetic resonance imaging (MRI). Materials and methods. The present study included the results of clinical and radiological examinations at the stages before and after conservative and dental types of treatment of 36 patients (31 women and 5 men) in the age range of 18-52 years. All patients were divided into four groups depending on the clinical manifestations of temporomandibular joint dysfunction. Group I (n = 11; 30.3%) - patients with pain syndrome with TMJ dysfunction; Group II (n = 14; 39.2%) - patients with manifestation of acoustic effects in TMJ dysfunction and group III (n = 5; 13.7%) - patients with degenerative changes in bone tissue. Group IV (n = 6; 16.8%) - was a control group – volunteers without clinical manifestations of TMJ dysfunction. Patients of all groups underwent radiological diagnostic methods at various stages of treatment: MSCT examination at treatment and 12 months after the initial examination; MRI - at treatment, at 6 and 12 months. Results. According to the study, it was revealed that the asymmetric arrangement of the heads of the condylar processes of the lower jaw (n = 14; 42.4%) was noted in view of the violation of the biomechanics of the act of chewing. The presence of pronounced dystrophic processes on the part of the lesion in groups I, II, III was regarded by us as changes as a result of functional overload, which was indirectly confirmed by the regression of the process after the complex treatment. The posterior position of the head of the condylar process of the lower jaw was found much more often than any other localization, especially in the destructive process of the cartilaginous component in 20 patients (60.6%). According to MSCT data, the size of the joint space before and after the treatment was modernized: in the anterior section from 1.761.8 to 3.08.51.5 mm; in the middle section from 1.181.7 to 1.862.5mm after treatment and in the back section from 0.802.5 to 3.421.3mm after treatment In the absence of violations of the integrity of the dentition and trauma in the anamnesis in 25 patients (75.7%), a predominance of the active function of the masticatory muscles on the leading side was noted. According to MRI data, the volumetric characteristics of the lateral pterygoid muscles before and after treatment ranged from 17.81.9 to 15.12.5 mm; medial pterygoid muscles from 13.351.5 to 11.211.5 mm and the masticatory muscles proper from 18.531.5 to 14.221.6 mm. A statistically significant increase in the volumetric parameters (thickness) of the masticatory muscles in 25 patients (75.7%) indicates a functional overload of the masticatory apparatus, since the volumetric characteristics of the studied muscles became comparable with the data of the control group (n=6; 16,8%) after the treatment. Changes in the parameters of the articular disc, MRI studies revealed the following changes before and after the treatment: in the anterior region from 2.32.6 to 2.72.7 mm, in the central region from P 1 - I.M. Sechenov First Moscow State Medical University (Sechenov University). Moscow, Russia. 2 - Tver State Medical University. Tver, Russia. RUSSIAN ELECTRONIC JOURNAL OF RADIOLOGY | www.rejr.ru | REJR. 2021; 11 (1):88-102 DOI: 10.21569/2222-7415-2021-11-1-88-102 Страница 90 0.52,9 to 1.91.7 mm, in the posterior section from 3.22.7 to 4.32.1 mm. Bone density indicators of patients (n = 31; 100.0%) varied from +234.55.8 HU (in group III) to +565.55.9 HU (in group I) during the primary study, which made it possible to differentiate the severity of osteoporotic changes in bone tissue to correct the treatment. Conclusion. The use of highly informative methods of radiological diagnostics (MSCT, MRI) in patients with TMJ dysfunction is an integral part both at the stage of initial consultation and after treatment.