Endothelial Dysfunction: Associations with Exposure to Ambient Fine Particles in Diabetic Individuals

BACKGROUND: Exposure to fine airborne particulate matter [<= 2.5 mu m in aerodynamic diameter (PM2.5)] has been associated with cardiovascular and hematologic effects, especially in older people with cardiovascular disease. Some epidemiologic studies suggest that adults with diabetes also may be a particularly susceptible population. OBJECTIVES: The purpose of this study was to analyze the short-term effects of ambient PM2.5 on markers of endothelial function in diabetic volunteers.METHODS: We conducted a prospective panel study in 22 people with type 2 diabetes mellitus in Chapel Hill, North Carolina (USA), from November 2004 to December 2005. We acquired daily measurements of PM2.5 and meteorologic data at central monitoring sites. On 4 consecutive days, we measured endothelial function by brachial artery ultrasound in all participants and by pulsewave measurements in a subgroup. Data were analyzed using additive mixed models with a random participant effect and adjusted for season, day of the week, and meteorology. RESULTS: Flow-mediated dilatation decreased in association with PM2.5 during the first 24 hr, whereas small-artery elasticity index decreased with a delay of 1 and 3 days. These PM2.5-associated decrements in endothelial function were greater among participants with a high body mass index, high glycosylated hemoglobin Ale, low adiponectin, or the null polymorphism of glutathione S-transferase M1. However, high levels of myeloperoxidase on the examination day led to strongest effects on endothelial dysfunction. CONCLUSIONS: These data demonstrate that PM2.5 exposure may cause immediate endothelial dysfunction. Clinical characteristics associated with insulin resistance were associated with enhanced effects of PM on endothelial function. In addition, participants with greater oxidative potential seem to be more susceptible

Controlling Active Site Loop Dynamics in the (β/α)8 Barrel Enzyme Indole-3-Glycerol Phosphate Synthase

The β1α1 loop in the tryptophan biosynthetic enzyme indole-3-glycerol phosphate synthase (IGPS) is important for substrate binding, product release and chemical catalysis. IGPS catalyzes the ring closure of the substrate 1-(o-carboxyphenylamine)-1-dexoyribulose 5-phosphate to form indole-3-glycerol phosphate, involving distinct decarboxylation and dehydration steps. The ring closure step is rate-determining in the thermophilic Sulfolobus sulfataricus enzyme (ssIGPS) at high temperatures. The β1α1 loop is especially important in the dehydration step as it houses the general acid Lys53. We propose that loop dynamics are governed by competing interactions on the N- and C-terminal sides of the loop. We had previously shown that disrupting interactions with the N-terminal side of the loop through the N90A substitution decreases catalytic efficiency, slows down the dehydration step and quenches loop dynamics on the picosecond to millisecond timescales. Here, we show that disrupting interactions on the C-terminal side of the loop through the R64A/D65A substitutions likewise decreases catalytic efficiency, slows down the dehydration step and quenches loop dynamics. Interestingly, the triple substitution R64A/D65A/N90A leads to new μs–ms timescale loop dynamics and makes the ring-closure step rate-determining once again. These results are consistent with a model in which the β1α1 loop is maintained in a structurally dynamic state by these competing interactions, which is important for the dehydration step of catalysis. Competing interactions in other enzymes may likewise keep their loops and other structural elements appropriately mobile

Impact of Maternal Thyroperoxidase Status on Fetal Body and Brain Size

The obstetric consequences of abnormal thyroid function during pregnancy have been established. Less understood is the influence of maternal thyroid autoantibodies on infant outcomes. The objective of this study was to examine the influence of maternal thyroperoxidase (TPO) status on fetal/infant brain and body growth. Six-hundred thirty-one (631) euthyroid pregnant women were recruited from prenatal clinics in Tampa Bay, Florida, and the surrounding area between November 2007 and December 2010. TPO status was determined during pregnancy and fetal/infant brain and body growth variables were assessed at delivery. Regression analysis revealed maternal that TPO positivity was significantly associated with smaller head circumference, reduced brain weight, and lower brain-to-body ratio among infants born to TPO+ white, non-Hispanic mothers only, distinguishing race/ethnicity as an effect modifier in the relationship. No significant differences were noted in body growth measurements among infants born to TPO positive mothers of any racial/ethnic group. Currently, TPO antibody status is not assessed as part of the standard prenatal care laboratory work-up, but findings from this study suggest that fetal brain growth may be impaired by TPO positivity among certain populations; therefore autoantibody screening among high-risk subgroups may be useful for clinicians to determine whether prenatal thyroid treatment is warranted

Impact of Maternal Thyroperoxidase Status on Fetal Body and Brain Size

The obstetric consequences of abnormal thyroid function during pregnancy have been established. Less understood is the influence of maternal thyroid autoantibodies on infant outcomes. The objective of this study was to examine the influence of maternal thyroperoxidase (TPO) status on fetal/infant brain and body growth. Six-hundred thirty-one (631) euthyroid pregnant women were recruited from prenatal clinics in Tampa Bay, Florida, and the surrounding area between November 2007 and December 2010. TPO status was determined during pregnancy and fetal/infant brain and body growth variables were assessed at delivery. Regression analysis revealed maternal that TPO positivity was significantly associated with smaller head circumference, reduced brain weight, and lower brain-to-body ratio among infants born to TPO+ white, non-Hispanic mothers only, distinguishing race/ethnicity as an effect modifier in the relationship. No significant differences were noted in body growth measurements among infants born to TPO positive mothers of any racial/ethnic group. Currently, TPO antibody status is not assessed as part of the standard prenatal care laboratory work-up, but findings from this study suggest that fetal brain growth may be impaired by TPO positivity among certain populations; therefore autoantibody screening among high-risk subgroups may be useful for clinicians to determine whether prenatal thyroid treatment is warranted

Impact of Maternal Thyroperoxidase Status on Fetal Body and Brain Size

The obstetric consequences of abnormal thyroid function during pregnancy have been established. Less understood is the influence of maternal thyroid autoantibodies on infant outcomes. The objective of this study was to examine the influence of maternal thyroperoxidase (TPO) status on fetal/infant brain and body growth. Six-hundred thirty-one (631) euthyroid pregnant women were recruited from prenatal clinics in Tampa Bay, Florida, and the surrounding area between November 2007 and December 2010. TPO status was determined during pregnancy and fetal/infant brain and body growth variables were assessed at delivery. Regression analysis revealed maternal that TPO positivity was significantly associated with smaller head circumference, reduced brain weight, and lower brain-to-body ratio among infants born to TPO+ white, non-Hispanic mothers only, distinguishing race/ethnicity as an effect modifier in the relationship. No significant differences were noted in body growth measurements among infants born to TPO positive mothers of any racial/ethnic group. Currently, TPO antibody status is not assessed as part of the standard prenatal care laboratory work-up, but findings from this study suggest that fetal brain growth may be impaired by TPO positivity among certain populations; therefore autoantibody screening among high-risk subgroups may be useful for clinicians to determine whether prenatal thyroid treatment is warranted

Development and validation of risk of CPS decline (RCD): a new prediction tool for worsening cognitive performance among home care clients in Canada

Abstract Background To develop and validate a prediction tool, or nomogram, for the risk of a decline in cognitive performance based on the interRAI Cognitive Performance Scale (CPS). Methods Retrospective, population-based, cohort study using Canadian Resident Assessment Instrument for Home Care (RAI-HC) data, collected between 2010 and 2018. Eligible home care clients, aged 18+, with at least two assessments were selected randomly for model derivation (75%) and validation (25%). All clients had a CPS score of zero (intact) or one (borderline intact) on intake into the home care program, out of a possible score of six. All individuals had to remain as home care recipients for the six months observation window in order to be included in the analysis. The primary outcome was any degree of worsening (i.e., increase) on the CPS score within six months. Using the derivation cohort, we developed a multivariable logistic regression model to predict the risk of a deterioration in the CPS score. Model performance was assessed on the validation cohort using discrimination and calibration plots. Results We identified 39,292 eligible home care clients, with a median age of 79.0 years, 62.3% were female, 38.8% were married and 38.6% lived alone. On average, 30.3% experienced a worsening on the CPS score within the six-month window (i.e., a change from 0 or 1 to 2, 3, 4, 5, or 6). The final model had good discrimination (c-statistic of 0.65), with excellent calibration. Conclusions The model accurately predicted the risk of deterioration on the CPS score over six months among home care clients. This type of predictive model may provide useful information to support decisions for home care clinicians who use interRAI data internationally

Development of a Mimotope Vaccine Targeting the <i>Staphylococcus aureus</i> Quorum Sensing Pathway

<div><p>A major hurdle in vaccine development is the difficulty in identifying relevant target epitopes and then presenting them to the immune system in a context that mimics their native conformation. We have engineered novel virus-like-particle (VLP) technology that is able to display complex libraries of random peptide sequences on a surface-exposed loop in the coat protein without disruption of protein folding or VLP assembly. This technology allows us to use the same VLP particle for both affinity selection and immunization, integrating the power of epitope discovery and epitope mimicry of traditional phage display with the high immunogenicity of VLPs. Previously, we showed that using affinity selection with our VLP platform identifies linear epitopes of monoclonal antibodies and subsequent immunization generates the proper antibody response. To test if our technology could identify immunologic mimotopes, we used affinity selection on a monoclonal antibody (AP4-24H11) that recognizes the <i>Staphylococcus aureus</i> autoinducing peptide 4 (AIP4). AIP4 is a secreted eight amino acid, cyclized peptide produced from the <i>S. aureus</i> accessory gene regulator (<i>agr</i>IV) quorum-sensing operon. The <i>agr</i> system coordinates density dependent changes in gene expression, leading to the upregulation of a host of virulence factors, and passive transfer of AP4-24H11 protects against <i>S. aureus agr</i>IV-dependent pathogenicity. In this report, we identified a set of peptides displayed on VLPs that bound with high specificity to AP4-24H11. Importantly, similar to passive transfer with AP4-24H11, immunization with a subset of these VLPs protected against pathogenicity in a mouse model of <i>S. aureus</i> dermonecrosis. These data are proof of principle that by performing affinity selection on neutralizing antibodies, our VLP technology can identify peptide mimics of non-linear epitopes and that these mimotope based VLP vaccines provide protection against pathogens in relevant animal models.</p></div

Vaccination with VLP mimotopes of AIP4 is efficacious in a mouse model of <i>S. aureus</i> SSTI.

<p>(A) Mice were vaccinated three times at two week intervals with 10 µg of VLP. One week after the final vaccination mice were inoculated subcutaneously with 1×10⁸ CFU of <i>S. aureus agr</i>-IV isolate AH1872, and abscess (B) and ulcer (C) areas were measured over the course of 72 hours. Data are shown as the mean ± SEM of at least two independent experments totalling 8–10 mice per group.</p

Affinity selected VLPs bind to and occupy the antigen binding site of mAb AP4-24H11.

<p>(A) ELISA was used to assess specific binding of VLP selectants to AP4-24H11. Wells were coated with the indicted VLPs and different concentrations of AP4-24H11 were applied. Error bars represent standard error of the mean. (B) For competition ELISAs, wells were coated with the indicated VLPs and AP4-24H11 was mixed with different concentration of the cyclical, bioactive AIP4 peptide prior to incubation with VLPs. Secondary antibody and detection was the same as above. As a control peptide, we used a linear form of AIP4. Results are representative of an experiment performed twice.</p