Caudal Sites Research Articles

Micro-computed tomography reveals high-density mineralised protrusions and microstructural lesions in equine stifle joint articular cartilage.

Stifle osteoarthritis (OA) lesions are most common in the medial femorotibial (MFT) compartment. Their characterisation and mapping will inform equine veterinarians towards an accurate diagnosis of OA. Investigate and map micro-CT (μCT) changes in the hyaline articular cartilage (HAC) in the medial femoral condyle (MFC) and medial tibial plateau (MTP). Ex vivo cadaveric. Stifles (n = 7 OA and 17 control [CO]) were retrieved from a tissue bank. The MFC and MFT were imaged with μCT. Regions of interest (ROIs) were cranial (MFCcr; MTPcr) and caudal (MFCca; MTPca) sites. In each ROI, μCT images were scored for HAC fibrillation, surface mineralisation and for the presence of high-density mineralised protrusions (HDMP). The lesions were mapped, and site-matched histology was performed. The microstructure of healthy and abnormal HAC was discernible on μCT images and confirmed with histology. HAC fibrillation was more prevalent (p = 0.019) in the MFCcr of the OA group (n = 7/7, 100%) when compared with the CO group (n = 7/17, 41%). Score 1 HAC surface mineralisation was more prevalent (p = 0.038) in the OA MFCca (n = 4/7, 57%) when compared with the CO group (n = 2/17, 12%). HDMP were heterogenous and hyperdense mineralised material protruding into the HAC and were more frequent (p = 0.033) in MFCs (n = 12/24, 50%) compared with MTPs (n = 5/24, 20%). Score 3 HDMPs were also more prevalent (p = 0.003) in the MFCcr (n = 7/24, 29%) compared with MFCca (n = 0/24, 0%) and in MFCs (n = 7/24, 29%) compared with MTPs (n = 3/24, 12.5%) (p = 0.046). Clinical history was not available for all specimens. Equine HDMP and HAC surface mineralisation are imaged for the first time in the MFT joint. HAC fibrillation and erosion and HDMP are more frequent in the cranial aspect of the MFC. μCT images of OA in equine stifle joints provide a novel perspective of lesions and improve understanding of OA.

Investigating post-traumatic syringomyelia and local fluid osmoregulation via a rat model

BackgroundSyringomyelia (SM) is characterized by the development of fluid-filled cavities, referred to as syrinxes, within the spinal cord tissue. The molecular etiology of SM post-spinal cord injury (SCI) is not well understood and only invasive surgical based treatments are available to treat SM clinically. This study builds upon our previous omics studies and in vitro cellular investigations to further understand local fluid osmoregulation in post-traumatic SM (PTSM) to highlight important pathways for future molecular interventions.MethodsA rat PTSM model consisting of a laminectomy at the C7 to T1 level followed by a parenchymal injection of 2 μL quisqualic acid (QA) and an injection of 5 μL kaolin in the subarachnoid space was utilized 6 weeks after initial surgery, parenchymal fluid and cerebrospinal fluid (CSF) were collected, and the osmolality of fluids were analyzed. Immunohistochemistry (IHC), metabolomics analysis using LC–MS, and mass spectrometry-based imaging (MSI) were performed on injured and laminectomy-only control spinal cords.ResultsWe demonstrated that the osmolality of the local parenchymal fluid encompassing syrinxes was higher compared to control spinal cords after laminectomy, indicating a local osmotic imbalance due to SM injury. Moreover, we also found that parenchymal fluid is more hypertonic than CSF, indicating establishment of a local osmotic gradient in the PTSM injured spinal cord (syrinx site) forcing fluid into the spinal cord parenchyma to form and/or expand syrinxes. IHC results demonstrated upregulation of betaine, ions, water channels/transporters, and enzymes (BGT1, AQP1, AQP4, CHDH) at the syrinx site as compared to caudal and rostral sites to the injury, implying extensive local osmoregulation activities at the syrinx site. Further, metabolomics analysis corroborated alterations in osmolality at the syrinx site by upregulation of small molecule osmolytes including betaine, carnitine, glycerophosphocholine, arginine, creatine, guanidinoacetate, and spermidine.ConclusionsIn summary, PTSM results in local osmotic disturbance that propagates at 6 weeks following initial injury. This coincides with and may contribute to syrinx formation/expansion.

Major complications of caudal block: A prospective survey of 973 cases in adult anorectal surgery

BackgroundWe conducted a prospective study of surgical inpatients at a teaching hospital to assess the incidence and potential risk factors for major complications of caudal anesthesia in anorectal surgery. MethodsA total of 973 patients undergoing anorectal surgery under caudal block were included in this prospective, observer-blinded trial after providing consent. Demographic information, detailed perioperative information, anesthesia-related complications and postoperative follow-up information were recorded. Meanwhile, the incidence and risk factors for major caudal anesthesia-related complications were analyzed. ResultsA total of 973 patients underwent caudal block. The effective rate was 95.38 % (928 cases). However, there were still 38 (3.91 %) cases with insufficient block and 7 (0.72 %) cases with no block. The major anesthesia-related complications were local anesthetic systemic toxicity (9, 0.92 %), cauda equine syndrome (1, 0.10 %), transient neurological symptoms (3, 0.31 %) and localized pain at the caudal insertion site (30, 3.08 %). The identified risk factor for local anesthetic systemic toxicity was multiple attempts locating the caudal space (OR = 5.30; 1.21–23.29). The identified risk factor for localized pain at the caudal insertion site was multiple attempts locating the caudal space (OR = 10.57; 4.89–22.86). ConclusionThe main complications of caudal block in adult patients are transient neurological symptoms, cauda equine syndrome, serious local anesthetic systemic toxicity and localized pain at the caudal insertion site. Overall, the incidence of complications is low and symptoms are mild. Caudal block is still a safe and reliable method for anesthesia in adult anorectal surgery.

Prevalence and distribution of ossification of the ligamenta flava in a 16th–18th century skeletal population sample from Poland

ObjectiveThis study aimed to determine the prevalence of the ossification of the ligamenta flava (OLF) among skeletal remains from Poland. Materials and methods124 skeletons aged 25 years and older were analyzed. The presence and size of OLF were observed macroscopically. OLF was recorded at the cranial and caudal attachment sites of each vertebra. The following factors were analyzed: age at death, sex, and presence of other spondyloarthropathies. ResultsThe crude prevalence of OLF in the analyzed series was 68.55 %. OLF was located most frequently in the lower thoracic spine. A statistically significant relationship was observed between the presence of OLF and age at death. OLF coincided with degenerative spondyloarthropathies of the thoracolumbar spine. ConclusionsThe results of this study indicate that OLF was not a rare condition in past populations of European ancestry. Analysis of OLF prevalence in skeletal materials can contribute to reconstruction of the conditions and lifestyles of past people. SignificanceThis study shed new light on the prevalence of OLF and provides information on the variability of OLF in past European populations. The evaluation of the prevalence of OLF represents an important contribution to the field of paleopathology in understanding disease changes in prehistoric and historic human populations. LimitationsThe analyzed material came from unknown populations without demographic data. Sex and age at death were assessed using standard anthropological methods. Suggestions for further researchIt is important to understand the influence of sociocultural factors and physical activity patterns on the development of OLF.

PO-03-098 DIFFERENTIAL PACING FOR IDENTIFYING MULTIPLE INTERATRIAL CONNECTIONS

Interatrial connection (IAC) is reported to be an anatomical structure associated with complex biatrial tachycardias. However, electrophysiological conduction between left atrium (LA) and right atrium (RA) has not been fully investigated. This study was to distinguish multiple IACs by using different pacing sites. Twenty patients with paroxysmal atrial fibrillation who underwent ablation were enrolled. High-density mapping of left and right atrial before ablation were created during continuous pacing from sinus node (SN) or low lateral RA (LL-RA), and LA appendage (LAA) or posterior wall (LA-PW), respectively. Focal activation sites were defined as IAC and breakthrough segments of each atrium were recorded. The average number of total IAC were 4.9±1.3 and 4.1±1.2 for RA-LA and LA-RA, respectively (Figure A1,2). There was no significant difference in number of IACs between each directional connections (cranial pacing, p=0.35; caudal pacing, p=0.62) (Figure B). Connections at the level of interatrial septum (IAS) and Bachmann’s bundle were mostly found as RA-LA connections, however more than one third of the patients had connections in right pulmonary veins, its carina, LA roof and coronary sinus musculature. LA-RA connections were mainly existed in IAS, however superior and inferior vena cava were also frequently related. Only either single site from SN or LL-RA pacing elucidated significantly smaller number of IACs for RA-LA compared to total IACs (SN vs total, 3.2±0.8 vs 4.9±1.3, p<0.001; LL-RA vs total, 3.2±1.5 vs 4.9±1.3, p<0.001) (Figure C1). Similarly, only either LAA or LA-PW pacing revealed significantly smaller number of IACs for LA-RA compared to total IACs (LAA vs total, 3.0±0.8 vs 4.1±1.2, p<0.001; LA-PW vs total, 3.0±0.8 vs 4.1±1.2, p<0.001) (Figure C2). Although difference of pacing sites did not influence the total number of interarial conductions (RA-LA, p=0.09; LA-RA, p=0.85), pacing from cranial and caudal sites preferentially disclosed IAC at upper and lower septal segments, respectively (upper connections of RA-LA, SN vs LL-RA, 73.4% vs 46.9%, p=0.0037; upper connections of LA-RA, LAA vs LA-PW pacing, 66.1% vs 41.0%, p=0.013) (Figure D1,2). Pacing from multiple locations may be required in order to reveal entire interatrial connections.

Anterior shift of the ventral dura mater: A novel concept of the posterior surgery for ossification of the posterior longitudinal ligament in thoracic spine.

Thoracic myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) remains one of the most difficult disorders to treat. The Ohtsuka procedure, extirpation, or anterior floating of the OPLL through a posterior approach, has shown great surgical outcomes after several modifications. However, these procedures are technically demanding and pose a significant risk of neurological deterioration. We have developed a novel modified Ohtsuka procedure in which removal or minimization of the OPLL mass is unnecessary; instead, the ventral dura mater is shifted anteriorly with the posterior part of the vertebral bodies and targeted OPLL. First, pedicle screws were inserted at more than three spinal levels above and below the spinal level where pediculectomies were performed. After laminectomies and total pediculectomies, partial osteotomy of the posterior vertebra adjacent to the targeted OPLL was performed by using a curved air drill. Then, the PLL is completely resected at the cranial and caudal sites of the OPLL using special rongeurs or a threadwire saw with a diameter of 0.36 mm. The nerve roots were not resected during surgery. Eighteen patients (follow-up ≥1 year) treated with our modified Ohtsuka procedure were assessed clinically, including the Japanese Orthopaedic Association (JOA) score for thoracic myelopathy and radiographically. The average follow-up period was 3.2 years (range, 1.3-6.1 years). The preoperative JOA score was 2.7 ± 1.7, which improved to 8.2 ± 1.8 at 1 year postoperatively; therefore, the recovery rate was 65.8 ± 19.8%. The CT scan at 1year after surgery revealed the anterior shift of the OPLL averaged 3.1 ± 1.7 mm and the ossification-kyphosis angle of the anterior decompression site decreased at an average of 7.2 ± 6.8 degrees. Three patients demonstrated temporary neurological deterioration, all of whom completely recovered within 4 weeks postoperatively. The concept of our modified Ohtsuka procedure is 1) not OPLL extirpation or minimization but only the creation of space between the OPLL and spinal cord by an anterior shift of the ventral dura mater, which is achieved by complete resection of the PLL at the cranial and caudal sites of the OPLL; and 2) no nerve roots are sacrificed to prevent ischemic spinal cord injury. This procedure is not technically demanding and safe and provides secure decompression for thoracic OPLL. The anterior shift of the OPLL was smaller than expected, but it resulted in a relatively good surgical outcome with a recovery rate ≥65%. Our modified Ohtsuka procedure is quite secure and is not technically demanding, with a recovery rate of 65.8%.

Pharmacokinetics and pharmacodynamics of intramuscular alfaxalone in central bearded dragons (Pogona vitticeps): effect of injection site

ObjectiveTo evaluate the pharmacodynamic effects and pharmacokinetics of a single intramuscular (IM) injection of alfaxalone in central bearded dragons (Pogona vitticeps) when injected at a cranial versus a caudal site. Study designProspective, masked, randomized crossover study. AnimalsA total of 13 healthy bearded dragons weighing 0.48 ± 0.1 kg. MethodsAlfaxalone (10 mg kg–1) was administered IM to 13 bearded dragons in the triceps muscle (cranial treatment) or the quadriceps muscle (caudal treatment) separated by 4 weeks. Pharmacodynamic variables included movement score, muscle tone score and righting reflex. Blood was obtained from the caudal tail vein using a sparse sampling methodology. Plasma alfaxalone concentrations were determined using liquid chromatography–mass spectrometry, and pharmacokinetic analysis was performed using nonlinear mixed-effects modeling. Differences in variables between injection sites were analyzed using a nonparametric Wilcoxon signed-rank test for paired data with significance set at p ≤ 0.05. ResultsTime to loss of righting reflex score was not different, median (interquartile range), between cranial and caudal treatments [8 (5–11) and 8 (4–12) minutes, respectively, p = 0.72]. Time to recovery of righting reflex was also not different between cranial and caudal treatments [80 (44–112) and 64 (56–104) minutes, respectively, p = 0.75]. Plasma alfaxalone concentrations were not significantly different between treatments. The population estimate (95% confidence intervals) for volume of distribution per fraction absorbed was 1.0 (0.79–1.20) L kg–1, clearance per fraction absorbed was 9.6 (7.6–11.6) mL minute–1 kg–1, absorption rate constant was 2.3 (1.9–2.8) minute–1 and elimination half-life was 71.9 (52.7–91.1) minutes. Conclusions and clinical relevanceRegardless of the injection site, IM alfaxalone (10 mg kg–1) produced reliable chemical restraint in central bearded dragons, appropriate for nonpainful diagnostic procedures or anesthetic premedication.

Spontaneous embryonic death in plains viscacha (Lagostomus maximus - Rodentia), a species with unique reproductive characteristics

Spontaneous embryonic death is a conserved reproductive event in Eutherians. The macro and microscopic characteristics of this type of death are similar between the different taxa. However, in the hystricomorphic rodent plains viscacha (Lagostomus maximus) is exceptional in terms of massiveness (80% embryonic resorption). In this species, of the 10–12 implantation sites (IS) (half in each uterine horn), only the caudal embryos will survive, resorbing the cranial and intermediate IS. We hypothesize that uterine structural variations in L. maximus restrict growth and promote embryo death, with the consequent loss of placental homeostasis in the cranial and middle IS. In this study, different studies (ultrasonography, macroscopy and microscopy) were carried out to analyze different aspects of the intermediate gestation of L. maximus (46 days postcoitus). Ultrasonographic studies revealed that the cranial and middle IS (IS-1, IS-2, and IS-3) had no recognizable embryonic and placental structures as compared to the caudal implantation sites (IS-4). Macroscopically, the areas corresponding to the embryos in the cranial and middle IS were occupied by a necrotic black semi-fluid mass. Moreover, the placenta in these IS was undifferentiated. However, in the caudal IS both the embryo and its placenta were distinguishable. Using histological and immunohistochemical techniques, it was observed that the placentas of IS-1, IS-2 and IS-3 were disorganized and showed hemorrhage, inflammatory infiltration containing neutrophils, macrophages, mast cells and foreign body giant cells, apoptotic trophoblast, and a layer of collagen fibers and fibroblasts that circumscribed each of these IS. In contrast, the placenta of the caudal IS showed an organized maternal-embryonic interface. The characteristics observed in IS in resorption of viscachas in intermediate gestation show that, regardless of gestation time, embryonic death has a similar macro and microscopic morphological pattern among eutherians with invasive placentation. However, the massiveness and sectorization of embryonic death in the plains viscacha make the species a unique model for the study of this reproductive event.

A comparative analysis of differentially expressed genes in rostral and caudal regions after spinal cord injury in rats.

The initial mechanical damage of a spinal cord injury (SCI) triggers a progressive secondary injury cascade, which is a complicated process integrating multiple systems and cells. It is crucial to explore the molecular and biological process alterations that occur after SCI for therapy development. The differences between the rostral and caudal regions around an SCI lesion have received little attention. Here, we analyzed the differentially expressed genes between rostral and caudal sites after injury to determine the biological processes in these two segments after SCI. We identified a set of differentially expressed genes, including Col3a1, Col1a1, Dcn, Fn1, Kcnk3, and Nrg1, between rostral and caudal regions at different time points following SCI. Functional enrichment analysis indicated that these genes were involved in response to mechanical stimulus, blood vessel development, and brain development. We then chose Col3a1, Col1a1, Dcn, Fn1, Kcnk3, and Nrg1 for quantitative real-time PCR and Fn1 for immunostaining validation. Our results indicate alterations in different biological events enriched in the rostral and caudal lesion areas, providing new insights into the pathology of SCI.

Microstructural changes at the osteochondral junction in naturally occurring osteoarthritis of the equine medial femorotibial joint

Purpose: Osteoarthritis (OA) is a progressive degenerative disease of the joint organ and affects all species. The medial femorotibial (MFT) joint is the knee compartment most commonly affected with OA in humans, dogs, and horses. We hypothesized that microCT (μCT) assessment of specimens with naturally occurring equine MFT-OA will provide new insight into the pathophysiology of OA in this joint. The aim of this study was to compare healthy and MFT-OA joint microarchitectural changes in both 2 and 3D μCT images. Methods: Equine medial femoral condyles (MFC; n = 24) and tibial plateaus (MTP; n = 24) were available in a tissue bank. Regions of interest (cranial and caudal) were scored for lesions. Articular surfaces were macroscopically scored for OA (cartilage fibrillation and erosion) and categorized into 2 groups (healthy and OA) for comparative purposes. MFCs and MTPs were scanned with μCT (Xtek HMXST 225, Nexus Metrology, Canada) and 2D and 3D images were assessed. Hyaline articular cartilage (HAC) was scored for fibrillation (0-3) and high density mineralized protrusions (HDMP) (0-3). The calcified cartilage/subchondral bone plate (ACC/SCP) was also assessed for radiolucencies and the subchondral trabecular bone (SCB) for sclerosis. Results: Seventeen healthy MFTs and 7 OA MFTs were studied. HAC fibrillation was more prevalent in the MFC OA group (100%) compared with the healthy MFC group (71%) and the scores (s) were also more severe: OA MFCs (s2- 29%, s3- 71%); healthy MFCs (s1- 29%, s2- 24%, s3- 18%). Although HAC fibrillation was almost equally observed in the MTP OA group (100%) and the healthy MTP group (94%), the scores were worse in the MTP OA group (s2- 29%, s3- 71%) compared with MTP healthy group (s1- 12%, s2- 43%, s3- 43%). HDMPs were observed frequently in both groups: in 57% OA MFCs and in 47% healthy MFCs. However, the HDMP scores were more severe in MFC OA (s1- 14%, s3- 43%) compared with healthy MFCs (s1- 12%, s2- 12%, s3- 23%). They were located almost exclusively in the cranial MFC (100% OA, 87% healthy) (Figure 1). Although HDMPs were more prevalent in the MTP OA group (43%) compared with the healthy MTP group (18%), the severity of the lesions was similar in both groups: OA MTPs (s1- 29%, s3- 14%); healthy MTPs (s1- 6%, s3- 12%). ACC/SCP radiolucency was never observed in either healthy or OA MFCs. However, ACC/SCP radiolucency was observed in the MTP: MTP OA (86%) and healthy (65%) and almost all were located in the caudal part of the plateau in both healthy (91%) and OA (100%) MTPs. SCB sclerosis had a similar prevalence in both healthy (82%) and OA (86%) MFCs but the distribution pattern was different. In the healthy MFCs, sclerosis was more frequent caudally (71%) whereas in OA MFCs, it was distributed equally in both regions (57%). At the tibial plateau, sclerosis was most frequently observed in MTP OA specimens (86%) and predominantly at the caudal site (86%). In healthy MTPs it was identified in 65% with a more balanced distribution between cranial (41%) and caudal (59%) sites. Conclusions: High density mineralized protrusions (HDMP) were observed protruding into macroscopically normal appearing cartilage and OA cartilage. However, they were more severe in OA joints. This confirms our previous identification of HDMP in equine post traumatic osteoarthritis (PTOA) of the carpal bones and extends them to the equine MFT where racing-induced PTOA is not a characteristic feature and suggests that HDMP is feature all forms of OA. ACC/SCP radiolucency was never observed in the MFCs but occurred in the caudal MTP of both groups, but more frequently in OA.

Long-term Outcomes of Extracardiac Total Cavopulmonary Connection for Apicocaval Juxtaposition

The long-term outcomes of a total cavopulmonary connection (TCPC) with an extracardiac conduit (ECC) for patients with apicocaval juxtaposition (ACJ) remain unclear. A total of 38 patients with ACJ who underwent TCPC with ECC between 1998 and 2014 were enrolled in this study. For 19 patients with a superior vena cava - inferior vena cava contralateral position, a long-curved route rounding the opposite side of the apex was selected (CC group). For 11 patients with a superior vena cava-inferior vena cava ipsilateral position, a long-curved route was principally selected (IC group); however, a short, straight route was selected for 8 patients because there was sufficient space behind the ventricular apex (IS group). Follow-up was completed in all patients, with a mean follow-up duration of 13.2 ± 4.9 years. The angles of the caudal conduit anastomosis site measured from the frontal view of cineangiography had significantly straightened in the CC group from 1 year to 15 years (P < .05) and in the IC group from 1 year to 10 years (P < .05). There were 2 late mortalities and 6 reoperations during follow-up. Overall survival and freedom from reoperation rates at 15 years were 95% and 82%, respectively. There were no conduit-related or route-related complications such as death, reoperations, pulmonary venous obstructions, conduit obstructions, or pulmonary arteriovenous malformations in any of the groups. Even though chronologic geometric changes of curved ECCs were observed, TCPC with ECC for patients with ACJ can be safely applied without conduit- or route-related complications in long-term follow-up.

Spinal motor mapping by epidural stimulation of lumbosacral posterior roots in humans.

SummaryEpidural electrical stimulation of the spinal cord is an emergent strategy for the neurological recovery of lower-extremity motor function. Motoneuron pools are thought to be recruited by stimulation of posterior roots. Here, we linked electromyographic data of epidurally evoked lower-extremity responses of 34 individuals with upper motoneuron disorders to a population model of the spinal cord constructed using anatomical parameters of thousands of individuals. We identified a relationship between segmental stimulation sites and activated spinal cord segments, which made spinal motor mapping from epidural space possible despite the complex anatomical interface imposed by the posterior roots. Our statistical approach provided evidence for low-threshold sites of posterior roots and effects of monopolar and bipolar stimulation previously predicted by computer modeling and allowed us to test the impact of different upper motoneuron disorders on the evoked responses. Finally, we revealed a statistical association between intraoperative and postoperative mapping of the spinal cord.

Control of food approach and eating by a GABAergic projection from lateral hypothalamus to dorsal pons

Electrical or optogenetic stimulation of lateral hypothalamic (LH) GABA neurons induces rapid vigorous eating in sated animals. The dopamine system has been implicated in the regulation of feeding. Previous work has suggested that a subset of LH GABA neurons projects to the ventral tegmental area (VTA) and targets GABA neurons, inhibiting them and thereby disinhibiting dopaminergic activity and release. Furthermore, stimulation-induced eating is attenuated by dopamine lesions or receptor antagonists. Here we explored the involvement of dopamine in LH stimulation-induced eating. LH stimulation caused sated mice to pick up pellets of standard chow with latencies that varied based on stimulation intensity; once food was picked up, animals ate for the remainder of the 60-s stimulation period. However, lesion of VTA GABA neurons failed to disrupt this effect. Moreover, direct stimulation of VTA or substantia nigra dopamine cell bodies failed to induce food approach or eating. Looking further, we found that some LH GABA fibers pass through the VTA to more caudal sites, where they synapse onto neurons near the locus coeruleus (LC). Similar eating was induced by stimulation of LH GABA terminals or GABA cell bodies in this peri-LC region. Lesion of peri-LC GABA neurons blocked LH stimulation-induced eating, establishing them as a critical downstream circuit element for LH neurons. Surprisingly, lesions did not alter body weight, suggesting that this system is not involved in the hunger or satiety mechanisms that govern normal feeding. Thus, we present a characterization of brain circuitry that may promote overeating and contribute to obesity.

115 Predicting Graft Failure in a Porcine Burn Model of Various Debridement Depths via Laser Speckle Imaging and Deep Learning

Abstract Introduction Early excision and grafting (E&amp;G) remains a mainstay in the treatment of burns. Procedures to remove necrotic tissue from severe burn wounds continue to be challenging and may affect rates of successful grafting. The use of laser speckle imaging (LSI) may help detect necrotic tissue remaining but requires human interpretation. Additional decision-making support is needed, especially in prolonged field care settings. The purpose of this study was to evaluate whether graft success or failure can be predicted from LSI using machine learning (ML) and deep learning (DL) techniques in a porcine burn model of various burn depths. Methods Anesthetized Yorkshire pigs (n=12) were burned with a 5x5 cm square brass block (0.4 kg/cm2) @ 100°C to produce partial, deep partial, or full thickness burns (PT, DPT, FT) at 10 square sections on the back of each pig. Debridement was randomized from 1 (0.030”) to 4 (0.120”) passes performed using a dermatome, and then meshed split thickness skin grafts taken from 4 caudal donor sites were applied to wounds. Post-debridement was denoted as Day 0. Graft success/failure (&amp;gt;70% graft take) was determined at Day 7. Laser speckle images were captured at Days 0, 3, 7, 10, and 14. ML and DL were used to develop models in order to predict graft failure and burn/debridement depth. Model performance was measured using loss, accuracy, and confusion matrices. Results Of 120 sections corresponding to 12 pigs, 7.5% (9/120) were not burned, 41.7% (50/120) were PT, 25.8% (31/120) were DPT, and 25.0% (30/120) were FT burns. Graft failure was 19.2% (23/120), with a 50.0% (10/20) rate for DPT burns involving 1- or 2-pass debridement. Both ML and DL used 600 images for algorithm development; 540 images, for training; and 60 images, for testing. DL was superior over ML in test accuracy (93.3% vs 75.0%, p&amp;lt; 0.05). A three-stage architecture plus image resizing was employed in DL to predict graft failure and burn/debridement depth. A best convolutional neural network for graft failure prediction was obtained, yielding a minimum cross entropy loss of 11.7% and accuracies of 96.5% (training), 93.3% (testing 1), 100.0% (testing 2), and 96.2% (overall). Promising results were also obtained for predicting burn/debridement depth: 97.6% (training), 93.3% (testing). Conclusions This study showed that graft success or failure can be predicted from LSI and DL in a porcine burn model of various debridement depths. Use of this technology may provide a potential approach for accurately assessing early E&amp;G in severely burned patients and may aid providers during prolonged field care scenarios. Applicability of Research to Practice Use of LSI in conjunction with DL may provide a potential approach for accurately assessing early E&amp;G in severely burned patients and may aid providers during prolonged field care scenarios.

Mesenchymal Stem Cell-Laden Hydrogel Microfibers for Promoting Nerve Fiber Regeneration in Long-Distance Spinal Cord Transection Injury

Mesenchymal stem cell (MSC)-based regenerative medicine is widely considered as a promising approach for repairing tissue and re-establishing function in spinal cord injury (SCI). However, low survival rate, uncontrollable migration, and differentiation of stem cells after implantation represent major challenges toward the clinical deployment of this approach. In this study, we fabricated three-dimensional MSC-laden microfibers via electrospinning in a rotating cell culture to mimic nerve tissue, control stem cell behavior, and promote integration with the host tissue. The hierarchically aligned fibrin hydrogel was used as the MSC carrier though a rotating method and the aligned fiber structure induced the MSC-aligned adhesion on the surface of the hydrogel to form microscale cell fibers. The MSC-laden microfiber implantation enhanced the donor MSC neural differentiation, encouraged the migration of host neurons into the injury gap and significantly promoted nerve fiber regeneration across the injury site. Abundant GAP-43- and NF-positive nerve fibers were observed to regenerate in the caudal, rostral, and middle sites of the injury position 8 weeks after the surgery. The NF fiber density reached to 29 ± 6 per 0.25 mm2 at the middle site, 82 ± 13 per 0.25 mm2 at the adjacent caudal site, and 70 ± 23 at the adjacent rostral site. Similarly, motor axons labeled with 5-hydroxytryptamine were significantly regenerated in the injury gap, which was 122 ± 22 at the middle injury site that was beneficial for motor function recovery. Most remarkably, the transplantation of MSC-laden microfibers significantly improved electrophysiological expression and re-established limb motor function. These findings highlight the combination of MSCs with microhydrogel fibers, the use of which may become a promising method for MSC implantation and SCI repair.

Pre-collecting lymphatic vessels form detours following obstruction of lymphatic flow and function as collecting lymphatic vessels

Previously, we showed that lymphatic vessels (LVs) formed detours after lymphatic obstruction, contributing to preventing lymphedema. In this study, we developed detours using lymphatic ligation in mice and we identified the detours histologically. Under anesthesia, both hindlimbs in mice were subcutaneously injected with Evans blue dye to detect LVs. We tied the right collecting LV on the abdomen that passes through the inguinal lymph node (LN) at two points. The right and left sides comprised the operation and sham operation sides, respectively. Lymphography was performed to investigate the lymph flow after lymphatic ligation until day 30, using a near-infrared fluorescence imaging system. Anti-podoplanin antibody and 5-ethynyl-2'-deoxyuridine (EdU) were used to detect LVs and lymphangiogenesis. Within 30 days, detours had developed in 62.5% of the mice. Detours observed between two ligation sites were enlarged and irregular in shape. Podoplanin+ LVs, which were located in the subcutaneous tissue of the upper panniculus carnosus muscle, connected to collecting LVs at the upper portion from the cranial ligation site and at the lower portion from the caudal ligation site. EdU+ cells were not observed in these detours. The sham operation side showed normal lymph flow and did not show enlarged pre-collecting LVs until day 30. Detours after lymphatic ligation were formed not by lymphangiogenesis but through an enlargement of pre-collecting LVs that functioned as collecting LVs after lymphatic ligation. Further studies are required to explore the developmental mechanism of the lymphatic detour for treatment and effective care of lymphedema in humans.

Origins of Neural Progenitor Cell-Derived Axons Projecting Caudally after Spinal Cord Injury.

SummaryNeural progenitor cells (NPCs) transplanted into sites of spinal cord injury (SCI) extend large numbers of axons into the caudal host spinal cord. We determined the precise locations of neurons in the graft that extend axons into the caudal host spinal cord using AAV9-Cre-initiated retrograde tracing into floxed-TdTomato-expressing NPC grafts. 7,640 ± 630 grafted neurons extended axons to a single caudal host spinal cord site located 2 mm beyond the lesion, 5 weeks post injury. While caudally projecting axons arose from neurons located in all regions of the graft, the majority of caudally projecting graft neurons (53%) were located within the caudal one-third of the graft. Numerous host corticospinal axons formed monosynaptic projections onto caudally projecting graft neurons; however, we find that the majority of host axonal neuronal projections formed by neural progenitor cell interneuronal “relays” across sites of SCI are likely polysynaptic in nature.

Gonadal sex differentiation and development during early ontogenesis in the breeding kisslip cuttlefish (Sepia lycidas)

To understand and obtain basic information on sex differentiation in the kisslip cuttlefish (Sepia lycidas), the gonadal sex differentiation process was investigated histologically. An undifferentiated gonad consisting of germ cells and somatic cells was found to form at a caudal site in the space between the internal yolk sacks of cuttlefish embryos at 14 and 21 days after spawning (DAS). Sexual dimorphism in the gonad was first detected at around 28 DAS. Meiotic oocytes were observed as the first visible morphological characteristic of ovaries in the gonads of some cuttlefish embryos at 28 DAS. In other individuals, neither meiotic germ cells, nor the appearance of a testicular structure, were observed in the gonad even after 10 days post hatching (DPH). Seminiferous tubules, consisting of a small number of spermatogonia and a surrounding basement membrane, were the first visible morphological characteristic of the testis in the male gonad, detected at around 20 DPH. This is the third report on the gonadal sex differentiation process in cephalopods.

Bayesian estimation of sensitivity and specificity of systematic thoracic ultrasound exam for diagnosis of bovine respiratory disease in pre-weaned calves

Among the different clinical presentations of bovine respiratory disease, active pneumonia, defined as an infection of the lower airway with signs of inflammation, is the most important to diagnose correctly so appropriate treatment can be initiated. Diagnostic tests that accurately identify cases of active pneumonia are lacking; however, thoracic ultrasonography (TUS) seems promising. The primary objective of this study was to estimate the accuracy of TUS compared to reference tests for the diagnosis of active pneumonia in pre-weaned calves, using a latent-class model method (LCM). The tests used for comparison were the Wisconsin Clinical Respiratory Scoring Chart (CRSC, positive if ≥5) and serum haptoglobin concentration (Hap, positive if ≥15 mg/dL). Secondary objectives were to assess the incremental value on TUS accuracy of combining TUS of the right cranial part and caudal parts, and to determine the accuracy of various thresholds for depth of consolidation (≥0 cm, ≥1 cm, or ≥3 cm) for diagnosis of active pneumonia. One population of veal calves (n = 209) and one of dairy calves (n = 301) were enrolled. TUS, CRSC and Hap were all performed on each calf on the same day. TUS was performed by screening the mid to ventral portion of the lung caudal of the heart (the caudal sites), as well as the right parenchyma cranial to the heart (the cranial site). The maximal depth of consolidation (DEPTH) on TUS was recorded and noted separately for caudal and cranial sites. Different TUS cases were defined according to site and DEPTH. The accuracy of TUS was estimated by LCM for three tests conducted in two populations. Prevalence of active pneumonia was low (0.05) in both populations. In general, higher minimal consolidation depth thresholds led to increased TUS specificity (Sp) estimates, with minimal effects on TUS sensitivity (Se). With a TUS DEPTH threshold of ≥3 cm, adding TUS of the cranial site had little effect on accuracy. Using the ≥3 cm threshold with caudal sites only, posterior Se and Sp median estimates of 0.89 (95%BCI: 0.55, 1.0) and 0.95 (95%BCI: 0.92, 0.98), respectively, were obtained. In conclusion, in populations with low active pneumonia prevalence, adding TUS of the cranial site did not enhance the performance of the test. We suggest using a DEPTH threshold of ≥3 cm solely on caudal sites to detect active pneumonia.

Hunchback is counter-repressed to regulate even-skipped stripe 2 expression in Drosophila embryos.

Hunchback is a bifunctional transcription factor that can activate and repress gene expression in Drosophila development. We investigated the regulatory DNA sequence features that control Hunchback function by perturbing enhancers for one of its target genes, even-skipped (eve). While Hunchback directly represses the eve stripe 3+7 enhancer, we found that in the eve stripe 2+7 enhancer, Hunchback repression is prevented by nearby sequences—this phenomenon is called counter-repression. We also found evidence that Caudal binding sites are responsible for counter-repression, and that this interaction may be a conserved feature of eve stripe 2 enhancers. Our results alter the textbook view of eve stripe 2 regulation wherein Hb is described as a direct activator. Instead, to generate stripe 2, Hunchback repression must be counteracted. We discuss how counter-repression may influence eve stripe 2 regulation and evolution.