Tunable interfacial Dzyaloshinskii-Moriya interaction in symmetrical Au/[Fe/Au]n multilayers

The interfacial Dzyaloshinskii-Moriya interaction (i-DMI) has been exploited in as-made symmetrical Au/[Fe/Au]n structures. By tailoring the chirality of the i-DMI at the Au/Fe interface, an overall enhancement of the i-DMI can be obtained in such a symmetrical structure. Furthermore, the tunability of the i-DMI was realized by changing the stacking number n. Compared to the top of Fe, a large tensile stress at the bottom of Fe due to lattice mismatch was responsible for the chirality change in the sub/Au/Fe system. Layer-resolved DMI calculations revealed that the sign of the spin-orbit coupling (SOC) energy was changed for Au near the interface of Au/Fe under tensile stress, subsequently reversing the chirality of the i-DMI from left-handed to right-handed. Our findings provide a simplest way to tune the i-DMI in a multilayer system, further benefiting the application of skyrmion-based devices.

Mitochondrial Perturbation in Alzheimer's Disease and Diabetes

Mitochondria are well-known cellular organelles that play a vital role in cellular bioenergetics, heme biosynthesis, thermogenesis, calcium homeostasis, lipid catabolism, and other metabolic activities. Given the extensive role of mitochondria in cell function, mitochondrial dysfunction plays a part in many diseases, including diabetes and Alzheimer's disease (AD). In most cases, there is overwhelming evidence that impaired mitochondrial function is a causative factor in these diseases. Studying mitochondrial function in diseased cells vs healthy cells may reveal the modified mechanisms and molecular components involved in specific disease states. In this chapter, we provide a concise overview of the major recent findings on mitochondrial abnormalities and their link to synaptic dysfunction relevant to neurodegeneration and cognitive decline in AD and diabetes. Our increased understanding of the role of mitochondrial perturbation indicates that the development of specific small molecules targeting aberrant mitochondrial function could provide therapeutic benefits for the brain in combating aging-related dementia and neurodegenerative diseases by powering up brain energy and improving synaptic function and transmission.

Hormonal and reproductive factors and risk of esophageal cancer in women: a meta-analysis

Currently published studies on the relationship between hormonal and reproductive factors and esophageal cancer (EC) risk in women have yielded contradictory findings. For a better understanding of this relationship, we first performed this meta-analysis by pooling all available publications. Sixteen independent studies were retrieved after a comprehensive search in PubMed and Embase databases. The pooled relative risks (RRs) with 95% confidence intervals (95% CIs) were calculated. The pooled RRs implicated that hormone replacement therapy was negatively associated with the risk of EC (RR = 0.72, 95% CI 0.60-0.86, P < 0.001) and esophageal squamous cell carcinoma (RR = 0.68, 95% CI 0.48-0.97, P = 0.031). Menopausal women were at an increased risk of EC (RR = 1.47, 95% CI 1.07-2.03, P = 0.018), particularly esophageal squamous cell carcinoma (RR = 1.66, 95% CI 1.12-2.48, P = 0.012). Additionally, decreased risk of EC (RR = 0.79, 95% CI 0.68-0.92, P = 0.003) and esophageal adenocarcinoma (RR = 0.66, 95% CI 0.53-0.82, P < 0.001) was demonstrated among women with breast-feeding history. Moreover, such associations were more significant among Caucasians, but not Asians. Our study suggests that menopause is an independent risk factor for EC, while hormone replacement therapy and breast-feeding history play a protective role against EC, particularly among Caucasians. All results are consistent with the hypothesis that effects of estrogen may lower the risk of EC in women.

Abstract P4-09-22: Quantitative immuno-fluorescent evaluation of Her2 expression levels in a prospectively collected cohort of breast cancer cases: Comparison to conventional IHC scoring and FISH

Background: According to the 2013 guidelines breast cancers are defined as Her2 positive if there is evidence of protein expression in at least 10% of tumor cells by IHC and/or gene amplification by FISH. Nevertheless, there are still IHC 2+ and FISH equivocal breast cancers resulting in repeat testing. It is also known that not all Her2 positive breast cancers respond to Trastuzumab, while up to 8% of Her2 "negative" classified patients benefit from Her2 targeting regimens. Toward the goal of generating a more accurate test, we report in situ quantification of Her2 protein levels on a prospectively collected cohort of breast cancers and comparison to conventional IHC and FISH evaluation.

Materials and Methods: A prospectively designed study was initiated at Yale University, comparing quantitative, in situ measurement of Her2 protein levels with conventional IHC and FISH evaluation. All breast cancer specimens were analyzed by IHC and FISH in our routine clinical laboratory, read and signed out by the breast pathologists. Serial sections were then stained and quantified for Her2 expression levels using the AQUA method of quantitative immunofluorescence (QIF). Data for all assays were obtained on 120 samples over a period of 6 months. Staining was performed using the DAKO Herceptest and the Epitomics EP3 Her2 antibody for IHC, the DAKO rabbit polyclonal antibody for QIF. The 30 highest cases were then retested for QIF and IHC using the Biocare c-erbB-2 [CB11] antibody. Each staining run included an index tissue microarray (TMA) consisting of 80 cases, cell lines and normal tissue for quality control, assay reproducibility and threshold definition of AQUA scores correlated to HER2 over expression and amplification.

Results: Out of 120 specimens analyzed for HER2, 13 were diagnosed as IHC 2+/3+, FISH amplified, 1 case had an equivocal score, 14 cases were IHC 2+/non amplified, 2 cases IHC 1+/FISH amplified and 89 specimens IHC 0/1+ non amplified. The continuous AQUA scores for Her2 expression of the samples significantly correlate with traditional clinical Her2 scoring. However, 5 IHC 0/1+, non amplified cases revealed high AQUA scores in the range of HER2 overexpression/amplification. Repeat testing of these by both QIF and IHC showed reproducibility of the results. AQUA scores of one IHC 3+/amplified sample were lower than the threshold of HER2 overexpression/amplification.

Conclusions: QIF measurement of HER2 protein levels in a prospectively collected cohort of 120 breast cancer specimens reveals significant association between continuous HER2 protein levels and the ordinal conventional scoring system. However, five discordant cases that were above the threshold for HER2 protein by QIF, were classified as negative by conventional methods. Given the accuracy and reproducibility of the QIF test, it raises the possibility that some of these patients might benefit from HER2 targeted therapy. In summary, while continuous scoring of HER2 protein correlates well with conventional methods, it identifies a subset of patients that are discordant with current methods. Further comparative studies in a patient cohort with response to targeted therapy need to be evaluated.

Citation Format: Neumeister VM, Yan SS, McGuire JA, Carvajal DE, Prasad ML, Rimm DL. Quantitative immuno-fluorescent evaluation of Her2 expression levels in a prospectively collected cohort of breast cancer cases: Comparison to conventional IHC scoring and FISH. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-22.

Determination of polybrominated diphenyl ethers in human semen

Some persistent organic pollutants (POPs) have been found in human semen but until this point it was unclear whether polybrominated diphenyl ethers (PBDEs) could be detected in human semen. In this study, PBDEs were found for the first time in human semen samples (n=101) from Taizhou, China. The concentrations of total PBDEs (∑PBDEs) varied from 15.8 to 86.8 pg/g ww (median=31.3 pg/g ww) and 53.2 to 121 pg/g ww (median=72.3 pg/g ww) in semen and blood samples, respectively. The ∑PBDE level in semen was about two times lower than in human blood, which was different in the distribution in the two matrices from other POPs. A correlation of ∑PBDE concentration was found between paired semen and in blood. The results suggest that semen could be used to detect PBDE burden in human body as a non-invasive matrix. In addition, the levels of BDE-209 and BDE-153, especially the latter, were much higher in blood than in semen, while the levels of BDE-28, BDE-47 and BDE-99 were comparable in the two matrices, suggesting that low brominated congeners could be more easily transferred to semen than high brominated congeners. Considering different toxicities among the PBDE congeners, it might be more significant to measure PBDEs in semen than in blood for evaluating male reproduction risks of PBDEs.

Bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers in wild frogs

To investigate bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers (PBDEs) in amphibians, we collected adult frogs (Rana limnocharis) from a rice field in an e-waste recycling site in China. We found that ∑PBDEs in the whole frogs and various tissues (brain, liver, testis and egg) ranged from 17.10 to 141.11 ng g(-1) wet weight. Various tissues exhibited a similar PBDE congener profile, which was characterized by intermediate brominated congeners (BDE-99 and BDE-153) as the largest contributors, with less lower brominated congeners (BDE-28 and BDE-47) and higher brominated congeners (BDE-209). The maternal transfer capacity of PBDEs declined with the increase in bromine numbers of PBDE congeners. We suggest that the bromine atom number (the molecular size, to some degree) might be a determining factor for the maternal transport of a PBDE congener rather than K(ow) (Octanol-Water partition coefficient), which expresses a compound's lipophilicity. ∑PBDEs concentrations in frogs decreased over time during a depuration period of 54 days when these wild frogs were brought to the lab from the e-waste recycling site. The half-life of ∑PBDEs was 35 days, with about 14 days for BDE-47, and 36 and 81 days for BDE-99 and BDE-153, respectively. The data shows that the elimination of PBDEs has no essential difference from aquatic and terrestrial species.

Determination of environmentally relevant exposure concentrations of polybrominated diphenyl ethers for in vitro toxicological studies

Toxicological studies at environmentally relevant concentrations are essential for understanding ecotoxic and health risks of pollutants such as polybrominated diphenyl ethers (PBDEs). However, no information is available on what exposure levels of PBDEs in vitro studies are environmentally relevant. We exposed MCF-7, HepG2, H295R and PC12 cells to BDE-47, and measured BDE-47 concentrations in the cells after exposure. We also used the percentile method to summarize literature data on environmental exposure levels of biotic tissues to PBDEs. The exposure concentration that resulted in a BDE-47 burden in cells close to the 90th percentile of PBDEs levels in tissues was assigned as the upper limit for the environmentally relevant concentration. Exposure to 1nM BDE-47 resulted in PBDEs burdens in MCF-7, HepG2 and H295R cells close to the 90th percentile but PBDEs burdens in PC12 cells were higher than the 90th percentile. In consideration of the high exposure levels in PBDE-polluted areas, we concluded that the highest environmentally relevant exposure concentration of PBDEs in culture media should be approximately 10nM for MCF-7, HepG2 and H295R cells, and<10nM for PC12 cells. These results provide an approximate reference for setting environmentally relevant exposure concentrations of PBDEs for studies in vitro.

Diffusion of polybrominated diphenyl ether (PBDE) from an e-waste recycling area to the surrounding regions in Southeast China

Using Cinnamomum camphora (C. camphora) leaves as biomonitors, we investigated that the diffusion of polybrominated diphenyl ethers (PBDEs) from an e-waste recycling area to the surrounding regions. Variance in sigma(32)PBDEs concentrations (0.46-399.93 ng g(-1) dry weight) in the leaves showed that PBDEs from the e-waste recycling area diffused into the surrounding regions, and resulted in a halo of PBDEs contamination, at least 74 km in radius. The attenuation of sigma(32)PBDEs in the diffusing process fitted in log-linear regression. The difference in the attenuating slopes of linear equations among different directions can be explained by terrain and wind direction. The attenuation of PBDE congeners also fitted well in log-linear regression. The findings that similar attenuating slopes and characteristic travel distance among congeners suggest that the transport behavior of lower brominated congeners might not differ from that of higher brominated congeners in short-range scale.

Resistance to multiple fluoroquinolones in a clinical isolate of Streptococcus pyogenes: identification of gyrA and parC and specification of point mutations associated with resistance

A strain of Streptococcus pyogenes resistant to multiple fluoroquinolones was isolated from the blood of an immunocompromised patient. Resistance to fluoroquinolones in S. pyogenes has not been previously studied. Compared to 10 sensitive strains of S. pyogenes, the fluoroquinolone-resistant clinical isolate of S. pyogenes presented point mutations in gyrA, predicting that serine-81 was changed to phenylalanine and that methionine-99 was changed to leucine, and in parC, predicting that serine-79 was changed to tyrosine. The mechanism of fluoroquinolone resistance in this isolate of S. pyogenes appears to be analogous to previously reported mechanisms for Streptococcus pneumoniae.

Performance of three enzyme immunoassays and two direct fluorescence assays for detection of Giardia lamblia in stool specimens preserved in ECOFIX

ECOFIX is a single-vial stool preservative that is both formalin- and mercury-free. We evaluated the abilities of three commercial Giardia lamblia-specific enzyme immunoassays (EIAs) (ProSpecT Giardia Microplate Assay [Alexon-Trend Inc.], Giardia Test [Techlab], and Premier Giardia lamblia [Meridian Diagnostics, Inc.]) and two commercial direct fluorescent-antibody (FA) assays for G. lamblia (Crypto/Giardia IF Test [Techlab] and Merifluor Cryptosporidium/Giardia [Meridian Diagnostics, Inc.]) to detect G. lamblia in 34 G. lamblia-positive and 44 G. lamblia-negative stool specimens (determined by traditional examination for ova and parasites) preserved in ECOFIX compared to their abilities to detect G. lamblia in the same specimens preserved in formalin as the "gold standard" for each assay. Of the 34 formalin-fixed positive specimens, the number detected by each assay was as follows:, Alexon EIA, 34; Meridian EIA, 27; Techlab EIA, 29; Meridian FA assay, 31; and Techlab FA assay, 28. Both FA tests and the Alexon EIA performed well with ECOFIX, but the other two EIAs detected fewer positive specimens (the difference was statistically significant with the Techlab EIA) when ECOFIX was the preservative. Use of G. lamblia cyst antigen from cultured organisms preserved in formalin and ECOFIX demonstrated that the Alexon EIA could detect smaller amounts of antigen in ECOFIX than the other two EIAs could and suggested that cyst antigen is more stable in formalin. We recommend that laboratories use an FA assay or the Alexon EIA if they plan to use ECOFIX as their stool preservative.

Meigs' syndrome--a case report

Bilateral ovarian fibromas combined with as and hydrothorax is a rare disorder. A case of bilateral ovarian fibromas combined with ascites and hyrothorax is presented. The ascites and hydrothorax disappeared spontaneously after removal of the ovarian tumors.

A modulatory lipoprotein related to cancer cell inhibition

Three fractions of lipoprotein were isolated from sera and ascites of cancer-bearing mice by polyanion precipitation and density centrifugation. The cancer modulatory activity of isolated lipoproteins was estimated by means of trypan blue exclusion and cell potassium content. The activity of one of the isolated lipoprotein fractions was to kill cancer cells in vitro with little effect on normal bone marrow cells. This lipoprotein migrated as one band on agarose electrophoresis. After incubating cancer cells with the lipoprotein, the membrane fluidity of the cancer cells was markedly changed (p less than 0.01). The mechanism of modulation may be related to interaction of lipoprotein with plasma membrane of cancer cells.