Vertical Transmission of SARS-CoV-2-Specific Antibodies and Cytokine Profiles in Pregnancy

Despite intensive characterization of immune responses after COVID-19 infection and vaccination, research examining protective correlates of vertical transmission in pregnancy are limited. Herein, we profiled humoral and cellular characteristics in pregnant women infected or vaccinated at different trimesters and in their corresponding newborns. We noted a significant correlation between spike S1-specific IgG antibody and its RBD-ACE2 blocking activity (receptor-binding domain-human angiotensin-converting enzyme 2) in maternal and cord plasma (P < .001, R > 0.90). Blocking activity of spike S1-specific IgG was significantly higher in pregnant women infected during the third trimester than the first and second trimesters. Elevated levels of 28 cytokines/chemokines, mainly proinflammatory, were noted in maternal plasma with infection at delivery, while cord plasma with maternal infection 2 weeks before delivery exhibited the emergence of anti-inflammatory cytokines. Our data support vertical transmission of protective SARS-CoV-2-specific antibodies. This vertical antibody transmission and the presence of anti-inflammatory cytokines in cord blood may offset adverse outcomes of inflammation in exposed newborns.

Melatonin: the placental antioxidant and anti-inflammatory

Melatonin (N-acetyl-5-methoxytryptamine) is an indolamine hormone with many physiological and biological roles. Melatonin is an antioxidant, anti-inflammatory, free radical scavenger, circadian rhythm regulator, and sleep hormone. However, its most popular role is the ability to regulate sleep through the circadian rhythm. Interestingly, recent studies have shown that melatonin is an important and essential hormone during pregnancy, specifically in the placenta. This is primarily due to the placenta's ability to synthesize its own melatonin rather than depending on the pineal gland. During pregnancy, melatonin acts as an antioxidant and anti-inflammatory, which is necessary to ensure a stable environment for both the mother and the fetus. It is an essential antioxidant in the placenta because it reduces oxidative stress by constantly scavenging for free radicals, i.e., maintain the placenta's integrity. In a healthy pregnancy, the maternal immune system is constantly altered to accommodate the needs of the growing fetus, and melatonin acts as a key anti-inflammatory by regulating immune homeostasis during early and late gestation. This literature review aims to identify and summarize melatonin's role as a powerful antioxidant and anti-inflammatory that reduces oxidative stress and inflammation to maintain a favorable homeostatic environment in the placenta throughout gestation.

Maternal SARS-CoV-2 infection in pregnancy disrupts gene expression in Hofbauer cells with limited impact on cytotrophoblasts

BACKGROUND

Hofbauer cells (HBCs) and cytotrophoblasts (CTBs) are major cell populations in placenta. The indirect impact of maternal SARS-CoV-2 disease on these cells that are not directly infected has not been extensively studied. Herein, we profiled gene expression in HBCs and CTBs isolated from placentae of recovered pregnant subjects infected with SARS-CoV-2 during all trimesters of pregnancy, placentae from subjects with active infection, SARS-CoV-2 vaccinated subjects, and those who were unexposed to the virus.

METHODS

Placentae were collected within 4 h post-delivery and membrane-free tissues were enzymatically digested for the isolation of HBCs and CTBs. RNA extracted from HBCs and CTBs were sequenced using 150bp paired-end reads. Differentially expressed genes (DEGs) were identified by DESeq2 package in R and enriched in GO Biological Processes, KEGG Pathway, Reactome Gene Sets, Hallmark Gene Sets, and Canonical Pathways. Protein-protein interactions among the DEGs were modelled using STRING and BioGrid.

RESULTS

Pregnant subjects (n = 30) were recruited and categorized into six groups: infected with SARS-CoV-2 in i) the first (1T, n = 4), ii) second (2T, n = 5), iii) third (3T, n = 5) trimester, iv) tested positive at delivery (Delivery, n = 5), v) never infected (Control, n = 6), and vi) fully mRNA-vaccinated by delivery (Vaccinated, n = 5). Compared to the Control group, gene expression analysis showed that HBCs from infected subjects had significantly altered gene expression profiles, with the 2T group having the highest number of DEGs (1,696), followed by 3T and 1T groups (1,656 and 958 DEGs, respectively). These DEGs were enriched for pathways involved in immune regulation for host defense, including production of cytokines, chemokines, antimicrobial proteins, ribosomal assembly, neutrophil degranulation inflammation, morphogenesis, and cell migration/adhesion. Protein-protein interaction analysis mapped these DEGs with oxidative phosphorylation, translation, extracellular matrix organization, and type I interferon signaling. Only 95, 23, and 8 DEGs were identified in CTBs of 1T, 2T, and 3T groups, respectively. Similarly, 11 and 3 DEGs were identified in CTBs and HBCs of vaccinated subjects, respectively. Reassuringly, mRNA vaccination did not induce an inflammatory response in placental cells.

CONCLUSIONS

Our studies demonstrate a significant impact of indirect SARS-CoV-2 infection on gene expression of inner mesenchymal HBCs, with limited effect on lining CTB cells isolated from pregnant subjects infected and recovered from SARS-CoV-2. The pathways associated with these DEGs identify potential targets for therapeutic intervention.

Machine learning to predict risk for community-onset Staphylococcus aureus infections in children living in southeastern United States

Staphylococcus aureus (S. aureus) is known to cause human infections and since the late 1990s, community-onset antibiotic resistant infections (methicillin resistant S. aureus (MRSA)) continue to cause significant infections in the United States. Skin and soft tissue infections (SSTIs) still account for the majority of these in the outpatient setting. Machine learning can predict the location-based risks for community-level S. aureus infections. Multi-year (2002-2016) electronic health records of children <19 years old with S. aureus infections were queried for patient level data for demographic, clinical, and laboratory information. Area level data (Block group) was abstracted from U.S. Census data. A machine learning ecological niche model, maximum entropy (MaxEnt), was applied to assess model performance of specific place-based factors (determined a priori) associated with S. aureus infections; analyses were structured to compare methicillin resistant (MRSA) against methicillin sensitive S. aureus (MSSA) infections. Differences in rates of MRSA and MSSA infections were determined by comparing those which occurred in the early phase (2002-2005) and those in the later phase (2006-2016). Multi-level modeling was applied to identify risks factors for S. aureus infections. Among 16,124 unique patients with community-onset MRSA and MSSA, majority occurred in the most densely populated neighborhoods of Atlanta's metropolitan area. MaxEnt model performance showed the training AUC ranged from 0.771 to 0.824, while the testing AUC ranged from 0.769 to 0.839. Population density was the area variable which contributed the most in predicting S. aureus disease (stratified by CO-MRSA and CO-MSSA) across early and late periods. Race contributed more to CO-MRSA prediction models during the early and late periods than for CO-MSSA. Machine learning accurately predicts which densely populated areas are at highest and lowest risk for community-onset S. aureus infections over a 14-year time span.

1947. Evaluating the Relationship Between Obesity and the Humoral Immune Response to COVID-19 Vaccines

Background

The pro-inflammatory state associated with obesity leads to B- and T-lymphocyte dysfunction that may lead to an inadequate immune response to natural infection and vaccination. Preliminary studies, conducted outside of the US, involving multiple COVID-19 vaccines indicate that obesity may impact antibody response. The objective of this study was to evaluate the role of inflammatory status as a mediator in the relationship between obesity and COVID-19 vaccine immune response in a predominantly African-American population.

Methods

This cross-sectional analysis involved 54 participants ≧ 18 years of age who had completed the primary dosing schedule and booster for Novavax’s recombinant COVID-19 vaccine, NVX-CoV2373. Weight, height, and waist circumference (WC) measurements were taken. Medical history including COVID-19 vaccination and known COVID-19 infection were obtained. Blood samples were taken for measurement of c-reactive protein (CRP) and anti-SARS-CoV-2 spike protein IgG levels. Spearman correlation coefficient was used to assess the presence of a relationship between BMI and CRP, WC and CRP, CRP and spike protein IgG, BMI and spike protein IgG, and finally, WC and spike protein IgG. Mediation analysis was used to evaluate the moderating effect of plasma CRP on the relationship between WC and spike protein IgG while adjusting for suspected confounders. Statistical significance was defined as p &lt; .05.

Results

There was an expected positive relationship between WC and CRP, (ρ = 0.37, p&lt; .05). CRP and spike protein IgG trended towards a weak, negative relationship (ρ= -0.13, p &gt; .05). WC and BMI both trended towards a positive relationship with anti-SARS-CoV-2 spike protein IgG (ρ = 0.29 and 0.15, respectively, p &gt;.05). The mediation analysis showed that WC positively influenced spike protein IgG (p&lt; .05), and this effect was not mediated by CRP.

Conclusion

Inflammation may be negatively associated with antibody response to COVID-19 vaccines. WC and antibody response may be positively related in NVX-CoV2373 recipients, in spite of chronic low-grade inflammation. Further research is needed to fully characterize the impact of obesity on COVID-19 vaccine immunogenic responses.

Disclosures

Lilly Immergluck, MD, MS, GSK: Clinical Trial- PI|Merck: Vaccine Trial Site- serve as PI|Moderna: Board Member|Novavax: Part of CoVID-19 Phase 3 Trial through US Covid Prevention Network.

2129. Maternal Transmission of SARS-CoV-2-specific Antibodies, but not Cytokines/Chemokines to Neonates Following Infection and Vaccination During Pregnancy

Background

Despite extensive studies of human immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination, research examining protective correlates of vertical transmission following maternal exposure in pregnancy remain limited. Here, we characterized antibody and cytokine responses in maternal and cord blood following infection or vaccination at various timepoints during gestation.

Methods

Spike S1 protein-specific binding antibodies and antibodies capable of blocking the interaction between the receptor binding domain (RBD) and the angiotensin converting enzyme 2 (ACE2) were measured in maternal and cord blood by ELISA. Serum concentrations of 74 cytokines/chemokines were measured by multiplex assay. Humoral responses and cytokine levels from matched maternal and fetal cord sera were compared and examined for potential correlations.

Results

We observed a highly significant correlation between Spike S1-specific antibody titer and RBD-ACE2 blocking antibody activity between maternal and fetal cord serum (p &lt; 2.2e-16, R &gt; 0.90). Blocking antibody activity was significantly higher for mothers infected during the 3rd trimester compared to earlier trimesters; however, vaccinated mothers developed and transferred higher antibody titers with greater RBD-ACE2 blocking antibody activity to their neonates than infected mothers. Furthermore, vaccine-induced Spike S1 IgG transfer ratios (fetal cord/maternal) were significantly higher than those induced by infection (p = 0.002). Multiplex assay showed significantly elevated levels of 33 cytokines/chemokines, mainly pro-inflammatory in infected maternal serum samples, while the paired fetal cord samples exhibited an anti-inflammatory cytokine predominance.

Conclusion

Our data support selective vertical transmission of potentially protective humoral responses against SARS-CoV-2, especially following vaccination in the 3rd trimester. The anti-inflammatory cytokine predominance in cord blood that persists despite maternal SARS-CoV-2 infection may offset the adverse outcomes of inflammation in pregnancy for the neonate.

Disclosures

All Authors: No reported disclosures.

A measure of SRS/SRT plan quality: Quantitative limits for intermediate dose spill (R50%) in linac-based delivery

Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) of multiple cranial targets using a single isocenter on conventional C‐arm linear accelerators are rapidly developing clinical techniques. However, no universal guidelines for acceptable intermediate dose spill limits are currently available or widely accepted. In this work, we propose an intermediate dose spill guidance range for cranial SRS/SRT delivered on C‐arm linacs with MLC collimation for single PTV plans and single isocenter multiple target plans with PTV volumes in the range 0.02–57.9 cm³. We quantify intermediate dose spill with the R50% metric (R50% = volume of 50% of prescription isodose cloud / volume of PTV) and test the proposed range using three clinical data sets, containing both 6 MV and 10 MV beams, previously published by other authors. Our proposed lower limit of R50% (LowerR50%) and upper limit of acceptable R50% (UpperR50%) bound over 90% of the clinical data used in this study, yet still provide a challenging benchmark for optimization and plan assessment of linac‐based, MLC collimated SRS/SRT.

Host-Viral Interactions at the Maternal-Fetal Interface. What We Know and What We Need to Know

In humans, the hemochorial placenta is a unique temporary organ that forms during pregnancy to support fetal development, gaseous exchange, delivery of nutrition, removal of waste products, and provides immune protection, while maintaining tolerance to the HLA-haploidentical fetus. In this review, we characterize decidual and placental immunity during maternal viral (co)-infection with HIV-1, human cytomegalovirus (HCMV), and Zika virus. We discuss placental immunology, clinical presentation, and epidemiology, before characterizing host susceptibility and cellular tropism, and how the three viruses gain access into specific placental target cells. We describe current knowledge on host-viral interactions with decidual and stromal human placental macrophages or Hofbauer cells, trophoblasts including extra villous trophoblasts, T cells, and decidual natural killer (dNK) cells. These clinically significant viral infections elicit both innate and adaptive immune responses to control replication. However, the three viruses either during mono- or co-infection (HIV-1 and HCMV) escape detection to initiate placental inflammation associated with viral transmission to the developing fetus. Aside from congenital or perinatal infection, other adverse pregnancy outcomes include preterm labor and spontaneous abortion. In addition, maternal HIV-1 and HCMV co-infection are associated with impaired fetal and infant immunity in postnatal life and poor clinical outcomes during childhood in exposed infants, even in the absence of vertical transmission of HIV-1. Given the rapidly expanding numbers of HIV-1-exposed uninfected infants and children globally, further research is urgently needed on neonatal immune programming during maternal mono-and co-infection. This review therefore includes sections on current knowledge gaps that may prompt future research directions. These gaps reflect an emerging but poorly characterized field. Their significance and potential investigation is underscored by the fact that although viral infections result in adverse consequences in both mother and developing fetus/newborn, antiviral and immunomodulatory therapies can improve clinical outcomes in the dyad.

Feasibility and Acceptability of Technology-supported Sexual Health Education Among Adolescents Receiving Inpatient Psychiatric Care

Mental illness in adolescence is associated with high-risk sexual behaviors including multiple sex partners, infrequent or inconsistent condom use, and nonuse of contraception. Inpatient psychiatric care represents a promising setting to provide sexual health education. This pilot study investigates the feasibility and acceptability of online sexual health education in this group by assessing usability and impact on short-term psychosocial outcomes. We administered online modules on healthy relationships, pregnancy prevention, condom use, and sexually transmitted infection (STI) prevention to youth. We evaluated outcomes using a single group, pre/post-intervention design. One quality improvement session assessed staff acceptability of the programming. Participants included 51 inpatients (mean age = 15.3; 61% female; 57% Hispanic or Latino; 55% heterosexual). Overall, the program was feasible to administer and highly acceptable to youth (84-89% liked the modules, 98-100% found them easy to use, 96-100% found them credible, 91-98% said information would lead to healthier dating relationships, and 78-87% would refer to a friend). Youth who completed modules demonstrated improvement in several outcomes: attitudes and norms towards violence (p < 0.001), intention to use a method of birth control other than condoms if having sex in the next 3 months (p < 0.001), condom knowledge (p < 0.001), condom use self-efficacy (p < 0.001), condom beliefs (p = 0.04), HIV/STI knowledge (p < 0.001), and perceived susceptibility to STI (p < 0.01). The quality improvement session revealed high acceptability by nursing staff on the unit. This intervention could be useful and efficacious in an inpatient setting and larger studies are warranted to understand its full impact.

Robust innate immune responses at the placenta during early gestation may limit in utero HIV transmission

In 2019, >90% of new HIV infections in infants globally occurred vertically. Studies suggest intrauterine transmission most often occurs in the third trimester; however, there are no mechanistic studies to support these observations. We therefore obtained early/mid-gestation and term placentae from 20 HIV/Hepatitis B/CMV negative women. Isolated primary placental macrophages (Hofbauer cells [HCs]) were exposed to HIV-1_BaL and/or interferon (IFN)-α, IFN-β, IFN-λ1, and RIG-I-like receptor (RLR) agonists. qRT-PCR, FACS, ELISA, Luminex, and Western blot analyses determined expression of activation markers, co-receptors, viral antigen, cytokines, antiviral genes, and host proteins. Early gestation HCs express higher levels of CCR5 and exhibit a more activated phenotype. Despite downregulation of CCR5, term HCs were more susceptible to HIV replication. Early gestation HCs displayed a more activated phenotype than term HCs and HIV exposure lead to the further up-regulation of T-cell co-stimulatory and MHC molecules. Limited HIV replication in early/mid gestation HCs was associated with increased secretion of anti-inflammatory cytokines, chemokines, and a more robust antiviral immune response. In contrast, term HCs were more susceptible to HIV replication, associated with dampening of IFN-induced STAT1 and STAT2 protein activation. Treatment of early/mid gestation and term HCs, with type I IFNs or RLR agonists reduced HIV replication, underscoring the importance of IFN and RLR signaling in inducing an antiviral state. Viral recognition and antiviral immunity in early gestation HCs may prevent in utero HIV infection, whereas diminished antiviral responses at term can facilitate transmission. Defining mechanisms and specific timing of vertical transmission are critical for the development of specific vaccines and antiviral therapeutics to prevent new HIV infections in children globally.

Mother-to-child transmission is the main source of HIV infection in children globally. Studies suggest vertical transmission most often occurs late in the third trimester; however, there are no studies to support these observations. Our study shows that gestational age plays a significant role in the ability of placental macrophages to generate robust antiviral responses, which are necessary to prevent or reduce viral burden. Specifically, we show that viral recognition by RIG-I-like receptors and robust antiviral immune responses in placental cells during early gestation may prevent in utero HIV infection. We also demonstrate that term placental macrophages are limited in their antiviral capacity due to restricted type I IFN signaling. Understanding the mechanisms and timing of vertical transmission are important to understand for the development of specific vaccines and antiviral therapeutics to prevent new HIV infections in children globally.

Efficient optimization of R50% when planning multiple cranial metastases simultaneously in single isocenter SRS/SRT

Simultaneous optimization of multiple Planning Target Volumes (PTVs) of varying size and location in the cranium is a non-trivial task. The rate of dose falloff around PTV structures is variable and depends on PTV characteristics such as the volume. The metric R50% is one parameter that can be used to quantify dose falloff achieved in a given treatment plan. An important treatment planning question is how to construct optimization conditions that result in the efficient production of acceptable plan outcomes considering metrics such as R50%. Guidance provided in literature suggests generating multiple shell control structures around each PTV. The constraints applied to these shells can vary significantly depending on PTV volume. Additionally, there is no clear guidance on how to prospectively determine objective constraints for the optimization shells to achieve a specified goal of R50%. Based on physical principles and empirical evidence, we provide clear quantitative guidance on how to translate the desired R50% outcome into appropriately sized optimization structures around PTVs via an equation that depends on a desired goal for R50% and the volume of PTV. Optimization schema are also provided that allow the goal R50% to be approached or achieved for all PTVs individually. We demonstrate the application of the methodology using commercially available treatment planning software and radiotherapy treatment equipment.

The surface area effect: How the intermediate dose spill depends on the PTV surface area in SRS

Purpose

Stereotactic radiosurgery (SRS) is rapidly becoming the standard of care for many intracranial targets. The characteristics of the planning target volume (PTV) can affect the intermediate dose spill and thus normal brain volume dose which is correlated with brain toxicity. R50% (volume receiving 50% of prescription dose divided by PTV volume) is a useful metric to quantify the intermediate dose spill. We propose a novel understanding of how the PTV surface area (SA_PTV) affects the intermediate dose spill of SRS treatments.

Methods

Using a phantom model provided by a computed tomography (CT) of the IROC Head Phantom® and Eclipse® Treatment Planning System, we investigate the relationship of R50% and SA_PTV in single‐target SRS treatments. The planning studies are conducted for SRS treatments on a Varian TrueBeam® linear accelerator with high‐definition MLC and a 6 MVFFF beam mode. These data are analyzed to ascertain trends in R50% related to SA_PTV. Since SA_PTV is not available as a structure property in the Eclipse RTPS, we introduce an Eclipse script to extract PTV surface area of arbitrary‐shaped PTVs. We compare a physically reasonable theoretical prediction of R50%, R50%_Analytic, to the R50% achieved in treatment planning studies.

Results

The SRS phantom study indicates good correlation between the plan R50% and SA_PTV. A near‐linear relationship of plan R50% vs SA_PTV is observed as predicted by the R50%_Analytic model. Agreement between plan R50% values and R50%_Analytic predictions is good for all but the very smallest PTV volumes.

Conclusions

We demonstrate dependence of the intermediate dose spill measured by R50% on the SA_PTV. We call that dependence the surface area effect. This dependence is explicit in the R50%_Analytic prediction model. The predicted value of R50%_Analytic for a given PTV could be used for guidance during SRS treatment plan optimization, and plan evaluation for that PTV.

An analytical expression for R50% dependent on PTV surface area and volume: A cranial SRS comparison

The intermediate dose spill for a stereotactic radiosurgery (SRS) plan can be quantified with the metric R50%, defined as the 50% isodose cloud volume (V_IDC50% ) divided by the volume of the planning target volume (PTV). By coupling sound physical principles with the basic definition of R50%, we derive an analytical expression for R50% for a spherical PTV. Our analytical expression depends on three quantities: the surface area of PTV (SA_PTV ), the volume of PTV (V_PTV ), and the distance of dose drop-off to 50% (Δr). The value of ∆r was obtained from a simple set of cranial phantom plan calculations. We generate values from our analytical expression for R50% (R50%_Analytic ) and compare the values to clinical R50% values (R50%_Clinical ) extracted from a previously published SRS data set that spans the V_PTV range from 0.15 to 50.1 cm³ . R50%_Analytic is smaller than R50%_Clinical in all cases by an average of 15% ± 7%, and the general trend of R50%_Clinical vs V_PTV is reflected in the same trend of R50%_Analytic . This comparison suggests that R50%_Analytic could represent a theoretical lower limit for the clinical SRS data; further investigation is required to confirm this. R50%_Analytic could provide useful guidance for what might be achievable in SRS planning.

Maternal obesity is associated with phenotypic alterations in fetal immune cells by single-cell mass cytometry

PROBLEM

Prenatal exposure to metabolic dysregulation arising from maternal obesity can have negative health consequences in post-natal life. To date, the specific effects of maternal obesity on fetal immunity at a cellular level have not been well characterized.

METHOD OF STUDY

Using cord blood mononuclear cells (CBMCs) and cord plasma (n = 9/group) isolated from infants born to women with a high body mass index (BMI>25kg/m² ) compared to women with a normal BMI (18-25kg/m² ), we evaluated differences in immune cell populations using single-cell mass cytometry (CyTOF). CBMCs were matched according to potentially confounding variables, such as maternal and gestational age, ethnicity, smoking status, and gravidity. Statistical results were adjusted for fetal sex. Data were analyzed by viSNE and FlowSOM softwares in Cytobank^™ .

RESULTS

In newborn CBMCs from women with high BMI, we observed changes in frequency and phenotype of immune cell populations, including significant increases in CD4⁺ T cells and decreases in myeloid cell populations. IL-12p40 and MDC concentrations were significantly elevated in the high BMI group compared to control.

CONCLUSION

This study demonstrates an association between maternal obesity and fetal immunity. Our results warrant following long-term immunologic outcomes and associated clinical risks in children born to women with a high pre-pregnancy BMI.

An analytical expression for R50% dependent on PTV surface area and volume: a lung SBRT comparison

In stereotactic body radiation therapy (SBRT), R50% is a common metric for intermediate dose spill and is defined in RTOG 0915 as the ratio of 50% isodose cloud volume (IDC50%) to the planning target volume (PTV). By coupling sound physical principles with the basic definition of intermediate dose spill, we derive an exact analytical expression for R50% for the case of a spherical volume. This expression for R50% depends on three quantities: the surface area of PTV (SA_PTV), the volume of PTV (V_PTV), and the dose gradient Δr. Validity of our analytical expression for R50% was confirmed via direct comparison to peer‐reviewed, multi‐institutional, diverse clinical data. The comparison of our R50% values computed from our analytical expression to the clinical data yielded an average percent difference of 3.8 ± 4.5%.

A physically meaningful relationship between R50% and PTV surface area in lung SBRT

Purpose

We propose a novel understanding of two characteristics of the planning target volume (PTV) that affect the intermediate‐dose spill in lung stereotactic body radiation therapy (SBRT) as measured by R50%. This phantom model research investigates two characteristics of the PTV that have a marked effect on the value of R50%: the mean dose deposited within the PTV (D_av) and the surface area of the PTV (SA_PTV).

Methods

Using a phantom model provided by a CT of the IROC Thorax‐Lung Phantom® (IROC Houston QA Center, Houston, TX) and Eclipse® Treatment Planning System (Varian Medical Systems, Palo Alto, CA), we investigate the two characteristics for spherical and cylindrical PTVs. A total of 135 plans with tightly controlled PTV characteristics are employed. A lower bound for R50% (R50%min_∆r) is derived and clearly establishes a relationship between R50% and SA_PTV that has not been fully appreciated previously.

Results

The study of PTV D_av revealed a local minimum for R50% as a function of the PTV D_av at D_av ≈ 110% of Rx dose. As PTV D_av increases above this local minimum, R50% increases; while for PTV D_av less than this local minimum, the R50% value also increases. The study of PTV surface area (SA_PTV) demonstrated that as the SA_PTV increases, the R50% increases if the PTV volume stays the same. The SA_PTV result is predicted by the theoretical investigation that yields the R50% lower bound, R50%min_∆r.

Conclusions

This research has identified two characteristics of the PTV that have a marked influence on R50%: PTV D_av and SA_PTV. These characteristics have not been clearly articulated in the vast body of previous research in SBRT. These results could help explain plans that cannot meet the RTOG criteria for R50%. With further development, these concepts could be extended to provide additional guidance for creating acceptable SBRT plans.

Human cytomegalovirus preferentially infects early gestation placental macrophages and evades their antiviral immunogenicity through evasion of the type I IFN response

Human cytomegalovirus (HCMV) is the leading cause of congenital viral infections. When a pregnant woman develops primary HCMV infection in early gestation, the risk of transplacental infection is ~40%. Studies have documented the presence of HCMV in placental macrophages (Hofbauer cells [HCs]) as a consequence of maternal viremia. However, the interplay between HCMV and placental macrophages (HCs) is poorly defined. With written informed consent, placentae were collected from 12 HIV-1/Hep B/HCMV seronegative women (&gt;18 years). HCs were exposed to human HCMV (TB40/E). qPCR, FACS, ELISA, and Western blot analysis determined the expression of activation markers, cytokines, antiviral genes, and host proteins. Here we found that HCs isolated from early gestation (15–23 weeks) placentae are more susceptible to HCMV infection than HCs isolated from term (&gt;39 weeks) placentae. HCMV infection of early gestation HCs led to a significant upregulation of activation markers, along with elevated secretion of proinflammatory cytokines, compared to HCMV-infected term HCs. In early gestation and term HC, HCMV rapidly induces the type I IFN pathway, leading to secretion of IFNs and strong induction of ISGs. However, HCMV diminishes type I IFN-mediated phosphorylation of STAT2, with early gestation HCs exhibiting the greatest level of inhibition. Our findings show that HCMV can subvert type I IFN signaling to support viral growth at the placenta, particularly during early gestation. Studying mechanisms used by viruses to prevent an immune response is of great importance for the development of new strategies to limit the sequelae of viral infections.

Maternal T Cells in the Human Placental Villi Support an Allograft Response during Noninfectious Villitis

During human pregnancy, proinflammatory responses in the placenta can cause severe fetal complications, including growth restriction, preterm birth, and stillbirth. Villitis of unknown etiology (VUE), an inflammatory condition characterized by the infiltration of maternal CD8⁺ T cells into the placenta, is hypothesized to be secondary to either a tissue rejection response to the haploidentical fetus or from an undiagnosed infection. In this study, we characterized the global TCR β-chain profile in human T cells isolated from placentae diagnosed with VUE compared with control and infectious villitis-placentae by immunoSEQ. Immunosequencing demonstrated that VUE is driven predominantly by maternal T cell infiltration, which is significantly different from controls and infectious cases; however, these T cell clones show very little overlap between subjects. Mapping TCR clones to common viral epitopes (CMV, EBV, and influenza A) demonstrated that Ag specificity in VUE was equal to controls and significantly lower than CMV-specific clones in infectious villitis. Our data indicate VUE represents an allograft response, not an undetected infection. These observations support the development of screening methods to predict those at risk for VUE and the use of specific immunomodulatory therapies during gestation to improve outcomes in affected fetuses.

Baby's First Macrophage: Temporal Regulation of Hofbauer Cell Phenotype Influences Ligand-Mediated Innate Immune Responses across Gestation

The importance of fetal placental macrophages (Hofbauer cell [HCs]) is underscored by their appearance 18 d postconception and maintenance through term; however, how human HCs evolve during healthy pregnancy and how microenvironment and ontogeny impact phenotype and function remain unknown. In this study, we comprehensively classify human HCs ex vivo, interrogate phenotypic plasticity, and characterize antiviral immune responses through gestation. Activated HCs were abundant in early pregnancy and decreased by term; molecular signatures emphasize inflammatory phenotypes early in gestation. Frequency of HCs with regulatory phenotypes remained high through term. Furthermore, term HCs exhibited blunted responses to stimulation, indicating reduced plasticity. IFN-λ1 is a key placental IFN that appeared less protective than IFN-α, suggesting a potential weakness in antiviral immunity. Ligand-specific responses were temporally regulated: we noted an absence of inflammatory mediators and reduced antiviral gene transcription following RIG-I activation at term despite all HCs producing inflammatory mediators following IFN-γ plus LPS stimulation. Collectively, we demonstrate sequential, evolving immunity as part of the natural history of HCs through gestation.

Human Cytomegalovirus Enhances Placental Susceptibility and Replication of Human Immunodeficiency Virus Type 1 (HIV-1), Which May Facilitate In Utero HIV-1 Transmission

Several co-pathogens that pose threats to the fetus during gestation, including human cytomegalovirus (HCMV), may also contribute to mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1). Within endemic settings, associations between maternal HCMV viral load and increased incidence of MTCT of HIV-1 are documented; however, the mechanisms that promote transmission are poorly characterized. Here we demonstrate that HCMV coinfection enhances susceptibility and viral replication of HIV-1 in placental macrophages (Hofbauer cells) in vitro. Consistent with enhanced viral susceptibility, HCMV exposure upregulates CCR5 and CD80 expression on Hofbauer cells. HCMV also significantly induces type I interferon (IFN), proinflammatory cytokines, and antiviral gene expression. Interestingly, we found that HCMV diminishes type I IFN-mediated phosphorylation of STAT2. Collectively, our data suggest that HCMV-induced activation, local inflammation, and antagonism of type I IFN responses in placental Hofbauer cells promote in utero transmission of HIV-1.

Cross-Reactive Dengue Virus Antibodies Augment Zika Virus Infection of Human Placental Macrophages

Zika virus (ZIKV), which emerged in regions endemic to dengue virus (DENV), is vertically transmitted and results in adverse pregnancy outcomes. Antibodies to DENV can cross-react with ZIKV, but whether these antibodies influence ZIKV vertical transmission remains unclear. Here, we find that DENV antibodies increase ZIKV infection of placental macrophages (Hofbauer cells [HCs]) from 10% to over 80% and enhance infection of human placental explants. ZIKV-anti-DENV antibody complexes increase viral binding and entry into HCs but also result in blunted type I interferon, pro-inflammatory cytokine, and antiviral responses. Additionally, ZIKV infection of HCs and human placental explants is enhanced in an immunoglobulin G subclass-dependent manner, and targeting FcRn reduces ZIKV replication in human placental explants. Collectively, these findings support a role for pre-existing DENV antibodies in enhancement of ZIKV infection of select placental cell types and indicate that pre-existing immunity to DENV should be considered when addressing ZIKV vertical transmission.

Jak Inhibitors Modulate Production of Replication-Competent Zika Virus in Human Hofbauer, Trophoblasts, and Neuroblastoma cells

Zika Virus (ZIKV) is a flavivirus that has been implicated in causing brain deformations, birth defects, and microcephaly in fetuses, and associated with Guillain-Barre syndrome. Mechanisms responsible for transmission of ZIKV across the placenta to the fetus are incompletely understood. Herein, we define key events modulating infection in clinically relevant cells, including primary placental macrophages (human Hofbauer cells; HC), trophoblasts, and neuroblastoma cells. Consistent with previous findings, HC and trophoblasts are permissive to ZIKV infection. Decrease of interferon signaling by Jak ½ inhibition (using ruxolitinib) significantly increased ZIKV replication in HC, trophoblasts, and neuroblasts. Enhanced ZIKV production in ruxolitinib-treated HC was associated with increased expression of HLA-DR and DC-SIGN. Nucleoside analogs blocked ruxolitinib-mediated production of extracellular virus. Although low-level ZIKV infection occurred in untreated HC and trophoblasts, replicating virions were incapable of infecting naive Vero cells. These deficient virions from untreated HC have “thin-coats” suggesting an immature structure. Blocking Jak ½ signaling (with ruxolitinib) restored replication competence as virions produced under these conditions confer cytopathic effects to naive Vero cells. These data demonstrate that Jak-STAT signaling directly impacts the ability of primary placental cells to produce replication-competent virus and is a key determinant in the production of mature virions in clinically relevant cells, including HC and trophoblasts. Design of targeted agents to prevent ZIKV replication in the placenta should consider Jak ½ signaling, the impact of its block on ZIKV infection, and subsequent transmission to the fetus.

Zika Virus Infects Human Placental Macrophages

The recent Zika virus (ZIKV) outbreak in Brazil has been directly linked to increased cases of microcephaly in newborns. Current evidence indicates that ZIKV is transmitted vertically from mother to fetus. However, the mechanism of intrauterine transmission and the cell types involved remain unknown. We demonstrate that the contemporary ZIKV strain PRVABC59 (PR 2015) infects and replicates in primary human placental macrophages, called Hofbauer cells, and to a lesser extent in cytotrophoblasts, isolated from villous tissue of full-term placentae. Viral replication coincides with induction of type I interferon (IFN), pro-inflammatory cytokines, and antiviral gene expression, but with minimal cell death. Our results suggest a mechanism for intrauterine transmission in which ZIKV gains access to the fetal compartment by directly infecting placental cells and disrupting the placental barrier.

Changes in reproductive physiology of mangrove rivulus Kryptolebias marmoratus following exposure to environmentally relevant doses of ethinyl oestradiol

Kryptolebias marmoratus exposed to 4 ng l(-1) of ethinyl oestradiol (EE2) for 30 days experienced significant changes in endogenous 17β-oestradiol (E2) and 11-ketotestosterone (KT) and qualitative changes in gonad morphology. Both hermaphrodites and males showed a significant decrease in E2, whereas only males exhibited a significant decrease in KT. Exposure to EE2 resulted in a decrease in spermatid and spermatocyte density in males and an increase in the number of early stage oocytes in hermaphrodites.

Cytomegalovirus upregulates expression of CCR5 in central memory cord blood mononuclear cells, which may facilitate in utero HIV type 1 transmission

Administration of combination antiretroviral therapy to human immunodeficiency virus type 1 (HIV-1)-infected pregnant women significantly reduces vertical transmission. In contrast, maternal co-opportunistic infection with primary or reactivated cytomegalovirus (CMV) or other pathogens may facilitate in utero transmission of HIV-1 by activation of cord blood mononuclear cells (CBMCs). Here we examine the targets and mechanisms that affect fetal susceptibility to HIV-1 in utero. Using flow cytometry, we demonstrate that the fraction of CD4(+)CD45RO(+) and CD4(+)CCR5(+) CBMCs is minimal, which may account for the low level of in utero HIV-1 transmission. Unstimulated CD4(+) CBMCs that lack CCR5/CD45RO showed reduced levels of HIV-1 infection. However, upon in vitro stimulation with CMV, CBMCs undergo increased proliferation to upregulate the fraction of T central memory cells and expression of CCR5, which enhances susceptibility to HIV-1 infection in vitro. These data suggest that activation induced by CMV in vivo may alter CCR5 expression in CD4(+) T central memory cells to promote in utero transmission of HIV-1.

Differences in caregiver self-efficacy and satisfaction related to sexual abuse of offspring

Research suggests parents of sexually abused children may experience negative perceptions of themselves and their parenting abilities following the victimization of their children, which may influence the recovery process in treatment for these families. This study assessed perceived self-efficacy and parenting satisfaction among female caregivers of sexually abused children and female caregivers whose children were not victimized. Results indicated that caregivers of child victims had significantly lower levels of perceived parenting efficacy than their counterparts. There were no significant differences found between groups with regard to parenting satisfaction. The results highlight the importance of evaluating perceived parenting competence in the treatment of nonoffending caregivers in order to facilitate optimal treatment of the child victim and all members of the family system.

Placental Hofbauer cells limit HIV-1 replication and potentially offset mother to child transmission (MTCT) by induction of immunoregulatory cytokines

Background

Despite readily detectable levels of the HIV-1 (co)-receptors CD4, CCR5 and DC-SIGN on placental macrophages (Hofbauer Cells [HCs]), the rate of HIV-1 infection in utero in the absence of interventions is only 7% of exposed infants. Here, we examine the replication kinetics of human HCs to the primary isolate HIV-1_BaL. We also determined the infectivity of HIV-1-exposed HCs by co-culturing with isolated cord and peripheral blood mononuclear cells [CBMCs, PBMCs]. To understand the limiting nature of HCs to HIV-1 replication, we examined the effect of endogenously secreted cytokines on replication kinetics.

Results

HCs have reduced ability to replicate HIV-1 in vitro (p < 0.01) and to transmit virus to CBMCs and PBMCs (p < 0.001 for both) compared to standard infections of MDMs. HCs were shown to release HIV-1 particles at levels comparable to MDMs, however exhibit significant decreases in viral transcription (gag and env), which may account for lower levels of HIV-1 replication. Un-stimulated HCs constitutively express significantly higher levels of regulatory cytokines, IL-10 and TGF-β, compared to MDMs (p < 0.01), which may contribute to immunoregulatory predominance at the placenta and possibly account for down-regulation of HIV-1 replication and infectivity by HCs. We further demonstrate that these regulatory cytokines inhibit HIV-1 replication within HCs in vitro.

Conclusion

HCs have reduced ability to replicate and disseminate R5-tropic HIV-1_BaLin vitro and potentially offset mother to child transmission (MTCT) of HIV-1 by the induction of immunoregulatory cytokines. Despite the potential for migration and infectivity, HCs are not present in the neighboring fetal circulation. These results implicate HCs as important mediators of protection at the feto-maternal interface during ongoing HIV-1 exposure.

CCR9-CCL25 interactions promote cisplatin resistance in breast cancer cell through Akt activation in a PI3K-dependent and FAK-independent fashion

Background

Chemotherapy heavily relies on apoptosis to kill breast cancer (BrCa) cells. Many breast tumors respond to chemotherapy, but cells that survive this initial response gain resistance to subsequent treatments. This leads to aggressive cell variants with an enhanced ability to migrate, invade and survive at secondary sites. Metastasis and chemoresistance are responsible for most cancer-related deaths; hence, therapies designed to minimize both are greatly needed. We have recently shown that CCR9-CCL25 interactions promote BrCa cell migration and invasion, while others have shown that this axis play important role in T cell survival. In this study we have shown potential role of CCR9-CCL25 axis in breast cancer cell survival and therapeutic efficacy of cisplatin.

Methods

Bromodeoxyuridine (BrdU) incorporation, Vybrant apoptosis and TUNEL assays were performed to ascertain the role of CCR9-CCL25 axis in cisplatin-induced apoptosis of BrCa cells. Fast Activated Cell-based ELISA (FACE) assay was used to quantify In situ activation of PI3K^p85, Akt^Ser473, GSK-3β^Ser9 and FKHR^Thr24 in breast cancer cells with or without cisplatin treatment in presence or absence of CCL25.

Results

CCR9-CCL25 axis provides survival advantage to BrCa cells and inhibits cisplatin-induced apoptosis in a PI3K-dependent and focal adhesion kinase (FAK)-independent fashion. Furthermore, CCR9-CCL25 axis activates cell-survival signals through Akt and subsequent glycogen synthase kinase-3 beta (GSK-3β) and forkhead in human rhabdomyosarcoma (FKHR) inactivation. These results show that CCR9-CCL25 axis play important role in BrCa cell survival and low chemotherapeutic efficacy of cisplatin primarily through PI3K/Akt dependent fashion.

CCL25-CCR9 interaction modulates ovarian cancer cell migration, metalloproteinase expression, and invasion

BACKGROUND

Ovarian carcinoma (OvCa) is the most lethal gynecological malignancy among women and its poor prognosis is mainly due to metastasis. Chemokine receptor CCR9 is primarily expressed by a small subset of immune cells and its only natural ligand, CCL25, is largely expressed in the thymus, which involutes with age. Other than the thymus, CCL25 is expressed by the small bowel. Interactions between CCL25 and CCR9 have been implicated in leukocyte trafficking to the small bowel, a frequent metastatic site for OvCa cells. The current study shows OvCa tissue and cells significantly express CCR9, which interacts with CCL25 to support carcinoma cell migration and invasion.

METHODS

RT-PCR and flow cytometry techniques were used to quantify the expression CCR9 by OvCa cells. OvCa tissue microarrays (TMA) was used to confirm CCR9 expression in clinical samples. The Aperio ScanScope scanning system was used to quantify immunohistochemical staining. Cell invasion and migration assays were performed using cell migration and matrigel invasion chambers. Matrix metalloproteinase (MMP) mRNAs were quantified by RT-PCR and active MMPs were quantified by ELISA.

RESULTS

Our results show significantly (p<0.001) higher expression of CCR9 by mucinous adenocarcinoma, papillary serous carcinoma, and endometriod ovarian carcinoma cases, than compared to non-neoplastic ovarian tissue. Furthermore, CCR9 expression was significantly elevated in OvCa cell lines (OVCAR-3 and CAOV-3) in comparison to normal adult ovarian epithelial cell mRNA. OvCa cells showed higher migratory and invasive potential towards chemotactic gradients of CCL25, which was inhibited by anti-CCR9 antibodies. Expression of collagenases (MMP-1, -8, and -13), gelatinases (MMP-2 and -9), and stromelysins (MMP-3, -10, and -11) by OvCa cells were modulated by CCL25 in a CCR9-dependent fashion.

CONCLUSIONS

These results demonstrate both biological significance and clinical relevance of CCL25 and CCR9 interactions in OvCa cell metastasis.

Migration depths of adult steelhead Oncorhynchus mykiss in relation to dissolved gas supersaturation in a regulated river system

Adult steelhead Oncorhynchus mykiss tagged with archival transmitters primarily migrated through a large river corridor at depths >2 m interspersed with frequent but short (<5 min) periods closer to the surface. The recorded swimming depths and behaviours probably provided adequate hydrostatic compensation for the supersaturated dissolved gas conditions encountered and probably limited development of gas bubble disease (GBD). Results parallel those from a concurrent adult Chinook salmon Oncorhynchus tshawytscha study, except O. mykiss experienced greater seasonal variability and were more likely to have depth uncompensated supersaturation exposure in some dam tailraces, perhaps explaining the higher incidence of GBD in this species.

Structure-activity relationships for reactivity of carbonyl-containing compounds with glutathione

For toxicological-based structure-activity relationships to advance, will require a better understanding of molecular reactivity. A rapid and inexpensive spectrophotometric assay for determining the reactive to glutathione (GSH) was developed and used to determine GSH reactivity (reactGSH) data for 21 aliphatic derivatives of esters, ketones and aldehydes. From these data, a series of structure-activity relationships were evaluated. The structure feature associated with reactGSH was an acetylenic or olefinic moiety conjugated to a carbonyl group (i.e. polarized alpha,beta-unsaturation). This structure conveys the capacity to undergo a covalent interaction with the thiol group of cysteine (i.e. Michael- addition). Quantitatively reactGSH of the alpha,beta-unsaturated carbonyl compounds is reliant upon the specific molecular structure with several tendencies observed. Specifically, it was noted that for alpha,beta-unsaturated carbonyl compounds: (1) the acetylenic-substituted derivatives were more reactive than the corresponding olefinic-substituted ones; (2) terminal vinyl-substituted derivatives was more reactive than the internal vinylene-substituted ones; (3) methyl substitution on the vinyl carbon atoms diminishes reactivity and methyl-substitution on the carbon atom farthest from the carbonyl group causes a larger reduction; (4) derivatives with carbon-carbon double bond on the end of the molecule (i.e. vinyl ketone) were more reactive than one with the carbon-oxygen bond at the end of the molecule (i.e. aldehyde) and (5) the ester with an additional unsaturated vinyl groups were more reactive than the derivative having an unsaturated ethyl group.

Effect of finasteride on bother and other health-related quality of life aspects associated with benign prostatic hyperplasia. PLESS Study Group. Proscar Long-term Efficacy and Safety Study

OBJECTIVES

To investigate the long-term effects of finasteride on bother and health-related quality of life (HRQOL) in men with symptomatic benign prostatic hyperplasia.

METHODS

A large prospective 4-year placebo-controlled trial (PLESS) of 3040 men with moderate to severe lower urinary tract symptoms and an enlarged prostate was performed that included self-administered questionnaires assessing HRQOL.

RESULTS

Significantly greater reductions in bother score were seen for finasteride compared with placebo at every time point after 4 months. Analysis of bother scores by baseline serum prostate-specific antigen (PSA), as it is highly correlated with prostate volume, suggested greater differences from placebo for men with PSA 1.4 ng/mL or greater, primarily due to worsening after the first-year improvement in the placebo group. An activity interference domain score was significantly improved for finasteride over placebo at each time point (P<0.01), with greater treatment differences in men with higher baseline PSA levels. Comparable results were seen for worry at each time point and embarrassment due to urinary symptoms in the last 2 years of the trial. Mean changes in sexual interest and satisfaction were somewhat better for the placebo group overall, as has been previously reported, but little difference between treatments was found in sexual satisfaction measures for men with PSA 1.4 ng/mL or greater.

CONCLUSIONS

Compared with placebo, men receiving finasteride had significantly less bother, activity interference, and worry due to urinary symptoms, with more pronounced differences for men with baseline PSA 1.4 ng/mL or greater. As expected, sexual satisfaction and sexual drive were slightly worse for finasteride overall, but little difference in sexual satisfaction measures was found for men with a higher baseline PSA. Thus, HRQOL was improved for finasteride compared with placebo, especially for men with a baseline PSA 1.4 ng/mL or greater.

Evaluation of a fiber optic immunosensor for quantitating cocaine in coca leaf extracts

A fiber optic evanescent fluoroimmunosensor was used to rapidly detect and quantitate coca alkaloids as cocaine equivalents in leaf extracts of five Erythroxylum species. A monoclonal antibody (mAb) made against benzoylecgonine (BE), a major metabolite of cocaine, was immobilized covalently on quartz fibers and used as the biological sensing element in the portable fluorometer. Benzoylecgonine-fluorescein (BE-FL) was used as the optical signal generator when it bound to the fiber. If present, cocaine competed for the mAb and interfered with the binding of BE-FL, thereby reducing the fluorescence transmitted by the fiber. Calibration curves were prepared by measuring (over 30 s) the rates of fluorescence increase in the absence, or presence of cocaine. Ethanol or acid extracts of dry coca leaves were assayed by this fiber optic biosensor, gas chromatography and a fluorescent polarization immune assay. Biosensor values of cocaine content of leaves from five Erythroxylum species were not significantly different from gas chromatography values, but had higher variance. The biosensor assay was rapid and did not require cleanup of the crude leaf extracts. Cocaine in acid extracts was reduced significantly after 4 weeks at 23 degrees C and after 3 weeks at 37 degrees C. Fibers (mAb-coated), stored at 37 degrees C in phosphate-buffered solution (0.02% NaN3), gave stable responses for 14 days.

Pixel driven implementation of filtered backprojection for reconstruction of fan beam SPECT data using a position dependent effective projection bin length

Filtered backprojection is commonly implemented as a pixel driven algorithm in which the density is reconstructed on an array of grid points that are usually associated with the centres of square image pixels. In fan beam geometry, this conventional pixel driven approach using two-bin linear interpolation leads to an inefficient use of the projection data due to magnification at the projection line. For typical count limited SPECT data, this results in increased reconstructed image noise. We propose an alternative type of pixel driven algorithm that makes efficient use of projection data by averaging over all bins within a position dependent "effective' projection bin interval. The effective bin interval is equivalent to the image pixel length magnified on the projection line. This heuristic method leads to more complete use of the projection data and results in reconstructed images with superior noise properties compared with the conventional method while presenting similar spatial resolution characteristics.

A sensitive high-performance liquid chromatographic assay for the cholecystokinin-B antagonist, CI-988, in human and monkey plasma

A sensitive and specific high-performance liquid chromatographic assay for the non-peptide cholecystokinin subtype B receptor antagonist, CI-988, in human and cynomolgus monkey plasma has been developed and validated. The method involves isolation of CI-988 and internal standard by batch robotic solid phase extraction with a C18 cartridge, liquid chromatographic separation on a C18 column and quantitation by fluorescence detection. The human plasma assay is linear from 0.25 to 500 ng/mL for a 1.00-mL plasma aliquot. Assay precision for CI-988 based on human plasma quality control samples was within +/- 7.2% relative standard deviation with an accuracy of +/- 5.6% relative error. The monkey plasma assay is linear from 1.00 to 250 ng/mL for a 0.500-mL plasma aliquot. Assay precision based on monkey plasma quality control samples was within +/- 11.0% relative standard deviation with an accuracy of +/- 2.6% relative error.

Quantitation of 211At in small volumes for evaluation of targeted radiotherapy in animal models

We have evaluated SPECT and two planar imaging methods, geometric mean (GM) and buildup factor (BF), for their potential to quantitate in vivo 211At distributions in rat spinal subarachnoid spaces using phantom studies. The use of medium-energy collimators and the small diameter (3 mm) of the subarachnoid space complicate quantitation. Net activities from distributions in various backgrounds were obtained using a large region of interest with background subtraction. Results showed quantitation accuracy within 10% for SPECT and BF in low backgrounds increasing to 25% at higher background levels while GM errors ranged from 20 to 45%. We have also obtained images of [211At]astatide distributions, administered intrathecally, in rats.

A new buffer system for acid PAGE typing of equine protease inhibitor

A new buffer system for acid PAGE typing of protease inhibitor (Pi) is described. This buffer system replaces pyridine and cacodylic acid with L-histidine and MES, making the buffer less toxic and less expensive than the acid PAGE system commonly used but with no loss of resolution.

Diurnal fluctuations of cocaine and potential precursors in leaves of Erythroxylum coca

Cocaine is abundant in leaves of Erythroxylum coca var. coca Lam. Consequently, cocaine and two of its early biosynthetic precursors were monitored for 24 h to determine whether they fluctuated diurnally. E. coca was grown under controlled environmental conditions in a growth chamber in soil at pH 3.5. After 17.5 months of growth, leaves not less than 35 days old were harvested every 2 and 4 h for 24 h for arginine, phenylalanine and cocaine content, respectively. The content of cocaine was determined by GC/MS and amino acid content by HPLC. Diurnal fluctuation of cocaine occurred during the 24 h cycle. Cocaine was highest in leaves of E. coca at 8 and 16 h where its content was 7.67 and 9.45 mg.g-1 dry weight, respectively. Arginine and phenylalanine in leaves of E. coca also displayed diurnal rhythmic patterns of fluctuation. The content of arginine declined from hours 6 to 12 and increased to the highest content at 13 h (21.8 mg.g-1 dry weight). Overall, phenylalanine content was lower than arginine, but had two peak periods of accumulation during the 24 h cycle, occurring at 8 and 14 h. The content of phenylalanine in leaves of E. coca during the peak hours was 6.98 and 6.54 mg.g-1 dry weight, respectively.

Measurement of volumetric coronary blood flow with a Doppler catheter: validation in an animal model

Although Doppler catheter recordings are used to determine coronary flow velocity, their accuracy in the estimation of volumetric blood flow has not been validated. To address this issue, Doppler-derived coronary flow was measured in a canine model and compared with that obtained by means of an electromagnetic flowmeter. A carotid artery-to-circumflex coronary artery shunt was created in six dogs with tubing that incorporated an inline electromagnetic flow device. The circumflex artery was occlusively cannulated by means of a rigid metal stent of known internal diameter, which was placed 2 cm into the vessel, and flow was measured in the stent region by means of a 3F Doppler catheter. Analysis of Doppler shift signals was performed by means of a zero-crossing detector (ZCD) and an off-line fast-Fourier transformation (FFT) system. Flow derived from peak FFT velocities corresponded closely to electromagnetic flow (slope 1.09, r = 0.93), whereas mean FFT and ZCD velocities underestimated electromagnetic flow (with slopes of 0.47 and 0.46, respectively) despite a close correlation (r = 0.92, 0.94). Thus FFT analysis of the Doppler signal with determination of peak velocity gives the most accurate representation of flow, whereas measurements based on ZCD mean velocities may significantly underestimate coronary flow.