Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin-GnRH-III conjugates developed for targeted drug delivery

Gonadotropin releasing hormone-III (GnRH-III), a native isoform of the human GnRH isolated from sea lamprey, specifically binds to GnRH receptors on cancer cells enabling its application as targeting moieties for anticancer drugs. Recently, we reported on the identification of a novel daunorubicin–GnRH-III conjugate (GnRH-III–[4Lys(Bu), 8Lys(Dau=Aoa)] with efficient in vitro and in vivo antitumor activity. To get a deeper insight into the mechanism of action of our lead compound, the cellular uptake was followed by confocal laser scanning microscopy. Hereby, the drug daunorubicin could be visualized in different subcellular compartments by following the localization of the drug in a time-dependent manner. Colocalization studies were carried out to prove the presence of the drug in lysosomes (early stage) and on its site of action (nuclei after 10 min). Additional flow cytometry studies demonstrated that the cellular uptake of the bioconjugate was inhibited in the presence of the competitive ligand triptorelin indicating a receptor-mediated pathway. For comparative purpose, six novel daunorubicin–GnRH-III bioconjugates have been synthesized and biochemically characterized in which 6Asp was replaced by D-Asp, D-Glu and D-Trp. In addition to the analysis of the in vitro cytostatic effect and cellular uptake, receptor binding studies with 125I-triptorelin as radiotracer and degradation of the GnRH-III conjugates in the presence of rat liver lysosomal homogenate have been performed. All derivatives showed high binding affinities to GnRH receptors and displayed in vitro cytostatic effects on HT-29 and MCF-7 cancer cells with IC50 values in a low micromolar range. Moreover, we found that the release of the active drug metabolite and the cellular uptake of the bioconjugates were strongly affected by the amino acid exchange which in turn had an impact on the antitumor activity of the bioconjugates

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

BACKGROUND: During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study\u27s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. METHODS: We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March-31 May 2020. The prior 1-year control period (1 March-31 May 2019) was obtained to account for seasonal variation. FINDINGS: There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI -24.3% to -20.7%, p\u3c0.0001). Embolisation of ruptured aneurysms declined with 1170-1035 procedures, respectively, representing an 11.5% (95%CI -13.5% to -9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI -28.0% to -22.1%, p\u3c0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile. INTERPRETATION: There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Development of mechanoreceptors.

The important morphogenetic and trophic interactions between axon terminals and their associated cells are widely studied. The first experiments examining this relationship were done by denervation studies in different types of mechanoreceptors. Not much was known about the precise nature of the factors, which may be involved in these interactions. The discovery of the nerve growth factor (NGF) made a breakthrough and the new expansion of this field of research started to focuse on bioactive agents and neurotrophic factors. The role of some of these new factors in the developing mechanoreceptors is described in this thesis. It focuses on the control factors of the cutaneous mechanoreceptors and proprioceptors development. It describes results of our studies of the Merkel cells developmental origin, the role of neurotrophins in their differentiation and maintenance, as well as our results concerning the role of ingrowing axons and the target tissue in the periphery on the number and structure of Herbst corpuscles and muscle spindles. In addition, the role of neurotrophins in Pacinian corpuscles and the role of transcription factors in the development of muscle spindles and Golgi tendon organs are described.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Reconstruction of carotid stenosis hemodynamics based on guidewire pressure data and computational modeling.

A comparative analysis between intravascular guidewire-obtained and computational fluid dynamic (CFD) flow velocity and pressure data using simplified carotid stenosis models was performed. This information was used to evaluate the viability of using guidewire pressure data to provide inlet conditions for CFD flow, and to study the relationship between stenotic length and hemodynamic behavior. Carotid stenosis models differing in diameter and length were prepared and connected to a vascular pulsatile flow simulator. Time-dependent flow velocity and pressure measurements were taken by microcatheter guidewires and compared with CFD data. Guidewire and CFD-generated pressure profiles matched closely in all measurement locations. The guidewire was unable to reliably measure flow velocity at areas associated with higher CFD flow velocities (r = 0.92). CFD results showed that an increased length of stenosis generated expansive regions of elevated wall shear stress (WSS) within and distal to the stenosis. Low WSS was found immediately outside the stenosis outlet. An increase in stenotic length produced higher flow velocities with minimal lengthening of the distal high velocity flow jet due to faster dissipation of translational kinetic energy through turbulence. We found the accuracy of guidewire-obtained velocity measurements is limited to regions unaffected by disturbed flow. WSS and turbulence behavior distal to the stenosis may be important markers to evaluate the severity of atherosclerotic progression as a function of stenotic length

Abstract 214: Predictors of Mechanical Thrombectomy Success and Failure: A Preliminary Analysis

Introduction Mechanical thrombectomy (MT) is now the standard of care in treatment of large vessel occlusion (LVO) in acute ischemic stroke (AIS). However, a significant minority of patients do not achieve successful recanalization. Previous case series’ have reported failed recanalization at a rate of approximately 12% (1). In the present study, we investigated clinical and procedural characteristics predictive of MT success and failure. Methods We conducted a retrospective analysis of MT patients with LVO presenting to our academic comprehensive stroke center from 2015‐2020. Recanalization failure was defined as TICI 0‐2a and success as TICI 2b‐3. We compared all 49 consecutive failure cases to a random selection of 85 successful MT cases. Demographic, clinical, procedural, and outcome data were compared between the two groups. Results In this cohort, there was no statistically significant difference in sex, pre‐stroke modified Rankin score (mRS), admission National Institutes of Health Stroke Scale (NIHSS), door‐to‐groin time, thrombolytic use, or site of occlusion between the two groups. In the success group, patients were older (76 vs 61, p=0.003), and had a higher average number of atherosclerotic risk factors (p=0.002). There was a higher proportion of embolic stroke of undetermined source (ESUS) in the success group compared with the failure group (8.5% vs 0%, p=0.039). A higher proportion of failure cases were due to large artery atherosclerosis (30.6% vs 19.5%, p=0.12) and cardioembolism (55.1% vs 67.1%, p=0.27), though neither of these differences were statistically significant. Stent‐retrieval alone (SR) was a more common first pass technique in failed than in successful MT (14.3% vs 0%, p=0.001). Conclusion This study investigated clinical and procedural factors associated with successful and failed recanalization in MT. In this cohort, stent‐retrieval alone as a first pass technique was more commonly associated with failed MT. Stroke etiology was associated with rates of failure, with a significantly higher proportion of ESUS in successful cases and a trend toward a higher proportion of large vessel atherosclerosis and cardioembolism in failed MT

Endovascular Approaches to the Cavernous Sinus in the Setting of Dural Arteriovenous Fistula

Dural arteriovenous fistulas involving the cavernous sinus can lead to orbital pain, vision loss and, in the setting of associated cortical venous reflux, intracranial hemorrhage. The treatment of dural arteriovenous fistulas has primarily become the role of the endovascular surgeon. The venous anatomy surrounding the cavernous sinus and venous sinus thrombosis that is often associated with these fistulas contributes to the complexity of these interventions. The current report gives a detailed description of the alternate endovascular routes to the cavernous sinus based on a single center's experience as well as a literature review supporting each approach. A comprehensive understanding of the anatomy and approaches to the cavernous sinus available to the endovascular surgeon is vital to the successful treatment of this condition

A convenient synthetic method to improve immunogenicity of mycobacterium tuberculosis related T-cell epitope peptides

Epitopes from different proteins expressed by Mycobacterium tuberculosis (Rv1886c, Rv0341, Rv3873) were selected based on previously reported antigenic properties. Relatively short linear T-cell epitope peptides generally have unordered structure, limited immunogenicity, and low in vivo stability. Therefore, they rely on proper formulation and on the addition of adjuvants. Here we report a convenient synthetic route to induce a more potent immune response by the formation of a trivalent conjugate in spatial arrangement. Chemical and structural characterization of the vaccine conjugates was followed by the study of cellular uptake and localization. Immune response was assayed by the measurement of splenocyte proliferation and cytokine production, while vaccine e�cacy was studied in a murine model of tuberculosis. The conjugate showed higher tendency to fold and increased internalization rate into professional antigen presenting cells compared to free epitopes. Cellular uptake was further improved by the incorporation of a palmitoyl group to the conjugate and the resulted pal-A(P)I derivative possessed an internalization rate 10 times higher than the free epitope peptides. Vaccination of CB6F1 mice with free peptides resulted in low T-cell response. In contrast, significantly higher T-cell proliferation with prominent expression of IFN- , IL-2, and IL-10 cytokines was measured for the palmitoylated conjugate. Furthermore, the pal-A(P)I conjugate showed relevant vaccine e�cacy against Mycobacterium tuberculosis infection

Abstract 1122‐000243: Capacity and Characteristics of Thrombectomy Centers World‐wide Using the MT2020+ Global Thrombectomy Tracking Smartphone App

Introduction : Mechanical thrombectomy (MT) has been established as a first line therapy for large vessel occlusion stroke; however, MT remains underutilized globally with massive disparity in access based on country income level. Mission Thrombectomy 2020+ (MT2020+) is a global alliance and campaign that aims to reduce this disparity and democratize MT access for patients. A novel smartphone application, Global Thrombectomy Tracking App, was designed to characterize thrombectomy centers on a global‐level and numerically track MT cases in near real‐time. Methods : The MT2020 App was launched in November 2019. To gain insight into local systems of care, neurointerventionalists were prompted to participate in an optional 11‐question survey over a 19‐month period. Questions pertained to population density, organizational structure, academic affiliation, available imaging modalities, tPA usage, and case volumes. Results : Of 338 active users from 9 countries, 49‐neurointerventionalists participated in the survey. The majority (71.5%) practiced in large metropolis with population >1‐million, of which 16.3% were in mega‐cities (>10‐million). The centers were government funded (46.9%), private (40.8%) or charitable (12.2%). Most were academic hospitals (81.6%) with neurointerventional trainees (55.1%). At most centers (87.7%), IV‐tPA was available with annual treatment rate >5% for 55.1%. Most centers (57.1%) utilize additional CT perfusion scans prior to MT. For 69.3% respondents, the annual MT case volume was between 10–100 cases. Conclusions : Our survey analysis shows that the global MT tracking APP can generate important thrombectomy capacity and characteristics at regional levels on a global scale, which can be used for targeted funding and resource allocation to accelerate access to MT

Abstract Number ‐ 110: Case Report of Glue Embolism Complication after Lingual Artery Embolization and Rescue Thrombectomy

Introduction 68‐year‐old right‐handed female with right tongue‐base squamous cell carcinoma status‐post wide surgical‐excision and flap reconstruction, whopresented with large volume right‐sided orolingual hemorrhage. Due to concerns of impending airway compromise and a history of difficult intubation, Interventional Neuroradiology was consulted to perform an angiogram and embolization. Methods A 6FrEnvoy was advanced into the external carotid artery and the origin of the lingual artery. Despite repeated attempts using a variety of microsystems, distal access within the lingual artery could not be achieved (Fig. 1B). N‐butyl‐2‐cyanoacrylate was prepared and injected with adequate penetration. Negative pressure was applied to the microcatheter and withdrawn. The guide catheter was aspirated and rapidly withdrawn under negative pressure. A control angiogram was being prepared when an intracranial glue cast was seen and confirmed to be a proximal M2‐occlusion. 4000U of Heparin werebolusedat this time. An Advantage Exchange wire facilitated an exchange for an 8Fr groin sheath and a Walrus catheter. The glue was crossed with a microsystem microsystem and a Solitaire‐4×40mm was deployed. A ZOOM55 was advanced to the face of the glue caste and together these were pulled into the Walrus catheter. Serial angiograms revealed stenosis, but patency. Results Initial post‐thrombectomy exam revealed mild left‐hand paresis. However, the patient’s neurologic status declined and progressed to left arm hemiparesis, facial droop, and right gaze‐preference. An angiogram was performed, which revealed re‐occlusion of the left M2 trunk. Using aTrevo‐3×32mmstentriever, the M2‐occlusion was recanalized with persistent stenosis. Serial angiograms were concerning for progressing re‐occlusion. The patient improved with residual distal left hemiparesis. Conclusions •Distal access may be extremely difficult in select cases. The proximal location of the microcatheter relative to the origin of the lingual artery and the external carotid artery off the common carotid artery, likely contributed to the embolic event. The use of progressively smaller microcatheters to facilitate distal access in turn biased the choice of embolization materials. Lastly, there was evidence of vasospasm in the lingual artery, which may have contributed to proximal polymerization and adherence to the catheters during their removal. •After successful retrieval of the glue material, there was residual stenosis of unclear etiology, possibly due to denuded endothelium, dissection, or residual glue promoting in‐situ thrombosis. The eventual clearing of thebolusedheparin may have contributed to the delayed re‐occlusion. Recanalization after re‐occlusion was only possible after thrombectomy. •The use of an intermediate catheter may mitigate the risk of glue embolization by facilitating distal access and/or by providing an additional conduit for aspirating refluxed glue. If distal access into a culprit vessel can not be achieved, coil embolization may be a safer choice. Re‐canalized glue embolisms may be prone to re‐occlusion. Continuing a heparin drip may be prudent practice to prevent re‐occlusion

Abstract 081: Clinical Presentation and Treatment of 26 Spinal Epidural Arteriovenous Fistulas: A Single Center Experience

Introduction Spinal epidural arteriovenous fistulas (SEAVFs) are rarely diagnosed vascular malformations that can cause spinal cord compression and congestive myelopathy. Methods This is a single center, retrospective case series of patients with SEAVF who underwent observation or treatment at UCLA medical center from 1993 to 2023. Results A total of 26 patients were found to have a SEAVF at UCLA from 1993 to 2023. The median age at treatment was 59 years (range 4 months to 91 years). 16 of 26 patients (55.2%) were male. 12 were located in the cervical spine, 2 in the thoracic spine, 11 in the lumbar spine, and 1 in the sacral spine. Sacral, lumbar, and thoracic SEAVFs demonstrated a strong male predominance (12 of 14, 85.7%), while cervical SEAVFs were more common in women (8 of 12, 66.7%). The median duration of symptoms prior to treatment was 6.5 months (range 1 day to 8 years). Possible triggers included prior spinal surgery (n=3), turning neck (n=1), trauma to the neck (n=1), lifting a heavy box (n=1), prolonged period of bending over (n=1). The remaining patients did not have any particular trigger. All patients with lumbar and thoracic SEAVFs (except the 3‐month‐old) demonstrated flow voids and cord edema. Patients with cervical SEAVF did not demonstrate cord edema and only 5 of 12 explicitly mentioned flow voids. 22 patients were treated strictly endovascularly, 1 patient endovascularly and then surgically, 1 patient surgically, and 2 patients refused treatment. No patients treated endovascularly experienced complications. 19 of 23 patients (82.6%) treated endovascularly received complete cure after the first treatment. 1 patient had a successful subsequent embolization 2 days later. Of the 3 other incomplete treatments, one patient received subsequent successful surgery, one patient was a 3‐month‐old patient with Parkes‐Weber syndrome who subsequently died of other medical issues, and one was lost to follow‐up. One patient underwent surgical treatment alone due to the feeding arteries being too small to catheterize and unfortunately experienced a failed surgery on the first attempt and developed a surgical site infection after the second successful attempt at treatment. Onyx was used in 10 cases (9 of 10 successful). 2 cases treated with NBCA were unsuccessful. Cervical and Sacral SEAVFs were treated successfully (mostly prior to 2006) with coils and/or detachable balloons. Conclusion SEAVF is a rare disease that can be treated effectively and safely with endovascular embolization in most cases. Pre‐operative MRI demonstrated abnormalities in all cases. We found a strong male predominance in our cohort