Observing the universal screening of a Kondo impurity

The Kondo effect, deriving from a local magnetic impurity mediating electron-electron interactions, constitutes a flourishing basis for understanding a large variety of intricate many-body problems. Its experimental implementation in tunable circuits has made possible important advances through well-controlled investigations. However, these have mostly concerned transport properties, whereas thermodynamic observations - notably the fundamental measurement of the spin of the Kondo impurity - remain elusive in test-bed circuits. Here, with a novel combination of a 'charge' Kondo circuit with a charge sensor, we directly observe the state of the impurity and its progressive screening. We establish the universal renormalization flow from a single free spin to a screened singlet, the associated reduction in the magnetization, and the relationship between scaling Kondo temperature and microscopic parameters. In our device, a Kondo pseudospin is realized by two degenerate charge states of a metallic island, which we measure with a non-invasive, capacitively coupled charge sensor. Such pseudospin probe of an engineered Kondo system opens the way to the thermodynamic investigation of many exotic quantum states, including the clear observation of Majorana zero modes through their fractional entropy.

Modified Citrus Pectin as a Potential Sensitizer for Radiotherapy in Prostate Cancer

Background: Radiotherapy is one of the primary therapies for localized prostatic carcinoma. Therefore, there is an emerging need to sensitize prostatic cancer cells to chemotherapy/radiotherapy. Modified citrus pectin (MCP) is an effective inhibitor of galectin-3 (Gal-3), which is correlated with tumor progression, proliferation, angiogenesis, and apoptosis. Purpose: This study was directed to evaluate the efficacy of combining ionizing radiation (IR) with MCP on PCa cells. Study Design: Effects of treatments on PCa cells survival were evaluated using XTT assay, flow cytometry, and clonogenic survival assay. Expression of selected proteins was estimated using western blotting. Cell motility, migration, and invasion were determined. Contribution of reactive oxygen species production to treatment effects on cell viability was tested. Results: Radiotherapy combined with MCP reduced viability and enhanced radiosensitivity associated with a decrease in Gal-3, cleavage of the precursor of caspase-3, increased expression of the pro-apoptotic protein Bax, and downregulation of DNA repair pathways, poly-ADP-ribose polymerase, and proliferating cell nuclear antigen. MCP significantly reduced the invasive and migratory potential of PCa cells. Combining sodium pyruvate with MCP and IR mitigated the effect on cell viability. Conclusion: Our findings demonstrated that MCP sensitized PCa cells to IR by downregulating anti-apoptotic Gal-3, modulating DNA repair pathways, and increasing ROS production. For the first time the correlation between MCP, radiotherapy, and Gal-3 for prostatic cancer treatment was found. In addition, MCP reduced the metastatic properties of PCa cells. These findings provide MCP as a radiosensitizing agent to enhance IR cytotoxicity, overcome radioresistance, and reduce clinical IR dose.

Combined acetyl-11-keto-β-boswellic acid and radiation treatment inhibited glioblastoma tumor cells

Glioblastoma multiforme (GBM) is the most common and most aggressive subtype of malignant gliomas. The current standard of care for newly diagnosed GBM patients involves maximal surgical debulking, followed by radiation therapy and temozolomide chemotherapy. Despite the advances in GBM therapy, its outcome remains poor with a median survival of less than two years. This poor outcome is partly due to the ability of GBM tumors to acquire adaptive resistance to therapy and in particular to radiation. One of the mechanisms contributing to GBM tumor progression and resistance is an aberrant activation of NF-ĸB, a family of inducible transcription factors that play a pivotal role in regulation of many immune, inflammatory and carcinogenic responses. Acetyl-11-keto-β-boswellic acid (AKBA) is a pentacyclic terpenoid extracted from the gum Ayurvedic therapeutic plant Boswellia serrata. AKBA is anti-inflammatory agent that exhibits potent cytotoxic activities against various types of tumors including GBM. One of the mechanisms underlying AKBA anti-tumor activity is its ability to modulate the NF-ĸB signaling pathway. The present study investigated in vitro and in vivo the effect of combining AKBA with ionizing radiation in the treatment of GBM and assessed AKBA anti-tumor activity and radio-enhancing potential. The effect of AKBA and/or radiation on the survival of cultured glioblastoma cancer cells was evaluated by XTT assay. The mode of interaction of treatments tested was calculated using CalcuSyn software. Inducing of apoptosis following AKBA treatment was evaluated using flow cytometry. The effect of combined treatment on the expression of PARP protein was analysed by Western blot assay. Ectopic (subcutaneous) GBM model in nude mice was used for the evaluation of the effect of combined treatment on tumor growth. Immunohistochemical analysis of formalin-fixed paraffin-embedded tumor sections was used to assess treatment-related changes in Ki-67, CD31, p53, Bcl-2 and NF-ĸB-inhibitor IĸB-α. AKBA treatment was found to inhibit the survival of all four tested cell lines in a dose dependent manner. The combined treatment resulted in a more significant inhibitory effect compared to the effect of treatment with radiation alone. A synergistic effect was detected in some of the tested cell lines. Flow cytometric analysis with Annexin V-FITC/PI double staining of AKBA treated cells indicated induction of apoptosis. AKBA apoptotic activity was also confirmed by PARP cleavage detected by Western blot analysis. The combined treatment suppressed tumor growth in vivo compared to no treatment and each treatment alone. Immunohistochemical analysis showed anti-angiogenic and anti-proliferative activity of AKBA in vivo. It also demonstrated a decrease in p53 nuclear staining and in Bcl-2 staining and an increase in IĸB-α staining following AKBA treatment both alone and in combination with radiotherapy. In this study, we demonstrated that AKBA exerts potent anti-proliferative and apoptotic activity, and significantly inhibits both the survival of glioblastoma cells in vitro and the growth of tumors generated by these cells. Combination of AKBA with radiotherapy was found to inhibit factors which involved in cell death regulation, tumor progression and radioresistence, therefore it may serve as a novel approach for GBM patients.

Volumetric Modulated Arc Therapy as an Example of the Advanced Capability of Modern Radiotherapy

BACKGROUND

Family physicians and internal medicine specialists play an essential role in treating cancer patients. Modern technological advances in radiotherapy are not widely appreciated by primary care physicians. Bone metastases are a frequent complication of cancer. Palliative radiation therapy, as a component of modern advances in radiation treatments, should not subject normal bodily structures to excessive doses of irradiation. The sacrum is a common destination site for bone metastases, yet its concave shape along with its proximity to the rectum, intestines, and femoral heads creates treatment-planning challenges.

OBJECTIVES

To investigated whether the volumetric modulated arc therapy (VMAT) technique is preferable to more conventional radiation strategies.

METHODS

The study comprised 22 patients with sacral metastases who were consecutively treated between 2013 and 2014. Two plans were generated for the comparison: three-dimensional (3D) and VMAT.

RESULTS

The planning target volume (PTV) coverage of the sacrum was identical in VMAT and 3D planning. The median values for the rectal dose for 3D and VMAT were 11.34 ± 5.14 Gy and 7.7 ± 2.76 Gy, respectively. Distal sacral involvement (S4 and S5) was observed in only 2 of 22 cases, while the upper pole of the rectum ended at the level above S3 in just 3 cases.

CONCLUSIONS

Radiation therapy continues to be an integral component of the palliative armamentarium against painful metastases. Radiation oncologist, in conjunction with referral physicians, can tailor treatment plans to reflect the needs of a given patient.

Abstract 5555: Combined effect of modified citrus pectin and ionizing radiation on survival and metastatic activity of prostate cancer cells

Radio-resistance is a major cause of decreasing the efficiency of radiotherapy for prostate cancer. Modified citrus pectin (MCP) has been previously shown to demonstrate anti-proliferative and anti-metastatic activity in prostate cancer cells. However, its combination with radiation has not been evaluated. The aim of the present study was to investigate whether MCP radiosensitized prostate cancer cell lines and to unravel its underlying mechanism(s). XTT cell proliferation and clonogenic assays were used to assess MCP effect alone and in combination with radiation on viability of prostate cancer cell lines (DU-145, PC-3 and Cl-1). Calcusyn software analysis was used to determine the mode of interaction between the treatments tested. Flow cytometry analysis with propidium iodide staining, annexin-V-FITC and 7-aminoactinomycin D (7-AAD) double staining were used to evaluate effect on cell cycle, apoptosis and necrosis. Standard Transwell Assay with and without Matrigel was used to assess effect of MCP on invasiveness of cells. The effect of MCP and radiation on reactive oxygen species (ROS) production, and expression of galectin-3, PARP, caspase-3, caspase-9, Bak, Bax, and Bcl-2 and NF-κB pathways in treated cells are currently being investigated, and will be included in the presentation. Treatment of DU-145, PC-3 and Cl-1 prostate cancer cells with MCP induced a dose dependent decrease in cell viability tested by XTT assay (IC50 values were 1.07, 1.48, 1.29 mg/ml respectively). These cells demonstrated similar radio-sensitivity. The effect of the combined treatment were either synergistic (Combined index∼0.7, DU-145 and Cl-1 cells) at high dose (2 mg/ml) of MCP or additive (Combined index 1.1-0.9, PC-3 cells). Flow cytometric analysis showed that neither MCP nor radiation either alone or combined resulted in significant changes in cell cycle distribution. Double staining of DU-145 cells with annexin-V-FITC and 7-AAD revealed effect of combined treatment on apoptosis and necrosis. Treatment of cells with 2 mg/ml MCP reduced 20% of migrating cells and 40% of invasive cells. The effects of MCP and radiation on ROS production, pro-apoptotic and NF-κB pathways in treated cells are currently being investigated. These results suggest that MCP is a radiosensitizer in prostate cancer cells. Its mechanism of action is being investigated, and will be included in this presentation.

Citation Format: Isaac G. Eliaz, Sefora Conti, Akiva Vexler, Ben Koren, Nir Honig, Natan Shtraus, Yaron Meir, Shahar Lev-Ari, Ilan Ron. Combined effect of modified citrus pectin and ionizing radiation on survival and metastatic activity of prostate cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5555. doi:10.1158/1538-7445.AM2015-5555

AP-PA field orientation followed by IMRT reduces lung exposure in comparison to conventional 3D conformal and sole IMRT in centrally located lung tumors

Little attention has been paid to the fact that intensity modulated radiation therapy (IMRT) techniques do not easily enable treatment with opposed beams. Three treatment plans (3 D conformal, IMRT, and combined (anterior-posterior-posterio-anterior (AP-PA) + IMRT) of 7 patients with centrally-located lung cancer were compared for exposure of lung, spinal cord and esophagus. Combined IMRT and AP-PA techniques offer better lung tissue sparing compared to plans predicated solely on IMRT for centrally-located lung tumors.

Probing the Kondo density of states in a three-terminal quantum ring

We have measured the Kondo effect in a quantum ring connected to three terminals. In this configuration nonlinear transport measurements allow us to check which lead contributes to the Kondo density of states (DOS) and which does not. The ring geometry allows a fine-tuning of the coupling to each lead through the Aharonov-Bohm effect via application of a magnetic field. When the ring is connected to two strongly and one weakly coupled leads, conductance through the weakly coupled lead provides a direct measurement of the DOS in the Kondo regime. By applying a bias between the two strongly coupled leads, we demonstrate directly the splitting of the out-of-equilibrium Kondo DOS.

Early screening for fetal cardiac anomalies by transvaginal echocardiography in an unselected population: the role of operator experience

OBJECTIVES

To examine the accuracy of early transvaginal fetal echocardiography performed in an unselected population by operators with different levels of experience and to compare the results with those obtained from a referral population.

DESIGN

Prospective study.

METHODS

A series of 4785 unselected fetuses and 221 referred fetuses were screened at 13-15 weeks' gestational age by transvaginal echocardiography. For each fetus, visualization of the four-chamber view plus the origin of the great arteries was attempted. Color Doppler imaging was only performed in cases of cardiac malformations already identified by two-dimensional echocardiography. The scans were performed by seven operators with different levels of experience. Reliability was assessed by conventional transabdominal echocardiography at 20-22 weeks, by postnatal follow-up in the first 3 months of life, and/or by autopsy in all cases of termination or fetal death.

RESULTS

The rate of complete visualization (four-chamber view plus great arteries) was 47.5% in the unselected population, and 76.9% in the referral population. There were four (0.08%) true positives among the unselected fetuses, and five (2.3%) among referrals, mostly with enlarged nuchal translucency or other malformations. Among the unselected fetuses, nine false negatives were detected by transabdominal echocardiography. Improvement in the operators' ability to recognize cardiac anomalies in unselected population was disappointing and was influenced more by individual approach than by the number of examinations performed.

CONCLUSIONS

Early screening for cardiac anomalies among unselected fetuses is ill-advisable. The usefulness of an early approach is confirmed in high risk fetuses or in the presence of enlarged nuchal translucency when performed by expert operators.

Fetal heart screening in low-risk pregnancies

The aim of this study was to assess whether a screening program for fetal cardiac malformations is justified in a low-risk population, and which factors influence its accuracy. The fetal heart was evaluated in 7024 pregnant women at 20-22 weeks, and evaluation was repeated at a more advanced gestational age in 9% of cases. Cardiological follow-up was continued postnatally until 2 years of age. The overall prevalence of cardiac anomaly was 0.93%. The incidences of major and minor defects were 0.44% and 0.48%, respectively. There were 23 true positives (0.33%): in 20 cases, the diagnosis was made in the second trimester, and 13 women (65%) chose termination of pregnancy. Seventeen of the 20 cases identified in the second trimester were serious malformations. There were 42 false negatives (0.60%). Of these, 12 had signs of cardiac dysfunction at birth or within the 1st month of life, and three of them died as a result of their cardiac anomaly. There were eight false positives (0.11%), all of a minor type. Six abnormal karyotypes, out of a total of 21 performed in the true-positive group (28.5%), were found. In addition, five of the 42 newborns in the false-negative group had trisomy 21. The overall sensitivity was 35.4%, and 61.3% for major defects. The accuracy in two distinct periods was estimated because the level of experience of the operators was different: sensitivity was 45.2% in period 1 (1986-88) (77.8% for major defects) and 26.5% in period 2 (1989-92) (52.9% for major defects). We conclude that a fetal heart screening program in the obstetric population is justified. It defines a high-risk group for karyotyping, allows planning of delivery in a tertiary center or the choice of terminating the pregnancy for the parents and appears to have a positive cost-benefit ratio. A crucial factor is the level of training and experience of the operators, who need specific teaching support.

[The diagnostic capacities of transvaginal echography and hysteroscopy in the characterization of endometrial pathology]

The diagnostic accuracy of transvaginal sonography (TVS) and hysteroscopy in the assessment of endometrial pathology was studied comparing retrospectively both methods with the results of histologic findings after dilatation and curettage (D&C) performed in the last four years on 467 patients, 155 of whom were in postmenopause. Endometrial thickness, tissue texture, myometrial invasion and haemodynamic characteristics were studied with TVS. Uterine cavity, endometrial patterns and superficial vascularization were evaluated by hysteroscopy. For the purpose of this study all histologic findings were subdivided to a) normal (206 cases); b) benign lesions (240 cases); c) atypical hyperplasia or adenocarcinoma (21 cases). In our experience hysteroscopy was superior to TVS in detecting endometrial pathology. Both techniques were more sensitive in detecting premalignant and malignant lesions. Considering endometrial thickness evaluated with TVS as a single parameter in patients in postmenopause, we found that the most sensitive cut-off for defining normality was 3 mm; nevertheless, in the group of patients that had an endometrial thickness equal to or less than 3 mm there were 2 cases of malignancy. Therefore, neither TVS nor hysteroscopy are sufficiently reliable to replace curettage in the diagnosis of endometrial pathology.

[Staging of rectal carcinoma by endorectal ultrasonography]

Staging of rectal carcinoma is essential for its management. 23 patients with rectal lesions were examined by endorectal ultrasonography. Of these 19 had rectal carcinoma and in 4 there was an abscess of the rectal wall, previously diagnosed by sigmoidoscopic biopsy. 10 of those with carcinoma were examined by computerized tomography as well, and 10 were operated on. In most cases the staging of rectal carcinoma by endorectal ultrasonography was accurate and compared well with the operative histological results. We conclude that endorectal ultrasonography is the method of choice for staging of rectal carcinoma prior to treatment.

Retroperitoneal lymphadenopathy in familial Mediterranean fever

Peripheral lymphadenopathy is rarely observed, whereas mesenteric lymphadenopathy is found occasionally on laparotomies in patients with familial Mediterranean fever (FMF). Retroperitoneal lymphadenopathy was reported only once in an autopsy of a patient with FMF. Our case is the second one, and the first one to be diagnosed during life, by means of abdominal ultrasonography and computerized tomography. In patients with FMF, where lymph node biopsy was done, the pathological finding was non-specific lymphoid hyperplasia.