Conquering Mount Fuji: Resolution of Tension Pneumocephalus with a Foley Urinary Catheter

Tension pneumocephalus is the presence of air or gas in the cranium that is under pressure. It occurs due to disruption of the skull, including trauma to the head or face, after neurosurgical procedures and occasionally, spontaneously (Schirmer et al., 2010). Patients typically present with headache but can also have neurological deficits such as decreased mental status, numbness, and weakness (Schirmer et al., 2010). It is diagnosed by computerized tomography (CT) scan (Michel, 2010). The characteristic finding is that the two frontal poles of the brain are separated by air. After diagnosis, treatment is imperative for both symptomatic relief and preventing further compression. We present a case of a patient who presented with tension pneumocephalus and unconventional treatment that resulted in clinical improvement of his symptoms and radiographic resolution of his condition

Locked nucleic acids: Promising nucleic acid analogs for therapeutic applications

Locked Nucleic Acid (LNA) is a unique nucleic-acid modification possessing very high binding affinity and excellent specificity toward complementary RNA or DNA oligonucleotides. The remarkable properties exhibited by LNA oligonucleotides have been employed in different nucleic acid-based therapeutic strategies both in vitro and in vivo. Herein, we highlight the applications of LNA nucleotides for controlling gene expression

Developing Antidote Controlled Antiplatelet Therapies By Targeting The Vwf ‐ Gp Ib‐Ix‐V Interaction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106054/1/jth02400.pd

Antidote-Controlled Platelet Inhibition Targeting von Willebrand Factor with Aptamers

Thrombus formation is initiated by platelets and leads to cardiovascular, cerebrovascular, and peripheral vascular disease, the leading causes of morbidity and mortality in the Western world. A number of antiplatelet drugs have improved clinical outcomes for thrombosis patients. However, their expanded use, especially in surgery, is limited by hemorrhage. Here, we describe an antiplatelet agent that can have its activity controlled by a matched antidote. We demonstrate that an RNA aptamer targeting von Willebrand factor (VWF) can potently inhibit VWF-mediated platelet adhesion and aggregation. By targeting this important adhesion step, we show that the aptamer molecule can inhibit platelet aggregation in PFA-100 and ristocetin-induced platelet aggregation assays. Furthermore, we show that a rationally designed antidote molecule can reverse the effects of the aptamer molecule, restoring platelet function quickly and effectively over a clinically relevant period. This aptamer-antidote pair represents a reversible antiplatelet agent inhibiting a platelet specific pathway. Furthermore, it is an important step towards creating safer drugs in clinics through the utilization of an antidote molecule.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63204/1/oli.2007.0089.pd

Fourth Ventricular Schwannoma: Identical Clinicopathologic Features as Schwann Cell-Derived Schwannoma with Unique Etiopathologic Origins

Background. To our knowledge, this is the sixth reported case in the literature of fourth ventricular schwannoma. The etiology and natural history of intraventricular schwannomas is not well understood. A thorough review of potential etiopathogenic mechanisms is provided in this case report. Case Description. A 69-year-old man presented with an incidentally found fourth ventricular tumor during an evaluation for generalized weakness, gait instability, and memory disturbance. Magnetic resonance imaging (MRI) revealed a heterogeneously enhancing lesion in the fourth ventricle. A suboccipital craniotomy was performed to resect the lesion. Histopathological examination confirmed the diagnosis of schwannoma (WHO grade I). Conclusions. Schwannomas should be considered in the differential diagnosis of intraventricular tumors. Although the embryologic origins may be different from nerve sheath-derived schwannomas, the histologic, clinical, and natural history appear identical and thus should be managed similarly

Dose-dependent von Willebrand Factor inhibition by aptamer BB-031 correlates with thrombolysis in a microfluidic model of arterial occlusion

Von Willebrand Factor (VWF) plays a critical role in thrombus formation, stabilization, and propagation. Previous studies have demonstrated that targeted inhibition of VWF induces thrombolysis when administered in vivo in animal models of ischemic stroke. The study objective was to quantify dose-dependent inhibition of VWF-platelet function and its relationship with thrombolysis using BB-031, an aptamer that binds VWF and inhibits its function. VWF:Ac, VWF:RCo, T-TAS, and ristocetin-induced impedance aggregometry were used to assess BB-031-mediated inhibition of VWF. Reductions in original thrombus surface area and new deposition during administration of treatment were measured in a microfluidic model of arterial thrombolysis. Rotational thromboelastometry was used to assess changes in hemostasis. BB-031 induced maximal inhibition at the highest dose (3384 nM) in VWF:Ac, and demonstrated dose-dependent responses in all other assays. BB-031, but not vehicle, induced recanalization in the microfluidic model. Maximal lytic efficacy in the microfluidic model was seen at 1692 nM and not 3384 nM BB-031 when assessed by surface area. Minor changes in ROTEM parameters were seen at 3384 nM BB-031. Targeted VWF inhibition by BB-031 results in clinically measurable impairment of VWF function, and specifically VWF-GPIb function as measured by VWF:Ac. BB-031 also induced thrombolysis as measured in a microfluidic model of occlusion and reperfusion. Moderate correlation between inhibition and lysis was observed. Additional studies are required to further examine off-target effects of BB-031 at high doses, however, these are expected to be above the range of clinical targeted dosing

CELL-SELEX: Novel Perspectives of Aptamer-Based Therapeutics

Aptamers, single stranded DNA or RNA molecules, generated by a method called SELEX (systematic evolution of ligands by exponential enrichment) have been widely used in various biomedical applications. The newly developed Cell-SELEX (cell based-SELEX) targeting whole living cells has raised great expectations for cancer biology, -therapy and regenerative medicine. Combining nanobiotechnology with aptamers, this technology opens the way to more sophisticated applications in molecular diagnosis. This paper gives a review of recent developments in SELEX technologies and new applications of aptamers

A Reusable Impedimetric Aptasensor for Detection of Thrombin Employing a Graphite-Epoxy Composite Electrode

Here, we report the application of a label-free electrochemical aptasensor based on a graphite-epoxy composite electrode for the detection of thrombin; in this work, aptamers were immobilized onto the electrodes surface using wet physical adsorption. The detection principle is based on the changes of the interfacial properties of the electrode; these were probed in the presence of the reversible redox couple [Fe(CN)6]3−/[Fe(CN)6]4− using impedance measurements. The electrode surface was partially blocked due to formation of aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by Electrochemical Impedance Spectroscopy (EIS). The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles. The interference response caused by main proteins in serum has been characterized

ROTEM and von Willebrand Factor in COVID Patients Presenting with Acute Ischemic Stroke: A Case Series

OBJECTIVES: SARS-CoV-2 (COVID) induces systemic thrombotic complications including acute ischemic stroke. In this case series, we report markers of inflammation, coagulation factors including von Willebrand factor antigen, and rotational thromboelastometry (ROTEM) data. MATERIALS AND METHODS: Retrospective case series of COVID patients seen at a single comprehensive stroke center between 2020 - 2022. For patients undergoing mechanical thrombectomy (MT), ROTEM data was collected during the procedure and analyzed on ROTEM delta system. RESULTS: Fifteen patients (33.3% female) median age 65-years-old presented with COVID and acute ischemic stroke. Thirteen had LVO. The mean NIHSS was 15 (range 0 - 35) on admission and 18 (0 - 42) at discharge. Most were cryptogenic (N=7, 46.7%), followed by cardioembolic (N=6, 40%) and large artery-to-artery embolization (N=2, 13.3%). mRS was < 3 in 8 (53%) patients at discharge. None of the patients were on anticoagulation, and five were on antiplatelet therapy pre-hospitalization. Seven received thrombolytics with alteplase (tPA), and 10 had MT. Baseline platelet count was 102 K/uL (range 102 - 291 K/uL). vWF was measured in 12 patients, all elevated, with seven having levels >400 (180%). ROTEM data was collected in six patients. Three who received tPA had abnormal EXTEM and FIBTEM data (CT extem > 85secs, A10 EXTEM < 45mm, and A10 FIBTEM < 10mm). Notably, INTEM (CT INTEM >208secs) was abnormal in five of the six patients, two of whom did not receive tPA. CONCLUSIONS: Elevated vWF antigen levels with abnormal ROTEM data suggests that COVID induces changes in the clotting cascade. More robust research is needed to investigate these findings. Thrombolytics, MT, and antiplatelet agents should be utilized to treat COVID-related ischemic stroke based on current clinical guidelines

Cancer-selective antiproliferative activity is a general property of some G-rich oligodeoxynucleotides

Oligodeoxynucleotide libraries containing randomly incorporated bases are used to generate DNA aptamers by systematic evolution of ligands by exponential enrichment (SELEX). We predicted that combinatorial libraries with alternative base compositions might have innate properties different from the standard library containing equimolar A + C + G + T bases. In particular, we hypothesized that G-rich libraries would contain a higher proportion of quadruplex-forming sequences, which may impart desirable qualities, such as increased nuclease resistance and enhanced cellular uptake. Here, we report on 11 synthetic oligodeoxynucleotide libraries of various base combinations and lengths, with regard to their circular dichroism, stability in serum-containing medium, cellular uptake, protein binding and antiproliferative activity. Unexpectedly, we found that some G-rich libraries (composed of G + T or G + C nucleotides) strongly inhibited cancer cell growth while sparing non-malignant cells. These libraries had spectral features consistent with G-quadruplex formation, were significantly more stable in serum than inactive libraries and showed enhanced cellular uptake. Active libraries generally had strong protein binding, while the pattern of protein binding suggested that G/T and G/C libraries have distinct mechanisms of action. In conclusion, cancer-selective antiproliferative activity may be a general feature of certain G-rich oligodeoxynucleotides and is associated with quadruplex formation, nuclease resistance, efficient cellular uptake and protein binding