Assessment of the In Vitro Phosphatidylinositol Glycan Class A (PIG-A) Gene Mutation Assay Using Human TK6 and Mouse Hepa1c1c7 Cell Lines.

Gene mutations linked to diseases like cancer may be caused by exposure to environmental chemicals. The X-linked phosphatidylinositol glycan class A (PIG-A) gene, required for glycosylphosphatidylinositol (GPI) anchor biosynthesis, is a key target locus for in vitro genetic toxicity assays. Various organisms and cell lines may respond differently to genotoxic agents. Here, we compared the mutagenic potential of directly genotoxic ethyl methane sulfonate (EMS) to metabolically activated pro-mutagenic polycyclic aromatic hydrocarbons (PAHs). The two classes of mutagens were compared in an in vitro PIG-A gene mutation test using the metabolically active murine hepatoma Hepa1c1c7 cell line and the human TK6 cell line, which has limited metabolic capability. Determination of cell viability is required for quantifying mutagenicity. Two common cell viability tests, the MTT assay and propidium iodide (PI) staining measured by flow cytometry, were evaluated. The MTT assay overestimated cell viability in adherent cells at high benzo[a]pyrene (B[a]P) exposure concentrations, so PI-based cytotoxicity was used in calculations. The spontaneous mutation rates for TK6 and Hepa1c1c7 cells were 1.87 and 1.57 per million cells per cell cycle, respectively. TK6 cells exposed to 600 µM and 800 µM EMS showed significantly higher mutation frequencies (36 and 47 per million cells per cell cycle, respectively). Exposure to the pro-mutagen benzo[a]pyrene (B[a]P, 10 µM) did not increase mutation frequency in TK6 cells. In Hepa1c1c7 cells, mutation frequencies varied across exposure groups (50, 50, 29, and 81 per million cells per cell cycle when exposed to 10 µM B[a]P, 5-methylcholanthrene (5-MC), chrysene, or 16,000 µM EMS, respectively). We demonstrate that the choice of cytotoxicity assay and cell line can determine the outcome of the Pig-A mutagenesis assay when assessing a specific mutagen.

Current Indications, Trends, and Long-Term Results of 233 Bypasses to Treat Complex Intracranial Aneurysms: A Location-Specific Analysis.

BACKGROUND AND OBJECTIVES: Advances in endovascular flow diverters have led to a secular shift in the management of brain aneurysms, causing debate on current bypass indications. We therefore sought to investigate the long-term results, current indications, and trends of bypasses for brain aneurysms. METHODS: We retrospectively reviewed bypasses performed between 2005 and 2022 to treat brain aneurysms. Demographic, clinical, and radiological data were collected till the most recent follow-up. Aneurysm occlusion and graft patency was noted on cerebral angiogram in the immediate postoperative, 3-month, and most recent follow-up periods. Clinical outcomes (modified Rankin scores) and complications were assessed at 3 month and most recent follow-up. Trends in bypass volume and graft patency were assessed in 5-year epochs. Results were dichotomized based on aneurysm location to generate location-specific results and trends. RESULTS: Overall, 203 patients (mean age 50 years, 57% female patients) with 207 cerebral aneurysms were treated with 233 cerebral bypasses with a mean follow-up of 2 years. Fusiform morphology was the most common bypass indication. Aneurysm occlusion on immediate postoperative and final follow-up angiogram was 89% (184/207) and 96% (198/207), respectively. Graft patency rate in the immediate postoperative period and most recent follow-up was 95% (222/233) and 92% (215/233), respectively. Of 207 aneurysms, 5 (2%) recurred. Of 203 patients, 81% (165) patients had modified Rankin scores of 0-2 at the 3-month follow-up and 11 patients died (mortality 5%). Although there was a steady decrease in the bypass volume over the study period, the proportion of bypasses for recurrent aneurysms increased serially. Posterior circulation aneurysms had lower rates of aneurysm occlusion and significantly higher incidence of postoperative strokes and deaths (P = .0035), with basilar artery aneurysms having the worst outcomes. CONCLUSION: Bypass indications have evolved with the inception of novel flow diverters. However, they remain relevant in the cerebrovascular surgeon's armamentarium, and long-term results are excellent.

Traumatic Pseudoaneurysm of the Occipital Artery Treated with Open Surgical Ligation: 2-Dimensional Operative Video.

Scalp pseudoaneurysms occur most commonly because of trauma and are often in the superficial temporal artery due to the lack of soft tissue coverage between skin and bone, making it more vulnerable anatomically.1,2 Pseudoaneurysms of the occipital artery (OA) also occur but are extremely rare.2-4 An 80-year-old man presented with scalp bleeding and a small left-sided posterior scalp laceration after a fall and head strike 10 days prior. He was admitted and during his 2-week hospital stay, the occipital laceration continued to rebleed (Video 1). He developed a 2-cm pulsatile ulcerative mass with central necrosis on the left nuchal ridge. Computed tomography angiography revealed an ovoid left occipital lesion measuring 1.3 × 2.5 × 2.3 cm with delayed contrast filling and partial thrombosis. The base of the lesion had dense contrast filling continuous with the OA, diagnostic of OA pseudoaneurysm. OA pseudoaneurysm may be treated endovascularly or surgically. While surgical resection is the most common treatment, minimally invasive techniques have been successfully done through direct injection of N-butyl cyanoacrylate or endovascular embolization. The clinical presentation of this case was unique because this patient had an ulcerated lesion with central necrosis overlying the pseudoaneurysm. Endovascular management alone would not address the open lesion, which is at high risk for infection. The risk of infection would increase after embolization of the occipital artery, causing further necrosis of the tissue.

Treatment of In-Stent Stenosis Following Flow Diversion of Intracranial Aneurysms with Cilostazol and Clopidogrel.

In-stent stenosis is a feared complication of flow diversion treatment for cerebral aneurysms. We present 2 cases of patients treated with pipeline flow diversion for unruptured cerebral aneurysms. Initial perioperative dual antiplatelet therapy (DAPT) consisted of standard aspirin plus clopidogrel. At 6-month follow-up cerebral angiography, the patients were noted to have developed significant in-stent stenosis (63% and 53%). The patients were treated with cilostazol and clopidogrel for at least 6 months. Subsequent angiography at 1-year post-treatment showed significant improvement of the in-stent stenosis from 63% to 34% and 53% to 21%. The role of cilostazol as treatment of intracranial in-stent stenosis has not been previously described. Cilostazol's vasodilatory effect and suppression of vascular smooth muscle proliferation provides ideal benefits in this setting. Cilostazol plus clopidogrel may be a safe and effective alternative to standard DAPT for treatment of in-stent stenosis following flow diversion and warrants further consideration and investigation.

Direct Vertebral Artery Access for Coil Embolization of a Partially Thrombosed Mid-Basilar Trunk Aneurysm: Technical Limitations.

BACKGROUND AND IMPORTANCE: Partially thrombosed basilar aneurysms have a high morbidity from the rupture risk and mass effect prompting early treatment. Depending on the size and location, they pose a surgical challenge often requiring multiple endovascular treatment modalities. Here we present a partially thrombosed mid-basilar aneurysm successfully coil embolized with direct vertebral artery access and discuss the technical limitations of direct V1 access. CLINICAL PRESENTATION: A 70-yr-old woman presented with acute onset headache, nausea, and vomiting. A computed tomography (CT) head demonstrated a hyperdense prepontine mass which was further characterized as a partially thrombosed basilar aneurysm on CT angiography. After multiple failed attempts to access the vertebral artery via femoral and radial access the patient was taken to the operating room (OR) for surgical exposure of the right V1 segment and direct cannulation of the vertebral artery. The aneurysm was successfully coiled and the vertebral artery closed primarily. The patient was discharged home without any neurological deficits. CONCLUSION: Partially thrombosed mid-basilar aneurysms are difficult to treat both surgically and endovascularly. We present a case where endovascular access to the aneurysm was very challenging requiring direct exposure and cannulation of the V1 segment to successfully embolize with coils and discuss the technical limitations of this approach.

Fusion for subaxial bow hunter's syndrome results in remote osseous remodeling of the hyperostotic growth responsible for vertebral artery compression.

BACKGROUND: The authors present a previously unreported case of a patient with diffuse idiopathic skeletal hyperostosis (DISH) who developed bow hunter's syndrome (BHS) or positional vertebrobasilar insufficiency. In addition, the authors demonstrate angiographic evidence of remote osseous remodeling after segmental fusion without direct decompression of the offending bony growth. BHS is a rare, yet well established, cause of posterior circulation ischemia and ischemic stroke. Several etiologies such as segmental instability and spondylosis have been described as causes, however, DISH has not been associated with BHS before this publication. CASE DESCRIPTION: A 77-year-old man who presented with BHS was found to have cervical spine changes consistent with DISH, and angiography confirmed right vertebral artery (VA) stenosis at C4-5 from a large pathological elongation of the right C5 lateral mass. Head rotation resulted in occlusion of the VA. The patient underwent an anterior cervical discectomy and fusion and reported complete resolution of his symptoms. A delayed angiogram and CT of the cervical spine demonstrated complete resolution of the baseline stenosis, no dynamic compression, and remote osseous remodeling of the growth, respectively. CONCLUSION: This case represents the first publication in the literature of DISH as a causative etiology of BHS and of angiographic data demonstrating resolution of a compressive osseous pathology without direct decompression in BHS.

Neural Correlates of Vocal Auditory Feedback Processing: Unique Insights from Electrocorticography Recordings in a Human Cochlear Implant User.

There is considerable interest in understanding cortical processing and the function of top-down and bottom-up human neural circuits that control speech production. Research efforts to investigate these circuits are aided by analysis of spectro-temporal response characteristics of neural activity recorded by electrocorticography (ECoG). Further, cortical processing may be altered in the case of hearing-impaired cochlear implant (CI) users, as electric excitation of the auditory nerve creates a markedly different neural code for speech compared with that of the functionally intact hearing system. Studies of cortical activity in CI users typically record scalp potentials and are hampered by stimulus artifact contamination and by spatiotemporal filtering imposed by the skull. We present a unique case of a CI user who required direct recordings from the cortical surface using subdural electrodes implanted for epilepsy assessment. Using experimental conditions where the subject vocalized in the presence (CIs ON) or absence (CIs OFF) of auditory feedback, or listened to playback of self-vocalizations without production, we observed ECoG activity primarily in γ (32-70 Hz) and high γ (70-150 Hz) bands at focal regions on the lateral surface of the superior temporal gyrus (STG). High γ band responses differed in their amplitudes across conditions and cortical sites, possibly reflecting different rates of stimulus presentation and differing levels of neural adaptation. STG γ responses to playback and vocalization with auditory feedback were not different from responses to vocalization without feedback, indicating this activity reflects not only auditory, but also attentional, efference-copy, and sensorimotor processing during speech production.

Magnet-assist endoscopic augmentation of the lower esophageal sphincter for treatment of gastroesophageal reflux disease: cadaveric and survival studies in a porcine model (with video).

BACKGROUND: Augmentation of the lower esophageal sphincter (LES) is the primary goal of both surgical and endoscopic therapies for gastroesophageal reflux disease (GERD). The feasibility, efficacy, safety, and reversibility of a newly developed endotherapy for GERD using intraluminal magnets referred to as a magnet closure device (MCD) were evaluated. METHODS: This study involved nine cadaveric and six survival pigs. The MCD consisted of a ring neodymium magnet attached to a 2-0 polypropylene suture and suture anchor. The MCD was deployed onto the esophageal wall at the region of the LES using an endoscopic suturing device. Two to three MCDs were placed on opposing walls to induce closure of the esophageal lumen. LES pressures were measured using high-resolution manometry at the index procedure (baseline and immediately post-MCD placement) and at survival endoscopy. Endoscopic removal of the devices was performed followed by necropsy at week 2. RESULTS: MCDs were successfully deployed in all cadaveric (n = 22) and survival animals (n = 12). In cadavers, 20/22 (91%) sutures were full-thickness with no adjacent organ injury. In survival animals, mean LES pressure increased from 8.4 mmHg (baseline) to 32.4 mmHg immediately post-procedure (p < 0.01). No clinically significant adverse events occurred. Repeat endoscopy at two weeks showed intact MCDs in 4/6 (67%) animals with significant increase in median LES pressure (n = 4, 24.0 mmHg versus 7.4 mmHg [baseline], p < 0.05). Endoscopic removal of MCDs was successfully achieved. CONCLUSIONS: Endoscopic augmentation of the LES using a new MCD was feasible, safe and reversible with significantly increased LES pressures recorded. Future studies are needed to enhance durability. These preliminary results on a reversible technique are promising and may represent an attractive alternative to endoluminal GERD therapy.

Transpacific Aeromedical Evacuation for a Ruptured Brain Arteriovenous Malformation During the COVID-19 Pandemic.

The COVID-19 pandemic has altered preexisting patient treatment algorithms and referral patterns, which has affected neurosurgical care worldwide. Brain arteriovenous malformations are complex vascular lesions that frequently present with intracerebral hemorrhage. Care for these patients is best performed at large medical centers by specialists with high volumes. The authors describe the care of a patient who presented in extremis to a resource-limited, community-sized military treatment facility (MTF) in Southeast Asia. In the MTF, the patient underwent emergent neurosurgical therapy. However, given newly implemented restrictions enacted to mitigate COVID-19 spread, local transfer for definitive care to a tertiary care facility was not possible. In order to attain definitive care for the patient, a transpacific aeromedical evacuation augmented with a critical care air transport team was utilized for transfer to a tertiary care, teaching hospital. This case demonstrates the safe treatment of a patient with hemorrhagic arteriovenous malformations and postoperative management under limited conditions in an MTF outside the CONUS. Given the unique circumstances and challenges the pandemic presented, the authors feel that this patient's outcome was only possible by leveraging all the capability military medicine has to offer.

The Impact of the Deepwater Horizon Oil Spill upon Lung Health-Mouse Model-Based RNA-Seq Analyses.

We used a transcriptomic approach to interrogate the effects of a saline-accommodated fraction from the Macondo 252 well (MC252) oil and Corexit dispersants on lung tissue. Wild-type C57BL/6 male and female mice were exposed on days 0, 7 and 13 by oropharyngeal aspiration to saline accommodated fractions (SAF) of crude oil from the Macondo (MC252) well, Corexit 9500, Corexit 9527, 9500+oil and 9527+oil or a saline solution as the vehicle control. These treatments did not cause overt toxicity, with the exception of the Corexit exposures which caused brief weight loss after the first exposure. On day 14, total RNA was isolated from the left lung for RNA-seq analyses. KEGG-pathway-based differential expression revealed that Corexit 9527 elicited the strongest changes involving the upregulation of 19 KEGG pathways (FDR < 0.10), followed by Corexit 9500 with the upregulation of seven pathways (FDR < 0.10). As an important signature, pathways related to a response to DNA damage (e.g., p53 signaling and mismatch repair) dominate those upregulated by Corexit 9527 and Corexit 9500. In addition, pro-inflammatory pathways (e.g., cytokine-cytokine receptor interaction, IL-17 signaling pathway and TNF signaling pathways) were upregulated selectively in oil-treated male mice. Surprisingly, oil + dispersant combinations caused lesser effects than the individual treatments at the transcriptomic level. Overall, these findings support potential genotoxicity, inflammation and cell death due to dispersant or oil exposures. Similar exposures to lung tumor bearing K-RasLA1 mice provided evidence for tumor promotion by oil and Corexit dispersant treatments. Our mouse RNA-seq analyses may be relevant to the pulmonary health hazards of MC252 oil and dispersants experienced in exposed populations.

An Endovascular Surgery Experience in Far-Forward Military Healthcare-A Case Series.

INTRODUCTION: The advancement of interventional neuroradiology has drastically altered the treatment of stroke and trauma patients. These advancements in first-world hospitals, however, have rarely reached far forward military hospitals due to limitations in expertise and equipment. In an established role III military hospital though, these life-saving procedures can become an important tool in trauma care. MATERIALS AND METHODS: We report a retrospective series of far-forward endovascular cases performed by 2 deployed dual-trained neurosurgeons at the role III hospital in Kandahar, Afghanistan during 2013 and 2017 as part of Operations Resolute Support and Enduring Freedom. RESULTS: A total of 15 patients were identified with ages ranging from 5 to 42 years old. Cases included 13 diagnostic cerebral angiograms, 2 extremity angiograms and interventions, 1 aortogram and pelvic angiogram, 1 bilateral embolization of internal iliac arteries, 1 lingual artery embolization, 1 administration of intra-arterial thrombolytic, and 2 mechanical thrombectomies for acute ischemic stroke. There were no complications from the procedures. Both embolizations resulted in hemorrhage control, and 1 of 2 stroke interventions resulted in the improvement of the NIH stroke scale. CONCLUSIONS: Interventional neuroradiology can fill an important role in military far forward care as these providers can treat both traumatic and atraumatic cerebral and extracranial vascular injuries. In addition, knowledge and skill with vascular access and general interventional radiology principles can be used to aid in other lifesaving interventions. As interventional equipment becomes more available and portable, this relatively young specialty can alter the treatment for servicemen and women who are injured downrange.

Protocolization of Post-Transforaminal Lumbar Interbody Fusion Pain Control with Elimination of Benzodiazepines and Long-Acting Opioids.

BACKGROUND: The opioid epidemic continues to worsen with a concomitant increase in opioid-related mortality. In response, the Department of Defense and Veterans Health Agency recommended against the use of long-acting opioids (LAOs) and concurrent use of opioids with benzodiazepines. Subsequently, we eliminated benzodiazepines and LAOs from our postoperative pain control regimen. OBJECTIVE: To evaluate the impact of removing benzodiazepines and LAOs on postoperative pain in single-level transforaminal lumbar interbody fusion (TLIF) patients. METHODS: A retrospective cohort study of single-level TLIF patients from February 2016-March 2018 was performed. Postoperative pain control in the + benzodiazepine cohort included scheduled diazepam with or without LAOs. These medications were replaced with nonbenzodiazepine, opioid-sparing adjuncts in the -benzodiazepine cohort. Pain scores, length of hospitalization, trigger medication use, and opioid use and duration were compared. RESULTS: Among 77 patients, there was no difference between inpatient pain scores, but the -benzodiazepine cohort experienced a faster rate of morphine equivalent reduction (-18.7%, 95% CI [-1.22%, -36.10%]), used less trigger medications (-1.55, 95% CI [-0.43, -2.67]), and discharged earlier (0.6 d; 95% CI [0.01, 1.11 d]). As outpatients, the -benzodiazepine cohort was less likely to receive opioid refills at 2 wk (29.2% vs 55.8%, P = .021) and 6 mo postoperatively (0% vs 13.2%, P = .039), and was less likely to be using opioids by 3 mo postoperatively (13.3% vs 34.2%, P = .048). CONCLUSION: Replacement of benzodiazepines and LAOs in the pain control regimen for single-level TLIFs did not affect pain scores and was associated with decreased opioid use, a reduction in trigger medications, and shorter hospitalizations.

Dual Invasive Fungal Infection Presenting with Cervical Myelopathy.

Disseminated fungal infections are often seen in immunocompromised patients. Here we present a case of a previously healthy woman presenting with cervical myeloradiculopathy found to have two separate fungal infections in the setting of depressed CD4 cell counts and a genetic mutation predisposing to invasive fungal infections.

Aryl hydrocarbon receptor signaling, toxicity, and gene expression responses to mono-methylchrysenes.

Polycyclic aromatic hydrocarbons (PAHs) comprise a large family of toxic compounds that come from natural and anthropogenic sources. Chrysene is a PAH with multiple effects, but the toxic potentials of mono-methylchrysenes are less characterized. A comparison of chrysene and six mono-methylchrysenes was performed using assays for cytotoxicity, human aryl hydrocarbon receptor (AhR) reporter gene signaling, and AhR-regulated target gene and protein expression. Sulforhodamine B and trypan blue dye binding assays revealed these chrysenes to be similar in their cytotoxic effects on HepG2 cells. A yeast-based reporter assay detecting human AhR-mediated gene expression identified 4-methylchrysene as being six times more potent and 5-methylchrysene about one-third as potent as chrysene. Other methylchrysenes were more similar to chrysene in the ability to act as AhR ligands. The mono-methylchrysenes all strongly induced CYP1A1 mRNA and protein and moderately induced CYP1B1 expression in HepG2 cells. Levels of CYP1A2 mRNA were induced at higher concentrations of the chrysenes, but protein expression was not significantly altered. The PCR-based gene expression and immunoblotting analyses indicated induced expression differences across the chrysene members were similar to each other. Overall, the effects of methylated chrysenes were comparable to unsubstituted chrysene, suggesting members of this group may be considered approximately equivalent in their effects. © 2019 Wiley Periodicals, Inc.