Influence of the Compliance and Layering Method on the Wall Deflection of Simulated Cavities in Bulk-fill Composite Restoration

The aim of this study was to investigate the effects of the layering method and compliance on the wall deflection of simulated cavities in bulk-fill and conventional composite restorations and to examine the relationships between the wall deflection and the polymerization shrinkage, flexural modulus, and polymerization shrinkage stress of composites. Six light-cured composites were used in this study. Two of these were conventional methacrylate-based composites (Filtek Z250 and Filtek Z350 XT Flowable [Z350F]), whereas four were bulk-fill composites (SonicFill, Tetric N-Ceram Bulk-Fill, SureFil SDR Flow [SDR], and Filtek Bulk-Fill). One hundred eighty aluminum molds simulating a mesio-occluso-distal cavity (6 W×8 L×4 D mm) were prepared and classified into three groups with mold wall thicknesses of 1, 2, and 3 mm. Each group was further subdivided according to the composite layering method (bulk or incremental layering). Linear variable differential transformer probes were used to measure the mold wall deflection of each composite (n=5) over a period of 2000 seconds (33.3 minutes). The polymerization shrinkage, flexural modulus, and polymerization shrinkage stress of the six composites were also measured. All groups with bulk filling exhibited significantly higher deflection compared with groups with incremental layering. The deflection decreased as mold wall thickness increased. The highest and lowest polymerization shrinkage stresses were recorded for Z350F (5.07 MPa) and SDR (1.70 MPa), respectively. The correlation between polymerization shrinkage and the mold wall deflection decreased with increasing wall thickness. On the other hand, the correlation between flexural modulus and the mold wall deflection increased with increasing wall thickness. For all groups, wall deflection correlated strongly with polymerization shrinkage stress.

Aging exacerbates development of cerebral microbleeds in a mouse model

Background

Cerebral microhemorrhages (CMH) are commonly found in the aging brain. CMH are also the neuropathological substrate of cerebral microbleeds (CMB), demonstrated on brain MRI. Recent studies demonstrate the importance of systemic inflammation in CMH development, but the relationships among inflammation, aging, and CMH development are not well-defined. In the current study, we hypothesized that the pathogenesis of inflammation-induced CMH in mice differs by age.

Methods

We studied young (3 months, n = 20) and old (18 months, n = 25) C57BL/6 mice injected with low-dose lipopolysaccharide (LPS; 1 mg/kg, i.p.) or saline at 0, 6, and 24 h. Seven days after the first LPS/saline injection, brains were harvested, sectioned, and stained with hematoxylin and eosin (H&E) and Prussian blue (PB) to estimate acute/fresh and sub-acute CMH development, respectively. The relationships between microglial/macrophage activation (ionized calcium-binding adapter molecule-1), astrocyte activation (glial fibrillary acidic protein), blood-brain barrier (BBB) disruption (brain immunoglobulin G), aging, and CMH development were examined using immunohistochemistry.

Results

Aging alone did not increase spontaneous H&E-positive CMH development but significantly increased the number, size, and total area of LPS-induced H&E-positive CMH in mice. LPS- and saline-treated aged mice had significantly larger PB-positive CMH compared with young mice, but the total area of PB-positive CMH was increased only in LPS-treated aged mice. Aged mice had significantly increased microglial/macrophage activation, which correlated with H&E- and PB-positive CMH development. Aged mice treated with LPS had significantly increased astrocyte activation and BBB disruption compared with young LPS-treated mice.

Conclusions

Aging makes the brain more susceptible to inflammation-induced CMH in mice, and this increase in CMH with aging is associated with microglial/macrophage activation.

Abstract P4-06-18: Clinical application of multigene panel testing and genetic counseling for hereditary/familial breast cancer risk assessment: Prospective single center study

Background

The identification of individuals at elevated risk for hereditary cancers has allowed the development of consensus recommendations for cancer screening and prevention. The introduction of multigene panels may identify more individuals with breast cancer gene mutations than does testing for BRCA1/2 alone. Therefore, the multigenerational panel increase the need for genetic counseling suggesting preventive approach or cancer-specific screening to patients and family members. The rapid clinical introduction of multigene panel testing, however, have several issues such as low- to moderate-risk gene mutations and clinical recommendations. We collect the mutation results and clinical recommendations after testing with multigene panel and giving genetic counseling.

Methods

We had developed multigene panel consisted of 64 genes related to hereditary cancer through previous study and prospectively enrolled 104 individuals who were appropriate candidates for hereditary breast cancer evaluation. The patients were tested with 64-gene panel(Celemics) and results were provided by us 4˜10 weeks later. We checked the family history of cancer and made a pedigree before testing.

Result

Among 104 participants, 26 patients harbored deleterious mutations, most commonly in high to moderate-risk breast/ovarian cancer genes (BRCA1/2, BRIP, RAD51 and RAD51D), Lynch syndrome gene(MSH6) and other genes(FH, SPINK1). We recommended the cancer-specific screening and/or preventive approach for mutation-positive patients and suggested additional genetic test for the family members. Among them, 6 (23%) patients received Risk reducing procedures (Prophylactic mastectomy or oophorectomy) and most of them(19 patients(73%)) received cancer specific screening.

Conclusion

We demonstrate the use of multigene panel testing for hereditary breast cancer and will suggest the process of the genetic counseling including indication and results analysis with multigene panel testing.

Citation Format: Lee E-S, Han W, Kim Y, Rhu J, Park JH, Kim K-E, Ju YW, Kim R, Lee H-B, Moon H-G, Noh D-Y. Clinical application of multigene panel testing and genetic counseling for hereditary/familial breast cancer risk assessment: Prospective single center study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-06-18.

Regulation of glutamate transporter 1 (GLT-1) gene expression by cocaine self-administration and withdrawal

Downregulation of the astroglial glutamate transporter GLT-1 is observed in the nucleus accumbens (NAc) following administration of multiple drugs of abuse. The decrease in GLT-1 protein expression following cocaine self-administration is dependent on both the amount of cocaine self-administered and the length of withdrawal, with longer access to cocaine and longer withdrawal periods leading to greater decreases in GLT-1 protein. However, the mechanism(s) by which cocaine downregulates GLT-1 protein remains unknown. We used qRT-PCR to examine gene expression of GLT-1 splice isoforms (GLT-1A, GLT-1B) in the NAc, prelimbic cortex (PL) and basolateral amygdala (BLA) of rats, following two widely used models of cocaine self-administration: short-access (ShA) self-administration, and the long-access (LgA) self-administration/incubation model. While downregulation of GLT-1 protein is observed following ShA cocaine self-administration and extinction, this model did not lead to a change in GLT-1A or GLT-1B gene expression in any brain region examined. Forced abstinence following ShA cocaine self-administration also was without effect. In contrast, LgA cocaine self-administration and prolonged abstinence significantly decreased GLT-1A gene expression in the NAc and BLA, and significantly decreased GLT-1B gene expression in the PL. No change was observed in NAc GLT-1A gene expression one day after LgA cocaine self-administration, indicating withdrawal-induced decreases in GLT-1A mRNA. In addition, LgA cocaine self-administration and withdrawal induced hypermethylation of the GLT-1 gene in the NAc. These results indicate that a decrease in NAc GLT-1 mRNA is only observed after extended access to cocaine combined with protracted abstinence, and that epigenetic mechanisms likely contribute to this effect.

Signal self-enhancement by coordinated assembly of gold nanoparticles enables accurate one-step-immunoassays

Current immunoassays are in general performed through time-consuming multi-step procedures that depend on the use of premade signal-producing reporters and often cause assay inaccuracy. Here we report an advanced immunoassay technology that resolves the delayed, complex, and inaccurate assay problems of conventional immunoassays. We have developed an accurate, rapid, simple, and label-free one-step-immunoassay based on the self-enhancement of sensitive immunoassay signals in an assay solution. The nano-scale protein particles (hepatitis B virus capsid and human ferritin heavy chain particles) were genetically engineered to present many well-oriented antibody (or antigen) probes and multi-copies of poly-histidine peptides on their surface, resulting in the construction of 3-dimensional (3D) bioprobes that chemisorb gold ions via coordination bonding and sensitively detect both antigen and antibody analytes. Systematic numerical and experimental analyses show that the signal self-enhancement happens through two coupled reactions under reducing conditions: (1) 3D bioprobe-based sensitive immuno-detection of analytes and (2) coordinated assembly of free and chemisorbed gold nanoparticles around the 3D bioprobe-analyte-associated complexes, which is followed by the quick generation of apparent optical signals. This advanced one-step-immunoassay was successfully applied to diagnostic assays requiring high accuracy and/or speed, i.e. diagnosis of acute myocardial infarction and hepatitis C through detecting a cardiac protein (troponin I) and anti-hepatitis C virus antibodies in patient sera, indicating that it is applicable to the accurate and rapid detection of both antigen and antibody markers of a wide range of diseases.

Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

We identified rare coding variants associated with Alzheimer's disease in a three-stage case-control study of 85,133 subjects. In stage 1, we genotyped 34,174 samples using a whole-exome microarray. In stage 2, we tested associated variants (P < 1 × 10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, we used an additional 14,997 samples to test the most significant stage 2 associations (P < 5 × 10-8) using imputed genotypes. We observed three new genome-wide significant nonsynonymous variants associated with Alzheimer's disease: a protective variant in PLCG2 (rs72824905: p.Pro522Arg, P = 5.38 × 10-10, odds ratio (OR) = 0.68, minor allele frequency (MAF)cases = 0.0059, MAFcontrols = 0.0093), a risk variant in ABI3 (rs616338: p.Ser209Phe, P = 4.56 × 10-10, OR = 1.43, MAFcases = 0.011, MAFcontrols = 0.008), and a new genome-wide significant variant in TREM2 (rs143332484: p.Arg62His, P = 1.55 × 10-14, OR = 1.67, MAFcases = 0.0143, MAFcontrols = 0.0089), a known susceptibility gene for Alzheimer's disease. These protein-altering changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified risk genes in Alzheimer's disease. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to the development of Alzheimer's disease.

Effects of phosphodiesterase 3A modulation on murine cerebral microhemorrhages

BACKGROUND

Cerebral microbleeds (CMB) are MRI-demonstrable cerebral microhemorrhages (CMH) which commonly coexist with ischemic stroke. This creates a challenging therapeutic milieu, and a strategy that simultaneously protects the vessel wall and provides anti-thrombotic activity is an attractive potential approach. Phosphodiesterase 3A (PDE3A) inhibition is known to provide cerebral vessel wall protection combined with anti-thrombotic effects. As an initial step in the development of a therapy that simultaneously treats CMB and ischemic stroke, we hypothesized that inhibition of the PDE3A pathway is protective against CMH development.

METHODS

The effect of PDE3A pathway inhibition was studied in the inflammation-induced and cerebral amyloid angiopathy (CAA)-associated mouse models of CMH. The PDE3A pathway was modulated using two approaches: genetic deletion of PDE3A and pharmacological inhibition of PDE3A by cilostazol. The effects of PDE3A pathway modulation on H&E- and Prussian blue (PB)-positive CMH development, BBB function (IgG, claudin-5, and fibrinogen), and neuroinflammation (ICAM-1, Iba-1, and GFAP) were investigated.

RESULTS

Robust development of CMH in the inflammation-induced and CAA-associated spontaneous mouse models was observed. Inflammation-induced CMH were associated with markers of BBB dysfunction and inflammation, and CAA-associated spontaneous CMH were associated primarily with markers of neuroinflammation. Genetic deletion of the PDE3A gene did not alter BBB function, microglial activation, or CMH development, but significantly reduced endothelial and astrocyte activation in the inflammation-induced CMH mouse model. In the CAA-associated CMH mouse model, PDE3A modulation via pharmacological inhibition by cilostazol did not alter BBB function, neuroinflammation, or CMH development.

CONCLUSIONS

Modulation of the PDE3A pathway, either by genetic deletion or pharmacological inhibition, does not alter CMH development in an inflammation-induced or in a CAA-associated mouse model of CMH. The role of microglial activation and BBB injury in CMH development warrants further investigation.

Abstract P5-08-28: Incidence of germline BRCA1- and BRCA2-mutated breast cancer in the US

Background: Breast cancer is the most common cancer and second leading cause of cancer death among women in the United States (US).1 Inherited mutations in germline breast cancer susceptibility gene 1 and 2 (gBRCAm) are associated with increased risk of developing cancers, including breast cancer.2 No published reports of gBRCAm incidence within an unselected US breast cancer population are available based on a comprehensive literature review (CLR). The main objective of this analysis is to estimate the incidence of gBRCAm breast cancer in the US.

Methods: For this analysis the Surveillance, Epidemiology, and End Results (SEER) Program 18 registries captured incidence of breast cancer by stage, age and gender.3 The size of the US population was based on United Nation's population projections and standardized to the 2010 population.4 Age-specific gBRCAm distribution and gBRCAm-specific hormonal subtype for estrogen-receptor and progesterone-receptor (ER/PR), and human epidermal growth factor receptor-2 (HER2) estimates were determined from a CLR.5-8 Tumor cells negative for ER/PR and HER2 are referred to as triple-negative breast cancer (TNBC).

Results: In 2016, it is projected that approximately 250,000 individuals will be diagnosed with invasive breast cancer (all genders). Median age range of the population with invasive breast cancer is 65-69 years and 99% are females. Majority (72%) of female invasive breast cancer cases are ER/PR+ whereas 11% of cases are TNBC. Corroborating with current publications, gBRCAm is estimated at 5% for individuals less than 50 years old and 1% among all ages. Median age range of the gBRCAm cohort is 40-44 years. After applying currently available gBRCAm specific literature parameters, the majority (55%) of gBRCAm diagnoses are TNBC.

Conclusion: In the US, patients with gBRCAm represent a small proportion (1%) of all breast cancer tissues evaluated. Majority of gBRCAm patients are diagnosed with TNBC (55%) and are younger (median age range 40-44 years) than overall breast cancer population. Age differences noticed in gBRCAm may have been due to disparity in genetic screening practices among breast cancer population in the US rather than a reflection of gBRCAm expressions. These estimates of gBRCAm incidence are driven by limited reports on an unselected population of breast cancer gBRCAm cohort; therefore sensitivity analysis is required to assess the robustness of these estimates.

1. American Cancer Society. Facts and Figures 2016.

2. Miki Y et al. Science. 1994;266:66-71.

3. Surveillance, Epidemiology, and End Results (SEER) Program (www.seer.cancer.gov) Research Data (1973-2013), National Cancer Institute, DCCPS, Surveillance Research Program, Surveillance Systems Branch, released April 2016, based on the November 2015 submission.

4. United Nations Population Division. World Population Prospects, the 2015 Revision. http://esa.un.org/unpd/wpp/.

5. van den Broek et al. Eur J Hum Genet. 2015;23:588-95.

6.Turkovic L et al. BMC Cancer. 2010;10:466.

7. Atchley DP et al. J Clin Oncol. 2008;26:4282-4321.

8. Spurdle AB et al. Breast Cancer Res. 2014;16:3419.

Citation Format: Kim R, Peterson A, Isherwood A, Uppal H, Barlev A. Incidence of germline BRCA1- and BRCA2-mutated breast cancer in the US [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-08-28.

Abstract WMP75: Age- and Sex-Specific Development of Cerebral Microbleeds in a Mouse Model

Cerebral microbleeds (CMB), a common MRI finding that may predict intracerebral hemorrhage, are based on a pathological substrate of cerebral microhemorrhages (CMH). Recent clinical and laboratory studies have demonstrated the importance of systemic inflammation in the development of CMB. The effects of age and sex on CMB development have not been well-defined. In the current study, we hypothesized that there are age and sex differences in the pathogenesis of inflammation-induced CMB in mice. We studied young (3 months, n=39) and old (17 months, n=25) male and female C57BL/6 mice injected with LPS (1mg/kg, i.p.) or saline at 0, 6, and 24h. 7 days after first LPS injection, cardiac perfusion was performed, mice were sacrificed, and brains were harvested. CMH grossly visible on the brain surface were examined and 40 μm brain sections were prepared and stained with hematoxylin and eosin (H&E) to estimate the acute/fresh parenchymal CMH number, size and total area in young versus old mice. No surface CMH and negligible H&E-positive parenchymal CMH were observed in young and old saline controls. LPS treatment significantly (p<0.001) increased the development of surface CMH in aged male mice (mean±SEM=17±6 surface microhemorrhages/brain) compared to young male mice (2.8±1.5 surface microhemorrhages/brain). Negligible H&E-positive CMH were observed in LPS-treated young mice. Aging increased the number (1.3±0.7 vs 0.09±0.05 CMH/section; p<0.05), size (4510±1431 vs 471±188 μm 2 ; p<0.001) and area (0.03±0.02 vs 0.0005±0.0003 % total area; p<0.01) of H&E-positive parenchymal CMH in old LPS-treated male mice compared to young LPS-treated male mice. Consistent with previous studies from our lab, H&E-positive CMH were predominantly located in the cerebellum compared to the cortex and sub-cortex. No significant differences were observed in LPS-induced surface or parenchymal CMH development between young and aged female mice. In summary, effects of aging on LPS-induced microbleed development are demonstrable in males. Aging makes the brain more susceptible to inflammation-induced cerebral microbleeds in male mice.