Final analysis of phase II results with cemiplimab in metastatic basal cell carcinoma after hedgehog pathway inhibitors

BACKGROUND

Metastatic basal cell carcinoma (mBCC) is a rare condition with no effective second-line treatment options. Cemiplimab is an immune checkpoint inhibitor that blocks the binding of programmed cell death-1 (PD-1) to its ligands, programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2). Here, we present the final analysis of cemiplimab in patients with mBCC after first-line hedgehog pathway inhibitor (HHI) treatment (NCT03132636).

PATIENTS AND METHODS

In this open-label, single-arm, phase II study, adults with mBCC and Eastern Cooperative Oncology Group performance status ≤1, post-HHI treatment, received cemiplimab 350 mg intravenously every 3 weeks for ≤93 weeks or until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by independent central review (ICR). Duration of response (DOR) was a key secondary endpoint. Other secondary endpoints were ORR per investigator assessment, progression-free survival (PFS), overall survival (OS), complete response rate, safety, and tolerability.

RESULTS

Fifty-four patients were enrolled: 70% were male and the median age of patients was 64 [interquartile range (IQR) 57.0-73.0] years. The median duration of follow-up was 8 months (IQR 4-21 months). The ORR per ICR was 22% [95% confidence interval (CI) 12% to 36%], with 2 complete responses and 10 partial responses. Among responders, the median time to response per ICR was 3 months (IQR 2-7 months). The estimated median DOR per ICR was not reached [95% CI 10 months-not evaluable (NE)]. The disease control rate was 63% (95% CI 49% to 76%) per ICR and 70% (95% CI 56% to 82%) per investigator assessment. The median PFS per ICR was 10 months (95% CI 4-16 months); the median OS was 50 months (95% CI 28 months-NE). The most common treatment-emergent adverse events were fatigue [23 (43%)] and diarrhoea [20 (37%)]. There were no treatment-related deaths.

CONCLUSIONS

Cemiplimab demonstrated clinically meaningful antitumour activity, including durable responses, and an acceptable safety profile in patients with mBCC who had disease progression on or intolerance to HHI therapy.

Waterborne disease outbreaks in treated recreational water facilities: a Socio-Ecological Model perspective

Treated recreational water facilities, including swimming pools and water play parks, have often been implicated in infectious disease outbreaks. Addressing this problem is complex due to the multiple and interrelated factors contributing to outbreaks in these settings. These factors may relate to inappropriate behaviours of users and operators, lack of and inconsistent regulation of these facilities, insufficient facility maintenance, and problems associated with the design of these facilities. Given the complexity of this issue, we argue that the Socio-Ecological Model (SEM) provides a useful framework to help identify the multi-level influences and factors that have implications for designing interventions to prevent this public health problem, whilst assisting in guiding future research in this area. We apply the SEM to the current literature to help identify the influences and factors contributing to infectious disease outbreaks in treated recreational water facilities to support this argument. We also identify several gaps in the existing research that would benefit from further examination to help prevent infectious disease outbreaks in treated recreational water facilities such as public swimming pools and water play parks.

Glucocorticoid toxicity reduction with mepolizumab using the Glucocorticoid Toxicity Index

BACKGROUND

Reduction in glucocorticoid exposure is the primary benefit of new biologic treatments in severe asthma, but there is currently no evidence that reduction in glucocorticoid exposure corresponds to a proportionate reduction in associated toxicity.

OBJECTIVES

To use the validated Glucocorticoid Toxicity Index (GTI) to assess change in glucocorticoid toxicity after 12 months treatment with mepolizumab, and compare toxicity change to glucocorticoid reduction and change in patient-reported outcome measures (PROMs).

METHODS

A longitudinal, real-world prospective cohort of 101 consecutive patients with severe asthma commenced on mepolizumab in a specialist UK regional severe asthma clinic. GTI toxicity assessment, cumulative glucocorticoid exposure and PROMs were recorded on commencing mepolizumab (V1), and after 12 months treatment (V2).

RESULTS

There was significant reduction in oral glucocorticoid exposure (V1 median 4280 mg prednisolone per year (interquartile range 3083-5475 mg) versus V2 2450 mg prednisolone per year (1243-3360 mg), p<0.001). Substantial improvements in individual toxicities were observed, but did not correlate with oral glucocorticoid reduction. Mean±sd GTI aggregate improvement score (AIS) was -35.7±57.8 with a wide range in toxicity change at individual patient level (AIS range -165 to +130); 70% (71 out of 101) had a reduction in toxicity (AIS <0); 3% (three out of 101) had no change (AIS=0); and 27% (27 out of 101) an increase in overall toxicity. 62% (62 out of 101) of patients met the AIS minimally clinically important difference of ≤-10, but AIS did not correlate with glucocorticoid reduction or change in PROMs.

CONCLUSION

Mepolizumab resulted in substantial oral glucocorticoid reduction, but this did not correlate with reduction in oral glucocorticoid toxicity, which varies widely at the individual patient level. Oral glucocorticoid reduction is not a comprehensive measure of response to mepolizumab.

Quantification of Glucocorticoid-Associated Morbidity in Severe Asthma Using the Glucocorticoid Toxicity Index

BACKGROUND

Glucocorticoid (GC)-associated morbidity in severe asthma (SA) is well recognized but varies in individual patients; systematic measurement of GC toxicity is important to measure improvement with steroid-sparing monoclonal antibodies.

OBJECTIVE

To describe for the first time individual patient GC toxicity in steroid-dependent SA using the Glucocorticoid Toxicity Index (GTI).

METHODS

An observational consecutive patient cohort study was performed at a UK Regional SA Specialist clinic for systematic assessment of GC-associated morbidity using the GTI in routine clinical care. GTI was correlated with commonly used patient-reported outcome measures. An approach to GTI scoring, calculation of minimal clinically important difference (MCID), and development of digital GTI application in routine clinical care are described.

RESULTS

All patients had significant oral GC exposure (cumulative prednisolone/prior year, 4280 [3083, 5475] mg) with wide distribution of toxicity in individual patients (mean GTI score, 177.5 [73.7]). GTI score had only modest correlation with recent prednisolone exposure: maintenance prednisolone dose (rho = 0.26, P = .01), cumulative exposure/prior year (rho = 0.38, P < .001), and GC boosts/prior year (rho = 0.25, P = .01). GTI toxicity demonstrated stronger associations with asthma-related quality of life (mini-Asthma Quality of Life Questionnaire [mini-AQLQ] r = -0.50, P < .001 and St. George's Respiratory Questionnaire r = 0.42, P < .001). GTI MCID was calculated as 10 points. Multiple linear regression demonstrated that age and mini-AQLQ were strongest predictors of GC toxicity.

CONCLUSIONS

The GTI is a useful tool to systematically capture and quantify GC toxicity at the individual patient level. GC toxicity varies widely between individual patients with SA and correlated only modestly with GC exposure over the preceding year. Age and mini-AQLQ are better predictors of GC toxicity. The GTI and MCID will facilitate assessment of individual SA response to steroid-sparing agents in clinical trials and routine care.

Preventing and controlling Cryptosporidium spp. in aquatic facilities: environmental health practitioners' experiences in Victoria, Australia

OBJECTIVE

To identify barriers and enablers to preventing and controlling Cryptosporidium spp. in aquatic facilities as perceived by environmental health practitioners (EHPs).

METHODS

A qualitative, constructivist study with a purposive sample of seven EHPs from Victoria, Australia, was conducted. A focus group discussion was guided by a semi-structured interview schedule using open-ended questions. The audio-recorded focus group was transcribed verbatim and analysed using thematic analysis.

RESULTS

Five themes represented the perceived barriers and enablers: i) pool water testing methods; ii) resources and training for EHPs; iii) knowledge and behaviour of aquatic facility operators and swimming pool users; iv) regulation; and v) aquatic facility and swimming pool design. Two key barriers within these themes included aquatic facility regulation and unhealthy swimming behaviours.

CONCLUSIONS

Several barriers and enablers to preventing and controlling Cryptosporidium spp. in aquatic facilities were perceived by EHPs. Suggestions to overcome perceived barriers were also identified. Further research is required to determine the impact of these findings on the incidence of cryptosporidiosis associated with aquatic facilities. Implications for public health: The findings contribute to a greater understanding of the barriers and enablers to Cryptosporidium spp. prevention and control in aquatic facilities, which may improve the effectiveness of current prevention and control strategies.

Abstract OT1-04-01: Cambridge brain mets trial 1 (CamBMT1): A proof-of-principle phase 1b / randomised phase 2 study of afatinib penetration into brain metastases for patients undergoing neurosurgical resection, both with and without prior low-dose, targeted radiotherapy

Background

Failure of drugs to cross the blood brain barrier (BBB) can be a major reason for treatment failure for patients with brain tumors. For most patients who don't respond to treatment, it is not known whether this is due to inadequate drug concentrations in the tumor, or due to drug resistance. Preliminary data suggest that low-dose radiotherapy may disrupt the BBB, and could facilitate increased drug delivery into brain tumors. Afatinib is a potent, irreversible inhibitor of EGFR / HER2 / HER4 and takes approximately 8 days to achieve steady-state concentrations in cancer patients.

Aims

CamBMT1 has been designed to investigate the delivery of afatinib into brain metastases and whether this might be enhanced by low dose-radiotherapy.

Patient Population

Key eligibility criteria

Patients with operable brain metastases from breast or lung primaries for whom neurosurgical resection would be standard of care, as determined by the local multi-disciplinary team. ECOG PS 0, 1 or 2.

Trial design

After a phase 1b safety run- in, the phase 2 part of the trial randomises patients (n=60) into 3 pre-operative arms:

Arm 1afatinib alone for 11 days, then neurosurgery on day 12Arm 2afatinib for 11 days plus a single 2 Gy fraction on day 10, then neurosurgery on day 12Arm 3afatinib for 11 days plus a single 4 Gy fraction on day 10, then neurosurgery on day 12

Primary endpoint: to compare steady-state afatinib concentration in resected brain metastases, following afatinib administered alone, or in combination with radiotherapy (2 Gy or 4 Gy). Afatinib concentrations are measured in the resected brain metastases and in plasma.

Secondary endpoints: safety of afatinib administration in combination with radiotherapy; and multi-sequence MRI (optional) to detect changes in perfusion, vascular density, blood-brain-barrier permeability and interstitial pressure.

Exploratory endpoints: molecular profiling of resected brain metastases, for comparison with paired primary lung and breast cancers; the establishment and study of patient-derived xenografts.

Statistical methods

With 20 patients randomised in each of 3 arms in the phase 2 part of CamBMT1, the trial has a power of 84% at a significance level of 20% (one-sided) to detect an increase in afatinib concentrations with targeted radiotherapy, measured as a Cohen's D (standardised mean difference) ≥0.5.

Accrual

By the end of q2 2016, phase 1b had nearly completed enrolment. The randomised phase 2 part of CamBMT1 is due to open by q4 2016 at additional Experimental Cancer Medicine Centres.

Acknowledgments

CamBMT1 is funded by Cancer Research UK, the Brain Tumour Charity and Boehringer-Ingelheim.

Citation Format: Baird RD, Ramenatte N, Watts C, Jonson A, Jones L, Biggs H, Harrison E, Oberg I, Bullen G, Williams M, Qian W, Gilbert F, Jodrell D, Caldas C, Karabatsou K, Dunn L, Jena R, Whitfield G, Chalmers A, Jefferies S, Price S. Cambridge brain mets trial 1 (CamBMT1): A proof-of-principle phase 1b / randomised phase 2 study of afatinib penetration into brain metastases for patients undergoing neurosurgical resection, both with and without prior low-dose, targeted radiotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-04-01.

DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION

Production of radioisotopes in medical linear accelerators (linacs) is of concern when the beam energy exceeds the threshold for the photonuclear interaction. Staff and patients may receive a radiation dose as a result of the induced radioactivity in the linac. Gamma-ray spectroscopy was used to identify the isotopes produced following the delivery of 18 MV photon beams from a Varian 21EX and an Elekta Synergy. The prominent radioisotopes produced include ¹⁸⁷W, ⁶³Zn, ⁵⁶Mn, ²⁴Na and ²⁸Al in both linac models. The dose rate was measured at the beam exit window (12.6 µSv in the first 10 min) following 18 MV total body irradiation (TBI) beams. For a throughput of 24 TBI patients per year, staff members are estimated to receive an annual dose of up to 750 μSv at the patient location. This can be further reduced to 65 μSv by closing the jaws before re-entering the treatment bunker.

A phase II study of axitinib (AG-013736) in patients with incurable adenoid cystic carcinoma

BACKGROUND

Recurrent/metastatic adenoid cystic carcinoma (ACC) is an incurable disease with no standard treatments. The majority of ACCs express the oncogenic transcription factor MYB (also c-myb), often in the context of a MYB gene rearrangement. This phase II trial of the tyrosine kinase inhibitor (TKI) axitinib (Pfizer) tested the hypothesis that targeting pathways activated by MYB can be therapeutically effective for ACC.

PATIENTS AND METHODS

This is a minimax two-stage, phase II trial that enrolled patients with incurable ACC of any primary site. Progressive or symptomatic disease was required. Patients were treated with axitinib 5 mg oral twice daily; dose escalation was allowed. The primary end point was best overall response (BOR). An exploratory analysis correlating biomarkers to drug benefit was conducted, including next-generation sequencing (NGS) in 11 patients.

RESULTS

Thirty-three patients were registered and evaluable for response. Fifteen patients had the axitinib dose increased. Tumor shrinkage was achieved in 22 (66.7%); 3 (9.1%) had confirmed partial responses. Twenty-five (75.8%) patients had stable disease, 10 of whom had disease stability for >6 months. The median progression-free survival (PFS) was 5.7 months (range 0.92-21.8 months). Grade 3 axitinib-related toxicities included hypertension, oral pain and fatigue. A trend toward superior PFS was noted with the MYB/NFIB rearrangement, although this was not statistically significant. NGS revealed three tumors with 4q12 amplification, producing increased copies of axitinib-targeted genes PDGFR/KDR/KIT. Two 4q12 amplified patients achieved stable disease for >6 months, including one with significant tumor reduction and the longest PFS on study (21.8 months).

CONCLUSIONS

Although the primary end point was not met, axitinib exhibited clinical activity with tumor shrinkage achieved in the majority of patients with progressive disease before trial enrollment. Analysis of MYB biomarkers and genomic profiling suggests the hypothesis that 4q12 amplified ACCs are a disease subset that benefit from TKI therapy.

The symptom phenotype of oncology outpatients remains relatively stable from prior to through 1 week following chemotherapy

Some oncology outpatients experience a higher number of and more severe symptoms during chemotherapy (CTX). However, little is known about whether this high risk phenotype persists over time. Latent transition analysis (LTA) was used to examine the probability that patients remained in the same symptom class when assessed prior to the administration of and following their next dose of CTX. For the patients whose class membership remained consistent, differences in demographic and clinical characteristics, and quality of life (QOL) were evaluated. The Memorial Symptom Assessment Scale (MSAS) was used to evaluate symptom burden. LTA was used to identify subgroups of patients with distinct symptom experiences based on the occurrence of the MSAS symptoms. Of the 906 patients evaluated, 83.9% were classified in the same symptom occurrence class at both assessments. Of these 760 patients, 25.0% were classified as Low-Low, 44.1% as Moderate-Moderate and 30.9% as High-High. Compared to the Low-Low class, the other two classes were younger, more likely to be women and to report child care responsibilities, and had a lower functional status and a higher comorbidity scores. The two higher classes reported lower QOL scores. The use of LTA could assist clinicians to identify higher risk patients and initiate more aggressive interventions.

Internal Structure of the Children Helping Out: Responsibilities, Expectations, and Supports (CHORES) Measure

The purpose of this study was to examine the internal structure of the Children Helping Out: Responsibilities, Expectations, and Supports (CHORES), an assessment of household task participation for children. Rasch analysis was used to examine patterns of item response and scale structure with data collected from caregivers of 132 children and youth ages 6–14 yr with and without disabling conditions. Internal consistency was strong for the total measure and the subscales. The items in both subscales fit the measurement model, and the item difficulty order matched the expected pattern from harder to easier household task performance and degree of caregiver assistance. The sample distribution in the hierarchical continuum showed that younger participants and those with physical disabilities tended to score lower. Some inconsistencies in rating scale use suggest a need for further clarification of the scoring criteria for measurement coherence.

A large-scale, rapid public health response to rabies in an organ recipient and the previously undiagnosed organ donor

This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post-symptom onset. In response to an organ-transplant-related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post-exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation.

The demographics of the United States haemophilia treatment centre social workers: the results of a national survey

Social Workers (SWs) are vital members of the multidisciplinary health care teams at Hemophilia Treatment Centers (HTCs) across the US. However, little research has been done to identify the demographics and qualifications of HTC SWs. In response to this lack of data, a subcommittee from the Social Work Working Group sponsored by the National Hemophilia Foundation conducted a national online survey in 2010. The authors attempted to ascertain the demographics and characteristics of SWs who work at HTCs across the country. The purpose of this article is to report the results of this online survey and evaluate the parameters of SW demographics in HTCs. Electronic surveys were sent to 143 HTC SWs. Ten were excluded and 100 were completed and returned, yielding a 75% response rate. The great majority of HTC SWs are women and almost half are middle-aged (aged 40-59). They represent a highly educated, very experienced group of professionals. When asked why respondents stayed in their positions at the HTCs, answers appeared to highly correlate to factors related to the HTC multidisciplinary team model. The high survey response rate of 75% reflects the interest of HTC SWs in obtaining data that describe and quantify their qualifications. This information may serve as validation of the haemophilia SW role in times of funding cuts. It may also give a basis for the recruitment and retention of SWs in the haemophilia field.

Double-locus sequence typing using porA and peb1A for epidemiological studies of Campylobacter jejuni

Campylobacter jejuni is the leading cause of foodborne bacterial gastroenteritis worldwide. Bacterial typing schemes play an important role in epidemiological investigations to trace the source and route of transmission of the infectious agent by identifying outbreak and differentiating among sporadic infections. In this study, a double-locus sequence typing (DLST) scheme for C. jejuni based on concatenated partial sequences of porA and peb1A genes is proposed. The DLST scheme was validated using 50 clinical and environmental C. jejuni strains isolated from human (C5, H, H15-H19), chicken (CH1-CH15), water (W2-W17), and ovine samples (OV1-OV6). The scheme was found to be highly discriminatory (discrimination index [DI]=0.964) and epidemiologically concordant based on C. jejuni strains studied. The DLST showed discriminatory power above 0.95 and excellent congruence to multilocus sequence typing and can be recommended as a rapid and low-cost typing scheme for epidemiological investigation of C. jejuni. It is suggested that the DLST scheme is suitable for identification of outbreak strains and differentiation of the sporadic infection strains.

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

PURPOSE

Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment.

METHODS

A Perspex thorax phantom was used to simulate a patient. Three wooden "lung" inserts with embedded Perspex "lesions" were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours.

RESULTS

When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs. Breathing patterns with a rest period following expiration resulted in well-defined superior edges and were better aligned using an edge-to-edge alignment technique. In most cases, sinusoidal motion patterns resulted in the closest agreements to true values and the smallest misalignments.

CONCLUSIONS

Strategies are needed to compensate for volume losses at the extremes of motion for both 4DCT MIP and CBCT images for larger and varied amplitudes, and for patterns with rest periods following expiration. Lesions moving greater than 2 cm would warrant larger treatment margins added to the 4DCT MIP ITV to account for the volume being under-represented at the extremes of motion. Lesions moving with a rest period following expiration would be better aligned using an edge-to-edge alignment technique. Sinusoidal patterns represented the ideal clinical scenario, reinforcing the importance of investigating clinically relevant motions and their effects on 4DCT MIP and CBCT volumes. Since most patients do not breathe sinusoidally this may lead to misinterpretation of previous studies using only sinusoidal motion.

Household Task Participation of Children With and Without Physical Disability

We examined household task participation patterns of 46 children and youth with and without physical disability (PD) and explored the effects of age on roles of and expectations for these children in household task participation. Children with PD did not differ significantly from those without PD in the number of household tasks they performed; however, they did require more assistance than those without PD. In both groups, younger children performed significantly fewer household tasks and required significantly more help than older children. These findings further support the discriminant validity of the Children Helping Out: Responsibilities, Expectations, and Supports (Dunn, 2004) measure of household task participation and its use with adolescents. Assessing such participation would help caregivers and practitioners more successfully prepare children and youths with PD for independent living. Considering the roles and opportunities for social participation inherent in many household tasks will contribute to the usefulness of examining such participation.

Murine model of wound healing

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. Impaired wound healing, which occurs in diabetic patients for example, can lead to severe unfavorable outcomes such as amputation. There is, therefore, an increasing impetus to develop novel agents that promote wound repair. The testing of these has been limited to large animal models such as swine, which are often impractical. Mice represent the ideal preclinical model, as they are economical and amenable to genetic manipulation, which allows for mechanistic investigation. However, wound healing in a mouse is fundamentally different to that of humans as it primarily occurs via contraction. Our murine model overcomes this by incorporating a splint around the wound. By splinting the wound, the repair process is then dependent on epithelialization, cellular proliferation and angiogenesis, which closely mirror the biological processes of human wound healing. Whilst requiring consistency and care, this murine model does not involve complicated surgical techniques and allows for the robust testing of promising agents that may, for example, promote angiogenesis or inhibit inflammation. Furthermore, each mouse acts as its own control as two wounds are prepared, enabling the application of both the test compound and the vehicle control on the same animal. In conclusion, we demonstrate a practical, easy-to-learn, and robust model of wound healing, which is comparable to that of humans.

Adverse cardiac remodeling due to maternal low protein diet is associated with alterations in expression of genes regulating glucose metabolism

BACKGROUND AND AIMS

We have previously shown that a maternal low protein (LP) diet during pregnancy in the rat results in adverse ventricular remodeling and contractile deficiencies of the neonatal rat heart. Since pathological cardiac hypertrophy is associated with increased expression of genes involved in glucose handling, this study was undertaken to examine if maternal LP diet alters the expression of genes encoding for some key components of glucose metabolism and uptake, and of the insulin receptor (IR) signal transduction in the heart of male offspring.

METHODS AND RESULTS

We determined the effect of maternal LP and normal diet (90 and 180 g/casein/kg respectively) on IR β-subunit, insulin receptor substrate (IRS)-1, phosphotyrosyl protein phosphatase (PTP) 1B, GLUT4 and phosphatidylinositol (PI) 3-kinase in male rat offspring at 24 h and at 1, 4 and 8 wks post-partum. Quantitative real-time RT-PCR revealed significant age-dependent increases in the expression of IR β-subunit, IRS-1, PTP1B, GLUT4 and PI3-kinase in the LP group with concomitant increases in corresponding protein abundance at 4 wks of age. These changes were associated with increases in left ventricular (LV) internal diameters as well as increases in LV wall thickness.

CONCLUSION

A maternal LP diet can induce increases in the gene expression and protein levels of key components of glucose metabolism and the IR signal transduction pathway in the neonatal rat heart, which may be related to accelerated energy supply, demand and utilization for ventricular remodeling due to compromised contractile performance during early life.

A phantom for testing of 4D-CT for radiotherapy of small lesions

PURPOSE

The use of time-resolved four-dimensional computed tomography (4D-CT) in radiotherapy requires strict quality assurance to ensure the accuracy of motion management protocols. The aim of this work was to design and test a phantom capable of large amplitude motion for use in 4D-CT, with particular interest in small lesions typical for stereotactic body radiotherapy.

METHODS

The phantom of "see-saw" design is light weight, capable of including various sample materials and compatible with several surrogate marker signal acquisition systems. It is constructed of polymethylmethacrylate (Perspex) and its movement is controlled via a dc motor and drive wheel. It was tested using two CT scanners with different 4D acquisition methods: the Philips Brilliance Big Bore CT (helical scan, pressure belt) and a General Electric Discovery STE PET∕CT (axial scan, infrared marker). Amplitudes ranging from 1.5 to 6.0 cm and frequencies of up to 40 cycles per minute were used to study the effect of motion on image quality. Maximum intensity projections (MIPs), as well as average intensity projections (AIPs) of moving objects were investigated and their quality dependence on the number of phase reconstruction bins assessed.

RESULTS

CT number discrepancies between moving and stationary objects were found to have no systematic dependence on amplitude, frequency, or specific interphase variability. MIP-delineated amplitudes of motion were found to match physical phantom amplitudes to within 2 mm for all motion scenarios tested. Objects undergoing large amplitude motions (>3.0 cm) were shown to cause artefacts in MIP and AIP projections when ten phase bins were assigned. This problem can be mitigated by increasing the number of phase bins in a 4D-CT scan.

CONCLUSIONS

The phantom was found to be a suitable tool for evaluating the image quality of 4D-CT motion management technology, as well as providing a quality assurance tool for intercenter∕intervendor testing of commercial 4D-CT systems. When imaging objects with large amplitudes, the completeness criterion described here indicates the number of phase bins required to prevent missing data in MIPs and AIPs. This is most relevant for small lesions undergoing large motions.