Tracking Fibrinolysis of Chandler Loop-Formed Whole Blood Clots Under Shear Flow in An In-Vitro Thrombolysis Model.

Thromboembolism and related complications are a leading cause of morbidity and mortality worldwide and various assays have been developed to test thrombolytic drug efficiency both in vitro and in vivo. There is increasing demand for more physiologically relevant in-vitro clot models for drug development due to the complexity and cost associated with animal models in addition to their often lack of translatability to human physiology. Flow, pressure, and shear rate are important characteristics of the circulatory system, with clots that are formed under flow displaying different morphology and digestion characteristics than statically formed clots. These factors are often unrepresented in conventional in-vitro clot digestion assays, which can have pharmacological implications that impact drug translational success rates. The Real-Time Fluorometric Flowing Fibrinolysis (RT-FluFF) assay was developed as a high-fidelity thrombolysis testing platform that uses fluorescently tagged clots formed under shear flow, which are then digested using circulating plasma in the presence or absence of fibrinolytic pharmaceutical agents. Modifying the flow rates of both clot formation and clot digestion steps allows the system to imitate arterial, pulmonary, and venous conditions across highly diverse experimental setups. Measurements can be taken continuously using an in-line fluorometer or by taking discrete time points, as well as a conventional end point clot mass measurement. The RT-FluFF assay is a flexible system that allows for the real-time tracking of clot digestion under flow conditions that more accurately represent in-vivo physiological conditions while retaining the control and reproducibility of an in-vitro testing system.

Lowering Cranioplasty Infection Incidence with Novel Bone Flap Storage Protocol: A Retrospective Cohort Study.

BACKGROUND: After craniectomy, autologous bone flaps may be stored using wet or dry cryopreservation. After brain edema subsides, they are replaced during an operation termed cranioplasty. Cranioplasty is associated with 15% infection incidence. METHODS: We conducted a retrospective comparison of infection outcomes between wet and dry cryopreservation of cranioplasty bone flaps. Historically, bone flaps were stored utilizing wet cryopreservation-bone flap storage in 1 L of lactated Ringer's solution containing 80 mg gentamicin and 2 g nafcillin in a sterile plastic container secured in an unsterile plastic bag. Our newer dry cryopreservation protocol involved storage in gauze soaked in 80 mg gentamicin and 2 g nafcillin within a 3-layer sterile bag system. RESULTS: A total of 119 autologous bone flaps were included, with median follow-up of 3.9 months from cranioplasty. Overall, 10.9% became infected, requiring subsequent surgery; 18.4% of 49 bone flaps stored using wet cryopreservation became infected compared with only 5.7% of 70 dry cryopreservation bone flaps (P = 0.038; relative risk [RR] 0.311; absolute risk reduction 12.7%). Tobacco use (P = 0.076; RR 3.17) was not associated with increased infection risk. Infection incidence was similar for traumatic craniectomy indications compared to the other indications (12.0% trauma vs. 10.1% other; P = 0.750). On average, infected cranioplasty patients spent 8.5 more days hospitalized and faced increased risk of additional complications. CONCLUSIONS: Dry cryopreservation significantly decreases infection after cranioplasty when compared with wet cryopreservation, and this mitigates additional morbidity, mortality, and costs attributable to cranioplasty infection. Other nonmodifiable risk factors for cranioplasty infection were identified.

Does the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program bariatric risk/benefit calculator hold its weight? An assessment of its accuracy.

BACKGROUND: Bariatric clinical calculators have already been implemented in clinical practice to provide objective predictions of complications and outcomes. The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Surgical Risk/Benefit Calculator is the most comprehensive risk calculator in bariatric surgery. OBJECTIVES: Evaluate the accuracy of the calculator predictions regarding the 30-day complication risk, 1-year weight loss outcomes, and comorbidity resolution. SETTING: MBSAQIP-accredited center. METHODS: All adult patients who underwent primary laparoscopic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy at our institution between 2012 and 2019 were included. Baseline characteristics were used to generate the individualized outcome predictions for each patient through the bariatric risk calculator and were compared to actual patient outcomes. Statistical analysis was performed using c-statistics, linear regression models, and McNemmar chi-square test. RESULTS: One thousand four hundred fifty-three patients with a median age of 45 (37, 55) and consisting of 80.1% females were included in the study. The c-statistics for the complications and comorbidity resolution ranged from .533 for obstructive sleep apnea remission to .675 for 30-day reoperation. The number of comorbidity resolutions predicted by the calculator was significantly higher than the actual remissions for diabetes, hyperlipidemia, hypertension and obstructive sleep apnea (P < .001). On average, the calculator body mass index (BMI) predictions deviated from the observed BMI measurement by 3.24 kg/m2. The RYGB procedure (Coef -.89; P = .005) and preoperative BMI (Coef -.4; P = .012) were risk factors associated with larger absolute difference between the predicted and observed BMI. CONCLUSIONS: The MBSAQIP Surgical Risk/Benefit Calculator prediction models for 1-year BMI, 30-day reoperation, and reintervention risks were fairly well calibrated with an acceptable level of discrimination except for obstructive sleep apnea remission. The 1-year BMI estimations were less accurate for RYGB patients and cases with very high or low preoperative BMI measurements. Therefore, the bariatric risk calculator constitutes a helpful tool that has a place in preoperative counseling.

Subarachnoid haemorrhage associated with pituitary apoplexy and radiographically occult supraclinoid internal carotid artery aneurysms.

In patients with pituitary adenomas, incidental intracranial aneurysms have been documented. Previous studies have highlighted the importance of preoperative imaging in these patients. However, imaging may be limited and fail to show the presence of vascular abnormalities. In this report, we discuss a case of a man in his 30s presenting with a newly diagnosed pituitary adenoma. CT and MRI, on admission, showed a pituitary mass with extension into the right cavernous sinus. After a sudden neurological deterioration, emergent CT/CT angiography revealed pituitary apoplexy with subarachnoid extension without vascular abnormalities. Successful emergency transsphenoidal hypophysectomy was followed by digital subtraction angiography which revealed the presence of two right supraclinoid internal carotid artery aneurysms. With this case, we aim to highlight the need for further vascular imaging in patients with pituitary apoplexy and subarachnoid haemorrhage, as preoperative imaging may be negative for vascular abnormalities especially in the setting of cavernous sinus invasion.

Exploring microplastic impact on whole blood clotting dynamics utilizing thromboelastography.

This study investigates the influence of microplastics on blood clotting. It addresses the lack of comprehensive research on the effects of microplastic size and surface modification on clotting dynamics in human whole blood. Thromboelastography was used to examine aminated (aPS), carboxylated (cPS), and non-functionalized (nPS) polystyrene particles with sizes of 50, 100, and 500 nm. Results show that cPS consistently activated the clotting cascade, demonstrating increased fibrin polymerization rates, and enhanced clot strength in a size and concentration-dependent manner. nPS had minimal effects on clotting dynamics except for 50 nm particles at the lowest concentration. The clotting effects of aPS (100 nm particles) resembled those of cPS but were diminished in the 500 nm aPS group. These findings emphasize the importance of microplastic surface modification, size, concentration, and surface area on in-vitro whole blood clotting dynamics.

Effect of Chandler loop shear and tubing size on thrombus architecture.

Thrombosis can lead to a wide variety of life-threatening circumstances. As current thrombolytic drug screening models often poorly predict drug profiles, leading to failure of thrombolytic therapy or clinical translation, more representative clot substrates are necessary for drug evaluation. Utilizing a Chandler loop device to form clot analogs at high shear has gained popularity in stroke societies. However, shear-dependent clot microstructure has not been fully addressed and low shear conditions are often overlooked. We herein characterized the impact of wall shear rate (126 to 951 s-1) on clot properties in the Chandler loop. Different revolutions (20-60) per minute and tubing sizes (3.2 to 7.9 mm) were employed to create different sized clots to mimic various thrombosis applications. Increased shear resulted in decreased RBC counts (76.9 ± 4.3% to 17.6 ± 0.9%) and increased fibrin (10 to 60%) based on clot histology. Increased fibrin sheet morphology and platelet aggregates were observed at higher shear under scanning electron microscope. These results show the significant impact of shear and tubing size on resulting clot properties and demonstrate the capability of forming a variety of reproducible in-vivo-like clot analogs in the Chandler loop device controlling for simple parameters to tune clot characteristics.

Real-time tracking of fibrinolysis under constant wall shear and various pulsatile flows in an in-vitro thrombolysis model.

A great need exists for the development of a more representative in-vitro model to efficiently screen novel thrombolytic therapies. We herein report the design, validation, and characterization of a highly reproducible, physiological scale, flowing clot lysis platform with real-time fibrinolysis monitoring to screen thrombolytic drugs utilizing a fluorescein isothiocyanate (FITC)-labeled clot analog. Using this Real-Time Fluorometric Flowing Fibrinolysis assay (RT-FluFF assay), a tPa-dependent degree of thrombolysis was observed both via clot mass loss as well as fluorometrically monitored release of FITC-labeled fibrin degradation products. Percent clot mass loss ranged from 33.6% to 85.9% with fluorescence release rates of 0.53 to 1.17 RFU/min in 40 and 1000 ng/mL tPa conditions, respectively. The platform is easily adapted to produce pulsatile flows. Hemodynamics of human main pulmonary artery were mimicked through matching dimensionless flow parameters calculated using clinical data. Increasing pressure amplitude range (4-40 mmHg) results in a 20% increase of fibrinolysis at 1000 ng/mL tPA. Increasing shear flow rate (205-913 s-1) significantly increases fibrinolysis and mechanical digestion. These findings suggest pulsatile level affects thrombolytic drug activities and the proposed in-vitro clot model offers a versatile testing platform for thrombolytic drug screening.

Utility of neuromuscular blockade reversal in the evaluation of acute neurosurgical patients: A retrospective case-series.

OBJECTIVE: Sugammadex reversal of neuromuscular blocking agents (NMBAs) is usually performed postoperatively. A scarcity of literature exists exploring sugammadex use for timely neurological examination of neurosurgical patients. NMBAs, like rocuronium, are used in the Emergency Department during intubation and their unpredictable duration of action often impedes timely and accurate assessment of patient neurological status. We aim to explore the role of sugammadex in evaluating patients in need of acute neurosurgical care. METHODS: Retrospective assessment of patients presenting with traumatic brain injury or intracranial hemorrhage was conducted at our level 1 trauma center. Patients of interest were those for whom sugammadex reversal of rocuronium neuromuscular blockade, from intubating doses, was pursued to ensure timely neurologic assessment. Nine patients were identified for whom GCS pre-/post-sugammadex, rocuronium dosing, elapsed time between rocuronium administration and reversal, and clinical course data were retrieved. RESULTS: Arrival GCS was 5.2 ± 3.2, with intubation accomplished within 10 ± 2.5 min of presentation. Rocuronium dosing was consistent between patients, average single dose of 1.2 ± 0.3 mg/kg. Lingering neuromuscular blockade ranged from 28 to 132 min (87.3 ± 34.3 min). All patients exhibited a GCS of 3 T upon initial neurosurgical evaluation, prior to reversal. Post-reversal GCS rose to 6.0 T ± 2.2. Sugammadex facilitated more accurate clinical decision making in 8 of 9 patients, including prevention of unnecessary invasive procedures. Two of 9 patients were eventually discharged home or to a rehabilitation facility. CONCLUSIONS: Rocuronium neuromuscular blockade can linger beyond pharmacokinetic predictions, thus delaying timely and precise neurologic assessment. Our data suggests sugammadex may be a useful addition to the clinician's armamentarium for acute neurologic assessment in the neurosurgical population. Sugammadex may impact clinical decision-making in certain patients and allow for more informed decision-making by families and physicians alike. Prospective studies are needed to definitively assess the impact of sugammadex on outcomes in acute neurosurgical settings.

Warfarin versus factor Xa inhibitors in the long-term treatment of cerebral venous sinus thrombosis a single-center retrospective analysis.

Long-term anticoagulation in the treatment of Cerebral Venous Sinus Thrombosis (CVST) has revolved around the use of warfarin. The relatively recent introduction of Direct Oral Anticoagulants (DOACs), such as Factor Xa inhibitors, in treating CVSTs promises to offer numerous patient benefits. We aimed to examine the efficacy of Factor Xa inhibitors in comparison to warfarin in the long-term treatment of CVSTs. A single-center retrospective analysis was conducted in which 49 eligible patients having presented with a first-time CVST were identified. Long-term anticoagulation was achieved with Warfarin (n = 23) or Factor Xa Inhibitors (n = 26; Apixaban or Rivaroxaban). Outcomes of interest were improvements in patient functional status, modified Ranking Scores (mRS), and radiographic improvement/resolution in sinus thromboses. Secondary comparisons included complication rates, particularly recurring venous thrombotic events. Patient mRS scores by 7-to-18-month follow-up all fell within the extremely favorable range of 0-1 regardless of the long-term anticoagulant (P-value = 0.3591). Proportion of patients with radiographic improvement/resolution of thrombosed sinuses trended towards being higher in the Factor Xa Inhibitor group at the <12-month period, 69.2%, compared to 33.3% with Warfarin (P-value = 0.0548). By the >12-month follow-up period, Warfarin and Factor Xa inhibitor groups had similar rates of radiographic sinus improvement - 76.9% versus 71.4%, respectively (P-value = 0.6298). No statistically significant differences were documented between groups regarding complications. Factor Xa inhibitors are equally as effective as Warfarin in the long-term treatment of CVSTs, whether it be restoring patient functional status, sinus thrombus burden reduction, or minimizing bleeding complications whilst preventing recurrent venous thrombosis.

In-vitro thromboelastographic characterization of reconstituted whole blood utilizing cryopreserved platelets.

Conducting in-vitro thrombosis research presents numerous challenges, the primary of which is working with blood products, whether whole blood or fractionated whole blood, that have limited functional shelf-lives. As a result, being able to significantly prolong the clotting functionality of whole blood via fractionation and recombination promises greater accessibility via resource minimization in the realm of thrombosis research. Whole blood with CPDA1 from healthy volunteers was fractionated and stored as frozen platelet-free plasma (PFP, -20°C), refrigerated packed red blood cells (pRBCs, 4°C) and cryopreserved platelets (-80°C). Subsequent recombination of the above components into their native ratios were tested via thromboelastography (TEG) to capture clotting dynamics over a storage period of 13 weeks in comparison to refrigerated unfractionated WB+CPDA1. Reconstituted whole blood utilizing PFP, pRCBs and cryopreserved platelets were able to maintain clot strength (maximum amplitude) akin to day-0 whole blood even after 13 weeks of storage. Clots formed by reconstituted whole blood exhibited quicker clotting dynamics with nearly two-fold shorter R-times and nearly 1.3-fold increase in fibrin deposition rate as measured by TEG. Storage of fractionated whole blood components, in their respective ideal conditions, provides a means of prolonging the usable life of whole blood for in-vitro thrombosis research. Cryopreserved platelets, when recombined with frozen PFP and refrigerated pRBCs, are able to form clots that nearly mirror the overall clotting profile expected of freshly drawn WB.

High Rates of Nicotine Use Relapse and Ulcer Development Following Roux-en-Y Gastric Bypass.

PURPOSE: Given that smoking is known to contribute to gastrojejunal anastomotic (GJA) ulcers, cessation is recommended prior to laparoscopic Roux-en-Y gastric bypass (LRYGB). However, smoking relapse rates and the exact ulcer risk remain unknown. This study aimed to define smoking relapse, risk of GJA ulceration, and complications after LRYGB. MATERIALS AND METHODS: We performed a retrospective cohort study of patients who underwent primary LRYGB during 2011-2015. Initially, three patient categories were identified: lifetime non-smokers, patients who were smoking during the initial visit at the bariatric clinic or within the prior year (recent smokers), and patients who had ceased smoking more than a year prior to their initial clinic visit (former smokers). Smoking relapse, GJA ulcer occurrences, reinterventions, and reoperations were recorded and compared. RESULTS: A total of 766 patients were included in the analysis. After surgery, 53 (64.6%) recent smokers had resumed smoking. Out of these relapsed smokers, 51% developed GJA ulcers compared with 14.8% in non-relapsed recent smokers, 16.1% in former smokers, and 6% in lifetime nonsmokers (p < 0.001). Furthermore, relapsed smokers required more frequently endoscopic reinterventions (60.4%) compared with non-relapsed smokers (20.8%, p < 0.001), former smokers (20.7%, p < 0.001), and lifetime non-smokers (15.4%, p < 0.001). Additionally, relapsed smokers required a reoperation (18.9%) more often than non-relapsed recent smokers (5.7%, p < 0.001) and lifetime non-smokers (1.3%, p < 0.001). CONCLUSION: Smokers relapse frequently after LRYGB, and the majority experience GJA complications. They should be counseled about this risk preoperatively and directed towards less ulcerogenic procedures when possible. Alternatively, longer periods of preoperative smoking abstinence might be needed.

Stress hormone signaling through ß-adrenergic receptors regulates macrophage mechanotype and function.

Critical functions of immune cells require them to rapidly change their shape and generate forces in response to cues from their surrounding environment. However, little is known about how soluble factors that may be present in the microenvironment modulate key aspects of cellular mechanobiology-such as immune cell deformability and force generation-to impact functions such as phagocytosis and migration. Here we show that signaling by soluble stress hormones through ß-adrenoceptors (ß-AR) reduces the deformability of macrophages; this is dependent on changes in the organization of the actin cytoskeleton and is associated with functional changes in phagocytosis and migration. Pharmacologic interventions reveal that the impact of ß-AR signaling on macrophage deformability is dependent on actin-related proteins 2/3, indicating that stress hormone signaling through ß-AR shifts actin organization to favor branched structures rather than linear unbranched actin filaments. These findings show that through remodeling of the actin cytoskeleton, ß-AR-mediated stress hormone signaling modulates macrophage mechanotype to impact functions that play a critical role in immune response.-Kim, T.-H., Ly, C., Christodoulides, A., Nowell, C. J., Gunning, P. W., Sloan, E. K., Rowat, A. C. Stress hormone signaling through ß-adrenergic receptors regulates macrophage mechanotype and function.

The Role of Lipoproteins in Mycoplasma-Mediated Immunomodulation.

Mycoplasma infections, such as walking pneumonia or pelvic inflammatory diseases, are a major threat to public health. Despite their relatively small physical and genomic size, mycoplasmas are known to elicit strong host immune responses, generally inflammatory, while also being able to evade the immune system. The mycoplasma membrane is composed of approximately two-thirds protein and one-third lipid and contains several lipoproteins that are known to regulate host immune responses. Herein, the immunomodulatory effects of mycoplasma lipoproteins are reviewed. A better understanding of the immunomodulatory effects, both activating and evasive, of Mycoplasma surface lipoproteins will contribute to understanding mechanisms potentially relevant to mycoplasma disease vaccine development and treatment.

Spirochetal Lipoproteins and Immune Evasion.

Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment.