Selective Stabilization and Destabilization of Protein Domains in Tissue-Type Plasminogen Activator Using Formulation Excipients.

Multidomain biotherapeutic proteins present additional behavioral and analytical challenges for the optimization of their kinetic stability by formulation. Tissue-type plasminogen activator (tPA) comprises six protein domains that exhibit a complex and pH-dependent thermal unfolding profile, due to partially independent domain unfolding. Here we have used tPA as a model for evaluating the relationships between various thermal unfolding and aggregation parameters in multidomain proteins. We show that changes in the thermal unfolding profile of tPA were parametrized by the overall thermal midpoint transition temperature, Tm, and the Van't Hoff entropy for unfolding, Δ Svh, which is a measure of unfolding cooperativity. The kinetics of degradation at 45 °C, leading to aggregation, were measured as rates of monomer and activity loss. These two rates were found to be coincident at all pH. Aggregation accelerated at pH 4 due to the early unfolding of the serine protease N-terminal domain (SP-N), whereas at pH 5-8, the fraction unfolded at 45 °C ( f45) was <1%, resulting in a baseline rate of aggregation from the native ensemble. We used a Design of Experiments (DoE) approach to evaluate how formulation excipients impact and control the thermal unfolding profile for tPA and found that the relative stability of each of the tPA domains was dependent on the formulation. Therefore, the optimization of formulations for complex multidomain proteins such as tPA may need to be multiobjective, with careful selection of the desired attributes that improve stability. As aggregation rates (ln v) correlated well to Tm ( R2 = 0.77) and Δ Svh ( R2 = 0.71) but not Tagg ( R2 = 0.01), we analyzed how formulation excipients and pH would be able to optimize Tm and Δ Svh. Formulation excipient behaviors were found to group according to their combined impact on Tm and Δ Svh. The effects of each excipient were often selectively stabilizing or destabilizing to specific tPA domains and changed the stability of particular domains relative to the others. The types of mechanism by which this could occur might involve specific interactions with the protein surface, or otherwise effects that are mediated via the solvent as a result of the different surface hydrophobicities and polarities of each domain.

Tm-Values and Unfolded Fraction Can Predict Aggregation Rates for Granulocyte Colony Stimulating Factor Variant Formulations but Not under Predominantly Native Conditions.

Protein engineering and formulation optimization strategies can be taken to minimize protein aggregation in the biopharmaceutical industry. Short-term stability measures such as the midpoint transition temperature (Tm) for global unfolding provide convenient surrogates for longer-term (e.g., 2-year) degradation kinetics, with which to optimize formulations on practical time-scales. While successful in some cases, their limitations have not been fully evaluated or understood. Tm values are known to correlate with chemical degradation kinetics for wild-type granulocyte colony stimulating factor (GCSF) at pH 4-5.5. However, we found previously that the Tm of an antibody Fab fragment only correlated with its rate of monomer loss at temperatures close to the Tm. Here we evaluated Tm, the fraction of unfolded protein (fT) at temperature T, and two additional short-term stability measures, for their ability to predict the kinetics of monomer and bioactivity loss of wild-type GCSF and four variants, at 37 °C, and in a wide range of formulations. The GCSF variants introduced one to three mutations, giving a range of conformational stabilities spanning 7.8 kcal mol-1. We determined the extent to which the formulation rank order differs across the variants when evaluated by each of the four short-term stability measures. All correlations decreased as the difference in average Tm between each pair of GCSF variants increased. The rank order of formulations determined by Tm was the best preserved, with R2-values >0.7. Tm-values also provided a good predictor (R2 = 0.73) of the aggregation rates, extending previous findings to include GCSF variant-formulation combinations. Further analysis revealed that GCSF aggregation rates at 37 °C were dependent on the fraction unfolded at 37 °C (fT37), but transitioned smoothly to a constant baseline rate of aggregation at fT37 < 10-3. A similar function was observed previously for A33 Fab formulated by pH, ionic strength, and temperature, without excipients. For GCSF, all combinations of variants and formulations fit onto a single curve, suggesting that even single mutations destabilized by up to 4.8 kcal mol-1, are insufficient to change significantly the baseline rate of aggregation under native conditions. The baseline rate of aggregation for GCSF under native conditions was 66-fold higher than that for A33 Fab, highlighting that they are a specific feature of each native protein structure, likely to be dependent on local surface properties and dynamics.

First isolation of Arcanobacterium pinnipediorum from a grey seal pup (Halichoerus grypus) in the UK.

In the present study, a single Arcanobacterium (A.) pinnipediorum strain isolated from discharge of a jaw swelling of a grey seal pup (Halichoerus grypus) in England, UK, was identified. This strain was further characterized by phenotypical investigations, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), by Fourier transform infrared spectroscopy (FT-IR), and genotypically by sequencing the 16S rRNA gene and the genes gap encoding glyceraldehyde 3-phosphate dehydrogenase, tuf encoding elongation factor tu, and rpoB encoding the ß subunit of bacterial RNA polymerase. The present study gives a first detailed characterization of the species A. pinnipediorum from a grey seal in the UK. However, the route of infection of the grey seal with the bacterial pathogen remains unclear.

Ability and willingness to utilize telemedicine among rheumatology patients-a cross-sectional survey.

INTRODUCTION/OBJECTIVES: This study aims to assess the patients' ability and willingness to utilize telemedicine (TM) along with identifying some of the barriers to a more widespread adoption of TM in rheumatology. METHODS: An observational, cross-sectional study of patients visiting a rheumatology clinic was conducted in 2018. We used a survey to assess patients' attitude on the perceived effectiveness when comparing TM versus in-person visits, as well as patients' access to technology, distance traveled by the patient to attend the clinic visit, and demographic parameters. RESULTS: A total of 214 patients were included. Negative correlations were found between the increase in age and access to technologies (front-facing camera (mean age difference - 12.8), telephone (mean age difference - 14.4), and stable internet connection (mean age difference - 15.1)), as well as believing that their needs could be met through TM (r - .224, p < 0.001) and thinking that TM could be an appropriate alternative method of healthcare (r - .298, p < 0.001). Younger patients reported more conflict between appointments and work hours (mean age difference - 11.73). Follow-up patients were more likely to feel that their visit could have been possible over the phone (mean difference - 1.13) or video conferencing (mean difference - 1.13) compared to new patients. Older patients were less likely to think that the purpose of their rheumatology visits could be achieved over the phone (r - .207, p = 0.003) or video conferencing (r - .331, p = 0.001). The further the distance traveled, the more the patients were willing to utilize TM compared to in-person visits (r 0.167, p = 0.019). CONCLUSION: Out of necessity due to the COVID-19 pandemic, rheumatology clinics are increasingly turning to TM. The results of this study suggest that access and familiarity with technology may still be limited in certain demographics, particularly the elderly. Furthermore, this study helps to understand some of the additional barriers to more widespread adoption and patients' perceived limitations of TM. Key Points • This study aimed to assess rheumatology patients' willingness to utilize telemedicine (TM) while determining the factors and barriers that may exist for a more widespread adoption of TM, using a cross-sectional survey in the setting of a rheumatologic clinic. • The age of the patient was the most significant contributing factor in a patient's perception of TM, with older patients being less likely to think that the purpose of their rheumatology visits could be achieved over the phone or via videoconferencing. • The social trend of limited access to technology among the elderly population was reinforced by the results in this study. • Patients who had a greater commute to the clinic were more likely to willing to utilize TM consultations. • The results of this study highlight the elevated difficulty elderly patient populations have in utilizing TM. • With the current outbreak of COVID-19, the importance of utilizing TM specifically among the elderly population could prove vital. Future studies to focus on the elderly population and methods for helping these patients become familiar with TM would be beneficial. • Studies such as this can help to orchestrate future guidelines for TM in the field of rheumatology. Based on our study results, the new-patient encounter should be an in-person face-to-face encounter whenever possible, followed by TM visits for established patients who are able and open to using it, depending on the diagnosis and symptoms of the individual patients.

Epoxide ring-opening and Meinwald rearrangement reactions of epoxides catalyzed by mesoporous aluminosilicates.

Mesoporous aluminosilicates efficiently catalyze the ring-opening of epoxides to produce beta-alkoxyalcohols in high yields under extremely mild reaction conditions. These materials also catalyze the corresponding Meinwald rearrangement in non-nucleophilic solvents to give aldehydes which can be trapped in situ to provide the corresponding acetals in an efficient tandem process.

Assessing Voice Hearing in Trauma Spectrum Disorders: A Comparison of Two Measures and a Review of the Literature.

Voice hearing (VH) can occur in trauma spectrum disorders (TSD) such as posttraumatic stress disorder (PTSD) and dissociative disorders. However, previous estimates of VH among individuals with TSD vary widely. In this study, we sought to better characterize the rate and phenomenology of VH in a sample of 70 women with TSD related to childhood abuse who were receiving care in a specialized trauma program. We compared the rate of VH within our sample using two different measures: 1) the auditory hallucination (AH) item in the Structured Clinical Interview for DSM-IV-TR (SCID), and 2) the thirteen questions involving VH in the Multidimensional Inventory of Dissociation (MID), a self-report questionnaire that comprehensively assesses pathological dissociation. We found that 45.7% of our sample met threshold for SCID AH, while 91.4% met criteria for MID VH. Receiver operating characteristics (ROC) analyses showed that while SCID AH and MID VH items have greater than chance agreement, the strength of agreement is only moderate, suggesting that SCID and MID VH items measure related but not identical constructs. Thirty-two patients met criteria for both SCID AH and at least one MID VH item ("unequivocal VH"), 32 for at least one MID VH item but not SCID AH ("ambiguous VH"), and 6 met criteria for neither ("unequivocal non-VH"). Relative to the ambiguous VH group, the unequivocal VH group had higher dissociation scores for child voices, and higher mean frequencies for child voices and Schneiderian voices. Our findings suggest that VH in women with TSD related to childhood abuse is common, but that the rate of VH depends on how the question is asked. We review prior studies examining AH and/or VH in TSD, focusing on the measures used to ascertain these experiences, and conclude that our two estimates are consistent with previous studies that used comparable instruments and patient samples. Our results add to growing evidence that VH-an experience typically considered psychotic or psychotic-like-is not equivalent to having a psychotic disorder. Instruments that assess VH apart from psychotic disorders and that capture their multidimensional nature may improve identification of VH, especially among patients with non-psychotic disorders.