A chromosome-level genome for the nudibranch gastropod Berghia stephanieae helps parse clade-specific gene expression in novel and conserved phenotypes.

BACKGROUND: How novel phenotypes originate from conserved genes, processes, and tissues remains a major question in biology. Research that sets out to answer this question often focuses on the conserved genes and processes involved, an approach that explicitly excludes the impact of genetic elements that may be classified as clade-specific, even though many of these genes are known to be important for many novel, or clade-restricted, phenotypes. This is especially true for understudied phyla such as mollusks, where limited genomic and functional biology resources for members of this phylum have long hindered assessments of genetic homology and function. To address this gap, we constructed a chromosome-level genome for the gastropod Berghia stephanieae (Valdés, 2005) to investigate the expression of clade-specific genes across both novel and conserved tissue types in this species. RESULTS: The final assembled and filtered Berghia genome is comparable to other high-quality mollusk genomes in terms of size (1.05 Gb) and number of predicted genes (24,960 genes) and is highly contiguous. The proportion of upregulated, clade-specific genes varied across tissues, but with no clear trend between the proportion of clade-specific genes and the novelty of the tissue. However, more complex tissue like the brain had the highest total number of upregulated, clade-specific genes, though the ratio of upregulated clade-specific genes to the total number of upregulated genes was low. CONCLUSIONS: Our results, when combined with previous research on the impact of novel genes on phenotypic evolution, highlight the fact that the complexity of the novel tissue or behavior, the type of novelty, and the developmental timing of evolutionary modifications will all influence how novel and conserved genes interact to generate diversity.

A chromosome-level genome for the nudibranch gastropod Berghia stephanieae helps parse clade-specific gene expression in novel and conserved phenotypes.

How novel phenotypes originate from conserved genes, processes, and tissues remains a major question in biology. Research that sets out to answer this question often focuses on the conserved genes and processes involved, an approach that explicitly excludes the impact of genetic elements that may be classified as clade-specific, even though many of these genes are known to be important for many novel, or clade-restricted, phenotypes. This is especially true for understudied phyla such as mollusks, where limited genomic and functional biology resources for members of this phylum has long hindered assessments of genetic homology and function. To address this gap, we constructed a chromosome-level genome for the gastropod Berghia stephanieae (Valdés, 2005) to investigate the expression of clade-specific genes across both novel and conserved tissue types in this species. The final assembled and filtered Berghia genome is comparable to other high quality mollusk genomes in terms of size (1.05 Gb) and number of predicted genes (24,960 genes), and is highly contiguous. The proportion of upregulated, clade-specific genes varied across tissues, but with no clear trend between the proportion of clade-specific genes and the novelty of the tissue. However, more complex tissue like the brain had the highest total number of upregulated, clade-specific genes, though the ratio of upregulated clade-specific genes to the total number of upregulated genes was low. Our results, when combined with previous research on the impact of novel genes on phenotypic evolution, highlight the fact that the complexity of the novel tissue or behavior, the type of novelty, and the developmental timing of evolutionary modifications will all influence how novel and conserved genes interact to generate diversity.

The Use of Prone Magnetic Resonance Imaging to Rule Out Tethered Cord in Patients With Structural Spine Anomalies: A Diagnostic Technical Note for Surgical Decision-making.

Tethered cord syndrome (TCS) is a clinical diagnosis that can be difficult to establish, as symptoms do not always match classic radiological findings, such as a low-lying conus. Surgery for spinal detethering is not without risk and does not always result in clinical improvement. Prone magnetic resonance imaging (MRI) has been described as a tool to assess the mobility of the spine. This is a technical imaging report where prone imaging was a factor that influenced the decision to defer surgery in favor of conservative management. T1 and T2 sagittal and T1 axial MRI imaging were obtained with the patient supine, and then repeated in the prone position. An anteroposterior conus movement of >10% of the canal width was considered normal. There was significant anterior movement of the conus when switching to the prone position. Surgery was deferred, and the patient improved after a regimen of intensive physical therapy. Prone MRI can be a useful tool to have in our neurosurgical armamentarium when assessing spinal cord tethering. Surgery is not recommended when normal anteroposterior movement of the conus is present.

Resection of an Intramedullary Glomus-type Arteriovenous Malformation of the Conus Medullaris: Technical Note and Step-by-step Surgical Video.

Arteriovenous malformations (AVMs) of the spine include a broad spectrum of lesions that vary from a simple arteriovenous fistulous connection to a more complex net of abnormal vessels involving multiple spinal levels. These entities are poorly studied and understood because of their rarity and are often either managed conservatively with observation if the lesion is complex, or treated surgically or interventionally in the presence of an accessible and distinct fistulous connection. Most surgeons avoid intervening on more intricate lesions until they become symptomatic with progressive neurological decline. We describe the case of a 38-year-old man who presented with severe sharp back pain after an appendectomy procedure. A magnetic resonance angiogram (MRA) revealed an arteriovenous malformation of the conus medullaris, with a compact glomus-type nidus and arterial feeders originating from an enlarged artery of Adamkiewicz. The malformation was resected through a posterior midline approach, and the patient was neurologically intact at his discharge on postoperative Day 2. Follow-up angiography showed complete obliteration of the lesion. Our operative video is meant to serve as a step-by-step and systematic guide to the approach and management of conus arteriovenous spinal lesions, which can be difficult to treat. We provide a pre- and postoperative radiological description of the anomaly as well as a technical guide to the resection of a spinal vascular lesion. This video could serve as an operative guide and reference to neurosurgeons-both established and in training-when confronting similar disease processes in the future.

A Phase 2 Clinical Trial of SABR Followed by Immediate Vertebroplasty for Spine Metastases.

PURPOSE: To determine the pain response and prevention of vertebral compression fractures (VCFs) after single-fraction stereotactic ablative radiation therapy (SABR) in conjunction with immediate vertebroplasty for spine metastases. METHODS AND MATERIALS: Patients with localized spine metastases free from VCF associated with loss of vertebral height with a pain score ≥4 using the visual analog scale were enrolled. Spine SABR was performed with 20 Gy delivered to the gross disease and 14 Gy to the contiguous bone marrow in a single fraction. Immediate, prophylactic vertebroplasty was performed within 1 month after spine SABR. The primary endpoint was pain response at 3 months compared to the historical control with external beam radiation therapy from Radiation Therapy Oncology Group study 9714. Secondary endpoints included pain response at 1 month, duration of pain response, vertebroplasty rate, VCF rate, local control, and overall survival. RESULTS: Thirty-five patients were enrolled, of whom 29 were deemed eligible and underwent single-fraction spine SABR. Twenty-three of these patients subsequently underwent prophylactic vertebroplasty. The 3-month pain response was significantly improved compared to Radiation Therapy Oncology Group study 9714: 95% versus 51% (P < .0001). The local control with a median follow-up of 9.6 months was 92%. The freedom from VCF was 90% at 1 year. Spine SABR was well tolerated with no grade 2 or higher toxicities. A single patient with disease extending from the vertebral body into the spinal canal developed vertebroplasty-related myelopathy, which was corrected with surgery. CONCLUSIONS: Single-fraction SABR immediately followed by prophylactic vertebroplasty improves pain response compared with conventional radiation therapy while providing long-term pain control and structural stability of the treated spine. Vertebroplasty is well tolerated as a prophylactic measure in patients without loss of vertebral height after spine SABR. Pain response and VCF rates are similar to patients undergoing SABR alone. Thus, patients who would benefit most from the addition of vertebroplasty need to be further identified.

A 25-year experience with hemicorporectomy for terminal pelvic osteomyelitis.

BACKGROUND: Hemicorporectomy involves amputation of the pelvis and lower extremities by disarticulation through the lumbar spine with concomitant transection of the aorta, inferior vena cava, and spinal cord. In addition, conduits are constructed for diversion of both the urinary and fecal streams. Of 57 cases reported in the literature, limited experience exists with hemicorporectomy for terminal pelvic osteomyelitis, with only 11 cases described. Furthermore, there is little information available regarding perioperative mortality and long-term survival. This article describes the largest reported series of hemicorporectomies performed for terminal pelvic osteomyelitis. METHODS: A retrospective review of the medical records for nine patients who underwent hemicorporectomy at the authors' institution was conducted followed by interviews with all surviving patients. RESULTS: At follow-up, four patients were alive and five patients were dead. For all patients, the average survival after hemicorporectomy was 11.0 years (range, 1.7 to 22.0 years). There was no perioperative mortality within 30 days of surgery. None of the surviving patients suffered from recurrent decubitus ulcers. CONCLUSIONS: Including this clinical series, a total of 66 hemicorporectomies have now been reported in the literature. Twenty cases were performed for terminal pelvic osteomyelitis with no mortality within 30 days of surgery, and 53.3 percent of patients were alive and well at long-term follow-up. Given the low perioperative mortality along with the ability of patients to achieve long-term survival following this operation, hemicorporectomy should be offered to appropriate patients suffering from terminal pelvic osteomyelitis.

Hemicorporectomy: back to front.

Hemicorporectomy involves amputation of the pelvis and lower extremities by disarticulation through the lumbar spine with concomitant transection of the aorta, inferior vena cava, and spinal cord, as well as creation of conduits for diversion of the urinary and fecal streams. A review of the literature reveals that the surgical technique has been relatively unchanged since 1960. The standard anterior to posterior approach is associated with significant blood loss and morbidity, likely contributing to lengthy hospital stay. Herein, we describe our back-to-front approach to hemicorporectomy, involving early division of the vertebral structures and spinal cord, pre-empting engorgement of Batson's plexus, thus minimizing blood loss. In addition, this approach greatly improves exposure of the pelvic vessels, allowing for a technically less challenging and safer procedure.

Abnormal coagulation studies associated with levofloxacin. Report of three cases.

Complications arising from antibiotic use are of interest to neurosurgeons because many neurosurgical patients are treated for infection. In this report, the authors describe three patients with spine disorders who developed coagulopathies after treatment with levofloxacin, an antibiotic commonly used by neurosurgical services. Three patients with spine disorders developed urinary tract infections (UTIs) for which they received a 3-day course of oral levofloxacin. Subsequently, they demonstrated prolonged prothrombin times and increased international normalized ratios. One of those patients later developed acquired von Willebrand syndrome during surgery. Coagulopathies were successfully corrected preoperatively with parenteral vitamin K. The patient with acquired von Willebrand syndrome required multiple transfusions. There seems to be an association between levofloxacin and coagulation abnormalities in neurosurgical patients treated for UTIs. Neurosurgical services prescribing this common antibiotic should be aware of this problem.