bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Mental Health Workforce in Washington State: Using State Licensing Data to Examine Provider Supply in Rural and Urban Areas
Authors: Baldwin Laura‐Mae , Patanian Miriam M. , Larson Eric H. , Lishner Denise M. , Mauksch Larry B. , Katon Wayne J. , Walker Edward , Hart L. Gary
Published: October 2006

ABSTRACT: Context:Ensuring an adequate mental health provider supply in rural and urban areas requires accessible methods of identifying provider types, practice locations, and practice productivity.Purpose:To identify mental health shortage areas using existing licensing and survey data.Methods:The 1998‐1999 Washington State Department of Health files on credentialed health professionals linked with results of a licensure renewal survey, 1990 US Census data, and the results of the 1990‐1992 National Comorbidity Survey were used to calculate supply and requirements for mental health services in 2 types of geographic units in Washington state—61 rural and urban core health service areas and 13 larger mental health regions. Both the number of 9 types of mental health professionals and their full‐time equivalents (FTEs) per 100,000 population measured supply in the health service areas and mental health regions.Findings:Notable shortages of mental health providers existed throughout the state, especially in rural areas. Urban areas had 3 times the psychiatrist FTEs per 100,000 and more than 1.5 times the nonpsychiatrist mental health provider FTEs per 100,000 as rural areas. More than 80% of rural health service areas had at least 10% fewer psychiatrist FTEs and nonpsychiatrist mental health provider FTEs than the state ratio (10.4 FTEs per 100,000 and 306.5 FTEs per 100,000, respectively). Ten of the 13 mental health regions were more than 10% below the state ratio of psychiatrist FTEs per 100,000.Conclusions:States gathering a minimum database at licensure renewal can identify area‐specific mental health care shortages for use in program planning.
Posttraumatic Stress Disorder in Rural Primary Care: Improving Care for Mental Health Following Bioterrorism
Authors: Tsao Jennie C. I. , Dobalian Aram , Wiens Brenda A. , Gylys Julius A. , Evans Garret D.
Published: October 2006

ABSTRACT: 
Context: Recent bioterrorist attacks have highlighted the critical need for health care organizations to prepare for future threats. Yet, relatively little attention has been paid to the mental health needs of rural communities in the wake of such events. A critical aspect of bioterrorism is emphasis on generating fear and uncertainty, thereby contributing to increased needs for mental health care, particularly for posttraumatic stress disorder, which has been estimated to occur in 28% of terrorism survivors. Purpose: Prior experience with natural disasters suggests that first responders typically focus on immediate medical trauma or injury, leaving rural communities to struggle with the burden of unmet mental health needs both in the immediate aftermath and over the longer term. The purpose of the present article is to draw attention to the greater need to educate rural primary care providers who will be the frontline providers of mental health services following bioterrorism, given the limited availability of tertiary mental health care in rural communities. Methods: We reviewed the literature related to bioterrorist events and mental health with an emphasis on rural communities. Findings and Conclusions: Public health agencies should work with rural primary care providers and mental health professionals to develop educational interventions focused on posttraumatic stress disorder and other mental disorders, as well as algorithms for assessment, referral, and treatment of postevent psychological disorders and somatic complaints to ensure the availability, continuity, and delivery of quality mental health care for rural residents following bioterrorism and other public health emergencies.
Rural Illinois Hospital Chief Executive Officers’ Perceptions of Provider Shortages and Issues in Rural Recruitment and Retention
Authors: Glasser Michael , Peters Karen , MacDowell Martin
Published: October 2006

ABSTRACT: 
Background: It is important to assess rural health professions workforce needs and identify variables in recruitment and retention of rural health professionals. Purpose: This study examined the perspectives of rural hospital chief executive officers (CEOs) regarding workforce needs and their views of factors in the recruitment and retention process. Methods: A survey was mailed to CEOs of 28 Illinois rural hospitals, in towns ranging from 3,396 to 33,530 in population size. The survey addressed CEO perceptions of number of physicians needed by specialty, need for other health professionals, and variables important to recruitment and retention. Findings: Twenty‐two CEOs (79%) responded to the survey. Eighty‐six percent indicated a physician shortage in the community, with 64% reporting the need for family physicians. CEOs also indicated the need for physicians in obstetrics‐gynecology, general and orthopedic surgery, general internal medicine, cardiology, and psychiatry. In terms of needs for other health professionals, most often mentioned were registered nurses (91%), pharmacists (64%), and nurses’ aides (46%). Related to recruitment and retention, most often mentioned by the CEOs was community attractiveness in general, followed by practice and physician career opportunities. Conclusions: CEOs offer 1 important perspective on health professions needs, recruitment, and retention in rural communities. While expressing a range of opinions, rural hospital CEOs clearly indicate the need for more primary care physicians, call for an increased capacity in nursing, and point to community development as a key factor in recruitment and retention.
Demographic and Psychosocial Characteristics of Smokers and Nonsmokers in Low‐Socioeconomic Status Rural Appalachian 2‐Parent Families in Southern West Virginia
Authors: Song Hana , Fish Margaret
Published: October 2006

ABSTRACT: 
Context: Rural Appalachian women living in poverty have a high prevalence of prenatal smoking; yet, few studies have examined this issue. Purpose: To investigate the demographic and psychosocial characteristics of prenatal smokers and nonsmokers in low–socioeconomic status, rural Appalachian 2‐parent families. Methods: During an 18‐month period, two thirds of eligible low–socioeconomic status prenatal patients were recruited for a longitudinal study from a community health clinic in a rural West Virginia county. Data for the present report are from 92 women with a husband/partner (37 smokers and 55 nonsmokers) who completed a prenatal interview in the last trimester of pregnancy. This interview included demographics, personality traits, self‐esteem problems, social support, and marital/partner relationship. Findings: Compared to nonsmokers, prenatal smokers were less likely to have completed high school, less extroverted, and also had lower self‐esteem, less intimate support, and more negative marital relationship. Conclusions: High school graduation and variables related to positive personality and supportive relationships distinguished smokers from nonsmokers. The causal relationship between these variables and prenatal smoking requires more work in larger and varied populations, and this study provides some direction for ongoing longitudinal investigation.
Deblurring of breathing motion artifacts in thoracic PET images by deconvolution methods
Authors: Naqa Issam El , Low Daniel A. , Bradley Jeffrey D. , Vicic Milos , Deasy Joseph O.
Published: October 2006

In FDG‐PET imaging of thoracic tumors, blurring due to breathing motion often significantly degrades the quality of the observed image, which then obscures the tumor boundary. We demonstrate a deblurring technique that combines patient‐specific motion estimates of tissue trajectories with image deconvolution techniques, thereby partially eliminating breathing‐motion induced artifacts. Two data sets were used to evaluate the methodology including mobile phantoms and clinical images. The clinical images consist of PET/CT co‐registered images of patients diagnosed with lung cancer. A breathing motion model was used to locally estimate the location‐dependent tissue location probability function (TLP) due to breathing. The deconvolution process is carried by an expectation‐maximization (EM) iterative algorithm using the motion‐based TLP. Several methods were used to improve the robustness of the deblurring process by mitigating noise amplification and compensating for motion estimate uncertainties. The mobile phantom study with controlled settings demonstrated significant reduction in underestimation error of concentration in high activity case without significant superiority between the different applied methods. In case of medium activity concentration (moderate noise levels), less improvement was reported (10%–15% reduction in underestimation error relative to 15%–20% reduction in high concentration). Residual denoising using wavelets offered the best performance for this case. In the clinical data case, the image spatial resolution was significantly improved, especially in the direction of greatest motion (cranio‐caudal). The EM algorithm converged within 15 and 5 iterations in the large and small tumor cases, respectively. A compromise between a figure‐of‐merit and entropy minimization was suggested as a stopping criterion. Regularization techniques such as wavelets and Bayesian methods provided further refinement by suppressing noise amplification. Our initial results show that the proposed method provides a feasible framework for improving PET thoracic images, without the need for gated/4‐D PET imaging, when 4‐D CT is available to estimate tumor motion.
Influence of cassette type on the DQE of CR systems
Authors: Monnin P. , Holzer Z. , Wolf R. , Neitzel U. , Vock P. , Gudinchet F. , Verdun F. R.
Published: October 2006

In our recent paper by Monnin et al. [Med. Phys., 411–420 (2006)], an objective analysis of the relative performance of a computed radiography (CR) system using both standard single‐side (ST‐VI) and prototype dual‐side read (ST‐BD) plates was reported. The presampled modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) for the systems were determined at three different beam qualities representative of paediatric chest radiography, at an entrance detector air kerma of . Experiments demonstrated that, compared to the standard single‐side read system, the MTF for the dual‐side read system was slightly reduced, but a significant decrease in image noise resulted in a marked increase in DQE in the low spatial frequency range. However, the DQE improvement for the ST‐BD plate decreased with increasing spatial frequency, and, at spatial frequencies above , the DQE of the dual‐side read system was lower than that of the single‐side one.
CT volumetry of the skeletal tissues
Authors: Brindle James M. , Alexandre Trindade A. , Pichardo Jose C. , Myers Scott L. , Shah Amish P. , Bolch Wesley E.
Published: October 2006

Computed tomography (CT) is an important and widely used modality in the diagnosis and treatment of various cancers. In the field of molecular radiotherapy, the use of spongiosa volume (combined tissues of the bone marrow and bone trabeculae) has been suggested as a means to improve the patient‐specificity of bone marrow dose estimates. The noninvasive estimation of an organ volume comes with some degree of error or variation from the true organ volume. The present study explores the ability to obtain estimates of spongiosa volume or its surrogate via manual image segmentation. The variation among different segmentation raters was explored and found not to be statistically significant ( value ). Accuracy was assessed by having several raters manually segment a polyvinyl chloride (PVC) pipe with known volumes. Segmentation of the outer region of the PVC pipe resulted in mean percent errors as great as while segmentation of the pipe's inner region resulted in mean percent errors within . Differences between volumes estimated with the high‐resolution CT data set (typical of ex vivo skeletal scans) and the low‐resolution CT data set (typical of in vivo skeletal scans) were also explored using both patient CT images and a PVC pipe phantom. While a statistically significant difference ( value ) between the high‐resolution and low‐resolution data sets was observed with excised femoral heads obtained following total hip arthroplasty, the mean difference between high‐resolution and low‐resolution data sets was found to be only 1.24 and for spongiosa and cortical bone, respectively. With respect to differences observed with the PVC pipe, the variation between the high‐resolution and low‐resolution mean percent errors was a high as for the outer region volume estimates and only as high as for the inner region volume estimates. The findings from this study suggest that manual segmentation is a reasonably accurate and reliable means for the in vivo estimation of spongiosa volume. This work also provides a foundation for future studies where spongiosa volumes are estimated by various raters in more comprehensive CT data sets.
A semi‐automatic method for peak and valley detection in free‐breathing respiratory waveforms
Authors: Lu Wei , Nystrom Michelle M. , Parikh Parag J. , Fooshee David R. , Hubenschmidt James P. , Bradley Jeffrey D. , Low Daniel A.
Published: October 2006

The existing commercial software often inadequately determines respiratory peaks for patients in respiration correlated computed tomography. A semi‐automatic method was developed for peak and valley detection in free‐breathing respiratory waveforms. First the waveform is separated into breath cycles by identifying intercepts of a moving average curve with the inspiration and expiration branches of the waveform. Peaks and valleys were then defined, respectively, as the maximum and minimum between pairs of alternating inspiration and expiration intercepts. Finally, automatic corrections and manual user interventions were employed. On average for each of the 20 patients, 99% of 307 peaks and valleys were automatically detected in . This method was robust for bellows waveforms with large variations.
Practical cone‐beam lambda tomography
Authors: Yu Hengyong , Ye Yangbo , Wang Ge
Published: October 2006

As a potentially important technology for medical x‐ray computed tomography (CT), lambda tomography (LT) is to reconstruct a gradient‐like image only from local projection data. Based on our recently derived exact fan‐beam LT formula, [H. Y. Gu and G. Wang, Int. J. Biomed. Imaging 2006(1), 1–9 (2006)] here we propose a practical cone‐beam LT algorithm for LT reconstruction from local data collected along an arbitrary smooth three‐dimensional curve. A key step in our algorithm is to determine an appropriate vector perpendicular to the line connecting the x‐ray source and an image point. The algorithm is implemented assuming an equispatial planar detector and a nonstandard spiral trajectory. The numerical simulation results demonstrate the merits of our method.
A practical three‐dimensional dosimetry system for radiation therapy
Authors: Guo Pengyi , Adamovics John , Oldham Mark
Published: October 2006

There is a pressing need for a practical three‐dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE™) and a commercial optical computed tomography (CT) scanning system (OCTOPUS™). PRESAGE™ is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light‐scattering contrast. An evaluation of the performance and viability of the PRESAGE™/OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of , geometric accuracy within , and high reconstruction linearity (with a value of 0.9979 and a standard error of estimation of ) relative to independent measurement. The overall performance of the PRESAGE™/OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with EBT film and the calculated dose from a commissioned planning system. The “measured” dose distribution in a cylindrical PRESAGE™ dosimeter ( diameter and height) was determined by optical‐CT, using a filtered backprojection reconstruction algorithm. A three‐way Gamma map comparison (4% dose difference and distance to agreement), between the PRESAGE™, EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE™ dosimeter ( of radius). The EBT and PRESAGE™ distributions agreed more closely with each other than with the calculated plan, consistent with penumbral blurring in the planning data which was acquired with an ion chamber. In summary, our results support the conclusion that the PRESAGE™ optical‐CT combination represents a significant step forward in 3D dosimetry, and provides a robust, clinically effective and viable high‐resolution relative 3D dosimetry system for radiation therapy.
Amorphous selenium flat panel detectors for digital mammography: Validation of a NPWE model observer with CDMAM observer performance experiments
Authors: Segui Jennifer A. , Zhao Wei
Published: October 2006

Model observers have been developed which incorporate a specific imaging task, system performance, and human observer characteristics and can potentially overcome some of the limitations in using detective quantum efficiency for optimization and comparison of detectors. In this paper, a modified nonprewhitening matched filter (NPWE) model observer was developed and validated to predict object detectability for an amorphous selenium direct flat‐panel imager (FPI) where aliasing is severe. A preclinical digital mammography FPI with pixel size was used in this investigation. Its physical imaging properties including modulation transfer function (MTF), noise power spectrum, and DQE were fully characterized. An observer performance study was conducted by imaging the CDMAM 3.4 contrast‐detail phantom designed specifically for digital mammography and presenting these images to a panel of seven observers. X‐ray attenuation and scatter due to the phantom were determined experimentally for use in development of the model observer. The observer study results were analyzed via threshold averaging and signal detection theory (SDT) based techniques to produce contrast‐detail curves where threshold contrast is plotted as a function of disk diameter. Validity of the model was established using SDT analysis of the experimental data. The effect of aliasing on the detectability of small diameter disks was determined using the NPWE model observer. The signal spectrum was calculated using the presampling MTF of the detector with and without including the aliased terms. Our results indicate that the NPWE model based on Fourier domain parameters provides reasonable prediction of object detectability for the signal‐known‐exactly task in uniform image noise for direct FPI.
Progress toward a microradiation therapy small animal conformal irradiator
Authors: Stojadinovic Strahinja , Low Daniel A. , Vicic Milos , Mutic Sasa , Deasy Joseph O. , Hope Andrew J. , Parikh Parag J. , Grigsby Perry W.
Published: October 2006

Microradiation therapy (microRT) systems are being designed to provide conformal radiation therapy to small animals enabling quantitative radiation response evaluation. We used a Monte Carlo approach to estimate the radiation dose distributions from proposed blueprints and developed a beam model to aid in the microRT system design process. This process was applied to a prototype irradiator that uses a small (3 mm long and 3 mm in diameter), cylindrical, high‐activity source delivering the radiation beam using custom‐fabricated tungsten collimators. The BEAMnrc Monte Carlo code was used to simulate dose distributions from these prototype collimators. Simulations were performed at three source‐to‐surface distances (50, 60, and 70 mm), and with five circular field sizes (5, 7.5, 10, 12.5, and 15 mm). A dose to a water phantom with voxel spacing was computed. A multiparameter dose calculation algorithm was developed to efficiently and accurately calculate doses for treatment planning exercises. The parametrization was selected so that the parameters varied smoothly as a function of depth, source‐to‐surface distance, and field size, allowing interpolation for geometries that were not simulated using the Monte Carlo simulation. Direct comparison of the model with the Monte Carlo simulations showed that the variations were within 5% error for field sizes larger than 10 mm, and up to 10% for smaller field sizes.
Estimation of effective doses to adult and pediatric patients from multislice computed tomography: A method based on energy imparted
Authors: Theocharopoulos Nicholas , Damilakis John , Perisinakis Kostas , Tzedakis Antonis , Karantanas Apostolos , Gourtsoyiannis Nicholas
Published: October 2006

The purpose of this study is to provide a method and required data for the estimation of effective dose values to adult and pediatric patients from computed tomography (CT) scans of the head, chest abdomen, and pelvis, performed on multi‐slice scanners. Mean section radiation dose to cylindrical water phantoms of varying radius normalized over CT dose index free‐in‐air were calculated for the head and body scanning modes of a multislice scanner with use of Monte Carlo techniques. Patients were modeled as equivalent water phantoms and the energy imparted to simulated pediatric and adult patients was calculated on the basis of measured values. Body region specific energy imparted to effective dose conversion coefficients for adult male and female patients were generated from previous data. Effective doses to patients aged newborn to adult were derived for all available helical and axial beam collimations, taking into account age specific patient mass and scanning length. Depending on high voltage, body region, and patient sex, values ranged from for head scans to for chest scans. When scanned with the same technique factors as the adults, pediatric patients absorb as little as 5% of the energy imparted to adults, but corresponding effective dose values are up to a factor of 1.6 higher. On average, pediatric patients absorb 44% less energy per examination but have a 24% higher effective dose, compared with adults. In clinical practice, effective dose values to pediatric patients are 2.5 to 10 times lower than in adults due to the adaptation of tube current. A method is provided for the calculation of effective dose to adult and pediatric patients on the basis of individual patient characteristics such as sex, mass, dimensions, and density of imaged anatomy, and the technical features of modern multislice scanners. It allows the optimum selection of scanning parameters regarding patient doses at CT.
The management of respiratory motion in radiation oncology report of AAPM Task Group 76a)
Authors: Keall Paul J. , Mageras Gig S. , Balter James M. , Emery Richard S. , Forster Kenneth M. , Jiang Steve B. , Kapatoes Jeffrey M. , Low Daniel A. , Murphy Martin J. , Murray Brad R. , Ramsey Chester R. , Van Herk Marcel B. , Vedam S. Sastry , Wong John W. , Yorke Ellen
Published: October 2006

This document is the report of a task group of the AAPM and has been prepared primarily to advise medical physicists involved in the external‐beam radiation therapy of patients with thoracic, abdominal, and pelvic tumors affected by respiratory motion. This report describes the magnitude of respiratory motion, discusses radiotherapy specific problems caused by respiratory motion, explains techniques that explicitly manage respiratory motion during radiotherapy and gives recommendations in the application of these techniques for patient care, including quality assurance (QA) guidelines for these devices and their use with conformal and intensity modulated radiotherapy. The technologies covered by this report are motion‐encompassing methods, respiratory gated techniques, breath‐hold techniques, forced shallow‐breathing methods, and respiration‐synchronized techniques. The main outcome of this report is a clinical process guide for managing respiratory motion. Included in this guide is the recommendation that tumor motion should be measured (when possible) for each patient for whom respiratory motion is a concern. If target motion is greater than , a method of respiratory motion management is available, and if the patient can tolerate the procedure, respiratory motion management technology is appropriate. Respiratory motion management is also appropriate when the procedure will increase normal tissue sparing. Respiratory motion management involves further resources, education and the development of and adherence to QA procedures.
Impact of a community based fire prevention intervention on fire safety knowledge and behavior in elementary school children: Figure 1
Authors: Hwang V , Duchossois G P , Garcia-Espana J F , Durbin D R
Published: October 2006

The objective of this study was to determine the impact of a community based fire prevention intervention directed only to parents on the fire safety knowledge and behavior in elementary school children. This was a prospective, quasi-randomized controlled study in which third and fourth grade students from two elementary schools in an urban, poor, minority community completed knowledge/behavior surveys at baseline and following completion of the intervention. The intervention group received an in-home visit from fire department personnel who installed free lithium smoke detectors and provided a fire escape plan. After accounting for a small difference in baseline summary scores of knowledge and behavior between the control and intervention groups, this study found a modest improvement in fire safety behavior among children whose families received a fire prevention intervention reflecting a change in household fire safety practices. However, there was no significant change in fire safety knowledge.
Unspecified falls among youth: predictors of coding specificity in the emergency department
Authors: Kaida A K , Marko J , Hagel B , Lightfoot P , Sevcik W , Rowe B H
Published: October 2006

Background:Deficiencies in emergency department (ED) charting is a common international problem. While unintentional falls account for the largest proportion of injury related ED visits by youth, insufficient charting details result in more than one third of these falls being coded as “unspecified”. Non-specific coding compromises the utility of injury surveillance data.

Objective:To re-examine the ED charts of unspecified youth falls to determine the possibility of assigning more specific codes.

Methods:400 ED charts for youth (aged 0–19 years) treated at four EDs in an urban Canadian health region between 1997 and 1999 and coded as “Other or unspecified fall” (ICD-9 E888) were randomly selected. A structured chart review was completed and a blinded nosologist recoded the cause of injury using the extracted data. Differences in coding specificity were compared with the original data, and logistic regression was undertaken to examine variables that predicted assignment of a specific E-code.

Results:A more specific code was assigned to 46% of cases initially coded as unspecified. Of these, 73% were recoded as “Slips, trips, and stumbles” (E885), which still lacks the specificity required for injury prevention planning; 2% of charts had no fall documented. Multivariate analysis revealed that dichotomized injury severity (adjusted odds ratio (OR) = 1.75 (95% confidence interval, 1.11 to 2.78)), arrival at the ED by ambulance (adjusted OR = 5.41 (1.07 to 27.0)), and the availability of nurse’s notes or triage forms, or both, in the chart (adjusted OR = 3.75 (2.17 to 6.45)) were the strongest predictors of a more specific E-code assignment.

Conclusions:Deficiencies in both chart documentation and coding specificity contribute to the use of non-specific E-codes. More comprehensive triage coding, improved chart documentation, and alternative methods of data collection in the acute care setting are required to improve ED injury surveillance initiatives.
Evaluation of Safe Kids Week 2004: Age 4 to 9? It’s Booster Seat Time!
Authors: Howard A , Beben N , Rothman L , Fiissel D , MacArthur C
Published: October 2006

Objective:To assess the effectiveness of a national one week media campaign promoting booster seat use.

Design:Pre-test, post-test design based on nationally representative random digit dialing telephone survey, with control for exposure to campaign.

Setting:Canada.

Subjects:Parents of children aged 4–9 years.

Interventions:During a one week campaign in May 2004, information on booster seat use was distributed via a national media campaign, retail stores, medical clinics, and community events. Information included pamphlets with guidelines for booster seat use, as well as a growth chart (designed by Safe Kids Canada) to assist parents in determining if their child should be using a booster seat. Assessing seat belt fit was described in detail on the growth chart.

Main outcome measures:Knowledge, attitudes, and self-reported behaviors regarding booster seat use.

Results:Respondents in the group exposed to the campaign were twice as likely to report using a booster seat with lap and shoulder belt for their child (47%), compared to those in the pre-test (24%) and the unexposed (23%) groups (p<0.001). However, only small differences in general knowledge regarding booster seat use were found between the groups.

Conclusions:A one week national media campaign substantially increased self-reported use of booster seats. Parents did not remember details of the campaign content, but did remember implications for their own child.
Identification of strategies to prevent death after pesticide self-poisoning using a Haddon matrix: Table 1
Authors: Eddleston M , Buckley N A , Gunnell D , Dawson A H , Konradsen F
Published: October 2006

Despite pesticide self-poisoning causing around 300 000 deaths each year in the rural Asia Pacific region, no comprehensive public health response has yet been formulated. The authors have developed a Haddon matrix to identify factors that increase the risk of fatal rather than non-fatal pesticide self-poisoning in Sri Lanka. Many important host factors such as age, gender, and genetics are not alterable; factors that could be changed—alcohol use and mental health—have previously proved difficult to change. Interventions affecting agent or environmental factors may be easier to implement and more effective, in particular those limiting the human toxicity and accessibility of the pesticides, and the quality, affordability, and accessibility of health care in the community. Controlled studies are required to identify effective strategies for prevention and harm minimization and to garner political support for making the changes necessary to reduce this waste of life. Lessons learnt from Sri Lanka are likely to be highly relevant for much of rural Asia.
Car manufacturers and global road safety: a word frequency analysis of road safety documents: Table 1
Authors: Roberts I , Wentz R , Edwards P
Published: October 2006

Objective:The World Bank believes that the car manufacturers can make a valuable contribution to road safety in poor countries and has established the Global Road Safety Partnership (GRSP) for this purpose. However, some commentators are sceptical. The authors examined road safety policy documents to assess the extent of any bias.

Design:Word frequency analyses of road safety policy documents from the World Health Organization (WHO) and the GRSP.

Main outcome measures:The relative occurrence of key road safety terms was quantified by calculating a word prevalence ratio with 95% confidence intervals. Terms for which there was a fourfold difference in prevalence between the documents were tabulated.

Results:Compared to WHO’sWorld report on road traffic injury prevention, the GRSP road safety documents were substantially less likely to use the words speed, speed limits, child restraint, pedestrian, public transport, walking, and cycling, but substantially more likely to use the words school, campaign, driver training, and billboard.

Conclusions:There are important differences in emphasis in road safety policy documents prepared by WHO and the GRSP. Vigilance is needed to ensure that the road safety interventions that the car industry supports are based on sound evidence of effectiveness.
The criminal purchase of firearm ammunition
Authors: Tita G E , Braga A A , Ridgeway G , Pierce G L
Published: October 2006

Objective:Laws that prohibit certain individuals from owning firearms also pertain to ammunition. Whereas retail sales of firearms to criminals are regularly disrupted by instant background checks, sales of ammunition are essentially unchecked and the rate at which criminals acquire ammunition is unknown. This research describes the ammunition market and estimates the rate at which criminals are acquiring ammunition.

Design:Criminal background checks conducted on individuals purchasing ammunition in the City of Los Angeles in April and May 2004.

Setting:Los Angeles, CA, USA.

Subjects:Ammunition purchasers.

Main outcome measures:Criminal activity that prohibits one from owning, purchasing, or possessing ammunition.

Results:2.6% (95% CI 1.9% to 3.2%) of ammunition purchasers had a prior felony conviction or another condition that prohibited them from possessing ammunition. During the study period prohibited possessors purchased 10 050 rounds of ammunition in Los Angeles.

Conclusions:These estimates suggest that monitoring ammunition transactions may help reduce the supply of ammunition to criminals and the frequency of injuries from felonious gun assaults. Such a record can also provide information for generating leads on illegal firearm possession.
INFLUENCE OF POLARIZATION CHARGES AND ELECTRON TRAPPING IN THE BUFFER LAYER IN WURTZITE PHASE AlGaN/GaN HFETs
Authors: ARABSHAHI H. , GHASEMIAN M. H.
Published: October 2006

Ensemble Monte Carlo simulations have been performed to model electron transport in wurtzite phase AlGaN/GaN heterojunction FETs. Planar Al 0.2 Ga 0.8 N/GaN HFET structures with a 78 nm Al 0.2 Ga 0.8 N pseudomorphically strained layer were simulated, where the spontaneous and piezoelectric polarization effects were taken into account. Trap centers located in the buffer layer has also been simulated to include the effect of trapping levels on current collapse in GaN HFETs. The polarization effects was shown to not only increase the current density, but also improve the electron transport in the interface layer by inducing a higher electron density to the positive polarized sheet and away from the buffer layer.
RADIATIVE PHASE TRANSITIONS AND CASIMIR EFFECT INSTABILITIES
Authors: SIVASUBRAMANIAN S. , WIDOM A. , SRIVASTAVA Y. N.
Published: October 2006

Molecular quantum electrodynamics lead to photon frequency shifts and thus to changes in condensed matter free energies (often called the Casimir effect). Strong quantum electrodynamic coupling between radiation and molecular motions can lead to an instability beyond which one or more photon oscillators undergo a displacement phase transition. We show that the phase boundary of the transition can be located by a Casimir free energy instability.
Involvement of Mitochondrial and Akt Signaling Pathways in Augmented Apoptosis Induced by a Combination of Low Doses of Celecoxib and N-(4-Hydroxyphenyl) Retinamide in Premalignant Human Bronchial Epithelial Cells
Authors: Schroeder Claudia P. , Kadara Humam , Lotan Dafna , Woo Jong K. , Lee Ho-Young , Hong Waun Ki , Lotan Reuben
Published: October 2006

Celecoxib is being evaluated as a chemopreventive agent. However, its mechanism of action is not clear because high doses were used for in vitro studies to obtain antitumor effects. We found that celecoxib inhibited the growth of premalignant and malignant human bronchial epithelial cells with IC50 values between 8.9 and 32.7 μmol/L, irrespective of cyclooxygenase-2 (COX-2) expression. Normal human bronchial epithelial cells were less sensitive to celecoxib. Because these concentrations were higher than those attainable in vivo (≤5.6 μmol/L), we surmised that combining celecoxib with the synthetic retinoid N-(4-hydroxyphenyl) retinamide (4HPR) might improve its efficacy. Treatment of premalignant lung cell lines with combinations of clinically relevant concentrations of celecoxib (≤5 μmol/L) and 4HPR (≤0.25 μmol/L) resulted in greater growth inhibition, apoptosis induction, and suppression of colony formation than did either agent alone. This combination also decreased the levels of Bcl-2, induced the release of mitochondrial cytochrome c, activated caspase-9 and caspase-3, and induced cleavage of poly(ADP-ribose)polymerase at concentrations at which each agent alone showed no or minimal effects. Furthermore, combinations of celecoxib and 4HPR suppressed the phosphorylation levels of serine/threonine kinase Akt and its substrate glycogen synthase kinase-3β more effectively than the single agents did. Accordingly, overexpression of constitutively active Akt protected bronchial epithelial cells from undergoing apoptosis after incubation with both celecoxib and 4HPR. These findings indicate that activation of the mitochondrial apoptosis pathway and suppression of the Akt survival pathway mediate the augmented apoptosis and suggest that this combination may be useful for lung cancer chemoprevention. (Cancer Res 2006; 66(19): 9762-70)
Genotoxic Stress Induces Coordinately Regulated Alternative Splicing of the p53 Modulators MDM2 and MDM4
Authors: Chandler Dawn S. , Singh Ravi K. , Caldwell Lisa C. , Bitler Jaquelyn L. , Lozano Guillermina
Published: October 2006

The tumor suppressor protein p53 is a transcription factor that induces G1 arrest of the cell cycle and/or apoptosis. The murine double-minute protein MDM2 and its homologue MDM4 (also known as MDMX) are critical regulators of p53. Altered transcripts of the human homologue of mdm2, MDM2, have been identified in human tumors, such as invasive carcinoma of the breast, lung carcinoma, and liposarcoma. MDM2 alternate forms act to negatively regulate the normal MDM2 gene product, thus activating p53. Although many reports have documented a plethora of tumor types characterized by MDM2 alternative transcripts, few have investigated the signals that might initiate alternative splicing. We have identified a novel role of these alternative MDM2 transcripts in the normal surveillance mechanism of the cell and in DNA damage response. We report that alternate forms of MDM2 are detected after UV irradiation. Furthermore, we show that mouse cells treated with UV are also characterized by alternative transcripts of mdm2, suggesting that this is an important and evolutionarily conserved mechanism for regulating the expression of MDM2/mdm2. An additional p53 regulator and mdm2 family member, MDM4, is likewise alternatively spliced following UV irradiation. By activating alternative splicing of both MDM2 and MDM4, yet another layer of p53 regulation is initiated by the cells in response to damage. A stepwise model for malignant conversion by which alternate forms of MDM2 and MDM4 place selective pressure on the cells to acquire additional alterations in the p53 pathway is herein proposed. (Cancer Res 2006; 66(19): 9502-8)
Ras-induced Modulation of CXCL10 and Its Receptor Splice Variant CXCR3-B in MDA-MB-435 and MCF-7 Cells: Relevance for the Development of Human Breast Cancer
Authors: Datta Dipak , Flaxenburg Jesse A. , Laxmanan Sreenivas , Geehan Christopher , Grimm Martin , Waaga-Gasser Ana Maria , Briscoe David M. , Pal Soumitro
Published: October 2006

Interactions between chemokines and chemokine receptors have been proposed recently to be of importance in the development and progression of cancer. Human breast cancer cells express the chemokine CXCL10 (IP-10) and also its receptor CXCR3. In this study, we have investigated the role of Ras activation in the regulation of CXCL10 and its receptor splice variant CXCR3-B in two human breast cancer cell lines MDA-MB-435 and MCF-7. In cotransfection assays, using a full-length CXCL10 promoter-luciferase construct, we found that the activated form of Ras, Ha-Ras(12V), promoted CXCL10 transcriptional activation. Ras significantly increased CXCL10 mRNA and protein expression as observed by real-time PCR, fluorescence-activated cell sorting analysis, and ELISA. Selective inhibition of Ha-Ras by small interfering RNA (siRNA) decreased CXCL10 mRNA expression in a dose-dependent manner. Further, using effector domain mutants of Ras, we found that Ras-induced overexpression of CXCL10 is mediated primarily through the Raf and phosphatidylinositol 3-kinase signaling pathways. We also observed that the expression of the splice variant CXCR3-B, known to inhibit cell proliferation, was significantly down-regulated by Ras. Selective inhibition of CXCR3-B using siRNA resulted in an increase in CXCL10-mediated breast cancer cell proliferation through Gi proteins and likely involving CXCR3-A. Finally, we observed intense expression of CXCL10 and CXCR3 in association with human breast cancer in situ, indicating that these observations may be of pathophysiologic significance. Together, these results suggest that activation of Ras plays a critical role in modulating the expression of both CXCL10 and CXCR3-B, which may have important consequences in the development of breast tumors through cancer cell proliferation. (Cancer Res 2006; 66(19): 9509-18)
Genetic Profiling of Epithelial Cells Expressing E-Cadherin Repressors Reveals a Distinct Role for Snail, Slug, and E47 Factors in Epithelial-Mesenchymal Transition
Authors: Moreno-Bueno Gema , Cubillo Eva , Sarrió David , Peinado Héctor , Rodríguez-Pinilla Socorro María , Villa Sonia , Bolós Victoria , Jordá Mireia , Fabra Angels , Portillo Francisco , Palacios José , Cano Amparo
Published: October 2006

The transcription factors Snail, Slug, and bHLH E47 have been recently described as direct repressors of E-cadherin and inducers of epithelial-mesenchymal transition (EMT) and invasion when overexpressed in epithelial cells. Although a role of those factors in tumor progression and invasion has been proposed, whether the different repressors play distinct or redundant roles in the tumorigenic process has not been established. To further investigate this important issue, we have analyzed the gene expression profiling of Madin-Darby canine kidney (MDCK) epithelial cells expressing the different repressors (MDCK-Snail, MDCK-Slug, and MDCK-E47 cells) versus control MDCK cells by cDNA microarrays. A total of 243 clones (228 genes and 15 expressed sequence tags) were found to be differentially expressed between either of the three MDCK-derived cell lines and control MDCK cells. Twenty two of the candidate genes were validated by Northern blot, Western blot, immunofluorescence, and promoter analyses in cell lines and by immunohistochemistry in xenografted tumors. Gene clustering analysis indicated that about a third of the 243 candidate genes were common to MDCK cells expressing Snail, Slug, or E47 factors, whereas the rest of the genes were regulated in only one or two cell types. Differentially regulated genes include those related to EMT (45 genes), transcriptional regulation (18 genes), cell proliferation and signaling (54 genes), apoptosis (12 genes), and angiogenesis (9 genes). These results indicate that Snail, Slug, and E47 transcription factors induce common and specific genetic programs, supporting a differential role of the factors in tumor progression and invasion. (Cancer Res 2006; 66(19): 9543-56)
Enhanced Killing of Melanoma Cells by Simultaneously Targeting Mcl-1 and NOXA
Authors: Qin Jian-Zhong , Xin Hong , Sitailo Leonid A. , Denning Mitchell F. , Nickoloff Brian J.
Published: October 2006

By deciphering the dysregulation of apoptosis in melanoma cells, new treatment approaches exploiting aberrant control mechanisms regulating cell death can be envisioned. Among the Bcl-2 family, a BH3-only member, NOXA, functions in a specific mitochondrial-based cell death pathway when melanoma cells are exposed to a proteasome inhibitor (e.g., bortezomib). Some therapeutic agents, such as bortezomib, not only induce proapoptotic Bcl-2 family members and active conformational changes in Bak and Bax but also are associated with undesirable effects, including accumulation of antiapoptotic proteins, such as Mcl-1. To enhance the bortezomib-mediated killing of melanoma cells, the apoptotic pathway involving NOXA was further investigated, leading to identification of an important target (i.e., the labile Bcl-2 homologue Mcl-1 but not other survival proteins). To reduce Mcl-1 levels, melanoma cells were pretreated with several different agents, including Mcl-1 small interfering RNA (siRNA), UV light, or the purine nucleoside analogue fludarabine. By simultaneously triggering production of NOXA (using bortezomib) as well as reducing Mcl-1 levels (using siRNA, UV light, or fludarabine), significantly enhanced killing of melanoma cells was achieved. These results show binding interactions between distinct Bcl-2 family members, such as NOXA and Mcl-1, in melanoma cells, paving the way for novel and rational therapeutic combination strategies, which target guardians of the proapoptotic Bak- and Bax-mediated pathways, against this highly aggressive and often fatal malignancy. (Cancer Res 2006; 66(19): 9636-45)
Deleted in Colorectal Cancer Is a Putative Conditional Tumor-Suppressor Gene Inactivated by Promoter Hypermethylation in Head and Neck Squamous Cell Carcinoma
Authors: Carvalho André Lopes , Chuang Alice , Jiang Wei-Wen , Lee Juna , Begum Shahnaz , Poeta Luana , Zhao Ming , Jerónimo Carmen , Henrique Rui , Nayak Chetan S. , Park Hannah L. , Brait Mariana R.O. , Liu Chunyan , Zhou Shaoyu , Koch Wayne , Fazio Vito Michele , Ratovitski Edward , Trink Barry , Westra William , Sidransky David , Moon Chul-so , Califano Joseph A.
Published: October 2006

Deleted in colorectal cancer (DCC) is a candidate tumor-suppressor gene located at chromosome 18q21. However, DCC gene was found to have few somatic mutations and the heterozygous mice (DCC+/−) showed a similar frequency of tumor formation compared with the wild-type mice (DCC+/+). Recently, DCC came back to the spotlight as a better understating of its function and relationship with its ligand (netrin-1) had shown that DCC may act as a conditional tumor-suppressor gene. We evaluated hypermethylation as a mechanism for DCC inactivation in head and neck squamous cell carcinoma (HNSCC). DCC promoter region hypermethylation was found in 75% of primary HNSCC. There was a significant correlation between DCC promoter region hypermethylation and DCC expression (assessed by immunohistochemistry; P = 0.021). DCC nonexpressing HNSCC cell lines JHU-O12 and JHU-O19 with baseline hypermethylation of the DCC promoter were treated with 5-aza-2′-deoxycytidine (a demethylating agent) and reexpression of DCC was noted. Transfection of DCC into DCC-negative HNSCC cell lines resulted in complete abrogation of growth in all cell lines, whereas additional cotransfection of netrin-1 resulted in rescue of DCC-mediated growth inhibition. These results suggest that DCC is a putative conditional tumor-suppressor gene that is epigenetically inactivated by promoter hypermethylation in a majority of HNSCC. (Cancer Res 2006; 66(19): 9401-07)