Correlating Surface Activity with Interface-Induced Aggregation in a High-Concentration mAb Solution.

Interface-induced aggregation resulting in protein particle formation is an issue during the manufacturing and storage of protein-based therapeutics. High-concentration formulations of therapeutic proteins are even more prone to protein particle formation due to increased protein-protein interactions. However, the dependence of interface-induced protein particle formation on bulk protein concentration is not understood. Furthermore, the formation of protein particles is often mitigated by the addition of polysorbate-based surfactants. However, the details of surfactant-protein interactions that prevent protein particle formation at high concentrations remain unclear. In this work, a tensiometer technique was used to evaluate the surface pressure of an industrially relevant mAb at different bulk concentrations, and in the absence and presence of a polysorbate-based surfactant, polysorbate 20 (PS20). The adsorption kinetics was correlated with subvisible protein particle formation at the air-water interface and in the bulk protein solution using a microflow imaging technique. Our results showed that, in the absence of any surfactant, the number of subvisible particles in the bulk protein solutions increased linearly with mAb concentration, while the number of protein particles measured at the interface showed a logarithmic dependence on bulk protein concentration. In the presence of surfactants above the critical micelle concentration (CMC), our results for low-concentration mAb solutions (10 mg/mL) showed an interface that is surfactant-dominated, and particle characterization results showed that the addition of the surfactant led to reduced particle formation. In contrast, for the highest concentration (170 mg/mL), coadsorption of proteins and surfactants was observed at the air-water interface, even for surfactant formulations above CMC and the surfactant did not mitigate subvisible particle formation. Our results taken together provide evidence that the ratio between the surfactant and mAb molecules is an important consideration when formulating high-concentration mAb therapeutics to prevent unwanted aggregation.

Correlating Differences in the Surface Activity to Interface-Induced Particle Formation in Different Protein Modalities: IgG mAb Versus Fc-Fusion Protein.

The propensity of protein-based biologics to form protein particles during bioprocessing can be related to their interfacial properties. In this study, we compare the surface activity and interfacial film properties of two structurally different biologics, an IgG and Fc-fusion, in the absence and presence of interfacial dilatational stresses, and correlate these differences to their tendency to form interface-induced protein particles. Our results show that interface-induced particle formation is protein-dependent, with the Fc-fusion demonstrating greater interfacial stability. This observation can be correlated with faster adsorption kinetics of the Fc-fusion protein, and formation of a less incompressible film at the air-liquid interface. The addition of polysorbate 80 (PS80), commonly added to mitigate protein particle formation, led to a surfactant-dominant interface for quiescent conditions and coadsorption of protein and surfactant for the Fc-fusion when exposed to interfacial stress. On the other hand, for the IgG molecule, the surface always remained surfactant dominant. Image analysis demonstrated that PS80 was more effective in mitigating particle formation for the IgG than Fc-fusion. This suggests that a surfactant-dominant interface is necessary to prevent interface-induced protein particle formation. Further, while PS80 is effective in mitigating particle formation in the IgG formulation, it may not be the best choice for other protein modalities.

Telehealth Virtual Simulation Across the Family Nurse Practitioner Curriculum.

ABSTRACT: The American Association of Colleges of Nursing recognizes telehealth education as an essential aspect of nurse practitioner (NP) education because it increases accessibility to health care. Studies reported in the literature have focused on NP telehealth simulation, but findings for the inclusion of simulation in multiple courses throughout the curriculum are scarce. This pre- and post-survey design study aimed to evaluate family nurse practitioner students' perceptions of knowledge, confidence, and attitudes regarding telehealth before and after engaging in telehealth virtual simulations in six courses. Simulations were rated highly and telehealth knowledge increased in three of the six courses.

Comparison of Protein Particle Formation in IgG1 mAbs Formulated with PS20 Vs. PS80 When Subjected to Interfacial Dilatational Stress.

Polysorbates (PS) are nonionic surfactants that are commonly included in protein formulations to mitigate the formation of interfacial stress-induced protein particles and thus increase their long-term storage stability. Nonetheless, factors that dictate the efficiency of different polysorbates in mitigating protein particle formation, especially during the application of interfacial stresses, are often ill defined. Here, we used a Langmuir trough to determine the surface activity of two IgG1 monoclonal antibodies formulated with two different polysorbates (PS20 and PS80) when subjected to interfacial dilatational stress. Interfacial properties of these formulations were then correlated with characterization of subvisible protein particles measured by micro-flow imaging (MFI). Both mAbs, when formulated in PS20, demonstrate faster adsorption kinetics and higher surface activity compared to PS80 or surfactant-free formulations. Compression/expansion results suggest that when exposed to interfacial dilatational stresses, both mAb/PS20 formulations display interfacial properties of PS20 alone. In contrast, interfacial properties of both mAb/PS80 formulations suggest mAbs and PS80 are co-adsorbed to the air-water interface. Further, MFI analysis of the interface and the bulk solution confirms that PS20 is more effective than PS80 at mitigating the formation of larger particles in the bulk solution in both mAbs. Concomitantly, the efficiency of PS to prevent interface-induced protein particle formation also depended on the protein's inherent tendency to aggregate at a surfactant-free interface. Together, the studies presented here highlight the importance of determining the interfacial properties of mAbs, surfactants, and their combinations to make informed formulation decisions about the choice of surfactant.

Understanding the Impact of Combined Hydrodynamic Shear and Interfacial Dilatational Stress, on Interface-Mediated Particle Formation for Monoclonal Antibody Formulations.

During biomanufacturing, several unit operations expose solutions of biologics to multiple stresses, such as hydrodynamic shear forces due to fluid flow and interfacial dilatational stresses due to mechanical agitation or bubble collapse. When these stresses individually act on proteins adsorbed to interfaces, it results in an increase in protein particles in the bulk solution, a phenomenon referred to as interface-induced protein particle formation. However, an understanding of the dominant cause, when multiple stresses are acting simultaneously or sequentially, on interface-induced protein particle formation is limited. In this work, we established a unique set-up using a peristaltic pump and a Langmuir-Pockels trough to study the impact of hydrodynamic shear stress due to pumping and interfacial dilatational stress, on protein particle formation. Our experimental results together demonstrate that for protein solutions subjected to various combinations of stress (i.e., interfacial and hydrodynamic stress in different sequences), surface pressure values during adsorption and when subjected to compression/dilatational stresses, showed no change, suggesting that the interfacial properties of the protein film are not impacted by pumping. The concentration of protein particles is an order of magnitude higher when interfacial dilatational stress is applied at the air-liquid interface, compared to solutions that are only subjected to pumping. Furthermore, the order in which these stresses are applied, have a significant impact on the concentration of protein particles measured in the bulk solution. Together, these studies conclude that for biologics exposed to multiple stresses throughout bioprocessing and manufacturing, exposure to air-liquid interfacial dilatational stress is the predominant mechanism impacting protein particle formation at the interface and in the bulk solution.

The impact of the COVID-19 pandemic on infant and toddler development.

BACKGROUND: The COVID-19 pandemic has created new cultural norms with pervasive societal implications. Families have experienced a heightened amount of physical, psychological, emotional, and financial stress. Infants and children living with stress have the potential for delayed developmental milestones, difficulty with emotional regulation, and social or behavioral issues. PURPOSE: This study aims to determine if the pandemic has affected developmental outcomes in infants and toddlers. METHODOLOGY: Prepandemic and postpandemic developmental (ASQ-3) scores were obtained from charts of 1,024 patients (6, 12, 18, 24, and 36 months) from two pediatric practices. RESULTS: There were no significant differences in prepandemic and postpandemic ASQ-3 scores for the overall sample. Age-group analysis showed statistically significant differences in domain scores. Postpandemic problem-solving scores decreased among 6-month-olds while increasing among 24-month-olds. Categorization by score interpretation categories showed a slight decrease in postpandemic scores in the communication domain among 6- and 12-month-olds. CONCLUSIONS: The pandemic has the potential to affect childhood development. However, the results of this study are reassuring, showing only slight differences in developmental scores prepandemic versus postpandemic. More studies are needed to establish causation and possible trends in future developmental trajectories. IMPLICATIONS: An increased focus on communication screening and promotion of language and communication skills in young children postpandemic is needed. Education about the importance of parent-child engagement, nurturing relationships, opportunities for free-play and exploration, and caregiver support and stress reduction will continue to be of paramount importance.

Evaluating the Combined Impact of Temperature and Application of Interfacial Dilatational Stresses on Surface-mediated Protein Particle Formation in Monoclonal Antibody Formulations.

Formation of submicron and subvisible protein particles (0.1-100 µm) present a major obstacle during processing and storage of therapeutic proteins. While protein aggregation resulting in particle formation is well-understood in bulk solution, the mechanisms of aggregation due to interfacial stresses is less understood. Particularly, in this study, we focus on understanding the combined effect of temperature and application of interfacial dilatational stresses, on interface-induced protein particle formation, using two industrially relevant monoclonal antibodies (mAbs). The surface activity of Molecule C (MC) and Molecule B (MB) were measured at room temperature (RT) and 4 °C in the absence and presence of interfacial dilatation stress using a Langmuir trough. These results were correlated with Micro-flow imaging (MFI) to characterize formation of subvisible protein particles at the interface and in the bulk solution. Our results show that the surface activity for both proteins is temperature dependent. However, the extent of the impact of temperature on the mechanical properties of the monomolecular protein films when subjected to dilatational stresses is protein dependent. Protein particle analysis provided evidence that protein particles formed in bulk solution originate at the interface and are dependent on both application of thermal stresses and interfacial dilatational stresses. In the absence of any interfacial stresses, more and larger protein particles were formed at the interface at RT than at 4 °C. When mAb formulations are subjected to interfacial dilatational stresses, protein particle formation in bulk solution was found to be temperature dependent. Together our results validate that mAb solutions maintained at 4 °C can lower the surface activity of proteins and reduce their tendency to form interface-induced protein particles both in the absence and presence of interfacial dilatational stresses.

Transitioning the Doctor of Nursing Practice Final Project Defense to Large Venue Poster Sessions.

BACKGROUND: Accelerated growth in Doctor of Nursing Practice (DNP) programs has mandated the need for innovative strategies for doctoral students to defend their final scholarly work while protecting the integrity and rigor of the experience. METHOD: A poster defense strategy was implemented and evaluated via a faculty focus group and a Likert-scale survey. Sessions highlighting eight projects each were scheduled at 75-minute intervals allowing for both informal poster viewing and formal audience questioning facilitated by a moderator. Evaluation of the event trended positive, with focus group members celebrating the energy around each session, noting the significant increase in audience size compared to past podium defenses. CONCLUSION: Evaluators who attended previous DNP project defenses all indicated that the large venue poster session approach was just as or more effective than previous methods. [J Nurs Educ. 2020;59(1):51-53.].

Sleep apnea in hemodialysis patients: risk factors and effect on survival.

UNLABELLED: Sleep disorders are common in patients with end-stage renal disease (ESRD). Using a simple questionnaire, we estimate the probability of sleep apnea in ESRD patients, determine the factors associated with a higher probability of sleep apnea, and determine the association between the probability of sleep apnea and cardiovascular and all-cause mortality. STUDY DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: prevalent hemodialysis patients (n=270) in 7 urban outpatient hemodialysis units. PREDICTOR: Probability of sleep apnea as quantified by the Flemons questionnaire. OUTCOMES AND MEASUREMENTS: Clinical, demographic, and dialysis-related characteristics were obtained at baseline. Total and cardiovascular mortality was ascertained after a median follow-up of 34 months. The probability of sleep apnea was low in 79 (29%) patients, moderate in 116 (43%) patients, and high in 75 (28%) patients. Male gender (odds ratio [OR] 5.13, p<0.001), obesity (BMI >30, OR 7.58, p<0.01), and interdialytic weight gain (OR 1.72/kg change, p<0.004) were independently associated with a high probability of sleep apnea. A high probability of sleep apnea at baseline did not predict total (hazard ratio [HR] 0.81, p=NS) or cardiovascular mortality (HR 0.9, p=NS). The Flemons questionnaire is validated in the general population, but has not been tested specifically in hemodialysis patients. The study may not be adequately powered to detect a difference in mortality. A high proportion of hemodialysis patients are likely to have sleep apnea; a simple bedside questionnaire can be used for screening to identify these patients. Excessive interdialytic weight gain is a potentially modifiable factor that increases the likelihood of sleep apnea. Despite the presence of a strong association between sleep apnea and mortality in the general population, a similar association could not be demonstrated in ESRD patients with a high prevalence of this condition.

Providing Individualized Care to Adolescent Patients With Elevated Body Mass Indexes.

The purpose of this project was to develop a comprehensive, Nutritional Assessment Questionnaire encompassing adolescent eating habits. A Nutritional Assessment Questionnaire was developed and administered to a convenience sample of 15 patient participants. Four pediatric provider participants reviewed the questionnaire with the adolescents and documented accordingly. A chart comparison was completed to ascertain any differences in charting pre- and postimplementation. The providers participated in a focus group and responded to questions surrounding implementation of the questionnaire. Use of a comprehensive Nutritional Assessment Questionnaire can aid the pediatric provider in developing a patient-centered management plan.

Evolving role of pediatric nurse practitioners.

PURPOSE: To report and interpret findings from national pediatric nurse practitioner (PNP) job analysis surveys reflecting the changes in the knowledge and skills required for advanced practice. DATA SOURCES: National role delineation studies (RDS) conducted by American Nurses Credentialing Center (ANCC) in 2003, 2008, and 2011. CONCLUSIONS: Since the first nurse practitioner (NP) program was established in 1965 to train pediatric nurses for advanced practice, the role of the PNP has continued to develop. The RDS results demonstrate the increased autonomy of PNP's prescription of medication as the top work activity category identified, followed by the reporting of suspected abuse, exploitation, and/or neglect and immunizing based on current recommendations. IMPLICATIONS FOR PRACTICE: Analysis of the changes in role or work activities, tied to the knowledge and skills required to perform those activities, can provide content for educators updating curriculum, for clinicians to remain current in their practice and impact healthcare policy. The current PNP role has evolved to meet the workforce demands of providing primary care to the pediatric population with increasing complex social and healthcare needs. Role analysis is important as NPs move forward to practice to the full extent of their education and training.

Diurnal variation of blood pressure; reproducibility and association with left ventricular hypertrophy in hemodialysis patients.

OBJECTIVE: The objective of this paper is to describe the pattern of diurnal blood pressure (BP) change in hemodialysis patients, determine the association of the non-dipping pattern of diurnal BP with left ventricular mass index (LVMI), and to determine if the nocturnal profile of BP is reproducible when repeated over time. METHODS: In a cross-sectional study, ambulatory blood pressure monitoring (ABPM) was performed over a midweek 44-h period and echocardiography was performed on the interdialytic day. Patients with a night/day systolic and diastolic BP ratio on both days >0.9 were defined as non-dippers. Ambulatory blood pressure monitoring was repeated at 6 and 12 months follow-up. RESULTS: Of the 59 patients, 88% were African-American, and 48% were non-dippers. Mean LVMI was significantly higher in the non-dipper (68.3+/-25 g/height) compared to the dipper patients (55.6+/-16, P<0.05). Mean nocturnal systolic BP (r=0.35) and the night/day systolic BP ratio (r=0.39) had a higher correlation with M-mode LVMI than pre-dialysis (r=0.32). After adjustment for 44-h mean SBP, night/day systolic BP ratio remained independently associated with LVMI (beta coefficient 147.62, P=0.004). Of 12 patients who had a non-dipper profile at baseline, 11 (92%) demonstrated the same profile after 6 months and 1 year of follow-up. CONCLUSION: Many hemodialysis patients demonstrate a non-dipper profile; the degree of decline in nocturnal BP is independently associated with LVMI even after adjustment for mean BP. Patients who are identified as non-dippers consistently reproduce the same profile over time.

A comparison of standardized versus "usual" blood pressure measurements in hemodialysis patients.

Hypertension is very common and contributes to the high cardiovascular morbidity in patients undergoing chronic hemodialysis therapy. However, the accuracy of blood pressure measurement in this population has not been well studied. We conducted a cross-sectional study of 270 patients at seven outpatient hemodialysis units. Predialysis and postdialysis seated blood pressure readings obtained by the dialysis unit using automated blood pressure monitors were significantly higher than readings obtained by a research nurse following standard procedures for blood pressure measurement (14.3/7 mm Hg higher predialysis; P < 0.01; 13.6/4.4 mm Hg higher postdialysis; P < 0.05). In 55% of patients, the postdialysis systolic blood pressure measured in the dialysis unit was at least 10 mm Hg higher than the standard reading. Bland-Altman analyses indicated poor agreement between the two readings. This study shows a marked discrepancy between routine dialysis unit and standardized blood pressure measurements. Blood pressure is frequently overestimated by routine dialysis unit readings. In light of these findings, efforts should be made to standardize blood pressure readings in hemodialysis units based on American Heart Association recommendations for blood pressure measurement.

Patterns of antihypertensive medication use in hemodialysis patients.

PURPOSE: Patterns of antihypertensive drug use in patients undergoing long-term hemodialysis therapy were studied. METHODS: Patients attending seven outpatient hemodialysis units in Ohio were eligible for the study if they had been receiving the treatment for at least three months. Demographic and clinical data were obtained from patient interviews and computerized databases, and blood pressure (BP) measurements were obtained before dialysis. Labeled names and dosages of antihypertensive drugs were recorded from containers the patients brought with them. Patients were asked to describe their adherence to the medications, their ability to afford the drugs, and their knowledge and beliefs about hypertension. Physical impairments in taking medication were also evaluated. RESULTS: The frequency of hypertension was 89% in the 270 participants. Antihypertensive drugs were prescribed for 76% of the patients; 25% required three or more drugs. Hypertensive patients who were not receiving antihypertensive drugs (14%) had significantly higher BP than patients who were. Calcium-channel blockers were prescribed for 60% of patients, angiotensin-converting-enzyme inhibitors for 33%, and beta-blockers for 34%. Eighty-three percent said the cost of drugs was never a problem, and 23% said they sometimes forgot to take their medication. Almost all patients said they would not stop taking antihypertensive drugs if they were feeling better and agreed that monitoring BP was important. Twenty-two percent could not read the warning on a standard tablet container, and 12% could not remove one tablet from the container. CONCLUSION: Multidrug antihypertensive therapy was common among hemodialysis patients and was associated with significantly lower BP; calcium-channel blockers were the most frequently prescribed agents. Most patients said they could afford drugs and reported good adherence to antihypertensive drug therapy.

Determinants of salt sensitivity in black and white normotensive and hypertensive women.

Salt sensitivity (SS) has been linked to human hypertension. We examined ethnic differences in the relation between SS; erythrocyte sodium (Na+i), calcium (Ca2+i), potassium (K+i), and magnesium (Mg2+i); and sodium pump activity in African-American (AA) and white women. In a crossover protocol, similar numbers of normotensive, hypertensive, AA, and white women were randomized to 7 days of a 20 meq/d and a >200 meq/d salt diet (n=199). After an overnight inpatient stay, group differences in supine blood pressure (BP), heart rate, erythrocyte cations, and sodium pump activity were measured. The prevalence of SS (53.5% vs 51%) and salt resistance (26.3% vs 30.0%) was similar in both races. Greater mean BP increase with salt loading was seen in AA vs white hypertensives but not between the normotensive women. In hypertensives, increase in mean arterial pressure was 12.6 vs 8.2 mm Hg in AAs vs whites, respectively (P<0.01), and for systolic BP, it was 23 vs 14.8 mm Hg (P<0.01). Higher Na+i and Ca2+i were noted in SS and salt-intermediate AA than in the corresponding white subjects. Na+i, Ca2+i, and the ratios of Na+i to K+i and of Ca2+i to Mg2+i were positively correlated with salt responsiveness in AA but not in white women. Sodium pump activity was similar between groups, although the change in maximal activity trended to vary inversely with SS in AA. In closely matched AA and white women, the prevalence of SS is similarly high in both races, although the magnitude of BP increase is greater in AA hypertensives. In AA but not in whites, SS is positively associated with Na+i, Ca2+i, and the ratios of Na+i to K+i and of Ca2+i to Mg2+i.