SU-E-T-269: The Evaluation of Copper as an Alternative for Cerrobend Electron Shielding

PURPOSE

To evaluate the replacement of Cerrobend by copper for electron beam cutouts.

METHODS

The dosimetric comparisons for circular copper-and Cerrobend-cutouts with diameters (1.0, 2.0, 3.0, 5.0, 7.5, 10.0, and 12.5 cm) were made using electron beams with energies (6, 9, 12, 16, and 20 MeV) from 3 Varian accelerators. A PTW Farmer chamber (0.125cc-volume) was used for larger cutouts (diameters > 2cm), and an electron-diode for the 2 smallest cutouts. Also a Markus parallel plate chamber was used.

RESULTS

(1) The tests showed little difference for the electron dosimetric characteristics, Eo, Eop, R50, Rp, and dmax. For larger cutout, the parameters were virtually the same for copper and Cerrobend. for smaller cutout (diameter = 3cm), small discrepancies were observed i.e. differences < 1mm for R50, Rp and dmax, =0.1MeV for Eop, and =0.3MeV for Eo. (2) The larger-cutout outputs at dmax were also virtually the same (difference = 0.6%). For smaller cutouts (diameters = 3cm), the copper outputs were 2.0%∼5.0% higher than Cerrobend. (3) For lower energy electrons (<12MeV), more larger-angle scattered electrons from higher-Z Cerrobend raise the Cerrobend percentage-depth-dose (PDD) curve at shallow-depths, and more forward scatter dose after dmax from lower-Z copper shifts the copper PDD slightly away from the one of Cerrobend. for higher energy electrons (= 12MeV), the shallow-dose difference becomes smaller for both cutouts, but even more forward-scattered dose from copper shifts copper's PDD further away from Cerrobend's. (4) The higher X-ray transmission through copper is also observable; i.e. 12%, 10%, and 7% for 20MeV, 16MeV, and 12MeV, respectively, but such small transmitted amount is clinically insignificant.

CONCLUSIONS

Except for a higher x-ray transmission, other dosimetric differences brought in by the replacement of Cerrobend by copper cutout are negligible.

BaTiO3(001)-(2×1): surface structure and spin density

Using surface x-ray diffraction and ab initio calculations we present a model of the BaTiO3(001)-(2×1) surface structure, which has not been considered so far. While the crystal is terminated by two TiO2 layers similarly to SrTiO3(001)-(2×1), we find that one out of two surface layer Ti-atoms resides in a tetragonal pyramidal oxygen environment. This peculiar geometry leads to a metallic and magnetic surface involving local magnetic moments up to 2μ(B) in magnitude located at surface Ti and O atoms. Our results are important for the understanding of the intrinsic surface metallicity of insulating oxides in general.

Fabrication using a rapid prototyping system and in vitro characterization of PEG-PCL-PLA scaffolds for tissue engineering

In the field of tissue engineering new polymers are needed to fabricate scaffolds with specific properties depending on the targeted tissue. This work aimed at designing and developing a 3D scaffold with variable mechanical strength, fully interconnected porous network, controllable hydrophilicity and degradability. For this, a desktop-robot-based melt-extrusion rapid prototyping technique was applied to a novel tri-block co-polymer, namely poly(ethylene glycol)-block-poly(epsilon-caprolactone)-block-poly(DL-lactide), PEG-PCL-P(DL)LA. This co-polymer was melted by electrical heating and directly extruded out using computer-controlled rapid prototyping by means of compressed purified air to build porous scaffolds. Various lay-down patterns (0/30/60/90/120/150 degrees, 0/45/90/135 degrees, 0/60/120 degrees and 0/90 degrees) were produced by using appropriate positioning of the robotic control system. Scanning electron microscopy and micro-computed tomography were used to show that 3D scaffold architectures were honeycomb-like with completely interconnected and controlled channel characteristics. Compression tests were performed and the data obtained agreed well with the typical behavior of a porous material undergoing deformation. Preliminary cell response to the as-fabricated scaffolds has been studied with primary human fibroblasts. The results demonstrated the suitability of the process and the cell biocompatibility of the polymer, two important properties among the many required for effective clinical use and efficient tissue-engineering scaffolding.

Predictors of first lifetime episodes of major depression in midlife women

BACKGROUND

Little is known about factors that predict first lifetime episodes of major depression in middle-aged women. It is not known whether health-related factors and life stress pose more or less of a risk to the onset of clinical depression than does the menopausal transition.

METHOD

The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to assess diagnoses of lifetime, annual and current major depression in a community-based sample of premenopausal or early perimenopausal African American and White women. Menstrual cycle characteristics, psychosocial and health-related factors, and blood samples for assay of reproductive hormones were obtained annually. Two hundred and sixty-six women without a history of major depression at baseline constituted the cohort for the current analyses.

RESULTS

Over 7 years of follow-up, 42 (15.8%) women met criteria for a diagnosis of major depression. Frequent vasomotor symptoms (VMS; hot flashes and/or night sweats) (HR 2.14, p=0.03) were a significant predictor of major depression in univariate analyses. After simultaneous adjustment for multiple predictors in Cox proportional hazards analyses, frequent VMS were no longer significant; lifetime history of an anxiety disorder (HR 2.20, p=0.02) and role limitations due to physical health (HR 1.88, p=0.07) at baseline and a very stressful life event (HR 2.25, p=0.04) prior to depression onset predicted a first episode of major depression.

CONCLUSIONS

Both earlier (e.g. history of anxiety disorders) and more proximal factors (e.g. life stress) may be more important than VMS in contributing to a first episode of major depression during midlife.

Economic burden of haematological adverse effects in cancer patients: a systematic review

OBJECTIVE

Patients receiving cancer treatments commonly experience haematological adverse effects (AEs) related to chemotherapy or molecularly targeted therapies, which may be associated with high healthcare costs. The objective of this review was to summarise the published literature on the economic burden of neutropenia, thrombocytopenia and anaemia as AEs of cancer treatment.

METHODS

A systematic search of the medical literature published between 1990 and 2006 was conducted using PubMed/MEDLINE, EMBASE, BIOSIS, related article links and supplemental searches. References selected for inclusion were prospective or retrospective studies specifically designed to examine the burden of illness, direct medical costs, indirect costs and/or cost drivers associated with neutropenia, thrombocytopenia and anaemia in adult cancer patients. All costs are reported as originally published and adjusted to 2006 US dollars.

RESULTS

In the US, the cost of neutropenia ranged from $US 1893 (2006 value $US 2632) per outpatient episode to $US 38,583 ($US 49,917) per febrile neutropenia hospitalisation. For countries outside the US, the cost of neutropenia appeared to be lower. The cost of thrombocytopenia ranged from $US 1035 ($US 1395) to $US 5328 ($US 7635) per cycle or episode in the US. Costs attributable to anaemia ranged from $US 18,418 ($US 22,775) to $US 69,478 ($US 93,454) per year in the US. The costs of AEs for patients with haematological malignancies appeared to be up to 2-3 times higher than those for patients with solid tumours. Economic studies of the cost of haematological AEs specific to new molecularly targeted treatments for haematological malignancy have not been published.

CONCLUSIONS

Chemotherapy-related haematological AEs result in a substantial economic burden on patients, payers, caregivers and society in general. Because of their burden, the frequency and severity of these toxicities should be one of the key factors in the selection of optimal treatments for patients with cancer, especially those with haematological malignancies. Future research is needed to assess the economic burden of AEs associated with new molecularly targeted treatments for haematological malignancies.

Medical costs associated with imatinib (IM) non-compliance in chronic myeloid leukemia (CML) patients (pts)

17514

Background: Not adhering to treatment (tx) may lead to suboptimal outcomes. This study examined associations between medical costs and IM compliance in CML pts. Methods: CML pts under age 65 were identified with ICD-9 diagnosis code (205.1X) using MarketScan Commercial Claims data between 1/1/02–12/31/05. Pts were required to be continuously enrolled in the 4 months prior to (baseline) and the 6 months following (study period) IM initiation. CML severity was categorized into 3 groups by diagnosis of CML and related comorbidities. Compliance was defined by medication possession ratio (MPR=total days of IM supply in the study period divided by 180), and stratified into 3 groups (low: <65%, medium: 65–95%, high: 95–100%). Tx interruption was defined as tx gap of 30 or more consecutive days in the study period. Costs for inpatient (IP), ER, outpatient (OP) services and OP drugs during the study period were adjusted to 2005 dollars. Costs, the number of IP admissions and hospital days were compared across different levels of tx compliance using Wilcoxon tests. A generalized linear model (GLM) was also used to compare costs controlling for age, sex, CML severity, Charlson comorbidity index, year of IM start, etc. Results: The study sample consisted of 404 pts. Compared to the high MPR group, pts in the low MPR group incurred 1.6 times the average total health care costs (p <.001), 5.9 times the IP costs (p<.001), 2.6 times the OP costs (p=.722), 2.1 times the non-IM drug costs (p<.001), and 0.39 times the IM drug costs (p<.001). Compared to the high MPR pts, low MPR pts had on average 3.8 times the IP admissions (p<.001), and 7.3 times the IP days (p<.001). Comparing costs of pts interrupting tx versus those who did not showed similar trends. GLM regression showed that 6-month total health care costs per patient in the low MPR group were 1.4 times (p<.01) those of the high MPR group. Pts who had tx interruption had 1.3 times the total health care costs (p<.01) compared to those who did not. Conclusions: This study shows that better IM compliance was associated with significantly lower health care costs in CML pts, especially for IP costs. Further analyses will be conducted to confirm whether lower compliance leads to more hospitalizations.

No significant financial relationships to disclose.

The major lung cancer-derived mutants of ERBB2 are oncogenic and are associated with sensitivity to the irreversible EGFR/ERBB2 inhibitor HKI-272

Mutations in the ERBB2 gene were recently found in approximately 2% of primary non-small cell lung cancer (NSCLC) specimens; however, little is known about the functional consequences and the relevance to responsiveness to targeted drugs for most of these mutations. Here, we show that the major lung cancer-derived ERBB2 mutants, including the most frequent mutation, A775insYVMA, lead to oncogenic transformation in a cellular assay. Murine cells transformed with these mutants were relatively resistant to the reversible epidermal growth factor receptor (EGFR) inhibitor erlotinib, resembling the resistant phenotype found in cells carrying the homologous mutations in exon 20 of EGFR. However, the same cells were highly sensitive to the irreversible dual-specificity EGFR/ERBB2 kinase inhibitor HKI-272, as were those overexpressing wild-type ERBB2. Finally, the NSCLC cell line, Calu-3, overexpressing wild-type ERBB2 owing to a high-level amplification of the ERBB2 gene were highly sensitive to HKI-272. These results provide a rationale for treatment of patients with ERBB2-mutant or ERBB2-amplified lung tumors with HKI-272.

Control of Alternaria alternata by cassia oil in combination with potassium chloride or sodium chloride

AIMS

To compare antifungal effects of cassia oil alone and in combination with potassium chloride (KCl) or sodium chloride (NaCl) against Alternaria alternata in vitro and in vivo.

METHODS AND RESULTS

The inhibitory effect of cassia oil alone, or in combination with KCl and NaCl were tested in vitro. The spore germination and germ tube elongation of the pathogen was evaluated in potato dextrose broth with light microscopy analysis. The inhibitory effect of cassia oil alone, or in combination with KCl and NaCl, was determined on cherry tomatoes in vivo. The cassia oil in combination with KCl and NaCl exhibited strong antifungal effect in vivo and in vitro.

CONCLUSIONS

The antifungal effect of cassia oil against Alt. alternata was enhanced significantly by combining with KCl and NaCl both in vitro and in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combination of cassia oil and KCl or NaCl may enhance antifungal effect of cassia oil and reduce cost.

Distribution of the Alpha-Gal Epitope on Adult Porcine Bone Tissue

INTRODUCTION

Bone xenografts from pig to human appear to be an alternative to resolve the shortage of bone autologous and allografts. However, the major obstacle of pig-to-human xenotransplantation is the interaction between human natural anti-Gal antibody and the alpha-Gal epitope abundantly expressed on pig endothelium. It was important to investigate the expression of alpha-Gal epitopes in porcine bone tissue to look for an ideal method to remove the alpha-Gal epitopes.

METHODS

The cortical and trabecular bone were retrieved from five pigs. After the soft tissues and periosteum were removed, the blood and marrow cavity were cleaned with phosphate-buffered solution. All 5 mm x 5 mm x 5 mm samples were imbedded in paraffin and methyl methacrylate resin for histological sections. The mouse IgM M86 monoclonal antibody, which was highly specific for alpha-Gal epitopes, was used to document alpha-Gal epitope expression by immunostaining of tissues and immunofluorescence.

RESULTS

Gal-positive immunostaining and immunofluorescence were observed on the surface of osteocytes and Haversian canals. There was a significant difference in Gal expression between cortical and trabecular bone tissues. There was no Gal expression in the extracellular matrix of bone.

CONCLUSIONS

Major alpha-Gal epitopes were on the surface of osteocytes of porcine bone tissues. A method should be used to damage the osteocytes and eliminate the alpha-Gal epitopes to avoid the xenogenic rejection in xenotransplantation of porcine bone tissues.

The impact of non-compliance with imatinib (IM) therapy on health care costs

6083

Background: While compliance to drug therapy is vital to receive optimal patient benefits, the costs of delivering adequate medical care for cancer patients remain an important consideration for society and payers. This study examined the relationship between compliance with IM therapy and health care costs for patients with CML and GIST. Methods: Claims data from 6/1/01–3/31/04 from a US health plan were used to identify non-Medicare IM-treated patients with a CML or GIST diagnosis who had continuous pharmacy and medical benefits in the 3 months prior and 12 months following initiation of IM therapy. Compliance was defined by medication possession ratio (MPR=total days IM supply in the first year ÷365) and patients were stratified into three segments by MPR (<50%, 50–90%, 90–100%). Total health care costs include hospital, laboratory testing, office, ER, and pharmacy charges. Disease-related health care costs were also analyzed. Multivariate analyses were used to examine the relationship between MPR and first-year health care costs, controlling for age, sex, number of medications, initial starting dose, diagnosis (CML or GIST), year of initial IM fill, and complications due to underlying disease. Results: Total 878 IM-treated patients were identified of whom 413 had at least 15 months of continuous eligibility. Of these, 307 were non-Medicare CML or GIST patients. Total health care costs per patient in the first year of therapy in MPR < 50%, 50–90%, and 90–100% groups were $163,828, $53,924, and $40,924 respectively (p < 0.001). The corresponding numbers for disease-related health care costs were $103,118, $36,436, and $34,086 (p<0.001). Controlling for the variables listed above, a 10% increase in MPR is associated with a 5% decrease in total health care costs (p=0.021). Similar association was found between MPR and disease-related health care costs. Conclusions: Improved compliance with imatinib therapy is associated with decreased total health care costs and disease-related health care costs. Improving compliance to imatinib therapy may not only optimize clinical outcomes but may also reduce the overall societal burden of health care costs associated with cancer.

[Table: see text]

Compliance and persistency with imatinib

6038

Background: Imatinib is an oral therapy with efficacy in chronic myelogenous leukemia (CML) and gastrointestinal stromal tumors (GIST). Optimal dosing and adherence to treatment is critical to achieve the best clinical outcomes. This study examined compliance and persistency with imatinib and identified the clinical and patient characteristics related to compliance. Methods: Claims data from a US health plan were used to identify imatinib-treated patients from 6/1/01–3/31/04 who had continuous pharmacy and medical benefits in the 3 months prior and 12 months following initiation of imatinib therapy, and a diagnosis of CML or GIST (ICD-9-CM 205.1, 205.10, or 205.11 for CML; 159.0, 159.8, or 159.9 for GIST). Compliance was defined by medication possession ratio (MPR = total days supply of imatinib in the first year divided by 365). Persistency was defined as failure to refill imatinib within 30 days from the run-out date of the prior prescription. Multivariate analyses were used to identify key factors associated with compliance. Results: Total 878 imatinib-treated patients were identified of whom 413 had at least 15 months’ continuous eligibility. Sixty-nine percent (n = 286) were diagnosed with CML, 8% (n = 34) with GIST, and 23% (n = 93) with neither. Results are presented for CML and GIST patients. The average age was 51 and 58% were males. The average starting daily dose was 424 mg, with 80% (n = 255) initiating on 400 mg daily. The mean MPR was 76%. Overall, 28% patients discontinued imatinib for at least 30 consecutive days during the 1-year follow up period. Multivariate analyses indicated MPR improved with age until age 51 and then deteriorated (p < 0.001) but at a diminishing rate, decreased as the number of medications increased (p < 0.001), and was lower in women (p = 0.005) and patients with more cancer complications (p < 0.001). In addition, women were more likely to discontinue than men (OR = 2.08; p = 0.003). Conclusions: Compliance to imatinib was about 75% with 30% of patients interrupting therapy for at least 30 consecutive days in the first year. It has been found that interruption of imatinib therapy may lead to rapid tumor progression in GIST (PASCO05 Le Cesne #9031). Not having patients take the correct doses on a regular basis may lead to sub therapeutical clinical outcomes.

[Table: see text]