Spatial Heterogeneity of the Respiratory Health Impacts of Wildfire Smoke PM2.5 in California

Wildfire smoke fine particles (PM2.5) are a growing public health threat as wildfire events become more common and intense under climate change, especially in the Western United States. Studies assessing the association between wildfire PM2.5 exposure and health typically summarize the effects over the study area. However, health responses to wildfire PM2.5 may vary spatially. We evaluated spatially-varying respiratory acute care utilization risks associated with short-term exposure to wildfire PM2.5 and explored community characteristics possibly driving spatial heterogeneity. Using ensemble-modeled daily wildfire PM2.5, we defined a wildfire smoke day to have wildfire-specific PM2.5 concentration ≥15 μg/m3. We included daily respiratory emergency department visits and unplanned hospitalizations in 1,396 California ZIP Code Tabulation Areas (ZCTAs) and 15 census-derived community characteristics. Employing a case-crossover design and conditional logistic regression, we observed increased odds of respiratory acute care utilization on wildfire smoke days at the state level (odds ratio [OR] = 1.06, 95% confidence interval [CI]: 1.05, 1.07). Across air basins, ORs ranged from 0.88 to 1.57, with the highest effect estimate in San Diego. A within-community matching design and spatial Bayesian hierarchical model also revealed spatial heterogeneity in ZCTA-level rate differences. For example, communities with a higher percentage of Black or Pacific Islander residents had stronger wildfire PM2.5-outcome relationships, while more air conditioning and tree canopy attenuated associations. We found an important heterogeneity in wildfire smoke-related health impacts across air basins, counties, and ZCTAs, and we identified characteristics of vulnerable communities, providing evidence to guide policy development and resource allocation.

Co-synthesis and Electrochemical Investigation of the Nitrogen-Doped Carbon Layer with Metallic Nano Beads on the SiOx Anode for Lithium Secondary Batteries

The high theoretical capacity (∼2000 mAh g-1) of silicon suboxide (SiOx, with 1 < x < 2) can solve the energy density issue of the graphite anode in Li-ion batteries. In addition, it has an advantage in terms of volume expansion or side reactions compared to pure Si or Li metals, which are considered as next-generation anode materials. However, the loading content of SiOx is limited in commercial anodes because of its low cycle stability and initial coulombic efficiency. In this study, a nitrogen-doped carbon layer with Cu beads (N-C/Cu) derived from copper phthalocyanine (CuPc) is applied to a SiOx electrode to improve its electrochemical performance. The SiOx electrode is simultaneously coated with a Cu- and N-doped carbon layer using CuPc. N-C/Cu synergistically enhances the electric conductivity of the electrode, thus improving its electrochemical performance. The SiOx/N-C/Cu composite has better cyclability and higher capacity (1095.5 mAh g-1) than the uncoated electrode, even after 200 cycles in the 0.5 C condition. In full-cell cycling with NCM811 cathodes, the SiOx (60 wt % of SiOx, with a n/p ratio of 1.1) and graphite-mixed (7.8 wt % of SiOx, with a n/p ratio of 1.1) anodes also show improved electrochemical performances in the same conditions.

Aqueous Quaternary Polymer Binder Enabling Long-Life Lithium-Sulfur Batteries by Multifunctional Physicochemical Properties

Lithium-sulfur batteries (LSBs) have been considered promising candidates for application in high-density energy storage systems owing to their high gravimetric and volumetric energy densities. However, LSB technology faces many barriers from the intrinsic properties of active materials that need to be solved to realize high-performance LSBs. Herein, an aqueous binder, that is, PPCP, based on polyethyleneimine (PEI), polyvinylpyrrolidone (PVP), citric acid (CA), and polyethylene oxide (PEO), was developed. The synthesized PPCP binder has incredible mechanical properties, suitable viscosity, and essential functional groups for developing an effective and reliable LSB system. This study demonstrates that CA is crucial in cross-linking PEI-PVP polymer molecules, and PEO segments significantly enhance the flexibility of the PPCP binder; thus, the binder can mechanically stabilize the cathode structure over many operating cycles. The redistribution of active materials during the charge-discharge processes and reduction of the shuttle effect originate from the excellent chemical interactions of PPCP with lithium polysulfides, which is confirmed by the density functional theory calculation, enabling an ultra-long electrochemical cycle life of 1800 cycles with a low decay rate of 0.0278% cycle^-1.

Radiotherapy Quality Assurance in the PORTEC-3 (TROG 08.04) Trial

AIMS

Quality assurance in radiotherapy (QART) is essential to ensure the scientific integrity of a clinical trial. This paper reports the findings of the retrospective QART assessment for all centres that participated in PORTEC-3; a randomised controlled trial that compared pelvic radiotherapy with concurrent chemoradiotherapy to the pelvis followed by adjuvant chemotherapy. The trial showed an overall survival benefit for the addition of the chemotherapy in the management of women with high-risk endometrial cancer.

MATERIALS AND METHODS

Clinicians were invited to upload a randomly selected case/s treated at each of the participating sites. Panel reviewers analysed the contours to certify that the target volumes and organ at risk structures were contoured according to guidelines. The results were categorised into acceptable, minor variation, major variation or unevaluable. The radiotherapy plans were dosimetrically evaluated using the well-established Trans-Tasman Radiation Oncology Group (TROG) protocol.

RESULTS

Between August 2010 and January 2018, data from 146 patients of 686 consecutively treated patients were retrospectively reviewed. All 16 Australia and New Zealand and 71 of 77 international centres uploaded data for evaluation. In total, 3514 dosimetric and contour variables were reviewed. Of these, 3136 variables were deemed acceptable (89.2%), with 335 minor (9.6%) and 43 major variations (1.2%). Major contour variations included the clinical target volume vaginal vault, clinical target volume parametria and differential planning target volume vault expansion.

CONCLUSION

The results of the QART assessment confirmed high uniformity and low rates of both minor and major deviations in contouring and dosimetry in all sites. This supports the safe introduction of the PORTEC-3 treatment protocol into routine clinical practice.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Combined Treatment on an Al Surface to Improve the Metal-Polymer Adhesion Strength

The development of mobile industries and urban transportation today requires nanotechnology for research and processing of metallic surfaces. Here, aluminum alloys (Al) are the most common material with the best physical properties that need to be treated. The advantages of Al in manufacturing are obvious; however, the Al surface is sensitive to the presence of acid or base, and thus protecting the Al surface is mandatory. In this study, Al surfaces have been subjected to a new surface treatment process that includes sandblasting, anodizing, and subsequent post-etching steps. The treated surfaces are evaluated by surface morphology including contact angle measurement and polymer adhesion strength. The adhesion strength of blasted Al-polymer assemblies with and without an anodizing step have been performed with a single lap shear test. This clearly shows the profound effect of the combined treatment process. The results reveal that a combination of high surface roughness and area as well as a thick Al₂O₃ layer with micro-cavities created by a post-etch step can significantly improve the adhesion strength of the Al-polymer. This, in turn, enhances the quality of and longevity of Al surface in production and application.

Future hospital service utilisation in older adults living in long-term residential aged care or the community hospitalised with a fall-related injury

This study identified group-based trajectories of hospitalisation for older adults who were living in residential aged care facilities (RACF) or the community for up to 4 years after an index fall injury hospitalisation. Greater than 3 subsequent fall injury hospitalisations and time until move to a RACF were key predictors of RACF and community-living trajectory group memberships, respectively.

INTRODUCTION

To examine hospital service use trajectories of people aged ≥ 65 years who had a fall injury hospitalisation and were either living in a residential aged care facility (RACF) or the community at the time of the index fall and to identify factors predictive of their trajectory group membership.

METHOD

A group-based trajectory analysis of hospitalisations of people aged ≥ 65 years who had a fall injury hospitalisation during 2008-2009 in New South Wales, Australia, was conducted. Linked hospitalisation and RACF data were examined for a 5-year period. Group-based trajectory models were derived based on number of subsequent hospital admissions following the index fall injury hospitalisation. Multinominal logistic regression examined predictors of trajectory group membership.

RESULTS

There were 24,729 fall injury hospitalisations; 78.8% of fallers were living in the community and 21.2% in a RACF. Five distinct trajectory groups were identified for community-living and four trajectory groups for RACF residents. Key predictors of trajectory group membership for both community-living and RACF residents were age group, number of comorbidities and dementia status. For RACF residents, depression, assistance with activities of daily living and number of subsequent fall injury admissions were also predictors of group membership, with time to move to a RACF a predictor of group membership for community living.

CONCLUSIONS

Identifying trajectories of ongoing hospital use informs targeting of strategies to reduce hospital admissions and design of services to allow community-living individuals to remain as long as possible within their own residence.

Carbon Nitride Phosphorus as an Effective Lithium Polysulfide Adsorbent for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are attracting substantial attention because of their high-energy densities and potential applications in portable electronics. However, an intrinsic property of Li-S systems, that is, the solubility of lithium polysulfides (LiPSs), hinders the commercialization of Li-S batteries. Herein, a new material, that is, carbon nitride phosphorus (CNP), is designed and synthesized as a superior LiPS adsorbent to overcome the issues of Li-S batteries. Both the experimental results and the density functional theory (DFT) calculations confirm that CNP possesses the highest binding energy with LiPS at a P concentration of ∼22% (CNP22). The DFT calculations explain the simultaneous existence of Li-N bonding and P-S coordination in the sulfur cathode when CNP22 interacts with LiPS. By introducing CNP22 into the Li-S systems, a sufficient charging capacity at a low cutoff voltage, that is, 2.45 V, is effectively implemented, to minimize the side reactions, and therefore, to prolong the cycling life of Li-S systems. After 700 cycles, a Li-S cell with CNP22 gives a high discharge capacity of 850 mA h g^-1 and a cycling stability with a decay rate of 0.041% cycle^-1. The incorporation of CNP22 can achieve high performance in Li-S batteries without concerns regarding the LiPS shuttling phenomenon.

Abstract P5-14-11: An estimation of the population survival benefit of first-line chemotherapy and immunotherapy for breast cancer

Purpose:Randomized clinical trials describe the benefit of chemo-and immunotherapy for specific breast cancer patients with selected patient and disease characteristics. However, variability in practice occurs despite evidence-based guidelines [1]. The overall survival benefit for the whole population of breast cancer patients in Australia, if evidence-based guidelines for chemo-and immunotherapy were implemented, is unknown. Our study's purpose was to estimate the overall population survival benefit of routinely using evidence-based practice.

Methods and Materials:Decision trees with evidence-based indications for chemotherapy have been previously defined [2]. Each branch corresponds to a specific cohort who have, or do not have, defined indications for chemotherapy and/or immunotherapy. Chemo -and immunotherapy benefit was defined as the absolute incremental benefit of either chemotherapy and/or immunotherapy over no chemo- and/or immunotherapy for radical and palliative indications. Multiple electronic citation databases were systematically queried, including Medline and the Cochrane Library. In cases where there were multiple sources of the same level of evidence, hierarchical meta-analysis was performed. The benefits of chemo- and immunotherapy were estimated for 1, 5, 10-year survival. To assess the robustness of our estimates, sensitivity analyses were performed.

Results: The estimated 1-year, 5-year and 10-year absolute population-based overall survival benefits of optimally utilized chemo- and immunotherapy for breast cancer in Australia are 1.0% (95% CI, 0.9%-1.2%), 4.4% (95% CI, 4.3%-4.6%) and 5.2% (%-%), respectively. They are summarized in the Table 1.

Estimation of Population Survival Benefit for First Line Chemo- and Immuno TherapyBreast CancerProportion of all cancer in Australia1 year survival benefit (Sensitivity range)5 year survival benefit (Sensitivity range)10 year survival benefit (Sensitivity range)Stage I-II10.0%0.6% (0.6%-0.7%)4.8% (4.6%-5.0%)6.9% (6.7%- 7.2%)Stage III1.6%3.0% (3.0%-3.1%)6.1% (5.8%-6.3%)0%Stage IV0.5%5.3% (5.1%-5.5%)4.9% (4.7%-5.1%)0%Whole Breast Cancer population12.1%1.0% (0.9%-1.2)4.4% (4.3%-4.6%)5.2% (5.0%-5.4%)     

Conclusion: Chemo- and immunotherapy agents improves overall survival in breast cancer at 1-, 5- and 10-years. Chemo-and immunotherapy provides a modest survival benefit to this patient population in Australia when it is used in accordance with guideline recommendations. These outcomes may allow comparison of treatment outcomes in a jurisdiction against what would be considered optimal based on evidence.

1. Fong, A., et al., A comparison of systemic breast cancer therapy utilization in Canada (British Columbia), Scotland (Dundee), and Australia (Western Australia) with models of "optimal" therapy. Breast, 2012. 21(4): p. 562-9.

2. Ng, W., Estimating the optimal chemotherapy utilisation rate as an evidence-based benchmark in cancers of the breast, upper gastrointestinal tract, gynaecological tract, head and neck, kidney, bladder, thyroid and unknown primary., in University of NSW, Faculty of Medicine. 2010, UNSW: Sydney.

Citation Format: Delaney GP, Do V, Ng W, Barton MB. An estimation of the population survival benefit of first-line chemotherapy and immunotherapy for breast cancer [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 P5-14-11.

[Health of gypsy children: medical perinatal care until 6-year-old in Lille]

AIM

This study investigated the health of gypsy children, aged 0-6 years. We focused on pregnancy, birth, medical care, growth, and vaccinations.

PATIENTS AND METHODS

This study was conducted between May and December 2004, comparing a gypsy population group (GP) to a sedentary control group with a relatively low socioeconomic level. Both groups were covered by the CMU (French universal health coverage). This study was based on an oral investigation and each child's health records.

RESULTS

The population consisted of 241 children: 120 GP children and 121 CMU children. In the GP children, pregnancy care was lacking, whereas the CMU group received consistent care at regional university hospital centers. For both populations, 85% of births occurred after a mean 38 weeks and 5 days of amenorrhea by ordinary delivery. GP infants were more often transferred to neonatology centers. They were born and were shorter and weighed less than the CMU infants until 6 years of age. They were breast fed more often. They were hospitalized more often, usually for ORL and gastrointestinal infections. Siblings were more numerous. GP child medical care was deemed satisfactory in 40% of cases vs. 70% for CMU children. The vaccinations status was insufficient, particularly in the GP children.

CONCLUSION

Follow-up of GP should be improved.

Palliative radiation therapy for localized prostate symptoms in hormone refractory prostate cancer

Hormone refractory prostate cancer (HRPCa) can cause debilitating local pelvic symptoms including urinary obstruction, pelvic pain, haematuria and obstructive rectal symptoms. High-dose palliative radiation therapy (RT) is used in many centres to relieve these symptoms despite limited published evidence for its efficacy. This study aimed to assess if RT provides effective and durable palliation for local prostate symptoms in HRPCa. Thirty-five HRPCa patients received RT to the prostate for local symptoms between November 2002 and March 2006. The median dose was 60 Gy in 30 fractions (range 30-70 Gy). Response around a 6-month time point was scored as complete resolution, partial resolution, no change or local progression. Time to progression (defined as new or recurrent symptoms) or persistence of symptoms was recorded. Factors influencing outcome, such as dose, type and number of symptoms and previous transurethral resection, were examined. Twenty-one (60%) patients had a complete (n=3) or partial improvement (n=18) in symptoms. All three complete responders had haematuria as their only symptom. In the eight (23%) patients with local progression, half progressed during treatment and all had done so within 3 months. This series represents a bigger cohort than any reported in published works examining this issue. It suggests that radiation is effective in palliating the local pelvic symptoms in HRPCa.

Prognostic factors in brain metastases: can we determine patients who do not benefit from whole-brain radiotherapy?

AIMS

Whole-brain radiotherapy (WBRT) is a standard treatment recommendation for patients with brain metastases. The goal of treatment is symptom control, which in the short run can be often achieved by steroids. Patients with a short life expectancy may not derive benefit from the addition of radiation. The ability to identify this group would aid the decision of whether to recommend WBRT.

MATERIALS AND METHODS

Data on all patients referred for WBRT to palliative radiotherapy teams at two comprehensive cancer centres were prospectively collected over a 2-year period. The most frequent radiation dose and fractionation was 2000 cGy in 5 fractions over 1 week. Multivariate logistic regression analysis using forward stepwise selection process was used to develop a prediction model for early death (before 8 weeks). The variables considered were sex, performance status, primary disease, weight loss, age, time from primary diagnosis to brain metastases diagnosis, number of metastatic sites and Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) status.

RESULTS

Two hundred and seventy-five patients with brain metastases were assessed. The median follow-up was 19 weeks, and estimated median overall survival was 5.3 months. Multivariate regression revealed Eastern Cooperative Oncology Group (ECOG) performance status and number of metastatic sites to be significant predictors of early death. The odds ratios were 2.38 (95% confidence interval [CI] 1.77-3.19) and 1.39 (95% CI 1.07-1.81), respectively. Sixty-eight per cent of patients could be correctly classified; however, 55% would have been incorrectly predicted to die early.

CONCLUSIONS

Poor performance status and number of metastatic sites are useful predictors of early death. A regression model was highly predictive overall, but this was primarily due to a high negative predictive value of 86%. The ability to predict patients who would die early (positive predictive value) was only 45%. Thus, despite the understanding that we are over-treating a subset of patients, further research is required to identify patients who do not require radiotherapy.

Comparison of histologic grade between initial and follow-up biopsy in untreated, low to intermediate grade, localized prostate cancer

OBJECTIVE

To examine the change of histologic grade of untreated, low to intermediate grade, clinically localized prostate cancer over time on repeat prostate biopsy.

METHODS AND MATERIALS

In a prospective single-arm cohort study, patients were managed with observation alone unless they met pre-defined criteria of disease progression (PSA, clinical or histologic progression). Sixty-seven (54%) of a total of 123 eligible patients underwent follow-up prostate biopsy. Median time to the follow-up biopsy was 22 months (range: 7-60).

RESULTS

On the follow-up biopsy, Gleason score was unchanged in 20 patients (30%), upgraded in 19 (28%), and downgraded in 27 (40%). Twenty-one (31%) had no malignancy on the follow-up biopsy. Sixteen (37%) of 43 patients with < or = 2 positive cores on the initial biopsy had negative follow-up biopsy, while only 2 (11%) out of 18 with > or = 3 positive cores on the initial biopsy did. Five (7%) patients were upgraded to Gleason score 8. There was no correlation between the extent of grade change and baseline variables (age, clinical stage, and initial PSA) as well as PSA doubling time.

CONCLUSIONS

There was no consistent histologic upgrade on the follow-up biopsy at a median of 22 months in untreated, low to intermediate grade, clinically localized prostate cancer.

Urodynamic findings 3 months after radiotherapy in patients treated with conformal external beam radiotherapy for prostate carcinoma

OBJECTIVE

To quantify the effect of radiotherapy (RT) on urodynamic function 3 months after RT in patients with prostate cancer undergoing definitive external beam RT.

PATIENTS AND METHODS

Seventeen patients with clinically localized prostate cancer were accrued into a single-arm prospective study. Sixteen of the patients completed a scheduled multichannel video-urodynamic study at baseline and again 3 months after RT; the urodynamic variables were then compared to assess the nature and extent of urodynamic change caused by RT. Correlations were assessed between these quantitative changes and those in self-assessed qualitative urinary function measured by International Prostate Symptom Score (IPSS), Quality of Life assessment index (QoL) and urinary functional enquiry.

RESULTS

There were significant changes detected by the urodynamic study 3 months after RT in bladder volume at capacity (mean decrease 70 mL) and bladder volume at first sensation when supine (mean decrease 85 mL), and a lower postvoid residual volume (mean 50 mL). There was no significant change in the remaining urodynamic variables (including maximum flow rate and voided volume), nor in bladder compliance, bladder instability or bladder outlet obstruction. The self-assessed qualitative urological function measured by the IPSS, QoL and median urinary frequency/24 h showed no significant change after RT.

CONCLUSIONS

This is the first quantitative study to prospectively evaluate the effect of RT on urodynamics in patients with prostate cancer. Only a few urodynamic variables changed significantly 3 months after RT, while most, including self-assessed qualitative urinary function, did not. This finding corresponds well with the notion that most patients tolerate RT well and that acute RT-induced urinary symptoms resolve successfully, with the return of lower urinary tract function to baseline levels by 3 months after RT.

The role of serial free/total prostate-specific antigen ratios in a watchful observation protocol for men with localized prostate cancer

OBJECTIVE

To examine the change in the free/total prostate specific antigen ratio (f/tPSA) with time and to assess the potential value of serial measurements of f/tPSA as a determinant of disease progression in untreated, low-to-intermediate grade prostate cancer (T1b-T2b N0M0, Gleason score < or = 7 and PSA < or = 15 ng/mL).

PATIENTS AND METHODS

In a prospective single-arm cohort study from November 1995, patients were conservatively managed with watchful observation alone unless they met arbitrarily defined criteria (clinical, histological and biochemical) of disease progression. Patients were followed regularly and underwent blood tests including PSA and f/tPSA. The initial and mean f/tPSA and the rate of change of f/tPSA with time were evaluated against the rate constant for the PSA doubling time (PSATd). Correlation analyses were used to evaluate any association between baseline clinical variables and either the rate of change of f/tPSA or initial f/tPSA.

RESULTS

As of December 2000, 161 of a total of 206 accrued patients had three or more f/tPSA measurements and formed the basis of the study (median age 70 years; median follow-up 2.7 years). The median initial f/tPSA was 0.16; there was a significant negative correlation between this value and the initial total PSA. The mean f/tPSA and rate of change of f/tPSA with time were significantly negatively correlated with the rate constant for PSATd. Also, the rate of change of f/tPSA correlated negatively with clinical T stage, but not with other baseline variables, including initial PSA, age and Gleason score.

CONCLUSION

The f/tPSA in men with untreated, clinically localized prostate cancer varied widely. The negative correlation between the rate of change of f/tPSA with time and rate constant for PSATd suggests that both might provide valuable information to allow clinicians to develop a strategy for optimizing the timing of therapeutic intervention for those patients choosing watchful observation alone.

The effect of waiting for radiotherapy for grade III/IV gliomas

AIM

To determine the effect of waiting time for radiotherapy on the overall survival of patients with high-grade gliomas.

METHODS

We examined records of patients with grade III/IV gliomas who were referred to radiotherapy after surgery or biopsy - ECOG <3, any age, radical intent or palliative intent with dose >50 Gy, no interstitial or radiosurgery boost. Waiting time was defined in two ways, time from biopsy to radiotherapy and time from presentation to radiotherapy department to start of radiotherapy.

RESULTS

There were 182 patients in the study having a median survival of 8.5 months, with a median follow up of 10.5 months. The group comprised of 63 (35%) grade III and 119 (65%) grade IV gliomas. Median times and ranges from biopsy and presentation to treatment were 26 days (4-78 days) and 15 days (1-62 days), respectively. The median dose was 60 Gy in a median of 30 fractions over a median of 46 days. Tumour progression before and during radiotherapy occurred in seven patients (4%) and 19 patients (11%), respectively. One hundred and seventy-nine patients died of disease. The seven patients whose tumour progressed before radiotherapy were excluded from the analysis of prognostic variables. In a multivariate analysis the variables that were significantly associated with worse survival were older age, reduced dose and prolonged waiting time from presentation. The risk of death increased by 2% for each day of waiting for radiotherapy.

CONCLUSION

The study showed longer waiting time from presentation at radiotherapy department to treatment to be a significant predictor of overall survival for patients with high-grade glioma.

Differential regulation of mitogen-activated protein/ERK kinase (MEK)1 and MEK2 and activation by a Ras-independent mechanism

Mitogen-activated protein (MAP)/ERK kinase (MEK)1 and MEK2 are the upstream activators of the MAP kinases, ERK1 and ERK2. MEK1 and MEK2 are approximately 85% identical in sequence but have unique inserts in their C-terminal domains. MEK isoform-specific antibodies were used to examine expression and regulation of each enzyme. MEK1 and MEK2 were expressed in approximately equal amounts in several cell lines; in some, MEK1 was present in slight excess. Activation of tyrosine kinase-containing receptors, heterotrimeric G proteins, and protein kinase C enhanced the activities of both MEK isoforms in 293 and PC12 cells. AIF4-stimulated both MEK1 and MEK2 in PC12 cells expressing a dominant interfering Ras mutant that prevents nerve growth factor-dependent activation of the cascade. Carbachol also stimulated the pathway in these cells. Thus, in addition to their ability to activate Ras/Raf and the downstream ERK pathway, heterotrimeric G proteins also appear to trigger a Ras-independent mechanism to regulate this kinase cascade. In U373, Chinese hamster ovary (CHO), and INS-1 cells, MEK1 was activated by regulators of ERKs, while MEK2 was not. These data suggest that, like the MAP kinases ERK1 and ERK2, in some cell settings the two similar MEK isoforms are differentially regulated.