Polyethylene Glycol Camouflaged Earthworm Hemoglobin.

Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals' systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the colloid osmotic pressure or blood volume expansion capacity compared to LtEc, due to LtEc's already large molecular size. Taken together, these results further encourage the development of PEG-LtEc as an O2 carrying therapeutic

BIOMECHANICAL MECHANISMS OF ARTICULAR CARTILAGE DEGENERATION IN POST-TRAUMATIC OSTEOARTHRITIS

After injury that causes rupture of the anterior cruciate ligament (ACL), knee joint mechanics are altered, and post-traumatic osteoarthritis (PTOA) often ensues. During movement, the ACL-deficient knee exhibits increased anterior translation and internal rotation of tibia, causing specific regions of articular cartilage (AC) of the femoral condyles (FCs) to be exposed to increased loading and sliding. The resultant tissue-level contact biomechanics may cause direct mechanical or mechanobiological damage to AC and meniscus (MEN) tissues. While traditional histopathological analysis of vertical AC sections indicates that surface fibrillation and fissures can progress to tissue erosion, the limited surface area of such sections makes it difficult to assess how knee joint pathomechanics leads to AC damage in PTOA. Previously, en face imaging of the AC surfaces of normal and ACL-transected (ACLT) rabbit knees stained with India ink revealed areas of damage. In addition, radiological imaging in vivo has clarified joint and tissue mechanics of human knees. The overall aim of this work was to elucidate the biomechanics and mechanobiology of PTOA in rabbit knees due to ACLT by relating detailed patterns of AC surface damage to sites of abnormal loading and sliding. The following three studies were completed.In knees of adult rabbits subjected to ACLT in vivo and analyzed at 4 weeks, the patterns and extent of cartilage surface degeneration were mapped by 2-D en face high resolution imaging and 3-D histology. Six AC crack patterns, Haze, Dash, Transverse line, Longitudinal line, Reticular Sawtooth, and Broad Streak, indicating progressive states of deterioration and typical of human AC, were detected on ACLT FCs, and registered to 3-D histological features (roughening, fibrillation, horizontal and vertical fissures, and erosion). The site-specificity of patterns suggest progression pathways and mechanically mediated mechanisms of AC damage. In previously frozen rabbit hindlimbs, either subjected to ACLT or maintained intact ex vivo, the effects of cyclic loading to cause movement-like extension-flexion was assessed. Bone positions obtained by marker-based tracking during articulation indicated that ACLT led to increased anterior tibial translation. AC damage patterns were consistent with in vivo changes at 4-weeks. These effects of altered knee mechanics, in the absence of cell metabolism or metalloproteinase activity, suggest that knee pathomechanics can directly cause AC surface damage in PTOA. In previously frozen rabbit knees, the effects of ACLT ex vivo on AC and MEN contact was assessed using a custom micro-computed tomography jig that provided knee loading to mimic extension and allowed visualization of joint biomechanics. ACLT knees exhibited increased internal rotation and anterior translation of the tibia, posterior translation of MEN, and shifting of strain at contact. These changes are consistent with knee destabilization and areas of AC damage after ACLT. The above results have several implications. The identification of en face AC damage patterns at 4 weeks in the rabbit in vivo ACLT model suggests opportunities for early interventions to prevent such damage and subsequent deterioration. The recognition of distinct patterns of AC damage at sites subjected to more loading or more sliding indicates multiple biomechanical mechanisms by which instability contributes to PTOA. The mechanical basis of such damage, and possible interventions, may be tested in the ex vivo limb model. The experimental tie between biomechanics at the joint and tissue scale, facilitated by the custom micro-computed tomography jig, helps defines the local kinematics and tissue strains that can be studied in more detail to address both direct biomechanical damage or abnormal mechanobiology leading to AC and MEN damage in ACL-deficient knees

Identifying Possible Winners in Ranked Choice Voting Elections with Outstanding Ballots

Several election districts in the US have recently moved to ranked-choice voting (RCV) to decide the results of local elections. RCV allows voters to rank their choices, and the results are computed in rounds, eliminating one candidate at a time. RCV ensures fairer elections and has been shown to increase elected representation of women and people of color. A main drawback of RCV is that the round-by-round process requires all the ballots to be tallied before the results of an election can be calculated. With increasingly large portions of ballots coming from absentee voters, RCV election outcomes are not always apparent on election night, and can take several weeks to be published, leading to a loss of trust in the electoral process from the public. In this paper, we present an algorithm for efficiently computing possible winners of RCV elections from partially known ballots and evaluate it on data from the recent New York City Primary elections. We show that our techniques allow to significantly narrow down the field of possible election winners, and in some case identify the winner as soon as election night despite a number of yet-unaccounted absentee ballots, providing more transparency in the electoral process

Polyethylene Glycol Camouflaged Earthworm Hemoglobin.

Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals' systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the colloid osmotic pressure or blood volume expansion capacity compared to LtEc, due to LtEc's already large molecular size. Taken together, these results further encourage the development of PEG-LtEc as an O2 carrying therapeutic

Polyethylene Glycol Camouflaged Earthworm Hemoglobin.

Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals' systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the colloid osmotic pressure or blood volume expansion capacity compared to LtEc, due to LtEc's already large molecular size. Taken together, these results further encourage the development of PEG-LtEc as an O2 carrying therapeutic

Changes in functional capillary density (FCD) relative to baseline after hypervolemic infusion, of LtEc or PEG-LtEc.

<p>FCD was studied at plasma protein concentration to 0.5, 1.0, and 1.5 g/dL. FCD (capillaries per unit of area, cm⁻¹) at baseline for LtEc were 119 ± 14, and for PEG-LtEc were 116 ± 16, respectively. †, P < 0.05 relative to baseline; ‡, P < 0.05 compared to LtEc.</p

LtEc and PEG-LtEc pharmacokinetics after a 40% exchange transfusion (Top panels).

<p>The concentration of the reduced (Fe²⁺) and oxidized (Fe³⁺) forms of PEG-LtEc and LtEc as a function of time (bottom panels).</p

Effects of consecutive transfusions of LtEc, and PEG-LtEc on Hct, total Hb concentration, and plasma protein concentration.

<p>Effects of consecutive transfusions of LtEc, and PEG-LtEc on Hct, total Hb concentration, and plasma protein concentration.</p