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Rapid Measurement of Hemoglobin-Oxygen Dissociation by Leveraging Bohr Effect and Soret Band Bathochromic Shift
No full textOxygen (O2) binds to hemoglobin (Hb) in the lungs and is then released (dissociated) in the tissues. The Bohr effect is a physiological mechanism that governs the affinity of Hb for O2 based on pH, where a lower pH results in a lower Hb-O2 affinity and higher Hb-O2 dissociation. Hb-O2 affinity and dissociation are crucial for maintaining aerobic metabolism in cells and tissues. Despite its vital role in human physiology, Hb-O2 dissociation measurement is underutilized in basic research and in clinical laboratories, primarily due to the technical complexity and limited throughput of existing methods. We present a rapid Hb-O2 dissociation measurement approach by leveraging the Bohr effect and detecting the optical shift in the Soret band that corresponds to the light absorption by the heme group in Hb. This new method reduces Hb-O2 dissociation measurement time from hours to minutes. We show that Hb deoxygenation can be accelerated chemically at the optimal pH of 6.9. We show that time and pH-controlled deoxygenation of Hb results in rapid and distinct conformational changes in its tertiary structure. These molecular conformational changes are manifested as significant, detectable shifts in Hb\u27s optical absorption spectrum, particularly in the characteristic Soret band (414 nm). We extensively validated the method by testing human blood samples containing normal Hb and Hb variants. We show that rapid Hb-O2 dissociation can be used to screen for and detect Hb-O2 affinity disorders and to evaluate the function and efficacy of Hb-modifying therapies. The ubiquity of optical absorption spectrophotometers positions this approach as an accessible, rapid, and accurate Hb-O2 dissociation measurement method for basic research and clinical use. We anticipate this method\u27s broad adoption will democratize the diagnosis and prognosis of Hb disorders, such as sickle cell disease. Further, this method has the potential to transform the research and development of new targeted and genome-editing-based therapies that aim to modify or improve Hb-O2 affinity
Bacterial Contamination of Platelet Products
Get PDFTransfusion of bacterially contaminated platelets, although rare, is still a major cause of mortality and morbidity despite the introduction of many methods to limit this over the past 20 years. The methods used include improved donor skin disinfection, diversion of the first part of donations, use of apheresis platelet units rather than whole-blood derived pools, primary and secondary testing by culture or rapid test, and use of pathogen reduction. Primary culture has been in use the US since 2004, using culture 24 h after collection of volumes of 4–8 mL from apheresis collections and whole-blood derived pools inoculated into aerobic culture bottles, with limited use of secondary testing by culture or rapid test to extend shelf-life from 5 to 7 days. Primary culture was introduced in the UK in 2011 using a “large-volume, delayed sampling” (LVDS) protocol requiring culture 36–48 h after collection of volumes of 16 mL from split apheresis units and whole-blood derived pools, inoculated into aerobic and anaerobic culture bottles (8 mL each), with a shelf-life of 7 days. Pathogen reduction using amotosalen has been in use in Europe since 2002, and was approved for use in the US in 2014. In the US, recent FDA guidance, effective October 2021, recommended several strategies to limit bacterial contamination of platelet products, including pathogen reduction, variants of the UK LVDS method and several two-step strategies, with shelf-life ranging from 3 to 7 days. The issues associated with bacterial contamination and these strategies are discussed in this review
The mRNACalc Webserver Accounts for the N1-methylpseudouridine Hypochromicity to Enable Precise Nucleoside-Modified mRNA Quantification
Get PDFNucleoside-modified messenger RNA (mRNA) technologies necessarily incorporate N1-methylpseudouridine into the mRNA molecules to prevent the over-stimulation of cytoplasmic RNA sensors. Despite this modification, mRNA concentrations remain mostly determined through the measurement of UV absorbance at 260 nm wavelength (A260). Herein, we report that the N1-methylpseudouridine absorbs approximately 40% less UV light at 260 nm than uridine, and its incorporation into mRNAs leads to the under-estimation of nucleoside-modified mRNA concentrations, with 5%–15% error, in an mRNA-sequence-dependent manner. We therefore examined the RNA quantification methods and developed the mRNACalc webserver. It accounts for the molar absorption coefficient of modified nucleotides at 260 nm wavelength, the RNA composition of the mRNA, and the A260 of the mRNA sample to enable accurate quantification of nucleoside-modified mRNAs
Impact of Coverage and Guest Residue on Polyproline II Helix Peptide Antifouling
Get PDFPolyproline II (PPII) peptide sequences are recognized as promising biomaterials because of their attractive antifouling properties. However, the mechanisms behind their antifouling behavior have not been fully characterized. In this work we show that PPII peptide coverage, controlled by adsorption time, significantly reduces the fouling of bovine serum albumin (BSA, a model foulant). In addition, guest residues introduced into the PPII sequence are shown to significantly impact BSA adsorption as well as human mesenchymal stem cell (hMSC) spreading. This research will help guide future PPII peptide designs for incorporation into novel biomaterials
Protecting Our Futures: Challenges & Strategies for Women’s, Gender, and Sexuality Studies
Get PDFThis report, supported by the National Women\u27s Studies Association, addresses the current state of Women\u27s, Gender, and Sexualities Studies departments and programs across the United States. In particular, the report focuses on changes in support, resources, and enrollment, as well as the impact of anti-DEI legislation being passed across the country at this time.https://commons.case.edu/mathercenter-briefs/1004/thumbnail.jp
Trauma-Informed Care: Victim\u27s Advocacy at the Individual Level
Get PDFThis brief reviews core elements of trauma-informed care, and how these are applied when supporting individual survivors through advocacy.https://commons.case.edu/mathercenter-briefs/1002/thumbnail.jp
Real-Time Assessment of Rodent Engagement Using ArUco Markers: A Scalable and Accessible Approach for Scoring Behavior in a Nose-Poking Go/No-Go Task
Get PDFIn the field of behavioral neuroscience, the classification and scoring of animal behavior play pivotal roles in the quantification and interpretation of complex behaviors displayed by animals. Traditional methods have relied on video examination by investigators, which is labor-intensive and susceptible to bias. To address these challenges, research efforts have focused on computational methods and image-processing algorithms for automated behavioral classification. Two primary approaches have emerged: marker-and markerless-based tracking systems. In this study, we showcase the utility of “Augmented Reality University of Cordoba” (ArUco) markers as a marker-based tracking approach for assessing rat engagement during a nose-poking go/no-go behavioral task. In addition, we introduce a two-state engagement model based on ArUco marker tracking data that can be analyzed with a rect-angular kernel convolution to identify critical transition points between states of engagement and distraction. In this study, we hypothesized that ArUco markers could be utilized to accurately estimate animal engagement in a nose-poking go/no-go behavioral task, enabling the computation of optimal task durations for behavioral testing. Here, we present the performance of our ArUco tracking program, demonstrating a classification accuracy of 98% that was validated against the manual curation of video data. Furthermore, our convolution analysis revealed that, on average, our animals became disengaged with the behavioral task at ∼75 min, providing a quantitative basis for limiting experimental session durations. Overall, our approach offers a scalable, efficient, and accessible solution for automated scoring of rodent engagement during behavioral data collection
A Critical Review of Sociological Research on Sexual Pleasure
Get PDFSociologists of sexuality often invoke the theme of pleasure, but it is not always clear what scholars believe the implications and importance of pleasure are. To this end, this paper reviews the existing literature on sexual pleasure, specifically within the field of sociology, to demonstrate what questions about sexual pleasure are (and are not) currently being asked. Through a systematic literature review, I demonstrate that scholars often lack a justification for why pleasure is important. I also connect themes between the kind of questions being asked about pleasure and the justifications attached to these studies, relating to risk mitigation, relationship satisfaction and well‐being, power structures, and moral oversight. Based on this review, I make recommendations for the future of sexual pleasure research with the goal of centering pleasure for pleasure\u27s sake and embracing its liberatory possibilities
“I’m not the girl I was…”
Get PDFMy wife has Alzheimer’s. That might not be the precise diagnosis, but her symptoms are practically textbook for it. On a seven-stage scale of the disease, she would be in the latter part of the 5th and early 6th Stage. I have been asked by a number of colleagues to write down what has been happening to Gerda; but up until now, it was too painful and personal to record. I also believed that so much useful information has been written and published that there was no need to add to the literature. But when Gerda said the words I quoted to title this essay, I felt compelled to write what I have been telling family and friends about her condition
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