Ataxia-telangiectasia: Linkage analysis in highly inbred Arab and Druze families and differentiation from an ataxia-microcephaly-cataract syndrome

Ataxia-telangiectasia (A-T) is a progressive autosomal recessive disease featuring neurodegeneration, immunodeficiency, chromosomal instability, radiation sensitivity and a highly increased proneness to cancer. A-T is ethnically widespread and genetically heterogeneous, as indicated by the existence of four complementation groups in this disease. Several "A-T-like" genetic diseases share various clinical and cellular characteristics with A-T. By using linkage analysis to study North American and Turkish A-O families, the ATA (A-T, complementation group A) gene has been mapped to chromosome 11q23. A number of Israeli Arab A-T patients coming from large, highly inbred families were assigned to group A In one of these families, an additional autosomal recessive disease was identified, characterized by ataxia, hypotonia, microcephaly and bilateral congenital cataracts. In two patients with this syndrome, normal levels of serum immunoglobulins and alpha-fetoprotein, chromosomal stability in peripheral blood lymphocytes and skin fibroblasts, and normal cellular response to treatments with X-rays and the radiomimetic drug neocarzinostatin indicated that this disease does not share, with A-T, any additional features other than ataxia. These tests also showed that another patient in this family, who is also mentally retarded, is affected with both disorders. This conclusion was further supported by linkage analysis with 11q23 markers. Lod scores between A-O and these markers, cumulated over three large Arab families, were significant and confirmed the localization of the ATA gene to aq23. However, another Druze family unassigned to a specific complementation group, showed several recombinants between A-T and the same markers, leaving the localization of the A-T gene in this family open

The Potential Role of Coagulation Factor Xa in the Pathophysiology of COVID-19: A Role for Anticoagulants as Multimodal Therapeutic Agents

SARS-CoV-2 infection (COVID-19) results in local and systemic activation of inflammation and coagulation. In this review article, we will discuss the potential role of coagulation factor Xa (FXa) in the pathophysiology of COVID-19. FXa, a serine protease, has been shown to play a role in the cleavage of SARS-CoV-1 spike protein (SP), with the inhibition of FXa resulting in the inhibition of viral infectivity. FX is known to be primarily produced in the liver, but it is also expressed by multiple cells types, including alveolar epithelium, cardiac myocytes, and macrophages. Considering that patients with preexisting conditions, including cardiopulmonary disease, are at an increased risk of severe COVID-19, we discuss the potential role of increased levels of FX in these patients, resulting in a potential increased propensity to have a higher infectious rate and viral load, increased activation of coagulation and inflammation, and development of fibrosis. With these observations in mind, we postulate as to the potential therapeutic role of FXa inhibitors as a prophylactic and therapeutic treatment for high-risk patients with COVID-19

Coagulation Status and Venous Thromboembolism Risk in African Americans: A Potential Risk Factor in COVID-19

Severe acute respiratory syndrome coronavirus 2 infection (COVID-19) is known to induce severe inflammation and activation of the coagulation system, resulting in a prothrombotic state. Although inflammatory conditions and organ-specific diseases have been shown to be strong determinants of morbidity and mortality in patients with COVID-19, it is unclear whether preexisting differences in coagulation impact the severity of COVID-19. African Americans have higher rates of COVID-19 infection and disease-related morbidity and mortality. Moreover, African Americans are known to be at a higher risk for thrombotic events due to both biological and socioeconomic factors. In this review, we explore whether differences in baseline coagulation status and medical management of coagulation play an important role in COVID-19 disease severity and contribute to racial disparity trends within COVID-19

Device Prototype for Vaginal Delivery of Extremely Preterm Fetuses in the Breech Presentation

© 2021 by ASME. Vaginal delivery is typically avoided in the extremely preterm breech population due to the concern of entrapment by the cervix of the aftercoming head. A mechanical device concept is presented to enable vaginal delivery by preventing retraction of the cervix against the fetus during delivery. The two-part device was designed to dilate the cervix, prevent prolapse of small fetal parts and maintain sufficient dilation during delivery. The two-part device was designed and manufactured with the following modules: an inflatable saline-filled cervical balloon for dilation and a cervical retractor composed of semirigid beams to stabilize the cervix and maintain adequate dilation. The device was tested using a cervical phantom designed to simulate the compressive force the cervix exerts. The cervical balloon reached a maximum dilation of 8.5 cm, after which there was leakage of saline from the balloon. While this dilation was less than the target goal of 10 cm, the leaking was attributed to prototype manufacturing defects, which could be resolved with further development. The cervical retractor was able to withstand between 1-3 kPa. Although estimates of cervical pressure values can be upward of 30 kPa, there are no in vivo measurements to formally identify the pressure values for patients in preterm labor. This device serves as a viable proof-of-concept for utilizing an inflatable balloon device to prevent cervical retraction in the setting of extremely preterm vaginal breech delivery. Further manufacturing improvements and design changes could improve the device for continued development and testing

Manuka honey microneedles for enhanced wound healing and the prevention and/or treatment of Methicillin-resistant Staphylococcus aureus (MRSA) surgical site infection

© 2020, The Author(s). Manuka honey (MH) is currently used as a wound treatment and suggested to be effective in Methicillin-resistant Staphylococcus aureus (MRSA) elimination. We sought to optimize the synthesis of MH microneedles (MHMs) while maintaining the MH therapeutic effects. MHMs were synthesized using multiple methods and evaluated with in vitro assays. MHMs demonstrated excellent bactericidal activity against MRSA at concentrations ≥ 10% of honey, with vacuum-prepared honey appearing to be the most bactericidal, killing bacterial concentrations as high as 8 × 107 CFU/mL. The wound-healing assay demonstrated that, at concentrations of 0.1%, while the cooked honey had incomplete wound closure, the vacuum-treated honey trended towards faster wound closure. In this study, we demonstrate that the method of MHM synthesis is crucial to maintaining MH properties. We optimized the synthesis of MHMs and demonstrated their potential utility in the treatment of MRSA infections as well as in wound healing. This is the first report of using MH as a substrate for the formation of dissolvable microneedles. This data supports the need for further exploration of this new approach in a wound-healing model and opens the door for the future use of MH as a component of microneedle scaffolds

Multiphysics and multiscale modeling of microthrombosis in COVID-19.

Emerging clinical evidence suggests that thrombosis in the microvasculature of patients with Coronavirus disease 2019 (COVID-19) plays an essential role in dictating the disease progression. Because of the infectious nature of SARS-CoV-2, patients' fresh blood samples are limited to access for in vitro experimental investigations. Herein, we employ a novel multiscale and multiphysics computational framework to perform predictive modeling of the pathological thrombus formation in the microvasculature using data from patients with COVID-19. This framework seamlessly integrates the key components in the process of blood clotting, including hemodynamics, transport of coagulation factors and coagulation kinetics, blood cell mechanics and adhesive dynamics, and thus allows us to quantify the contributions of many prothrombotic factors reported in the literature, such as stasis, the derangement in blood coagulation factor levels and activities, inflammatory responses of endothelial cells and leukocytes to the microthrombus formation in COVID-19. Our simulation results show that among the coagulation factors considered, antithrombin and factor V play more prominent roles in promoting thrombosis. Our simulations also suggest that recruitment of WBCs to the endothelial cells exacerbates thrombogenesis and contributes to the blockage of the blood flow. Additionally, we show that the recent identification of flowing blood cell clusters could be a result of detachment of WBCs from thrombogenic sites, which may serve as a nidus for new clot formation. These findings point to potential targets that should be further evaluated, and prioritized in the anti-thrombotic treatment of patients with COVID-19. Altogether, our computational framework provides a powerful tool for quantitative understanding of the mechanism of pathological thrombus formation and offers insights into new therapeutic approaches for treating COVID-19 associated thrombosis

Apical branching is induced following chelation of iron.

<p>(A) Treatment with iron chelators increased branching compared to controls. EDTA provides non-specific chelation of free metal ion, while HBED and lactoferrin provide specific chelation of Fe. Lactoferrin (Fe) provides an iron-saturated negative control for lactoferrin iron chelation. (B) Iron chelation significantly reduced hyphal tip growth speed. Lack of growth inhibition by iron-saturated lactoferrin demonstrates the specificity of lactoferrin activity in this assay. N = 25 hyphae scored per condition from 3 experiments. Errors bars: mean ± SEM. Statistics: One-way ANOVA with Tukey’s post test. Adjusted p values: *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001.</p

Interaction with neutrophils induces hyphal branching.

<p>(A) Amplitude of neutrophil response correlates to reduction in velocity of hyphal growth, with larger numbers of neutrophils better able to slow growth. N ≥ 10 measurements from n ≥ 5 representative hyphae per group. (B) Induction of branching over time shows a linear correlation with number of neutrophil interactions. (C) Induction of new branches is enriched proximally to neutrophil interactions, with most branches occurring within 20–30 μm of an interaction point. (D) Following interaction, most branches are induced within 5–25 minutes post interaction. (E) Robust recruitment of neutrophils amplifies branch induction (iii-v, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s004" target="_blank">S2 Movie</a>) and slows hyphal growth. However, at least one hypha branch is usually able to avoid confrontation and continue growing unobstructed (vi). (F) Neutrophils are recruited to fungal hyphae in significantly higher numbers than other immune cells. (G) Neutrophil interaction with hyphae induces apical branching at more than twice the rate of other immune cells. N ≥ 24 hyphae scored from N ≥ 4 experiments. Error bars: mean ± SEM. Statistics: one-way ANOVA with Tukey’s post test. Adjusted p values: *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001.</p

Mechanical impedance of tip extension induces apical hyphal branching.

<p>(A) Representative example of branch induction following interaction with a single neutrophil. (i) Hyphal growth (green) through channels and interactions with neutrophils (blue), as observed in time-lapse microscopy (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s003" target="_blank">S1 Movie</a>) (ii-iv) Magnified view of frames extracted from time-lapse microscopy of interactions (dashed red square box in i), which demonstrate formation of actively growing new hypha tips (full white arrowheads) following interaction with a single neutrophil (open white arrowhead), in addition to the primary tip (open green arrowhead). (B) Induction of branching during interaction of the hyphal tip with a crescent-shaped obstacle. (i) Hyphal growth (green) through channels with obstacles, as observed in time-lapse microscopy (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s006" target="_blank">S4 Movie</a>) (ii-iv) Magnified view of frames extracted from time-lapse microscopy (dashed red square box in i), show efficient formation of a new hypha tip (full white arrowhead) in addition to the primary tip (open green arrowhead). (C) Comparison of branch induction by differently shaped obstacles. Square and crescent shaped obstacles provided robust branch induction. (D) Comparison of average hyphal tip velocity during interaction period (-20 to +25 mins relative to contact with obstacle). Crescent-shaped obstacles slowed hyphal tip extension most efficiently during interaction. (E) Graphing of instantaneous hyphal tip velocity during interaction with differently shaped obstacles (i-iv). Crescent shaped obstacles induced a striking decrease in tip velocity during the interaction, just prior to branching (black arrow indicates steep drop in tip velocity). N ≥ 9 measurements per condition from n ≥ 7 representative hyphae per group. Errors bars: mean ± SEM. Statistics: One-way ANOVA with Tukey’s post test. Adjusted p values: *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001.</p

Branching slows growth and increases hyphal vulnerability.

<p>(A) Sequential branching was induced by crescent-shaped obstacles to allow comparison of hyphal growth after multiple branches. Hyphae were induced to branch 3 times, increasing the number of growing tips exponentially from 1 to 8 (i, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s007" target="_blank">S5 Movie</a>). Comparison of hyphal tip velocity in zones 1–4 (i) demonstrated a significant reduction in hyphal growth speed with each branching event (ii). N ≥ 4 measurements for n ≥ 4 hyphae per zone. (B) Highly branched hyphae are more susceptible to killing by neutrophils. Staggered branch induction allowed comparison of hypha (full white arrowheads) that had undergone different numbers of branching events (i, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s008" target="_blank">S6 Movie</a>). Hyphae that had been branched the most were killed first (iv, open white arrowhead), while more established hypha took longer to kill (v-vi). (C) Branching significantly reduces hyphal diameter. Hyphal diameter was measured for hyphae following compound branch induction. Reduced diameters were observed following branching, with a minimum diameter of 2 μm observed. N ≥ 11 hyphae measured per condition from ≥ 3 fields of view. (D) Thinner hyphae are more susceptible to neutrophil-mediated killing. (i) Bar graph shows that more highly branched hyphae are killed more quickly by neutrophils, as indicated by loss of hyphal cytoplasmic EGFP fluorescence. N ≥ 11 hyphae measured per condition from ≥ 3 fields of view. (E) Scatterplot shows time taken for neutrophils to kill hyphae correlates well with hyphal diameter, with thicker hyphae taking longer to kill. N = 157 hyphae scored. (F) Neutrophils with reduced ROS (DPI-treated) or isolated from at-risk patients (transplant recipients, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006154#ppat.1006154.s001" target="_blank">S1 Table</a>) take longer to kill both thick (>4μm diameter) and thin (<4 μm diameter) hyphae. N≥ 20 hyphae scored per group, neutrophils from N≥ 3 individuals sampled per group. Error bars: mean ± SEM. Statistics: One-way ANOVA with Tukey’s post test. Adjusted p values: *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001.</p