We measure bone-conduction (BC) induced skull velocity, sound pressure at the tympanic membrane (TM) and inner-ear compound-action potentials (CAP) before and after manipulating the ear canal, ossicles, and the jaw to investigate the generation of BC induced ear-canal sound pressures and their contribution to inner-ear BC response in the ears of chinchillas. These measurements suggest that in chinchilla: i.) Vibrations of the bony ear canal walls contribute significantly to BC-induced ear canal sound pressures, as occluding the ear canal at the bone-cartilaginous border causes a 10 dB increase in sound pressure at the TM (P) at frequencies below 2 kHz.
View Article and Find Full Text PDFBackground: We aimed to identify the impact of COVID infection in children in the US prior to vaccine availability on clinical and healthcare utilization outcomes within 6 months of infection.
Methods: Using claims data from a large national insurer, we identified 223,842 children with a COVID diagnosis in May 2020-March 2021 and matched them to 223,842 children with a COVID test and no diagnosis. We compared the two cohorts' outcomes during the 6 months after infection/test.
Purpose: Targeted therapeutics are a goal of medicine. Methods for targeting T-cell lymphoma lack specificity for the malignant cell, leading to elimination of healthy cells. The T-cell receptor (TCR) is designed for antigen recognition.
View Article and Find Full Text PDFThere is growing interest in the role that morphological knowledge plays in literacy acquisition, but there is no research directly comparing the efficacy of different forms of morphological instruction. Here we compare two methods of teaching English morphology in the context of a memory experiment when words were organized by affix during study (e.g.
View Article and Find Full Text PDFWe conducted genome-wide association studies (GWAS) of relative intake from the macronutrients fat, protein, carbohydrates, and sugar in over 235,000 individuals of European ancestries. We identified 21 unique, approximately independent lead SNPs. Fourteen lead SNPs are uniquely associated with one macronutrient at genome-wide significance (P < 5 × 10), while five of the 21 lead SNPs reach suggestive significance (P < 1 × 10) for at least one other macronutrient.
View Article and Find Full Text PDFTyrosine kinase inhibitors (TKIs) induce molecular remission in the majority of patients with chronic myelogenous leukemia (CML), but the persistence of CML stem cells hinders cure and necessitates indefinite TKI therapy. We report that CML stem cells upregulate the expression of pleiotrophin (PTN) and require cell-autonomous PTN signaling for CML pathogenesis in BCR/ABL+ mice. Constitutive PTN deletion substantially reduced the numbers of CML stem cells capable of initiating CML in vivo.
View Article and Find Full Text PDFAn air-conduction circuit model was developed for the chinchilla middle ear and cochlea. The lumped-element model is based on the classic Zwislocki model of the same structures in human. Model parameters were fit to various measurements of chinchilla middle-ear transfer functions and impedances, using a combination of error-minimization-driven computer-automated and manual fitting methods.
View Article and Find Full Text PDFThe engineering of antibodies and antibody fragments for affinity maturation, stability, and other biophysical characteristics is a common aspect of therapeutic development. Maturation of antibodies in B cells during the adaptive immune response is the result of a process called somatic hypermutation (SHM), in which the activation-induced cytidine deaminase (AID) acts to introduce mutations into immunoglobulin (Ig) genes. Iterative selection and clonal expansion of B cells containing affinity-enhancing mutations drive an increase in the overall affinity of antibodies.
View Article and Find Full Text PDFTaylor, Davis, and Rastle employed an artificial language learning paradigm to compare phonics and meaning-based approaches to reading instruction. Adults were taught consonant, vowel, and consonant (CVC) words composed of novel letters when the mappings between letters and sounds were completely systematic and the mappings between letters and meaning were completely arbitrary. At test, performance on naming tasks was better following training that emphasised the phonological rather than the semantic mappings, whereas performance on semantic tasks was similar in the two conditions.
View Article and Find Full Text PDFWhile most models of cochlear function assume the presence of only two windows into the mammalian cochlea (the oval and round windows), a position that is generally supported by several lines of data, there is evidence for additional sound paths into and out of the inner ear in normal mammals. In this report we review the existing evidence for and against the 'two-window' hypothesis. We then determine how existing data and inner-ear anatomy restrict transmission of sound through these additional sound pathways in cat by utilizing a well-tested model of the cat inner ear, together with anatomical descriptions of the cat cochlear and vestibular aqueducts (potential additional windows to the cochlea).
View Article and Find Full Text PDFThe cochlear implant (CI) is the most successful neural prosthesis, restoring the sensation of sound in people with severe-to-profound hearing loss by electrically stimulating the cochlear nerve. Existing CIs have an external, visible unit, and an internal, surgically-placed unit. There are significant challenges associated with the external unit, as it has limited utility and CI users often report a social stigma associated with prosthesis visibility.
View Article and Find Full Text PDFWhile the cochlea is considered the primary site of the auditory response to bone conduction (BC) stimulation, the paths by which vibratory energy applied to the skull (or other structures) reaches the inner ear are a matter of continued investigation. We present acoustical measurements of sound in the inner ear that separate out the components of BC stimulation that excite the inner ear via ossicular motion (compression of the walls of the ear canal or ossicular inertia) from the components that act directly on the cochlea (cochlear compression or inertia, and extra-cochlear 'third-window' pathways). The results are consistent with our earlier suggestion that the inner-ear mechanisms play a large role in bone-conduction stimulation in the chinchilla at all frequencies.
View Article and Find Full Text PDFPurpose: An open-label, noninferiority study to evaluate the impact of epoetin alfa (EPO) on tumor outcomes when used to treat anemia in patients receiving chemotherapy for metastatic breast cancer.
Methods: Women with hemoglobin ≤ 11.0 g/dL, receiving first- or second-line chemotherapy for metastatic breast cancer, were randomly assigned to EPO 40,000 IU subcutaneously once a week or best standard of care.
Antibody engineering to enhance thermostability may enable further application and ease of use of antibodies across a number of different areas. A modified human IgG framework has been developed through a combination of engineering approaches, which can be used to stabilize antibodies of diverse specificity. This is achieved through a combination of complementarity-determining region (CDR)-grafting onto the stable framework, mammalian cell display and in vitro somatic hypermutation (SHM).
View Article and Find Full Text PDFDuring somatic hypermutation (SHM), deamination of cytidine by activation-induced cytidine deaminase and subsequent DNA repair generates mutations within immunoglobulin V-regions. Nucleotide insertions and deletions (indels) have recently been shown to be critical for the evolution of antibody binding. Affinity maturation of 53 antibodies using in vitro SHM in a non-B cell context was compared with mutation patterns observed for SHM in vivo.
View Article and Find Full Text PDFCurr Drug Discov Technol
March 2014
Human therapeutic antibody discovery has utilized a variety of systems, from in vivo immunization of human immunoglobulin-expressing mice, to in vitro display of antibody libraries. Of the in vitro antibody display technologies, mammalian cell display provides a number of advantages with the ability to co-select immunoglobulin molecules for high expression level in mammalian cells, native folding, and biophysical properties appropriate for drug development. Mammalian cell display has been achieved using either transient or stable expression systems, using a number of alternate transmembrane domains to present antibody on the cell surface.
View Article and Find Full Text PDFRecent advances are described for the isolation and affinity maturation of antibodies that couple in vitro somatic hypermutation (SHM) with mammalian cell display, replicating key aspects of the adaptive immune system. SHM is dependent on the action of the B cell specific enzyme, activation-induced cytidine deaminase (AID). AID-directed SHM in vitro in non-B cells, combined with mammalian display of a library of human antibodies, initially naïve to SHM, can be used to isolate and affinity mature antibodies via iterative cycles of fluorescence-activated cell sorting (FACS) under increasingly stringent sort conditions.
View Article and Find Full Text PDFA mammalian expression system has been developed that permits simultaneous cell surface display and secretion of the same protein through alternate splicing of pre-mRNA. This enables a flexible system for in vitro protein evolution in mammalian cells where the displayed protein phenotype remains linked to genotype, but with the advantage of soluble protein also being produced without the requirement for any further recloning to allow a wide range of assays, including biophysical and cell-based functional assays, to be used during the selection process. This system has been used for the simultaneous surface presentation and secretion of IgG during antibody discovery and maturation.
View Article and Find Full Text PDFA method for simultaneous humanization and affinity maturation of monoclonal antibodies has been developed using heavy chain complementarity-determining region (CDR) 3 grafting combined with somatic hypermutation in vitro. To minimize the amount of murine antibody-derived antibody sequence used during humanization, only the CDR3 region from a murine antibody that recognizes the cytokine hβNGF was grafted into a nonhomologous human germ line V region. The resulting CDR3-grafted HC was paired with a CDR-grafted light chain, displayed on the surface of HEK293 cells, and matured using in vitro somatic hypermutation.
View Article and Find Full Text PDFAntibodies are important tools for a broad range of applications due to their high specificity and ability to recognize virtually any target molecule. However, in order to be practically useful, antibodies must be highly stable and bind their target antigens with high affinity. We present a combinatorial approach to generate high-affinity, highly stable antibodies through the design of stable frameworks, specificity grafting and maturation via somatic hypermutation in vitro.
View Article and Find Full Text PDFA method has been developed for the rapid generation of high-affinity humanized antibodies from immunized animals without the need to make conventional hybridomas. Rearranged IgH D(J) regions were amplified from the spleen and lymph tissue of mice immunized with the human complement protein C5, fused with a limited repertoire of human germline heavy chain V-genes to form intact humanized heavy chains, and paired with a human light chain library. Completed heavy and light chains were assembled for mammalian cell surface display and transfected into HEK 293 cells co-expressing activation-induced cytidine deaminase (AID).
View Article and Find Full Text PDFA novel approach has been developed for the isolation and maturation of human antibodies that replicates key features of the adaptive immune system by coupling in vitro somatic hypermutation (SHM) with mammalian cell display. SHM is dependent on the action of the B cell specific enzyme, activation-induced cytidine deaminase (AID), and can be replicated in non-B cells through expression of recombinant AID. A library of human antibodies, based on germline V-gene segments with recombined human regions was used to isolate low-affinity antibodies to human β nerve growth factor (hβNGF).
View Article and Find Full Text PDFBackground And Objectives: Extended-interval dosing of epoetin alfa (EPO) is commonly used to treat anemia in patients with chronic kidney disease (CKD). This study aimed to demonstrate that EPO dosed every 2 weeks (Q2W) and every 4 weeks (Q4W) was noninferior to once-weekly (QW) dosing.
Design, Setting, Participants, & Measurements: 430 anemic subjects with stage 3 to 4 CKD receiving a stable QW dose of EPO were randomized 1:1:2 to QW, Q2W, and Q4W dosing for 36 weeks.
Background And Objectives: In clinical practice, physicians often use once-weekly (QW) and biweekly (Q2W) dosing of epoetin alfa to treat anemia in patients with chronic kidney disease (CKD). Although the literature supports this practice, previous studies were limited by short treatment duration, lack of randomization, or absence of the approved three times per week (TIW) dosing arm. This randomized trial evaluated extended dosing regimens of epoetin alfa, comparing QW and Q2W to TIW dosing in anemic CKD subjects.
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