Publications by authors named "Marcus A Zachariah"

Leptomeningeal disease occurs when cancer cells migrate into the ventricles of the brain and spinal cord and then colonize the meninges of the central nervous system. The triple-negative subtype of breast cancer often progresses toward leptomeningeal disease and has a poor prognosis because of limited treatment options. This is due, in part, to a lack of animal models with which to study leptomeningeal disease.

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  • * Various intraoperative imaging tools, like neuronavigation and ultrasound, can aid in surgery by providing real-time feedback, potentially improving the chances of complete tumor removal and reducing recurrences.
  • * This case report highlights a novel side-firing ultrasound probe as a cost-effective and efficient way to assist in the meticulous navigation required for safely resecting large clival chordomas using endoscopic techniques.
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Introduction: Multiple intraoperative navigation and imaging modalities are currently available as an adjunct to endoscopic transsphenoidal resection of pituitary adenomas, including intraoperative CT and MRI, fluorescence guidance, and neuronavigation. However, these imaging techniques have several limitations, including intraoperative tissue shift, lack of availability in some centers, and the increased cost and time associated with their use. The side-firing intraoperative ultrasound (IOUS) probe is a relatively new technology in endoscopic endonasal surgery that may help overcome these obstacles.

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Background: The features of long-term remission in acromegaly adenomectomy are incompletely understood. An intraoperative predictor for long-term outcome would be valuable for assessing resection of growth hormone (GH)-secreting tumors in real-time.

Objective: To evaluate whether intraoperative GH measurement could predict long-term outcomes for acromegaly.

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Background: Pituitary apoplexy (PA) is a rare, but life-threatening, condition characterized by pituitary infarction and hemorrhage, most often in the setting of a preexisting adenoma. The risk factors and mechanisms associated with PA are poorly understood. Although neurovascular manifestations of coronavirus disease 2019 (COVID-19) infection have been documented, its association with PA has not yet been determined.

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Objective: Aerosol-generating procedures, including endoscopic endonasal surgery (EES), are a major risk for physicians during the COVID-19 pandemic. Techniques for reducing aerosolization and risk of transmission of COVID-19 during these procedures would be valuable to the neurosurgical community. The authors aimed to simulate the generation of small-particle aerosols during EES and craniectomy in order to develop methods to reduce the spread of aerosolized particles, and to test the effectiveness of these methods.

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Background: Machine learning (ML)-based predictive models are increasingly common in neurosurgery, but typically require large databases of discrete variables for training. Natural language processing (NLP) can extract meaningful data from unstructured text.

Objective: To present an NLP model that predicts nonhome discharge and a point-of-care implementation.

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  • Breast cancer can spread to the brain, making it a serious problem, but scientists don’t fully understand how this happens.
  • Research shows that tumor cells taken from the blood of women with breast cancer behave differently when they grow in the brain compared to other areas.
  • A specific protein called HIF1A helps these cancer cells grow better in the brain, and stopping this protein could help treat brain tumors without affecting breast tumors as much.
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Background: Extradural anterior clinoidectomy (eAC) via the minipterional craniotomy (MPT) approach (MPT+eAC) has been recently introduced to the neurosurgical armamentarium to improve access to anterior and middle fossa skull base structures using a minimally invasive approach. However, the effect of extradural clinoidectomy on surgical exposure with the minipterional approach has not been evaluated. Moreover, the effect of eAC on surgical maneuverability has not been established for either traditional pterional or minipterional craniotomy.

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Monitoring patient response to treatment is challenging for most cancers, but it is particularly difficult in glioblastoma multiform, the most common and aggressive form of malignant brain tumor. These tumors exhibit a high degree of heterogeneity which may not be reflected in a biopsy. To determine if the current standard of care is effective, glioma patients are monitored using MRI or CT scans, an effective but sometimes misleading approach due to the phenomenon of pseudoprogression.

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T cell egress from the thymus is essential for adaptive immunity, yet the requirements for and sites of egress are incompletely understood. We have shown that transgenic expression of sphingosine-1-phosphate receptor-1 (S1P1) in immature thymocytes leads to their perivascular accumulation and premature release into circulation. Using an intravascular procedure to label emigrating cells, we found that mature thymocytes exit via blood vessels at the corticomedullary junction.

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Recent studies have begun to illuminate the mechanism of T-cell export from the thymus, with the identification of a required lysophospholipid receptor, two upstream transcription factors, and several downstream regulators of cytoskeleton dynamics. This work has generated immediate translational impact, aiding the design of immunosuppressant drugs and the identification of a novel form of human immunodeficiency.

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The splenic marginal zone is a site of blood flow, and the specialized B cell population that inhabits this compartment has been linked to the capture and follicular delivery of blood-borne antigens. However, the mechanism of this antigen transport has remained unknown. Here we show that marginal zone B cells were not confined to the marginal zone but continuously shuttled between the marginal zone and follicular areas, such that many of the cells visited a follicle every few hours.

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  • A total of 2,225 homes were surveyed in Nicaragua's two largest cities, with larvae identified in just 4 houses in León.
  • Following increased control efforts, the mosquito was reportedly eliminated from León, emphasizing the importance of ongoing surveillance in areas believed to be free of this mosquito species to prevent its resurgence.
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Sequence alignment underpins common tasks in molecular biology, including genome annotation, molecular phylogenetics, and homology modeling. Fundamental to sequence alignment is the placement of gaps, which represent character insertions or deletions. We assessed the ability of a generalized affine gap cost model to reliably detect remote protein homology and to produce high-quality alignments.

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