Structural basis for continued antibody evasion by the SARS-CoV-2 receptor binding domain.

Many studies have examined the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants on neutralizing antibody activity after they have become dominant strains. Here, we evaluate the consequences of further viral evolution. We demonstrate mechanisms through which the SARS-CoV-2 receptor binding domain (RBD) can tolerate large numbers of simultaneous antibody escape mutations and show that pseudotypes containing up to seven mutations, as opposed to the one to three found in previously studied variants of concern, are more resistant to neutralization by therapeutic antibodies and serum from vaccine recipients. We identify an antibody that binds the RBD core to neutralize pseudotypes for all tested variants but show that the RBD can acquire an N-linked glycan to escape neutralization. Our findings portend continued emergence of escape variants as SARS-CoV-2 adapts to humans.

Parenting, privilege, and pandemic: From surviving to thriving as a mother in the academy.

As women who have dual roles as parents and academicians, COVID-19 has presented new challenges and opportunities that have impacted our personal and professional lives. This essay provides insight into unique obstacles from the perspective of mothers, researchers, and social workers and challenges the traditional models of work/life balance as professionals in academics. This reflexive essay provides the narratives and experiences of one assistant professor and two doctoral students who are learning to navigate motherhood and professional responsibilities amidst a global pandemic. The prologue presents a perspective from a current assistant professor and her lived experiences followed by the reflections of two doctoral students on how to navigate the academy as mothers and as women. In addition to our personal stories and narratives, we hope to challenge, inspire, and reimagine how our dual roles can be viewed as an asset, rather than a weakness and encourage others in the academy to rise and support women.

Combination of soluble factors and biomaterial scaffolds enhance human adipose-derived stem/stromal cell myogenesis.

Volumetric muscle loss and muscle degeneration are conditions for which there are currently no effective treatment options. Human adipose stem cells (hASCs) offer promise in cell-based regenerative therapies to treat muscle damage due to their ability to self-renew and differentiate. However, in the absence of universal culture conditions that yield greater than 15% myogenic differentiation, the clinical potential of these cells is limited. Here we report on the evaluation of two different media recipes, three extracellular matrix (ECM) proteins, and a poly (ethylene glycol) (PEGDMA) hydrogel with a physiologically relevant elasticity to determine how the extracellular chemical and physical environment work together to enhance myogenic differentiation of hASCs. Our results identify a combination of unique biochemical and physical factors that promote myogenesis, laying the groundwork for creating a scaffold and culture medium that will effectively and efficiently direct myogenic differentiation of adult stem cells for clinical applications in the future.

Poly (ethylene glycol) hydrogel scaffolds with multiscale porosity for culture of human adipose-derived stem cells.

Three-dimensional (3 D) hydrogel scaffolds are an attractive option for tissue regeneration applications because they allow for cell migration, fluid exchange, and can be synthesized to closely mimic the physical properties of the extracellular matrix environment. The material properties of hydrogels play a vital role in cellular migration and differentiation. In light of this, in-depth understanding of material properties is required before such scaffolds can be used to study their influence on cells. Herein, various blends and thicknesses of poly (ethylene glycol) dimethacrylate (PEGDMA) hydrogels were synthesized, flash frozen, and dried by lyophilization to create scaffolds with multiscale porosity. Environmental scanning electron microscopy (ESEM) images demonstrated that lyophilization induced microporous voids in the PEGDMA hydrogels while swelling studies show the hydrogels retain their innate swelling properties. Change in pore size was observed between drying methods, polymer blend, and thickness when imaged in the hydrated state. Human adipose-derived stem cells (hASCs) were seeded on lyophilized and non-lyophilized hydrogels to determine if the scaffolds would support cell attachment and proliferation of a clinically relevant cell type. Cell attachment and morphology of the hASCs were evaluated using fluorescence imaging. Qualitative observations in cell attachment and morphology of hASCs on the surface of the different hydrogel spatial configurations indicate these multiscale porosity hydrogels create a suitable scaffold for hASC culture. These findings offer another factor of tunability in creating biomimetic hydrogels for various tissue engineering applications including tissue repair, regeneration, wound healing, and controlled release of growth factors.

Development of Responsive Chitosan-Genipin Hydrogels for the Treatment of Wounds.

Chronic wounds are characterized by an increased bacterial presence, alkaline pH, and excessive wound drainage. Hydrogel biomaterials composed of the carbohydrate polymer chitosan are advantageous for wound healing applications because of their innate antimicrobial and hemostatic properties. Here, genipin-cross-linked-chitosan hydrogels were synthesized and characterized, and their in vitro and in vivo performances were evaluated as a viable wound dressing. Characterization studies demonstrate that the developed chitosan-genipin hydrogels were able to neutralize an environmental pH, while averaging ∼230% aqueous solution uptake, demonstrating their use as a perfusive wound dressing. Bacterial activity studies demonstrate the hydrogels' ability to hinder Escherichia coli growth by ∼70%, while remaining biocompatible in vitro to fibroblast and keratinocyte cells. Furthermore, chitosan-genipin hydrogels promote an enhanced immune response and cellular proliferation in induced pressure wounds in mice. All together, these results reflect the potential of the developed hydrogels to be used as a proactive wound dressing.

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior.

Coordinated investigations into the interactions between biologically mimicking (biomimetic) material constructs and stem cells advance the potential for the regeneration and possible direct replacement of diseased cells and tissues. Any clinically relevant therapies will require the development and optimization of methods that mass produce fully functional cells and tissues. Despite advances in the design and synthesis of biomaterial scaffolds, one of the biggest obstacles facing tissue engineering is understanding how specific extracellular cues produced by biomaterial scaffolds influence the proliferation and differentiation of various cell sources. Matrix elasticity is one such tailorable property of synthetic scaffolds that is known to differ between tissues. Here, we investigate the interactions between an elastically tailorable polyethylene glycol (PEG)-based hydrogel platform and human bone marrow-derived mesenchymal stem cells (hMSCs). For these studies, two different hydrogel compositions with elastic moduli in the ranges of 50-60 kPa and 8-10 kPa were implemented. Our findings demonstrate that the different elasticities in this platform can produce changes in hMSC morphology and proliferation, indicating that the platform can be implemented to produce changes in hMSC behavior and cell state for a broad range of tissue engineering and regenerative applications. Furthermore, we show that the platform's different elasticities influence stem cell differentiation potential, particularly when promoting stem cell differentiation toward cell types from tissues with stiffer elasticity. These findings add to the evolving and expanding library of information on stem cell-biomaterial interactions and opens the door for continued exploration into PEG-based hydrogel scaffolds for tissue engineering and regenerative medicine applications.

Synthesis of (±)-Bisavenanthramide B-6 by an Anionic Anhydride Mannich Reaction.

Bisavenanthramide B-6 (2) is a highly substituted γ-lactam derived from oat leaves. Development of a new base-promoted anhydride Mannich reaction with N-sulfonylated imines that forms the core structure of 2 in a single step is presented. Further elaboration allows for a facile one-pot double Buchwald N-arylation to install the final rings onto the densely substituted γ-lactam core. This route provides the natural product in a longest linear sequence of nine steps.

Impact of pH on plasma protein binding in equilibrium dialysis.

Many pharmacokinetic analyses require unbound plasma concentrations, including prediction of clearance, volume of distribution, drug-drug interactions, brain uptake analysis, etc. It is most often more convenient to measure the total drug concentration in plasma rather than the unbound drug concentration. To arrive at unbound plasma concentrations, separate in vitro determinations of the plasma protein binding of a drug are usually carried out in serum or in plasma, and the plasma pharmacokinetic results are then mathematically adjusted by this fraction unbound ( f u,p). Plasma protein binding or the drug fraction unbound in plasma ( f u,p) is known to be affected by protein, drug, free fatty acid concentrations, lipoprotein partitioning, temperature, pH, and the presence or absence of other drugs/displacing agents within plasma samples. Errors in f u,p determination caused by lack of adequate pH control in newer assay formats for plasma protein binding (e.g., 96-well equilibrium thin walled polypropylene dialysis plates) will have significant drug-specific impact on these pharmacokinetic calculations. Using a diverse set of 55 drugs and a 96-well equilibrium dialysis plate format, the effect of variable pH during equilibrium dialysis experiments on measured values of f u,p was examined. Equilibrium dialysis of human plasma against Dulbecco's phosphate buffered saline at 37 degrees C under an air or 10% CO 2 atmosphere for 22 h resulted in a final pH of approximately 8.7 and 7.4, respectively. The ratio of f u,p at pH 7.4 (10% CO 2) vs pH 8.7 (air) was >or=2.0 for 40% of the 55 compounds tested. Only one of the 55 compounds tested had a ratio <0.9. Select compounds were further examined in rat and dog plasma. In addition, physicochemical properties were calculated for all compounds using ACD/Labs software or Merck in-house software and compared to plasma protein binding results. Changes in plasma protein binding due to pH increases which occurred during the equilibrium dialysis experiment were not species specific but were drug-specific, though nonpolar, cationic compounds had a higher likely hood of displaying pH-dependent binding. These studies underscore the importance of effectively controlling pH in plasma protein binding studies.

Infliximab therapy for sarcoidosis (lupus pernio).

Sarcoidosis is a chronic granulomatous disease of unknown aetiology in which the primary cytokine tumour necrosis factor (TNF)-alpha appears to play a major role. Older immune-modulating drugs including corticosteroids, antimalarials and thalidomide, as well as cytotoxic drugs with immune modulatory effects, have been used to control disease. We present a patient with severe mutilating cutaneous sarcoidosis (lupus pernio) who had showed only partial response to courses of a wide spectrum of immune modulators and cytotoxic therapies, and who had developed significant side-effects due to prolonged high-dose corticosteroids. However, the patient's cutaneous disease responded rapidly to the TNF-alpha inhibitor infliximab.

Durable loss of a malignant T-cell clone in a stage IV cutaneous T-cell lymphoma patient treated with high-dose interferon and photopheresis.

Stage IV cutaneous T-cell lymphoma (CTCL) has a notoriously poor prognosis and many treatment options exist. We describe the successful treatment of a case of stage IV CTCL with combination photopheresis and high-dose interferon alfa (IFNalpha). The patient was treated with combination therapy of monthly photopheresis and daily doses of IFNalpha up to 36 MU. Response to therapy was followed by clinical observation and Southern blot analysis for the detection of a malignant clone. The findings of this case were compared with others using a computer-based literature review. A complete clinical response lasting 64 months was achieved. Clinical relapse was preceded by an increase in the CD4/CD8 ratio and by reappearance of the T-cell receptor gene rearrangement. Combined photopheresis and high-dose IFNalpha led to a durable and sustained complete response in stage IV CTCL. CD4/CD8 ratios and T-cell gene rearrangements may be helpful in patient management.

Positive effects of a clinical performance assessment program.

Since 1986, there has been a clinical performance assessment program for fourth-year students at the University of Massachusetts Medical School. Students interact with several standardized patients (SPs) and complete other tasks such as interpretation of electrocardiograms and interpretation of X-rays. Scores are generated both by checklists and rating forms completed by the SPs and by paperwork completed by the students at the end of each encounter. Since 1986, students have been asked how frequently they have been observed by faculty and residents as they interacted with actual patients; the students report that such observations have markedly increased. Since 1989, there has been increased feedback to students by the attending faculty during and following clinical rotations. Although it is difficult to claim cause and effect, it is clear that since the inception of this exercise, the faculty have made a conscious effort to improve students' clinical skills by providing increased observation and feedback.

Results of a survey on the use of standardized patients to teach and evaluate clinical skills.

In 1989, a survey was sent to each U.S. and Canadian medical school requesting information about how standardized patients are used for teaching and evaluating clinical skills, and 95% of the schools responded. Although there was widespread use of standardized patients throughout the curricula, the role and training of these patients varied markedly within a given school as well as across schools. One outcome of this survey is the development of a network to share resources, protocols, and training material to enhance the development of this educational strategy.

Withholding medical treatment from the severely demented patient. Decisional processes and cost implications.

We performed an observational study to determine the prevalence of severe dementia in a general medicine unit, the categories of acute medical care provided to these patients, the process by which treatment decisions are made, and their cost implications. The prevalence of severe dementia was 4.4%. The patients from whom some form of acute medical care was withheld (26 [45.6%] of 57) were more severely ill at admission and had a mortality rate five times higher than those who received full care. Physicians cited family wishes in 75.9% of the decisions to limit care but in only 10.9% of the decisions to give full care. The only differences in charges incurred were due to differential mortality rates in individuals from whom care was withheld. We recommend that hospitals develop and implement protocols for decision making in the care of the severely demented to promote open discussions among providers and families and to increase family contributions to decision making. We believe that the extension of this consultative approach to decisions involving severely demented patients may have the virtue of combining more humane care with more cost-effective care.

Teaching the emotional aspects of cancer care.

In response to an awareness of the emotional needs of cancer patients and their families, a psychosocial oncology conference was begun at the Veterans Administration Medical Center in Houston, TX approximately 10 years ago. Its goal has been to educate medical staff about the mental health issues of cancer patients and to educate mental health professionals regarding the medical problems facing cancer patients. This article discusses the development of the conference, its objectives, its format, and its accomplishments. Patients are selected for the conference on the basis of the presenting problem and the potential for optimal education of staff members. The patient's case is presented, a live interview with the patient is conducted, and a discussion of the pertinent issues follows. Illustrative case examples are presented in order to demonstrate the value of this meeting for the participants. Throughout its history, the conference has undergone a number of changes, primarily in response to the reactions and needs of those involved. These modifications are described, along with the results which have been achieved and the implications for the expansion of this concept.