Diffusion-weighted MRI as a potential imaging biomarker reflecting the metastatic potential of upper urinary tract cancer

OBJECTIVE

To evaluate the role of diffusion-weighted MRI (DW-MRI) as an imaging biomarker for upper urinary tract cancer (UUTC) that has already metastasized or will metastasize soon.

METHODS

61 patients clinically diagnosed with UUTC were prospectively enrolled in this study. All the patients underwent MRI, including DW-MRI, prior to any interventions. Correlations between apparent diffusion coefficient (ADC) and other clinicopathological variables, including metastasis-free survival, were analysed.

RESULTS

Median follow-up period was 938 days. Of the 61 patients, 12 had any metastases at the initial diagnosis. 11 patients developed metastases during the follow-up period. These 23 patients were categorized as "Metastatic". Of the remaining 38 patients, 35 with a follow-up period longer than 400 days were categorized as "Localized". ADC was significantly lower in the Metastatic category than in the Localized (p = 0.0002) category. Multivariate analysis of pre-operative variables identified ADC (cut-off value, 1.08 × 10(-3) mm(2) s(-1)) and clinical T stage based on T2 weighted MRI as an independent predictive factor of metastatic UUTC. 46 patients without any metastases during the initial diagnosis were stratified into a high-risk group (16 patients with low ADC and clinical T3-4) and a low-risk group (30 patients with high ADC or clinical Ta-2). The 3-year metastasis-free survivals were 45% and 93%, respectively.

CONCLUSION

In the current study, UUTC with lower ADC value is more likely to have metastatic potential. Incorporating ADC with clinical T stage helps to differentiate metastatic UUTC at the initial diagnosis.

ADVANCES IN KNOWLEDGE

DW-MRI is a potential imaging biomarker reflecting metastatic propensity of UUTC.

Impact force measurement of a spherical body dropping onto a water surface

We propose a method for measuring the impact force of a spherical body dropping onto a water surface. The velocity of the center of gravity of a metal spherical body, in which a cube corner prism is embedded so that its optical center coincides with the center of gravity of the sphere, is accurately measured using an optical interferometer. The acceleration, displacement, and inertial force of the sphere are calculated from the velocity. The sphere is also observed using a high-speed camera. The uncertainty in measuring the instantaneous value of the impact force with a sampling interval of approximately 1 ms is estimated to be 8 mN, which corresponds to 0.8% of the maximum force of approximately 1.0 N.

An Anomalous Isotope Effect of 235U in U(IV)-U(VI) Chemical Exchange

The abundance ratios of 234U, 235U, 236U and 238U were determined by mass spectrometry on uranium samples obtained from a chromatographic uranium enrichment process based on the U(IV) - U(VI) chemical exchange reaction. According to standard theory, the elementary isotope effect in processes based on equilibrium chemical exchange is proportional to the mass difference of the isotopes. In the present work this has been confirmed for 234U, 236U and 238U. However, according to the observed data the fractionation between 234U and 235U is much smaller than the one between 235U and 236U in spite of the same mass difference in either isotopic pair. The anomaly of the fractionation is concluded to be due to the characteristics of 235U, which is the only odd mass number isotope in the present system.

Some inconvenient truths about biosignatures involving two chemical species on Earth-like exoplanets

The detection of strong thermochemical disequilibrium in the atmosphere of an extrasolar planet is thought to be a potential biosignature. In this article we present a previously unidentified kind of false positive that can mimic a disequilibrium or any other biosignature that involves two chemical species. We consider a scenario where the exoplanet hosts a moon that has its own atmosphere and neither of the atmospheres is in chemical disequilibrium. Our results show that the integrated spectrum of the planet and the moon closely resembles that of a single object in strong chemical disequilibrium. We derive a firm limit on the maximum spectral resolution that can be obtained for both directly imaged and transiting planets. The spectral resolution of even idealized space-based spectrographs that might be achievable in the next several decades is in general insufficient to break the degeneracy. Both chemical species can only be definitively confirmed in the same object if absorption features of both chemicals can be unambiguously identified and their combined depth exceeds 100%.

Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

Observation of electron neutrino appearance in a muon neutrino beam

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

Abstract P5-13-07: Genetic polymorphism of estrogen metabolizing enzyme CYP17A1 rs743572 impacts on serum testosterone level in Japanese premenopausal women

The incidence of breast cancer in Japanese women has doubled in all age groups over the past two decades. We recently demonstrated that this marked increase is mostly due to an increase in the estrogen receptor (ER)-positive subtype, and we created risk prediction models for ER-positive breast cancer in both pre- and post- menopausal women using genetic factors (single nucleotide polymorphism (SNP)), environmental risk factors, serum hormones and growth factors by logistic regression analysis. Serum level of testosterone, which is the precursor of estradiol in estradiol synthesis, was found to be a risk predictor in both pre- and post- menopausal women. On the other hand, it has been reported that some SNPs, including those of estrogen-related genes such as ESR1 and CYP17A1, are correlated with breast cancer risk by genome-wide association studies. To acquire some insights into this mechanism, we analyzed genetic factors (14 SNPs), serum hormones and growth factors (estradiol, testosterone, prolactin, insulin-like growth factor 1 (IGF1) and IGF binding protein 3 (IGFBP3)) in 913 women with breast cancer and 278 disease-free controls for correlation between them.

Serum testosterone and prolactin levels were significantly higher in ER-positive breast cancer patients than in disease-free controls in both pre- (p&lt;0.0001, p&lt;0.0001) and post- (p&lt;0.0001, p = 0.007) menopausal women, and serum estradiol level was significantly higher in ER-positive breast cancer patients than in disease-free controls only in premenopausal women (p = 0.0005). There were significant differences in serum hormone levels among the women with each SNP genotype (homozygotes of major allele, heterozygotes and homozygotes of minor allele), including testosterone among rs743572 genotype (p = 0.014), estradiol among rs827421 genotype (p = 0.016), IGF-1 among rs6905370 genotype (p = 0.032), and prolactin among rs1042522 genotype (p = 0.035) in premenopausal women, as well as estradiol among rs3803662 genotype (p = 0.027) and IGFBP3 among rs6905370 genotype (p = 0.036) in postmenopausal women. In particular, serum testosterone level was significantly different among the rs743572, which is one of the enzymes that convert testosterone to estradiol, of genotypes (AA: 0.308 +/- 0.180 ng/ml, AG: 0.319 +/- 0.193 ng/ml and GG: 0.380 +/- 0.187 ng/ml, p = 0.014). On the other hand, the rs743572 heterozygotes of CYP17A1 have been reported to have increased breast cancer risk than homozygotes of both the major allele and minor allele in premenopausal women. Further studies are required to clarify this mechanism.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-07.

Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam

The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

Zfp296 is a novel Klf4-interacting protein and functions as a negative regulator

Pluripotency and self-renewing ability of embryonic stem (ES) cells are regulated by several transcription factors, including Oct3/4, Sox2, Kruppel-like factor 4 (Klf4), and c-Myc. These transcription factors reprogram somatic cells into induced pluripotent stem (iPS) cells. Zinc finger protein (Zfp) 296 has been reported to enhance iPS cell formation. Here we found that Zfp296 interacts with Klf4. A maltose-binding protein pull-down assay demonstrated that Klf4 binds to the Zfp296 158-483 amino acid region, and that Zfp296 binds to the Klf4 DNA-binding domain (DBD). A quantitative reverse transcription-polymerase chain reaction analysis revealed that expression of Zfp296 and Klf4 decreased during differentiation of E14 and ZHBTc4 ES cells. We also found that green fluorescent protein-labeled Zfp296 and Klf4 were localized to the nucleus. Because Zfp296 bound to the Klf4 DBD, we next examined the influence of Zfp296 on Klf4 DNA-binding activity. A biotin DNA pull-down assay showed that Klf4 binds to the Lefty1 promoter region, and that binding activity was sustained even in the presence of Zfp296. In contrast, a reporter assay showed that the Lefty1 promoter was activated by Klf4, and that the enhanced activity was repressed by Zfp296. These findings suggest that Zfp296 is a functional regulator of Klf4 in ES cells.

High-speed impact test using an inertial mass and an optical interferometer

A high-speed impact testing method for evaluating mechanical properties of materials is proposed using an inertial mass and a dual beat-frequencies laser Doppler interferometer (DB-LDI). In this method, an inertial mass levitated using an aerostatic linear bearing is made to collide with the material being tested at a high initial velocity. During the collision, the velocity of the mass, which is even higher than the critical velocity (±0.56 m/s) defined by the frequency difference of the Zeeman laser, is accurately measured using the DB-LDI. The position, acceleration, and impact force of the mass are calculated from the measured velocity. Using the proposed method, the mechanical properties of a visco-elastic material under a high-speed impact loading condition can be accurately evaluated.

New constraint on the existence of the μ+ → e+ γ decay

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay μ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.