Effect of RMGI Roughness and Dentin Bonding Primer on Shear Bond Strength of Sandwich-type Restorations

BACKGROUND

The open sandwich technique is a reliable alternative to amalgam placement in deep proximal box preparations, where proper isolation and enamel bonding may not be possible. It is often difficult to prepare the box for composite placement without affecting the resin-modified glass ionomer (RMGI) that has been placed in the gingival portion. We hypothesized that RMGI surfaces that are roughened or those that use all steps in the manufacturing bonding protocol, including the priming solution, applied before placing a bonded composite increment, would have greater composite/RMGI shear bond strength.

DESIGN AND METHODS

Shear bond strengths (SBS) of RMGI tested in the presence and absence of SiC roughening and primer-coating were tested using a fourth-generation dentin bonding agent to composite after thermocycling. Twenty specimens for four test conditions were fabricated and investigated. Data were subjected to a two-way ANOVA and the Holm-Sidak post-hoc test.

RESULTS

Placing dentin primer on unabraded RMGI provided a statistically significant improvement in SBS, but only modestly. Furthermore, because bond failure consistently occurred within the RMGI itself, none of the surface modifications have a clinically relevant impact on SBS at the RMGI to the composite interface.

CONCLUSIONS

Clinicians should be aware that they need not avoid RMGI abrasion and do not need to incorporate all components of a fourth-generation bonding system when covering an RMGI sandwich layer with composite.

Childhood-Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short-Term Kidney Status and Variation in Care

OBJECTIVE

The goal was to characterize short-term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood-onset systemic lupus erythematosus (cSLE) and nephritis.

METHODS

We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy-proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded.

RESULTS

We identified 222 patients with kidney biopsy-proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8-29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21-12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01-1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers.

CONCLUSION

In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short-term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long-term kidney outcomes.

Local-Regional Recurrence After Neoadjuvant Endocrine Therapy: Data from ACOSOG Z1031 (Alliance), a Randomized Phase 2 Neoadjuvant Comparison Between Letrozole, Anastrozole, and Exemestane for Postmenopausal Women with Estrogen Receptor-Positive Clinical Stage 2 or 3 Breast Cancer

BACKGROUND

The ACOSOG Z1031 trial addressed the ability of three neoadjuvant aromatase inhibitors (NAIs) to reduce residual disease (cohort A) and to assess whether switching to neoadjuvant chemotherapy (NCT) after 4 weeks of receiving NAI with Ki67 greater than 10% increases pathologic complete response (pCR) in postmenopausal women with estrogen receptor-enriched (Allred score 6-8) breast cancer (BC).

METHODS

The study enrolled 622 women with clinical stage 2 or 3 estrogen receptor-positive (ER+) BC. Cohort A comprised 377 patients, and cohort B had 245 patients. The analysis cohort consisted of 509 patients after exclusion of patients who did not meet the trial eligibility criteria, switched to NCT or surgery due to 4-week Ki67 greater than 10%, or withdrew before surgery. Distribution of time to local-regional recurrence (LRR) was estimated using the competing-risk approach, in which distant recurrence and second primaries were considered to be competing-risk events. Patients who died without LRR, distant recurrence, or a second primary were censored at the last evaluation.

RESULTS

Of the 509 patients, 342 (67.2%) had breast-conserving surgery (BCS). Of 221 patients thought to require mastectomy at presentation, 50% were able to have BCS. Five (1%) patients had no residual disease in the breast or nodes at surgery. Among 382 women alive at this writing, 90% have been followed longer than 5 years. The 5-year cumulative incidence rate for LRR is estimated to be 1.53% (95% confidence interval 0.7-3.0%).

CONCLUSIONS

Rarely does NAI result in pCR for patients with stage 2 or 3 ER+ BC. However, a significant proportion will have downstaged to allow for BCS. Local-regional recurrence after surgery is uncommon (1.5% at 5 years), supporting the use of BCS after NAI.

PATTERNS OF MULTIMORBIDITY IN AGING, RADIATION-EXPOSED NON-HUMAN PRIMATES

Resilience to stressors is a major component of biological aging and may mediate the onset of multimorbidity in older adults. The Wake Forest Non-Human Primate Radiation Survivor Cohort (RSC) provides a novel opportunity to study aging and resilience in 250 rhesus macaques (Macaca mulatta) with single-dose radiation exposures 0–15 years prior and 50 controls with semi-annual clinical, imaging, and biomarker measurements taken over their lifespan. Multimorbidity is extremely common among irradiated animals. Only 38% of animals have none of 20 common chronic diseases, falling to 16% of animals over age 8 and 11% over age 10 (middle-aged animals). 70% of animals have 5 or more diagnoses in this oldest cohort. The presence of any one disease increases the likelihood of having a second, co-morbid condition. Nevertheless, some animals continue disease-free until late in life, highlighting substantial variability in resilience. To identify patterns of multimorbidity, survival curves for each diagnosis were generated for age and time since radiation and k-median clustered resulting in four groupings of aging-associated morbidities. Bone, brain, and gastrointestinal disorders arise 3.5 years after radiation on average, followed by skin, heart, and cataracts. At 4.65 years, animals are at increased risk of being underweight and overweight and developing diabetes, hypertension, and hepatic dysfunction. Tumor, lung, and kidney disorders arise approximately 6 years after exposure. In all cases, these age-related disorders occur significantly earlier in irradiated animals than controls. These findings highlight the clustering of multimorbidities in aging, radiation-challenged primates and the potential of the RSC in studying resilience.

Abstract A021: Clinical and molecular characterization of naturally-occurring colorectal cancer in rhesus macaques reveals mismatch repair deficiency driven by epigenetic silencing of MLH1

Naturally occurring colorectal cancers (CRC) in rhesus macaques share many features with their human counterparts and emerge at similar life stages as in human patients, but the carcinogenesis and molecular background remain elusive, limiting the value of the model for human disease and cancer therapy. In order to better understand this naturally occurring model, we established a diagnostic and staging pipeline including imaging (18F-FDG PET, plain and contrast-enhanced CT), histopathology, and clinical assessments. We observed cancer symptoms and co-morbidities in our cohort (n=16, all Indian-origin, 11 females, mean age at arrival 20.2y) such as hypoalbuminemia, fecal occult blood, and microcytic anemia, as frequently described in human CRC patients. Pathologically, all cancers were right-sided, involving the proximal colon and/or ileocecocolic junction, and most were densely fibrotic, restricting the colonic lumen. Most cancers appeared with glandular morphology and some (18.8%) had mucinous components. Immunohistochemistry revealed loss of MLH1 and PMS2 in 100% of investigated CRCs, indicating mismatch repair deficiency which furthermore resulted in microsatellite instability (PCR & fragment analysis). Whole exome sequencing revealed the close genetic relatedness to human CRCs, particularly exemplified by mutations affecting KRAS (37.5%, e.g., p.G12D), APC (31.3%), TP53 (18.8%, e.g. p.R175H), ARID1A (56.3%), and ALK (43.8%), as similarly annotated in the human COSMIC database. Nonetheless, somatic mutations do not explain the loss of MLH1 in the entire CRC cohort. Transcriptomics on the other hand revealed the transcriptional suppression of MLH1 but not MSH2, MSH6, or PMS2 in rhesus CRC in comparison to adjacent healthy colon. Moreover, comparison of differentially expressed gene sets of rhesus CRC with a human annotated database (IPA) confirmed the disease similarities observed clinically, genetically, and histopathologically. Subsequently, we investigated DNA methylation of the promoter region of MLH1 and retranslated markers for the CpG island methylator phenotype (CIMP) as described in human CRC. While only 56.3% of CRCs were considered CIMP positive (≥3/5 markers hypermethylated), 100% of investigated CRCs exhibited MLH1 promoter hypermethylation. As a result, epigenetic silencing is suggested to suppress MLH1 transcription, cause the loss of MLH1 protein, and drive mismatch repair deficiency and genomic instability in naturally occurring CRC in rhesus macaques. We therefore consider spontaneous, uninduced CRC in rhesus macaques, their treatment-naïve nature, and their unaltered immune competence an outstanding model for human disease and in particular for human cancer immunotherapy.

Citation Format: Simon Deycmar, Brendan Johnson, Karina Ray, David Caudell Caudell, John Olson, Greg Dugan, W. Shane Sills, Declan Ryan, Christopher Whitlow, Kiran K. Solingapuram Sai, Betsy Ferguson, Benjamin Bimber, Cassandra Cullin, Brandy Dozier, Emily Romero, Francois Villinger, Armando Burgos, Jeff Chou, Bruno Gomes, Michael Hettich, Maurizio Ceppi, Jehad Charo, J. Mark Cline. Clinical and molecular characterization of naturally-occurring colorectal cancer in rhesus macaques reveals mismatch repair deficiency driven by epigenetic silencing of MLH1 [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr A021.

Intraarticular steroids as DMARD-sparing agents for juvenile idiopathic arthritis flares: Analysis of the Childhood Arthritis and Rheumatology Research Alliance Registry

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) who achieve a drug free remission often experience a flare of their disease requiring either intraarticular steroids (IAS) or systemic treatment with disease modifying anti-rheumatic drugs (DMARDs). IAS offer an opportunity to recapture disease control and avoid exposure to side effects from systemic immunosuppression. We examined a cohort of patients treated with IAS after drug free remission and report the probability of restarting systemic treatment within 12 months.

METHODS

We analyzed a cohort of patients from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry who received IAS for a flare after a period of drug free remission. Historical factors and clinical characteristics and of the patients including data obtained at the time of treatment were analyzed.

RESULTS

We identified 46 patients who met the inclusion criteria. Of those with follow up data available 49% had restarted systemic treatment 6 months after IAS injection and 70% had restarted systemic treatment at 12 months. The proportion of patients with prior use of a biologic DMARD was the only factor that differed between patients who restarted systemic treatment those who did not, both at 6 months (79% vs 35%, p < 0.01) and 12 months (81% vs 33%, p < 0.05).

CONCLUSION

While IAS are an option for all patients who flare after drug free remission, it may not prevent the need to restart systemic treatment. Prior use of a biologic DMARD may predict lack of success for IAS. Those who previously received methotrexate only, on the other hand, are excellent candidates for IAS.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

Coagulopathy, Bleeding Events, and Outcome According to Rotational Thromboelastometry in Patients With Acute Liver Injury/Failure

BACKGROUND AND AIMS

Patients with acute liver injury or failure (ALI/ALF) experience bleeding complications uncommonly despite an abnormal hemostatic profile. Rotational thromboelastometry (ROTEM), which assesses clot formation in whole blood, was used to determine the nature of abnormal hemostasis and whether it contributes to bleeding events, illness severity, or survival.

APPROACH AND RESULTS

A total of 200 patients were recruited from sites of the ALF Study Group. Blood collected daily for up to 5 days was analyzed using ROTEM delta devices. Consistent with standard laboratory evidence of hypocoagulability (median international normalized ratio = 2.9 and platelet count = 144 × 109 /L), patients frequently exhibited ROTEM parameters outside the normal range (73% and 62% had abnormalities in clot formation from extrinsic and intrinsic clotting cascades, respectively); however, measures of clot stability were generally normal. Eighteen patients (9%) experienced bleeding events, in whom clot initiation, assembly, and firmness were more severely deranged than patients without bleeding. Abnormal ROTEM parameters were more frequently observed in patients with non-acetaminophen ALI/ALF than those with acetaminophen ALI/ALF (clot initiation [P < 0.001], assembly [P = 0.02], firmness at 10 minutes [P = 0.05], and maximal firmness [P = 0.06]). Patients with more severe systemic complications (high-grade hepatic encephalopathy and need for renal replacement therapy) also had a higher incidence of abnormal ROTEM parameters. Finally, more hypocoagulable ROTEM parameters (clot initiation (P = 0.005), stiffness at 10 minutes (P = 0.05), and maximal stiffness by fibrin assembly (P = 0.004)) were observed in patients who died or underwent liver transplantation than those who survived with their native liver.

CONCLUSIONS

In patients with ALI/ALF, abnormal ROTEM parameters are frequent and proportional to disease severity. Whether the increased bleeding risk associated with abnormal ROTEM indicates hemostatic failure or is a proxy for disease severity requires additional study.

Ion Heating and Flow Driven by an Instability Found in Plasma Couette Flow

We present the first observation of instability in weakly magnetized, pressure dominated plasma Couette flow firmly in the Hall regime. Strong Hall currents couple to a low frequency electromagnetic mode that is driven by high-β (>1) pressure profiles. Spectroscopic measurements show heating (factor of 3) of the cold, unmagnetized ions via a resonant Landau damping process. A linear theory of this instability is derived that predicts positive growth rates at finite β and shows the stabilizing effect of very large β, in line with observations.

Laboratory Resolved Structure of Supercritical Perpendicular Shocks

Supermagnetosonic perpendicular flows are magnetically driven by a large radius theta-pinch experiment. Fine spatial resolution and macroscopic coverage allow the full structure of the plasma-piston coupling to be resolved in laboratory experiment for the first time. A moving ambipolar potential is observed to reflect unmagnetized ions to twice the piston speed. Magnetized electrons balance the radial potential via Hall currents and generate signature quadrupolar magnetic fields. Electron heating in the reflected ion foot is adiabatic.

Implementing harm reduction in non-urban communities affected by opioids and polysubstance use: A qualitative study exploring challenges and mitigating strategies

BACKGROUND

Harm reduction services, which typically provide overdose education and prevention with distribution of naloxone and other supplies related to safer drug use, help reduce opioid-related overdose and infectious disease transmission. However, structural stigma and the ongoing criminalization of drug use have limited the expansion of harm reduction services into many non-urban communities in the United States that have been increasingly affected by the health consequences of opioid and polysubstance use.

METHODS

We conducted qualitative interviews with 22 professionals working with people who use drugs in cities and towns across Rhode Island and Massachusetts to understand challenges and strategies for engaging communities in accepting harm reduction perspectives and services.

RESULTS

Our thematic analysis identified several interrelated challenges to implementing harm reduction services in non-urban communities, including: (1) limited understandings of harm reduction practice and preferential focus on substance use treatment and primary prevention, (2) community-level stigma against people who use drugs as well as the agencies supporting them, (3) data reporting and aggregating leading to inaccurate perceptions about local patterns of substance use and related health consequences, and (4) a "prosecutorial mindset" against drug use and harm reduction. From key informants' narratives, we also identified specific strategies that communities could use to address these challenges, including: (1) identifying local champions to advocate for harm reduction strategies, (2) proactively educating communities about harm reduction approaches before they are implemented, (3) improving the visibility of harm reduction services within communities, and (4) obtaining "buy-in" from a wide range of local stakeholders including law enforcement and local government.

CONCLUSION

These findings carry important implications for expanding harm reduction services, including syringe service programs and safe injection sites, into non-urban communities that have a demonstrated need for evidence-based interventions to reduce drug-related overdose and infectious disease transmission.

Weakly Magnetized, Hall Dominated Plasma Couette Flow

A novel plasma equilibrium in the high-β, Hall regime that produces centrally peaked, high Mach number Couette flow is described. Flow is driven using a weak, uniform magnetic field and large, cross field currents. Large magnetic field amplification (factor 20) due to the Hall effect is observed when electrons are flowing radially inward, and near perfect field expulsion is observed when the flow is reversed. A dynamic equilibrium is reached between the amplified (removed) field and extended density gradients.

Stratified glucocorticoid monotherapy is safe and effective for most cases of giant cell arteritis

Objectives

High-dose glucocorticoids anchor standard care in GCA but are associated with significant toxicity. We aimed to evaluate the safety and effectiveness of a stratified approach to glucocorticoid tapering. The strategy aggressively reduced glucocorticoid doses in those manifesting an adequate early response to treatment, with a view to minimizing glucocorticoid complications.

Methods

A retrospective, population-based study of GCA was performed. All cases were confirmed by temporal artery biopsy between November 2010 and November 2015. Baseline and outcome data were extracted from secondary and primary care records at diagnosis and 1 year follow-up. The primary outcome was loss of vision. Secondary outcomes included remission and relapse rates and CS-related complications.

Results

The cohort consisted of 73 patients (76% female; mean age 73.5 years, s.d. 7.6 years). At presentation, a reduction in visual acuity was recorded in 17 patients (22.3%). The median CRP at diagnosis was 69.5 mg/l [interquartile range (IQR) 40.5–101 mg/l], with a median ESR of 80 mm/h (IQR 60–91 mm/h). At 1 year, remission was achieved in 64 patients (87.7%), whereas 10 patients (13.7%) relapsed. A single patient sustained visual loss after initiation of therapy. The median CRP at 1 year was 4 mg/l (IQR 4–9.5 mg/l) and the mean prednisolone dose was 5.4 mg (0–15 mg). CS-related complications were observed in 10 patients (13.7%).

Conclusion

A stratified approach to CS tapering appeared safe and effective in GCA. It was associated with a high rate of remission and promisingly low rates of relapse at 1 year follow-up. These real-world data indicate that glucocorticoid exposure can be minimized safely in some patients with GCA.

Carbon-14 content in surface soils near atmospheric and below ground nuclear detonations

Global and regional releases of ¹⁴C have resulted from nuclear weapons testing activities; assessment of the chemical behavior and mechanisms of environmental transport and deposition of this radionuclide can assist remediation strategy development efforts and provide insights into global carbon cycling processes. This work reports a systematic evaluation of ¹⁴C in surface soils taken from the Nevada National Security Site. Surface soil samples are derived from above- and underground test locations, with underground test sites representing a range from near complete containment to uncontrolled radioactive releases. Only one surface soil taken from a underground test location (i.e. the Baneberry shot) shows elevated ¹⁴C concentrations (319 ± 9 pMC) in addition to elevated concentrations of ¹³⁷Cs, ⁶⁰Co and ¹⁵²Eu above regional backgrounds. Surface soils from above-ground test locations show extremely high ¹⁴C content (~1000 to 10,000 pMC); elevated concentrations of ¹⁵²Eu and ⁶⁰Co for these soils are also observed, with ¹³⁷Cs at or below background levels. Taken together, these data suggest that ¹⁴C in surface soils from above-ground tests is primarily derived from in-situ neutron activation of the native soil material, whereas ¹⁴C in surface soils from underground tests may be from either recondensed particulate material or soil activation.

Abstract P1-11-09: Sleep disturbance and quality of life among breast cancer survivors

Introduction: Breast cancer survivors are at risk for substantial sleep disturbance, which can negatively affect quality of life. Sleep disturbance can be exacerbated by co-occurring emotional concerns such as depressive symptoms and anxiety. Prior research has largely focused on linkages between sleep disturbance and emotional concerns among individuals with early stage disease. To dive deeper, we examined sleep disturbance and its correlates among breast cancer survivors with and without metastatic disease.

Methods: 631 female breast cancer survivors (168 ever experiencing metastatic disease [MBC]; 463 never metastatic [BC]) enrolled in the Cancer Support Community's online Cancer Experience Registry, provided socio-demographic information, and reported cancer-related distress (CancerSupportSource®, a 25-item measure with depression and anxiety risk screening subscales) and levels of pain interference (PI) and sleep disturbance (PROMIS-29 subscales). We examined associations between risk for depression/anxiety, PI, and worse sleep disturbance with multivariate regression, adjusting for metastatic disease, treatment history, and number of comorbidities.

Results: Participants were 84% non-Hispanic White; mean age=54.8 years, SD=12.2; mean time since diagnosis=4.4 years, SD=5.5. 72% ever received chemotherapy; 60% radiation therapy; 56% hormone therapy; 91% had surgery for their cancer. 47% reported moderate to very serious concern about sleep problems; concern about sleep did not differ by metastatic history. 20% of participants reported a level of sleep disturbance that was significantly worse (&gt;1SD) than the U.S. population average and 18% reported PI that was significantly worse (&gt;1SD) than the U.S. population average; these did not differ by metastatic history. Using CancerSupportSource anxiety and depression risk screening subscales, 47% of participants were identified as at risk for clinically significant levels of anxiety, and 35% at risk for clinically significant levels of depression. Participants with MBC were more likely to be at risk for clinically significant levels of anxiety (χ2=.7.98, p&lt;.01). Depression risk did not differ between MBC and BC survivors. Greater sleep disturbance was associated with having ever received radiation therapy (r=.11, p&lt;.01), number of reported comorbidities (r=.37, p&lt;.001), greater PI (r=.46, p&lt;.001), and greater risk for clinically significant depression (r=.38, p&lt;.001) and anxiety (r=.35, p&lt;.001). In multivariate analysis, risk for clinically significant levels of depression (semipartial r=.12, p&lt; .005), anxiety (semipartial r=.05, p&lt; .05), and greater PI (semipartial r=.24, p&lt; .001) remained associated with greater sleep disturbance after controlling for treatment history, metastatic status, and number of comorbidities, (R2=.28, F(4,588)=56.26, p&lt;.001).

Conclusion: Being at risk for clinically significant levels of depression and anxiety and experiencing greater pain interference are associated with worse sleep disturbance among breast cancer survivors across the illness trajectory. Health care providers are encouraged to discuss with patients how they can address sleep disturbance concerns, including referrals to integrative therapies that address the constellation of affective, pain, and sleep symptoms.

Citation Format: McManus S, Zaleta AK, Miller MF, Olson J, Saxton MC, Stein K. Sleep disturbance and quality of life among breast cancer survivors [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-11-09.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Towards harmonization of external quality assessment/proficiency testing in hemostasis

Quality in diagnostic testing represents a key target of laboratory medicine, for which an assurance around the quality of testing is expected from all involved in the process. Laboratories attempt to assure the quality of their testing by various processes, but especially by performance of internal quality control and external quality assessment (EQA). This is especially true for tests of hemostasis and coagulation. EQA in general provides information on test accuracy and on evaluation of long-term laboratory performance. EQA providers support laboratory performance by various means, including distribution of material for testing of analytes (“proficiency testing”), educational support through expert advice, distribution of publications or case series. Participation in EQA is often a laboratory accreditation requirement. This review aims to identify some of the strengths and weaknesses of EQA, and targets attempts towards harmonization of EQA practice, in order to achieve the best outcome for participant laboratories and, thus, for patients and their clinical care providers.

Development of a Ki-67-based clinical trial assay for neoadjuvant endocrine therapy response monitoring in breast cancer

PURPOSE

The recent publication of the ACOSOG Z1031 trial results demonstrated that Ki-67 proliferation marker-based neoadjuvant endocrine therapy response monitoring could be used for tailoring the use of adjuvant chemotherapy in ER+HER2-negative breast cancer patients. In this paper, we describe the development of the Ki-67 clinical trial assay used for this study.

METHODS

Ki-67 assay assessment focused on reproducing a 2.7% Ki-67 cut-point (CP) required for calculating the Preoperative Endocrine Prognostic Index and a 10% CP for poor endocrine therapy response identification within the first month of neoadjuvant endocrine treatment. Image analysis was assessed to increase the efficiency of the scoring process. Clinical outcome concordance for two independent Ki-67 scores was the primary performance metric.

RESULTS

Discordant scores led to a triage approach where cases with complex histological features that software algorithms could not resolve were flagged for visual point counting (17%). The final Ki-67 scoring approach was run on T1/2 N0 cases from the P024 and POL trials (N = 58). The percent positive agreement for the 2.7% CP was 87.5% (95% CI 61.7-98.5%); percent negative agreement 88.9% (95% CI: 65.3-98.6%). Minor discordance did not affect the ability to predict similar relapse-free outcomes (Log-Rank P = 0.044 and P = 0.055). The data for the 10% early triage CP in the POL trial were similar (N = 66), the percentage positive agreement was 100%, and percent negative agreement 93.55% (95% CI: 78.58-99.21%). The independent survival predictions were concordant (Log-rank P = 0.0001 and P = 0.01).

CONCLUSIONS

We have developed an efficient and reproducible Ki-67 scoring system that was approved by the Clinical Trials Evaluation Program for NCI-supported neoadjuvant endocrine therapy trials. Using the methodology described here, investigators are able to identify a subgroup of patients with ER+HER2-negative breast cancer that can be safely managed without the need of adjuvant chemotherapy.

The FIELDS Instrument Suite for Solar Probe Plus: Measuring the Coronal Plasma and Magnetic Field, Plasma Waves and Turbulence, and Radio Signatures of Solar Transients

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.

Spaceflight-Relevant Challenges of Radiation and/or Reduced Weight Bearing Cause Arthritic Responses in Knee Articular Cartilage

There is little known about the effect of both reduced weight bearing and exposure to radiation during spaceflight on the mechanically-sensitive cartilage lining the knee joint. In this study, we characterized cartilage damage in rat knees after periods of reduced weight bearing with/without exposure to solar-flare-relevant radiation, then cartilage recovery after return to weight bearing. Male Sprague Dawley rats (n = 120) were either hindlimb unloaded (HLU) via tail suspension or remained weight bearing in cages (GROUND). On day 5, half of the HLU and GROUND rats were 1 Gy total-body X-ray irradiated during HLU, and half were sham irradiated (SHAM), yielding 4 groups: GROUND-SHAM; GROUND-IR; HLU-SHAM; and HLU-IR. Hindlimbs were collected from half of each group of rats on day 13. The remaining rats were then removed from HLU or remained weight bearing, and hindlimbs from these rats were collected on day 62. On day 13, glycosaminoglycan (GAG) content in cartilage lining the tibial plateau and femoral condyles of HLU rats was lower than that of the GROUND animals. Likewise, on day 13, immunoreactivity of the collagen type II-degrading matrix metalloproteinase-13 (MMP-13) and of a resultant metalloproteinase-generated neoepitope VDIPEN was increased in all groups versus GROUND-SHAM. Clustering of chondrocytes indicating cartilage damage was present in all HLU and IR groups versus GROUND-SHAM on day 13. On day 62, after 49 days of reloading, the loss of GAG content was attenuated in the HLU-SHAM and HLU-IR groups, and the increased VDIPEN staining in all treatment groups was attenuated. However, the increased chondrocyte clustering remained in all treatment groups on day 62. MMP-13 activity also remained elevated in the GROUND-IR and HLU-IR groups. Increased T2 relaxation times, measured on day 62 using 7T MRI, were greater in GROUND-IR and HLU-IR knees, indicating persistent cartilage damage in the irradiated groups. Both HLU and total-body irradiation resulted in acute degenerative and pre-arthritic changes in the knee articular cartilage of rats. A return to normal weight bearing resulted in some recovery from cartilage degradation. However, radiation delivered as both a single challenge and when combined with HLU resulted in chronic cartilage damage. These findings suggest that radiation exposure during spaceflight leads to and/or impairs recovery of cartilage upon return to reloading, generating long-term joint problems for astronauts.

Experimental Demonstration of the Collisionless Plasmoid Instability below the Ion Kinetic Scale during Magnetic Reconnection

The spontaneous formation of magnetic islands is observed in driven, antiparallel magnetic reconnection on the Terrestrial Reconnection Experiment. We here provide direct experimental evidence that the plasmoid instability is active at the electron scale inside the ion diffusion region in a low collisional regime. The experiments show the island formation occurs at a smaller system size than predicted by extended magnetohydrodynamics or fully collisionless simulations. This more effective seeding of magnetic islands emphasizes their importance to reconnection in naturally occurring 3D plasmas.

Novel plasmid conferring kanamycin and tetracycline resistance in the turkey-derived Campylobacter jejuni strain 11601MD

In Campylobacter spp., resistance to the antimicrobials kanamycin and tetracycline is frequently associated with plasmid-borne genes. However, relatively few plasmids of Campylobacter jejuni have been fully characterized to date. A novel plasmid (p11601MD; 44,095nt) harboring tet(O) was identified in C. jejuni strain 11601MD, which was isolated from the jejunum of a turkey produced conventionally in North Carolina. Analysis of the p11601MD sequence revealed the presence of a high-GC content cassette with four genes that included tet(O) and a putative aminoglycoside transferase gene (aphA-3) highly similar to kanamycin resistance determinants. Several genes putatively involved in conjugative transfer were also identified on the plasmid. These findings will contribute to a better understanding of the distribution of potentially self-mobilizing plasmids harboring antibiotic resistance determinants in Campylobacter spp. from turkeys and other sources.

Use of trimetasphere metallofullerene MRI contrast agent for the non-invasive longitudinal tracking of stem cells in the lung

Magnetic Resonance Imaging (MRI) is a commonly used, non-invasive imaging technique that provides visualization of soft tissues with high spatial resolution. In both a research and clinical setting, the major challenge has been identifying a non-invasive and safe method for longitudinal tracking of delivered cells in vivo. The labeling and tracking of contrast agent labeled cells using MRI has the potential to fulfill this need. Contrast agents are often used to enhance the image contrast between the tissue of interest and surrounding tissues with MRI. The most commonly used MRI contrast agents contain Gd(III) ions. However, Gd(III) ions are highly toxic in their ionic form, as they tend to accumulate in the liver, spleen, kidney and bones and block calcium channels. Endohedral metallofullerenes such as trimetallic nitride endohedral metallofullerenes (Trimetasphere®) are one unique class of fullerene molecules where a Gd3N cluster is encapsulated inside a C80 carbon cage referred to as Gd3N@C80. These endohedral metallofullerenes have several advantages over small chelated Gd(III) complexes such as increased stability of the Gd(III) ion, minimal toxic effects, high solubility in water and high proton relativity. In this study, we describe the evaluation of gadolinium-based Trimetasphere® positive contrast agent for the ​in vitro labeling and in vivo tracking of human amniotic fluid-derived stem cells within lung tissue. In addition, we conducted a 'proof-of-concept' experiment demonstrating that this methodology can be used to track the homing of stem cells to injured lung tissue and provide longitudinal analysis of cell localization over an extended time course.

The potential utility of non-invasive imaging to monitor restoration of bladder structure and function following subtotal cystectomy (STC)

Background

Restoration of normal bladder volume and function (i.e., bioequivalent bladder) are observed within 8 weeks of performing subtotal cystectomy (STC; removal of ~70 % of the bladder) in 12-week old rats. For analysis of bladder function in rodents, terminal urodynamic approaches are largely utilized. In the current study, we investigated the potential for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans to noninvasively track restoration of structure and function following STC.

Methods

Twelve week old female Fisher F344 rats underwent STC and were scanned via CT and/or MRI 2, 4, 8, and 12 weeks post-STC, followed by urodynamic testing. After euthanasia, bladders were excised for histological processing.

Results

MRI scans demonstrated an initial decline followed by a time-dependent increase to normal bladder wall thickness (BWT) by 8 weeks post-STC. Masson’s trichrome staining showed a lack of fibrosis post-STC, and also revealed that the percent of smooth muscle in the bladder wall at 2 and 4 weeks positively correlated with pre-operative baseline BWT. Moreover, increased BWT values before STC was predictive of improved bladder compliance at 2 and 4 weeks post-STC. Cystometric studies indicated that repeated MRI manipulation (i.e. bladder emptying) apparently had a negative impact on bladder capacity and compliance. A “window” of bladder volumes was identified 2 weeks post-STC via CT scanning that were commensurate with normal micturition pressures measured in the same animal 6 weeks later.

Conclusions

Taken together, the data indicate some limitations of “non-invasive” imaging to provide insight into bladder regeneration. Specifically, mechanical manipulation of the bladder during MRI appears to negatively impact the regenerative process per se, which highlights the importance of terminal cystometric studies.

Abstract P149: Distinct Profiles of Brain Medullary Metabolites Detected by 1 H-Magnetic Resonance Spectroscopy Correlate with Indices of Autonomic Function and Visceral Fat in Healthy Adults

Higher forebrain myoinositol (mIns), a marker of glial inflammation/proliferation as detected by proton magnetic resonance spectroscopy (MRS), correlates with systemic inflammation. Elevated circulating markers of inflammation are associated with lower baroreceptor reflex sensitivity (BRS) and heart rate variability (HRV) as well as visceral fat or central obesity. To determine whether transmitters/metabolites in a cardiovascularly (CV) relevant brain region correlate with age-related declines in BRS and HRV and markers of abdominal fat, autonomic profiles were determined by spectral and sequence analysis from continuous blood pressure and HR values in the supine position of healthy subjects 22 - 76 yrs old (12F, 4M); subjects later underwent a single voxel (10 x 7 x 20mm) proton MRS scan of dorsal medulla on a 3T magnet (n = 11; 9F, 2M) and measures of abdominal fat by computerized tomography (CT) (n = 9; 7F,2M). The mean arterial pressure was 88 ± 3 mm Hg, HR 64 ± 3 beats/min and BMI 27 ± 1 kg/m 2 . Glutamate (Glu) correlated directly with vagal (HF RRI r = 0.72, p < 0.02) and inversely with sympathetic (LF RRI r = -0.72, p < 0.02) control of HR. Markers of Glu metabolism and neuronal integrity/activity, N-acetyl-aspartate acid (NAA) + N-acetyl aspartyl glutamate (NAAG), did not correlate with age, but did correlate inversely with BRS (Seq ALL: r = -0.69, P < 0.02), HRV (rMSSD: r = -0.76, p < 0.008) and directly with HR (r = 0.68, p < 0.03). Total visceral fat had a negative correlation with BRS (Seq Up: r = -0.70, p < 0.02). mIns and markers of demyelination and reduced axonal integrity such as Glycerophosphocholine (GPC) and total choline containing compounds (GPC+PCh) exhibited striking positive correlations with percent visceral fat (r = 0.97, 0.81 and 0.82, P < 0.02). BMI and GPC correlated with HR (r = 0.55, 0.72, p < 0.04), but neither these nor mIns or choline compounds correlated with autonomic function. Thus, in healthy adults, Glu concentration in dorsal medulla directly correlates with cardiac vagal function, whereas markers of Glu metabolism inversely correlate with BRS and HRV. In contrast, markers of glial inflammation directly associate with increases in visceral adiposity, but not autonomic dysfunction. P30-AG21332, Farley Hudson, Hypertension & Vasc Res Ctr

Outcome of Adult Brain Tumor Consortium (ABTC) prospective dose-finding trials of I-125 balloon brachytherapy in high-grade gliomas: challenges in clinical trial design and technology development when MRI treatment effect and recurrence appear similar

OBJECTIVES

The aim of this study is to define the maximal safe radiation dose to guide further study of the GliaSite balloon brachytherapy (GSBT) system in untreated newly diagnosed glioblastoma (NEW-GBM) and recurrent high-grade glioma (REC-HGG). GBST is a balloon placed in the resection cavity and later filled through a subcutaneous port with liquid I-125 Iotrex, providing radiation doses that diminish uniformly with distance from the balloon surface.

METHODS

The Adult Brain Tumor Consortium initiated prospective dose-finding studies to determine maximum tolerated dose in NEW-GBM treated before standard RT or after surgery for REC-HGG. Patients were inevaluable if there was progression before the 90-day posttreatment toxicity evaluation point.

RESULTS

Ten NEW-GBM patients had the balloon placed, and 2/10 reached the 90 day timepoint. Five REC-HGG enrolled and two were assessable at the 90-day evaluation endpoint. Imaging progression occurred before 90-day evaluation in 7/12 treated patients. The trials were closed as too few patients were assessable to allow dose escalation, although no dose-limiting toxicities (DLTs) were observed. Median survival from treatment was 15.3 months (95 % CI 7.1-23.6) for NEW-GBM and 12.8 months (95 % CI 4.2-20.9) for REC-HGG.

CONCLUSION

These trials failed to determine a maximum tolerated dose (MTD) for further testing as early imaging changes, presumed to be progression, were common and interfered with the assessment of treatment-related toxicity. The survival outcomes in these and other related studies, although based on small populations, suggest that GSBT may be worthy of further study using clinical and survival endpoints, rather than standard imaging results. The implications for local therapy development are discussed.

High-power synchronously pumped femtosecond Raman fiber laser

We report a high-power synchronously pumped femtosecond Raman fiber laser operating in the normal dispersion regime. The Raman laser is pumped by a picosecond Yb(3+)-doped fiber laser. It produces highly chirped pulses with energy up to 18 nJ, average power of 0.76 W and 88% efficiency. The pulse duration is measured to be 147 fs after external compression. We observed two different regimes of operation of the laser: coherent and noise-like regime. Both regimes were experimentally characterized. Numerical simulations are in a good agreement with experimental results.

Direct conversion of human myoblasts into brown-like adipocytes by engineered super-active PPARγ

OBJECTIVE

To determine whether super-activation of PPARγ can reprogram human myoblasts into brown-like adipocytes and to establish a new cell model for browning research.

METHODS

To enhance the PPARγ signaling, M3, the transactivation domain of MyoD, was fused to PPARγ. PPARγ and M3-PPARγ-lentiviral vectors were used to convert human myoblasts into adipocytes. Brown adipocyte markers of the reprogrammed adipocytes were assessed by qPCR and protein analyses. White adipocytes differentiated from subcutaneous stromal vascular cells and perithyroid brown fat tissues were used as references.

RESULTS

In transient transfections, M3-PPARγ had a stronger constitutive activity than PPARγ by reporter assay. Although the transduction of either PPARγ or M3-PPARγ induced adipogenesis in myoblasts, M3-PPARγ drastically induced the brown adipocyte markers of UCP1, CIDEA, and PRDM16 by 1,050, 2.4, and 5.0 fold, respectively and increased mitochondria contents by 4 fold, compared to PPARγ.

CONCLUSIONS

Super-activation of PPARγ can effectively convert human myoblasts into brown-like adipocytes and a new approach to derive brown-like adipocytes.

Radiation-induced cognitive impairment and altered diffusion tensor imaging in a juvenile rat model of cranial radiotherapy

PURPOSE

To assess the long-term effects of fractionated whole brain irradiation (fWBI) using diffusion tensor imaging (DTI) and behavior in a pediatric rodent model for the clinical presentation of adult pediatric cancer survivors.

MATERIALS AND METHODS

Five-week-old, male F344xBN rats were randomized to receive 0, 5, or 6.5 Gy fractions biweekly for 3 weeks, resulting in Sham, Irradiated-30 (IR-30) and IR-39 Gy total dose groups. Magnetic Resonance Imaging occurred at 1, 3, 6 and 9 months with behavioral assessment at 10-11 months post-fWBI.

RESULTS

Irradiation reduced brain size (p < 0.001) and body weight (p < 0.001) proportionate to dose. At 1 month post-fWBI and throughout follow-up, diffusion was reduced in IR-30 and IR-39 relative to shams (p < 0.001). IR-30 but not IR-39 rats were impaired relative to Shams on the reversal trial of the Morris Water Maze (p < 0.05), and IR-30 rats preferred a striatum- mediated strategy (p < 0.06).

CONCLUSIONS

Hippocampal performance was impaired in IR-30 but not IR-39 animals. While gross size differences exist, white matter integrity is preserved in rats after fWBI at 5 weeks. This significant departure from childhood cancer survivors and single fraction rodent studies where white matter degradation is a prominent feature are discussed.

Total-body irradiation produces late degenerative joint damage in rats

PURPOSE

Premature musculoskeletal joint failure is a major source of morbidity among childhood cancer survivors. Radiation effects on synovial joint tissues of the skeleton are poorly understood. Our goal was to assess long-term changes in the knee joint from skeletally mature rats that received total-body irradiation while skeletal growth was ongoing.

MATERIALS AND METHODS

14 week-old rats were irradiated with 1, 3 or 7 Gy total-body doses of 18 MV X-rays. At 53 weeks of age, structural and compositional changes in knee joint tissues (articular cartilage, subchondral bone, and trabecular bone) were characterized using 7T MRI, nanocomputed tomography (nanoCT), microcomputed tomography (microCT), and histology.

RESULTS

T2 relaxation times of the articular cartilage were lower after exposure to all doses. Likewise, calcifications were observed in the articular cartilage. Trabecular bone microarchitecture was compromised in the tibial metaphysis at 7 Gy. Mild to moderate cartilage erosion was scored in the 3 and 7 Gy rats.

CONCLUSIONS

Late degenerative changes in articular cartilage and bone were observed after total-body irradiation in adult rats exposed prior to skeletal maturity. 7T MRI, microCT, nanoCT, and histology identified potential prognostic indicators of late radiation-induced joint damage.