Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

Does renal failure worsen radiation cystitis following radical prostatectomy?

OBJECTIVE

To investigate the impact of renal function on the risk, severity, and management of radiation cystitis in patients who underwent postoperative radiation therapy for prostate cancer.

METHODS

Retrospective data was assessed from patients treated with adjuvant/salvage radiation therapy at a single academic institution between 2006 and 2020. The incidence, severity, and management of radiation cystitis were compared between three groups: CKD 0-2, CKD 3-4, and CKD 5. Associations of clinicopathologic factors with radiation cystitis were assessed in univariate and multivariate Cox regression models.

RESULTS

A total of 110 patients who underwent radiation therapy following robot-assisted laparoscopic radical prostatectomy were included. The incidence of radiation cystitis following postoperative radiation therapy was 17% with a median presentation time of 34 months (interquartile range 16-65 months). The incidence of radiation cystitis was 100% in CKD 5 patients compared to 15% in CKD 0-2 and 17% in CKD 3-4 patients (p < 0.001). CKD 5 patients required more treatments, emergency department visits, and longer hospitalization times than CKD 0-4 patients (all p < 0.001). Multivariate analyses identified CKD 5 as the only significant factor associated with radiation cystitis (HR = 10.39, p = 0.026).

CONCLUSION

End-stage renal failure is associated with the risk and severity of radiation cystitis in patients receiving postoperative radiation therapy. Knowledge of the potential morbidity of this complication in this population could guide physicians and patients as they evaluate risks and benefits prior to selecting adjuvant or salvage radiation therapy.

The Pseudo-Bladder: A Case of the Prostatic Urethra Masquerading as the Bladder

Congenital bladder underdevelopment has detrimental genitourinary effects. We present a male infant with declining renal function, recurrent urinary tract infections, and epididymo-orchitis, in the setting of bilateral high grade hydronephrosis and vesicoureteral reflux. Cystoscopic evaluation revealed the presumed "bladder" to be a massively dilated prostatic urethra. The small dysplastic "true bladder" was found at the anterior surface of the prostatic urethra with massively dilated ureteral orifices. Temporizing diversion was performed in the form of bilateral cutaneous ureterostomies, with an ultimate plan for reconstructive bladder surgery. This case presents diagnostic challenges utilizing current modalities due to a massively dilated prostatic urethra in the rare case of bladder dysplasia.

Screening over Speech in Unselected Populations for Clinical Trials in AD (PROSPECT-AD): Study Design and Protocol

BACKGROUND

Speech impairments are an early feature of Alzheimer's disease (AD) and consequently, analysing speech performance is a promising new digital biomarker for AD screening. Future clinical AD trials on disease modifying drugs will require a shift to very early identification of individuals at risk of dementia. Hence, digital markers of language and speech may offer a method for screening of at-risk populations that are at the earliest stages of AD, eventually in combination with advanced machine learning. To this end, we developed a screening battery consisting of speech-based neurocognitive tests. The automated test performs a remote primary screening using a simple telephone.

OBJECTIVES

PROSPECT-AD aims to validate speech biomarkers for identification of individuals with early signs of AD and monitor their longitudinal course through access to well-phenotyped cohorts.

DESIGN

PROSPECT-AD leverages ongoing cohorts such as EPAD (UK), DESCRIBE and DELCODE (Germany), and BioFINDER Primary Care (Sweden) and Beta-AARC (Spain) by adding a collection of speech data over the telephone to existing longitudinal follow-ups. Participants at risk of dementia are recruited from existing parent cohorts across Europe to form an AD 'probability-spectrum', i.e., individuals with a low risk to high risk of developing AD dementia. The characterization of cognition, biomarker and risk factor (genetic and environmental) status of each research participants over time combined with audio recordings of speech samples will provide a well-phenotyped population for comparing novel speech markers with current gold standard biomarkers and cognitive scores.

PARTICIPANTS

N= 1000 participants aged 50 or older will be included in total, with a clinical dementia rating scale (CDR) score of 0 or 0.5. The study protocol is planned to run according to sites between 12 and 18 months.

MEASUREMENTS

The speech protocol includes the following neurocognitive tests which will be administered remotely: Word List [Memory Function], Verbal Fluency [Executive Functions] and spontaneous free speech [Psychological and/ or behavioral symptoms]. Speech features on the linguistic and paralinguistic level will be extracted from the recordings and compared to data from CSF and blood biomarkers, neuroimaging, neuropsychological evaluations, genetic profiles, and family history. Primary candidate marker from speech will be a combination of most significant features in comparison to biomarkers as reference measure. Machine learning and computational techniques will be employed to identify the most significant speech biomarkers that could represent an early indicator of AD pathology. Furthermore, based on the analysis of speech performances, models will be trained to predict cognitive decline and disease progression across the AD continuum.

CONCLUSION

The outcome of PROSPECT-AD may support AD drug development research as well as primary or tertiary prevention of dementia by providing a validated tool using a remote approach for identifying individuals at risk of dementia and monitoring individuals over time, either in a screening context or in clinical trials.

Association between Longitudinal Cerebrospinal Fluid Alzheimer's Biomarkers and the Lifestyle for Brain Health (LIBRA) Index: Findings from the European Prevention of Alzheimer's Dementia Cohort Study (EPAD LCS)

BACKGROUND

In the absence of preventative pharmacological interventions for Alzheimer's Disease dementia, there is a growing interest in modifiable risk factors associated with AD. Such risk factors are thought to contribute up to 40% of the risk of dementia. The Lifestyle for Brain Health (LIBRA) index, a dementia risk score which focuses exclusively on modifiable factors, has been found to be associated with increased risk of dementia and cognitive decline. It is currently unclear how the LIBRA index relates to cerebrospinal fluid (CSF) biomarkers of Alzheimer's Disease.

OBJECTIVES

To examine the association between LIBRA index scores and trajectories of phospho-tau 181 and total tau in the European Prevention of Alzheimer's Dementia Longitudinal Cohort Study (EPAD LCS), and to examine whether these trajectories differ between participants with high and low CSF amyloid-beta 1-42 (Aβ42).

DESIGN

Analysis of CSF biomarker and LIBRA index scores from the European Prevention of Alzheimer's Dementia Longitudinal Cohort Study.

SETTING

The European Prevention of Alzheimer's Dementia Longitudinal Cohort Study is a multi-centre, pan-European study.

MEASUREMENTS

Cerebrospinal fluid samples were taken by lumbar puncture and analysed using electrochemiluminescence. LIBRA index scores were calculated from self-reported variables, questionnaires, and physiological measurements.

RESULT

In the total sample (n = 1715; mean age = 66.0, 56.4% female), there were no significant associations between LIBRA scores (mean = 0.73 points) and rate of change in cerebrospinal fluid biomarkers. In participants with high Aβ, reflecting less deposition in the brain, (n = 1134), LIBRA scores were significantly associated with the rate of change in total tau, where higher LIBRA scores (denoting higher dementia risk) were associated with increases in t-tau. There were no significant associations between LIBRA scores and change in cerebrospinal biomarkers in participants with low Aβ.

CONCLUSION

We found an association between modifiable risk factors and total tau accumulation in participants without dementia and without Aβ accumulation. This suggests that increasing levels of total tau may be driven by factors other than Aβ accumulation and highlights the need for developing and examining tau-targeting drugs in Alzheimer's Disease development.

Thulium versus holmium for in situ lower pole laser lithotripsy

INTRODUCTION

During in situ lower pole laser lithotripsy, the dependent location may result in increased challenge fragmenting stones and a risk for stone regrowth if residual fragments remain. The purpose of this study was to compare the thulium fiber laser (TFL) with the holmium laser (HL) for in situ lower pole lithotripsy.

MATERIALS AND METHODS

In a 3D printed kidney benchtop model, sixty 1 cm BegoStones were placed in the lower pole and fragmented in situ until fragments passed through a 2 x 2 mm mesh. Laser lithotripsy was performed using twelve energy, frequency and fiber size combinations and residual fragments were compared. In addition, laser fiber diameters and subsequent ureteroscope deflections and flow rates were compared between fibers.

RESULTS

The TFL resulted in decreased residual fragments compared to the HL (11% vs. 17%, p < 0.001) and the three settings with least residual fragments were all TFL. Compared to the 150 µm TFL (265° deflection), there was a loss of 9° and 34° in the 200 µm TFL and 272 µm HL fibers, respectively. The measured fiber sizes were greater than manufacturer specified fiber size in every instance. Irrigation rates inversely correlated with fiber size.

CONCLUSION

The TFL resulted in 35% less residual stone fragments, up to 34° additional deflection, and an increased irrigation rate when compared to the HL. Optimal fragmentation settings are identified to further improve lower pole lithotripsy. The combination of reduced residual fragments, improved deflection, and better flow rates make the TFL advantageous for in situ lower pole lithotripsy.

Oxidative stress in the pathophysiology of male infertility

The effects of reactive oxygen species on male fertility are governed by the oxidative paradox, defined by a delicate balance between oxidative stress and antioxidant capacity. When regulated appropriately, reactive oxygen species ensure effective function; however, when uninhibited, they represent key players in male factor infertility. Mechanisms responsible for this include oxidative destruction of sperm lipid membranes, damage to gamete DNA both by gene mutation and by direct breakdown of the DNA backbone, mitochondrial dysfunction and apoptotic cell death. Utilizing various male pathologies as case studies, we see ways in which oxidative stress has the potential to impact fertility in a negative way. Varicocele, erectile dysfunction, testicular cancer and even idiopathic male infertility highlight common mechanistic pathways, as well as subtle variations in the ways reactive oxygen species can operate. Oxidative biomarkers have emerged to better study male infertility, predict reproductive success and modify assisted reproductive technologies to minimize oxidative stress.

Bilateral Ureteroenteric Strictures: A Case of the "Reverse 7"

Anastomotic stricture is a well-known complication of the urinary diversion that accompanies radical cystectomy. Management options range from endoscopic procedures to open surgeries, with a subset of the latter employing bowel as the interposing segment. In this report, we describe a rare patient, who successfully underwent a "Reverse 7" procedure, bypassing strictures at both anastomotic junctions between ureters and neobladder.

The Effect of Hemodialysis on Whole Blood, Plasma and Erythrocyte Viscosity

The effect of hemodialysis (HD) on blood viscosity has not been adequately investigated. We studied blood viscosity during HD employing coneplate viscometry. Ten patients with end-stage renal disease were studied before and immediately after HD. To dissect the possible effects of HD on plasma and red blood cell (RBC) determinants, we measured whole blood, plasma, and reconstituted erythrocyte viscosities. The latter consisted of RBC's suspended in a buffered saline solution (pH = 7.4 units). In addition, serum, electrolytes and hematocrit (HCT) were measured. The results revealed a significant rise in whole blood viscosity after dialysis. Likewise, plasma viscosity rose considerably with dialysis. However, when the RBC's were reconstituted to a constant HCT, no significant difference was noted before and after HD. As expected, body weight, blood urea nitrogen (BUN) and creatinine concentrations fell while HCT and protein concentration rose with HD. A significant correlation was found between the observed rise in HCT, and dialysis-induced rise in whole blood viscosity. Likewise, the observed rises in plasma viscosity after dialysis significantly correlated with the rise in protein concentration. In addition, the change in whole blood and plasma viscosity values correlated with the degree of ultrafiltration (weight loss). In conclusion, whole blood and plasma viscosity rises with hemodialysis. The observed rise in viscosity is primarily due to hemoconcentration.

The disappearing PI-RADS 5 prostate lesion

Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) identifies prostate cancer on the basis of multiparametric MRI (mpMRI). As an assessment tool, it correctly predicts clinically significant cancer in the vast majority of cases. In this light, we report a rare patient, for whom a PI-RADS 5 lesion vanished over the course of 13 months.

Microwave-assisted synthesis of organically functionalized hexa-molybdovanadates

The microwave-assisted reaction of (TBA)₄[β-Mo₈O₂₄] and (TBA)₃[H₃V₁₀O₂₈] with pentaerythritol or tris(hydroxymethyl)aminomethane yields polyanions with the general formula (TBA)₂[V₃Mo₃O₁₆(O₃–R)] (R: C₅H₈OH – 1; R: C₄H₆NH₂ – 3). Post-synthetic esterification of 1 yields the acylated derivative 2, with all compounds being characterized in the solid and solution state.

Jackets Off: The Impact of Laser Fiber Stripping on Power Output and Stone Degradation

PURPOSE

To investigate the effect of laser fiber stripping on stone fragmentation and laser fiber power output.

MATERIALS AND METHODS

In a benchtop simulation of laser lithotripsy, 20 BegoStone phantoms were positioned within a ureteral model and irradiated for 10 minutes at 8 Hz and 0.8 J. A freshly cleaved 365 μm laser fiber was used for all trials, with half of the fibers also undergoing stripping. Power output was measured at 1-minute intervals, beginning with an initial prelithotripsy recording at 0 minutes. Fiber tips were imaged with scanning electron microscopy. In a single-blinded manner, final masses of residual stone fragments were measured and used to quantify stone breakdown. Independent-sample Mann-Whitney U tests were performed with significance set at p < 0.05, comparing stripped and unstripped fiber tips with respect to power output and fraction of stone fragmentation.

RESULTS

Mean power output after 1 minute of lasing was significantly greater in unstripped laser fibers (p = 0.015), while fibers, whether stripped or not, demonstrated no significant output differences prelithotripsy or at any time from 2 to 10 minutes. However, stripped laser fibers achieved significantly increased stone breakdown compared to unstripped fibers (p = 0.004), fragmenting 63 mg (25%) more of the initial stone mass per trial.

CONCLUSIONS

Although unstripped laser fibers provided superior power output at 1 minute, output at all other time points was similar between stripped and unstripped fibers. However, despite similar optical output, stripped laser fibers achieved greater stone fragmentation, possibly due to improved contact between stone and fiber tip.

PRECISION MEDICINE - The Golden Gate for Detection, Treatment and Prevention of Alzheimer's Disease

During this decade, breakthrough conceptual shifts have commenced to emerge in the field of Alzheimer's disease (AD) recognizing risk factors and the non-linear dynamic continuum of complex pathophysiologies amongst a wide dimensional spectrum of multi-factorial brain proteinopathies/neurodegenerative diseases. As is the case in most fields of medicine, substantial advancements in detecting, treating and preventing AD will likely evolve from the generation and implementation of a systematic precision medicine strategy. This approach will likely be based on the success found from more advanced research fields, such as oncology. Precision medicine will require integration and transfertilization across fragmented specialities of medicine and direct reintegration of Neuroscience, Neurology and Psychiatry into a continuum of medical sciences away from the silo approach. Precision medicine is biomarker-guided medicine on systems-levels that takes into account methodological advancements and discoveries of the comprehensive pathophysiological profiles of complex multi-factorial neurodegenerative diseases, such as late-onset sporadic AD. This will allow identifying and characterizing the disease processes at the asymptomatic preclinical stage, where pathophysiological and topographical abnormalities precede overt clinical symptoms by many years to decades. In this respect, the uncharted territory of the AD preclinical stage has become a major research challenge as the field postulates that early biomarker guided customized interventions may offer the best chance of therapeutic success. Clarification and practical operationalization is needed for comprehensive dissection and classification of interacting and converging disease mechanisms, description of genomic and epigenetic drivers, natural history trajectories through space and time, surrogate biomarkers and indicators of risk and progression, as well as considerations about the regulatory, ethical, political and societal consequences of early detection at asymptomatic stages. In this scenario, the integrated roles of genome sequencing, investigations of comprehensive fluid-based biomarkers and multimodal neuroimaging will be of key importance for the identification of distinct molecular mechanisms and signaling pathways in subsets of asymptomatic people at greatest risk for progression to clinical milestones due to those specific pathways. The precision medicine strategy facilitates a paradigm shift in Neuroscience and AD research and development away from the classical "one-size-fits-all" approach in drug discovery towards biomarker guided "molecularly" tailored therapy for truly effective treatment and prevention options. After the long and winding decade of failed therapy trials progress towards the holistic systems-based strategy of precision medicine may finally turn into the new age of scientific and medical success curbing the global AD epidemic.

Microwave assisted synthesis of a mono organoimido functionalized Anderson polyoxometalate

The synthesis of an aliphatic organoimido functionalized polyoxometalate has been achieved through a microwave assisted reaction protocol in the absence of any activating reagents.

Abstract 2327: Oncogenic K-Ras and H-Ras differentially regulate cancer stem cell-like properties via repression of non-canonical Wnt signaling

Cancer stem cells (CSCs) can cause cancer treatment failures and tumor recurrence due to their stem cell-like properties, such as the unlimited self-renewal, tumorigenicity, and chemo-resistance. Ras is the most common oncogene in human cancers, but its roles in stem cell-like properties have not been convincingly demonstrated. With a high degree of sequence homology as well as common sets of downstream effectors and upstream affecters, the three isoforms of Ras, N-, H- and K-Ras, have long been assumed to be functionally redundant. However, knockout of K-Ras, not N- or H-Ras, in mice leads to embryonic lethality, suggesting a non-redundant role of K-Ras in embryonic development. Herein, we report that oncogenic K-Ras, differentially from H-Ras, causes CSC-like properties in transformed mouse fibroblast and pancreatic cancer cells. When compared to the NIH3T3 cells with H-RasV12, the cells transformed with K-RasV12 demonstrated significantly enhanced sphere forming efficiency, elevated resistance toward cisplatin, and heightened sensitivity to the CSC inhibitor, salinomycin, while the RasGTPase, p-Erk and p-Akt activities are comparable. In the comparison with H-RasV12 transformed cells, K-RasV12 transformed NIH3T3 cells possessed significantly increased tumor initiating frequency in limited cell transplantation and in vivo serial transplantation assays. Through stem cell signaling-related genes focusing PCRarray, we further identified Frizzled 8 (Fzd8), a Wnt receptor and potential activator of non-canonical Wnt/Ca2+ signaling, was significantly down-regulated in K-RasV12 transformed NIH3T3 cells when compared to normal cells or H-RasV12- transformed cells. In clinical human pancreatic tissues, Fzd8 was dramatically reduced in malignant specimens, whereas normal tissue showed high expressions of Fzd8. Knockdown of K-Ras in pancreatic cancer cells led to significant increases in Fzd8 at RNA and protein levels, suggesting oncogenic K-Ras repress the expression of Fzd8. TOPFlash assay revealed that K-RasV12 transformed NIH3T3 had dramatically enhanced canonical beta-catenin activity when compared to normal or H-RasV12- transformed cells. Human pancreatic cancer cells with K-Ras knocked down showed significantly reduced canonical beta-catenin activity. In a syngenic mouse model, over-expression of Fzd8 in oncogenic K-Ras driven mouse pancreatic cancer cells delayed the orthotropic tumor formation, and further decreased peritoneal metastatic spreads. Our data collectively suggest that oncogenic K-Ras regulates the stem cell-like properties of cancer cells, differentially from oncogenic H-Ras, through repression of Fzd8-mediated non-canonical Wnt/Ca2+ signaling. Restoration of Fzd8 suppressed oncogenic K-Ras induced pancreatic tumorigenesis, providing an alternative way to target this “undruggable” oncogene.

Citation Format: Man-Tzu Wang, Jacqueline Galeas, Cayde Ritchie, Frank McCormick. Oncogenic K-Ras and H-Ras differentially regulate cancer stem cell-like properties via repression of non-canonical Wnt signaling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2327. doi:10.1158/1538-7445.AM2013-2327

Abstract LB-94: Nanoparticle-based RNAi therapy for the delivery of personalized siRNA payloads to KRAS-driven tumors

The current landscape of druggable disease targets represents only ~10% of the human genome. Among those targets that are frequently mutated in cancer yet remain undruggable by conventional small molecules are the Ras family of GTPases. Somatic mutations in KRAS occur in 35% of colorectal cancers, 16% of lung cancers and 61% of pancreatic cancers. Common KRAS mutations lock the enzyme in the active GTP-bound state, which leads to constitutive activation of downstream effector modules such as MAPK, PI3K, Ral, Rac and Rho, which promote tumor growth, proliferation and survival.

RNAi interference allows for the ablation of any gene product through the engagement of the endogenous microRNA machinery. The successful delivery of siRNA against KRAS or downstream effectors to tumors would represent a novel alternative treatment for KRASmut cancers, which currently lack strong clinical options. We have thus developed an RNAi therapy that employs 1) a cyclodextrin-based nanoparticle with high siRNA carrying capacity and tumor-targeting modules; and 2) highly potent “Sensor” siRNAs that can be used at low dose to efficiently ablate gene targets while avoiding off-target effects.

We have assembled a library of potent Sensor siRNAs, which are identified using a massively parallel biological assay. These siRNA sequences are screened in high-throughput in KRASmut cell lines for negative effects on viability and disruption of cellular signaling pathways (ViBE, Bioscale). To subsequently assess the ability of these personalized nanoparticle-siRNA treatments to inhibit the growth of KRASmut tumors, we have developed an in vivo screening platform to monitor nanoparticle-siRNA delivery and payload efficacy at varying siRNA doses. Successful delivery of siRNAs to solid tumors has been one of the major hurdles to the advancement of RNAi therapy. Our fluorescent reporter system thus allows for the careful tracking of nanoparticle delivery and siRNA payload activity in real time using optical imaging. Additionally, the effect of different nanoparticle-siRNA treatments on transduced tumor cells can be measured non-invasively in real time.

We demonstrate that delivery of low dose Sensor siRNAs targeting KRAS and other effector genes to KRASmut xenograft tumors significantly impedes tumor growth by inhibition of MAPK signaling and induction of apoptosis. The highly customizable nature of the siRNA payload offers a promising and universal platform to access previously intractable targets such as KRAS and personalize treatment for various oncogene-addicted tumors.

Citation Format: Tina L. Yuan, Chih-Shia Lee, Christof Fellmann, Cayde Ritchie, Changwoo Lee, Colin Merrifield, Thomas Schluep, Scott W. Lowe, Ji Luo, Frank McCormick. Nanoparticle-based RNAi therapy for the delivery of personalized siRNA payloads to KRAS-driven tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-94. doi:10.1158/1538-7445.AM2013-LB-94

Shared learning for oral health therapy and dental students: enhanced understanding of roles and responsibilities through interprofessional education

INTRODUCTION

To enhance interprofessional learning outcomes, The School of Dentistry at The University of Queensland redesigned first-year curricula. Courses for Bachelor of Oral Health (OHT) and Bachelor of Dental Science (DS) students were combined, and learning content created to support the development of skills, knowledge and attitudes required for the oral healthcare team to work effectively in providing the best possible care for patients.

METHODS

Over a 2-year period, all commencing OHT and DS students were invited to participate in this study. One cohort (n = 93) was enrolled into a traditional, discipline-specific programme (TRAD), whereas the other cohort (n = 93) experienced an integrated learning programme (INT) with combined courses for OHT and DS students. The Readiness for Interprofessional Learning Scale (RIPLS) and a modified dental and dental care professional roles and responsibilities (DRR) survey were completed to determine students' awareness of dental professionals' roles and responsibilities, and their attitudes to interprofessional education and teamwork.

RESULTS

Following completion of 1 year of learning, both INT and TRAD cohorts showed similar levels of readiness for shared learning. At the commencement of the second year of the study programme, however, there was a significantly better understanding of shared care amongst INT students.

CONCLUSIONS

This study provides initial support for the integrated learning approach adopted by this university. The INT cohort had significantly improved understandings of the roles and responsibilities of dentists and oral health therapists. The results of this study have been used to refine ongoing curriculum developments.

Abstract P2-12-14: Use of the MD Anderson Symptom Inventory to Screen for Depression in Breast Cancer

Background: The prevalence of depression among breast cancer patients is estimated to be twice that in the general population, is linked to diminished quality of life and impaired adherence to therapy. Depression is frequently underdiagnosed or misdiagnosed in this population. Efficient screening for depression is central to patient-centered care and enhanced clinical outcomes for breast cancer patients.

Purpose: To evaluate the use of a commonly utilized symptom assessment instrument as a screen to enhance identification of breast cancer patients experiencing depression.

Methods: Data from a longitudinal surveillance database in outpatient supportive and palliative care were utilized, 174 breast cancer patient contacts were evaluated. Patients completed both the MD Anderson Symptom Inventory (MDASI) and the 9-item Patient Health Questionnaire (PHQ-9) as components of a routinely collected patient-reported outcomes battery. Performance of the MDASI (using the 1–10 Depression question) in identifying cases of depression (defined as a score ≥ 15 on the PHQ-9) was determined using receiver operating characteristic (ROC) analysis.

Results: Data were available on 174 patient contacts. When scored as a continuous measure, the MDASI performed well with an area under the ROC curve of 0.87 (95% confidence interval [CI], 0.81–0.94). An MDASI cutoff score of &gt;= 6 provided a sensitivity of 73% (95% CI, 58%–88%), a specificity of 80% (95% CI, 74%–87%), a positive predictive value (PPV) of 46%, and a negative predictive value (NPV) of 93%.

Conclusion: The “depression” component of the MDASI as a screening instrument for depression in breast cancer patients yields suboptimal sensitivity and specificity for use as a screening tool. Further efforts to evaluate subsequent iterations of the MDASI and combinations of elements in the MDASI that may enhance performance are indicated.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-12-14.

Reliability and validity of physical fitness field tests for adults aged 55 to 70 years

The aim of this study was to examine the reliability and validity of field tests for assessing physical function in mid-aged and young-old people (55-70 y). Tests were selected that required minimal space and equipment and could be implemented in multiple field settings such as a general practitioner's office. Nineteen participants completed 2 field and 1 laboratory testing sessions. Intra-class correlations showed good reliability for the tests of upper body strength (lift and reach, R= .66), lower body strength (sit to stand, R = .80) and functional capacity (Canadian Step Test, R= .92), but not for leg power (single timed chair rise. R = .28). There was also good reliability for the balance test during 3 stances: parallel (94.7% agreement), semi-tandem (73.7%), and tandem (52.6%). Comparison of field test results with objective laboratory measures found good validity for the sit to stand (cf 1RM leg press, Pearson r= .68, p < .05), and for the step test (cf PWC140, r = -.60, p < .001), but not for the lift and reach (cf 1RM bench press, r = .43, p > .05), balance (r = -.13, -.18, .23) and rate of force development tests (r = -.28). It was concluded that the lower body strength and cardiovascular function tests were appropriate for use in field settings with mid-aged and young-old adults.

Strength of evidence linking oral conditions and systemic disease

Associations between dental diseases and systemic outcomes are potentially important because of the high occurrence of dental diseases. If this extremely common source of chronic infection (dental disease) leads to an increased morbidity and mortality rate, the public health impact of oral disease on millions of Americans would be substantial. Recent studies demonstrate an association between dental and systemic diseases, including systemic infections, cardiovascular disease, pregnancy outcomes, respiratory diseases, and increased all-cause mortality rate. Because there are several common risk factors for oral and systemic diseases, and limitations in published studies, a careful interpretation is needed. Confounding (shared risk factors for both systemic and dental disease) may explain part of the reported associations. It is also plausible that there may be a causal link. It is likely that if there is a causal link, several pathways and mediators coexist, linking oral and systemic disease. Bacteremia, bacterial endotoxins, cytokines, and other inflammatory mediators could conceivably be playing a direct or indirect role. Missing teeth are a surrogate marker for previous dental infection, and may also lead to altered dietary intake. Hence, diet may be an additional mediator for several of these outcomes. We caution clinicians not to recommend extracting infected teeth, based on the periodontal-systemic disease associations, if the teeth do not warrant extraction otherwise, because loss of teeth and edentulousness are associated with increased risk of systemic diseases. When assessed against causal-defined criteria, the evidence suggests possible causal associations between chronic periodontal disease and tooth loss with cardiovascular disease, bacterial endocarditis, pregnancy outcomes, and all-cause overall mortality. Further studies are needed to show consistency, to corroborate that the associations are independent of common risk factors for both systemic and dental disease, including healthy lifestyle factors, and to evaluate different biological pathways.

Clostridium perfringens type A enterotoxin forms mepacrine-sensitive pores in pure phospholipid bilayers in the absence of putative receptor proteins

Clostridium perfringens enterotoxin (CPE) is an important cause of food poisoning with no significant homology to other enterotoxins and its mechanism of action remains uncertain. Although CPE has recently been shown to complex with tight junction proteins, we have previously demonstrated that CPE increases ionic permeability in single Caco-2 cells using the whole-cell patch-clamp technique, thereby excluding any paracellular permeability. In this paper we demonstrate that CPE forms pores in synthetic phospholipid membranes in the absence of receptor proteins. The properties of the pores are consistent with CPE-induced permeability changes in Caco-2 cells suggesting that CPE has innate pore-forming ability.

Effects of the nicotinic antagonist mecamylamine on inspection time

RATIONALE

Several lines of evidence suggest that nicotinic acetylcholine receptors (nAchRs) are involved in speed of information processing, and inspection time appears to be particularly sensitive to nicotinic manipulation.

OBJECTIVE

The present study sought to examine the effects of the nAchR antagonist mecamylamine on inspection time. Furthermore, the extent to which the anticholinesterase donepezil would reverse the effects of mecamylamine on inspection time was also examined.

METHODS

A double-blind, repeated measures design was employed. Subjects (n = 6) received placebo, mecamylamine (20 mg PO) or mecamylamine (20 mg PO) and donepezil (5 mg PO). Inspection time and physiological measures were then assessed.

RESULTS

The mecamylamine condition and the mecamylamine and donepezil condition were associated with an increase in heart rate, when compared to the placebo condition. There was a significant slowing of inspection time in the mecamylamine condition; compared to placebo, which was partly reversed by donepezil.

CONCLUSIONS

The slowing of inspection time following mecamylamine is consistent with the role of nAchRs in speed of information processing, and add to the evidence that IT may in part index nAchR system integrity.

Splenectomy during partial remission in thrombotic thrombocytopenic purpura with prolonged plasma exchange dependency

Some patients with thrombotic thrombocytopenic purpura (TTP) remain plasma-exchange-dependent for prolonged periods of time. This exposes patients to risk, uses substantial resources, and requires prolonged hospitalization. We have splenectomized 7 such patients following 25-42 plasma exchanges while patients were in partial remission only and were clinically stable. In 6 patients, including 1 with TTP secondary to mitomycin C, thrombocytopenia promptly resolved. Relapse has not occurred during 18 or more months of observation. The seventh patient did not respond. We conclude that splenectomy should be considered as an alternative to continued plasma-exchange therapy in such patients.