A multi-ancestry genetic study of pain intensity in 598,339 veterans

Chronic pain is a common problem, with more than one-fifth of adult Americans reporting pain daily or on most days. It adversely affects the quality of life and imposes substantial personal and economic costs. Efforts to treat chronic pain using opioids had a central role in precipitating the opioid crisis. Despite an estimated heritability of 25-50%, the genetic architecture of chronic pain is not well-characterized, in part because studies have largely been limited to samples of European ancestry. To help address this knowledge gap, we conducted a cross-ancestry meta-analysis of pain intensity in 598,339 participants in the Million Veteran Program, which identified 126 independent genetic loci, 69 of which are new. Pain intensity was genetically correlated with other pain phenotypes, level of substance use and substance use disorders, other psychiatric traits, education level and cognitive traits. Integration of the genome-wide association studies findings with functional genomics data shows enrichment for putatively causal genes (n = 142) and proteins (n = 14) expressed in brain tissues, specifically in GABAergic neurons. Drug repurposing analysis identified anticonvulsants, β-blockers and calcium-channel blockers, among other drug groups, as having potential analgesic effects. Our results provide insights into key molecular contributors to the experience of pain and highlight attractive drug targets.

Does polygenic risk for substance-related traits predict ages of onset and progression of symptoms?

BACKGROUND AND AIMS

Genetic risk can influence disease progression. We measured the impact of genetic risk for substance use disorders (SUDs) on substance use onset and progression of symptoms.

DESIGN, SETTING, PARTICIPANTS

Using findings from genome-wide association studies (GWASs) of alcohol use disorder (AUD), opioid use disorder (OUD) and smoking trajectory (SMK) as discovery samples, we calculated polygenic risk scores (PRSs) in a deeply phenotyped independent target sample. Participants in the target sample were recruited from 2000 to 2020 from US inpatient or outpatient settings or through advertisements and comprised 5692 European-ancestry individuals (EUR) (56.2% male) and 4918 African-ancestry individuals (AFR) (54.9% male).

MEASUREMENTS

This study measured age of first substance use, regular use, reported problems and dependence diagnosis and progression from regular use to onset of problems and dependence for alcohol, opioids and smoking. We examined the contribution of PRS to each milestone and progression measure.

FINDINGS

EUR and males reported an earlier onset and shorter progression times than AFR and females, respectively. Among EUR, higher AUD PRS predicted earlier onset and more rapid progression to alcohol-related milestones (P < 0.001). Although the AUD PRS was a stronger moderator of problem onset among females (P = 0.017), it was more predictive of the progression to problems among males (P = 0.005). OUD and SMK PRS in EUR also predicted earlier onset of the respective milestones (P < 0.001). Among AFR, where power is lower due to the smaller discovery sample, AUD PRS predicted age of regular alcohol use (P = 0.039) and dependence (P = 0.001) and progression from regular use to diagnosis (P = 0.045), while SMK PRS predicted earlier age of initiation (P = 0.036).

CONCLUSIONS

Genetic risk for SUDs appears to predict substance use milestones and symptom progression among European-ancestry individuals and, to a lesser extent, African-ancestry individuals.

Artificial Intelligence (AI) in Radiology: A Deep Dive Into ChatGPT 4.0's Accuracy with the American Journal of Neuroradiology's (AJNR) "Case of the Month"

The advent of artificial intelligence (AI), particularly large language models (LLMs) such as ChatGPT 4.0, holds significant potential in healthcare, specifically in radiology. This study examined the accuracy of ChatGPT 4.0 (July 20, 2023, version) in solving diagnostic quizzes from the American Journal of Neuroradiology's (AJNR) "Case of the Month." We evaluated the diagnostic accuracy of ChatGPT 4.0 when provided with a patient's history and imaging findings weekly over four weeks, using 140 cases from the AJNR "Case of the Month" portal (from November 2011 to July 2023). The overall diagnostic accuracy was found to be 57.86% (81 out of 140 cases). The diagnostic performance varied across brain, head and neck, and spine subgroups, with accuracy rates of 54.65%, 67.65%, and 55.0%, respectively. These findings suggest that AI models such as ChatGPT 4.0 could serve as useful adjuncts in radiological diagnostics, thus potentially enhancing patient care and revolutionizing medical education.

Sinogram: A Valuable Diagnostic Tool for an Adult Male With Discharging Heel Ulcer and Suspected Calcaneal Osteomyelitis

This report highlights the clinical significance of a sinogram in diagnosing osteomyelitis in resource-poor areas. We report a case in which a sinogram was used successfully for the diagnosis of calcaneal osteomyelitis. A 25-year-old male patient sought medical attention for persistent pain in the right ankle joint and heel, accompanied by a discharging ulcer over the right heel. He had a history of foot trauma involving vegetative matter sustained during a farming injury one month prior to the onset of symptoms. An ankle radiograph revealed an osteolytic lesion involving the calcaneum, prompting further investigation with a sinogram, which indicated a subcutaneous sinus tract with intramedullary extension into the calcaneum. Despite the clinical necessity for a magnetic resonance imaging (MRI) or computed tomography (CT) evaluation to precisely assess the lesion's extent and aid in formulating an appropriate treatment plan, the patient faced significant financial constraints that hindered him from undergoing the essential imaging procedure.

Merkel Cell Carcinoma of the Left Cheek With Testicular Metastasis: An Uncommon Occurrence

Merkel cell carcinoma (MCC) is an infrequent and aggressive neuroendocrine tumor of the skin. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is an effective imaging technique with good diagnostic accuracy that may be used to help stage MCC and for detecting unexpected recurrences and distant metastatic disease. Other causes of testicular neoplasms, such as primary testicular tumors, lymphomas, or anaplastic small cell melanomas, are difficult to differentiate from MCC testicular metastases on imaging, and tumor markers and histopathology will help confirm it. The current case is a 65-year-old non-immunocompromised male with Merkel cell carcinoma who was incidentally identified with testicular metastases on PET/CT and confirmed on histopathology.

Large Chorioangioma in Triplets: An Uncommon Occurrence

A 25-year-old primigravida presented at 26 weeks of gestation by dates, the first time for the routine antenatal checkup. No histories were suggestive of pregnancy-induced hypertension (PIH) and edema. On physical examination, pallor was present with microcytic hypochromic anemia. Raised beta-human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) levels were present. Ultrasonography revealed triples with two thin echogenic intertwining membranes. Anomaly scan did not reveal any abnormality in fetuses. The placenta showed a large oval hypoechoic mass arising from its edge and bulge into the amniotic fluid. A central feeding vessel with a branching pattern and pulsatile color flow like that of the umbilical artery is noted on the color Doppler. She was spontaneously preterm delivered vaginally at 28 weeks of gestation. All three fetuses were stillborn. Histopathological diagnosis of angiomatous chorioangioma was confirmed. This case classically represents a grave complication of the large chorioangioma.

The genetic architecture of pain intensity in a sample of 598,339 U.S. veterans

Chronic pain is a common problem, with more than one-fifth of adult Americans reporting pain daily or on most days. It adversely affects quality of life and imposes substantial personal and economic costs. Efforts to treat chronic pain using opioids played a central role in precipitating the opioid crisis. Despite an estimated heritability of 25-50%, the genetic architecture of chronic pain is not well characterized, in part because studies have largely been limited to samples of European ancestry. To help address this knowledge gap, we conducted a cross-ancestry meta-analysis of pain intensity in 598,339 participants in the Million Veteran Program, which identified 125 independent genetic loci, 82 of which are novel. Pain intensity was genetically correlated with other pain phenotypes, level of substance use and substance use disorders, other psychiatric traits, education level, and cognitive traits. Integration of the GWAS findings with functional genomics data shows enrichment for putatively causal genes (n = 142) and proteins (n = 14) expressed in brain tissues, specifically in GABAergic neurons. Drug repurposing analysis identified anticonvulsants, beta-blockers, and calcium-channel blockers, among other drug groups, as having potential analgesic effects. Our results provide insights into key molecular contributors to the experience of pain and highlight attractive drug targets.

A study on impact of coronavirus pandemic on the education system

Objective: Because of the recent COVID-19 outbreak, the government decides to close the schools to avoid the virus chain. However, that made a tremendous impact on the education system. Hence, the research’s main aim focuses on the effect of the education system on the corona. Method: Research has implemented a descriptive method. Through the standardized questionnaire using the Likert scale, the data was collected via an online survey, where 300 respondents were found to be used as the sample size and regression analysis to prove the significance of the findings. Findings: The study found that obstacles act as a roadblock in the education system, while the study found resources that were also helpful to students and teachers. Practical Implication: Application of such factors by leveraging the educational sector as an opportunity could work for them if effectively applied. Students will learn something new and develop technological skills they would not have had before. Originality/Value: Researchers have studied challenges and opportunities during a pandemic situation by applying theories and analyzing the impact on the education system. The current research considers such aspects as to what effect on the education sector or how it handles the framework as a burden or as an opportunity.

OrderRex clinical user testing: a randomized trial of recommender system decision support on simulated cases

OBJECTIVE

To assess usability and usefulness of a machine learning-based order recommender system applied to simulated clinical cases.

MATERIALS AND METHODS

43 physicians entered orders for 5 simulated clinical cases using a clinical order entry interface with or without access to a previously developed automated order recommender system. Cases were randomly allocated to the recommender system in a 3:2 ratio. A panel of clinicians scored whether the orders placed were clinically appropriate. Our primary outcome included the difference in clinical appropriateness scores. Secondary outcomes included total number of orders, case time, and survey responses.

RESULTS

Clinical appropriateness scores per order were comparable for cases randomized to the order recommender system (mean difference -0.11 order per score, 95% CI: [-0.41, 0.20]). Physicians using the recommender placed more orders (median 16 vs 15 orders, incidence rate ratio 1.09, 95%CI: [1.01-1.17]). Case times were comparable with the recommender system. Order suggestions generated from the recommender system were more likely to match physician needs than standard manual search options. Physicians used recommender suggestions in 98% of available cases. Approximately 95% of participants agreed the system would be useful for their workflows.

DISCUSSION

User testing with a simulated electronic medical record interface can assess the value of machine learning and clinical decision support tools for clinician usability and acceptance before live deployments.

CONCLUSIONS

Clinicians can use and accept machine learned clinical order recommendations integrated into an electronic order entry interface in a simulated setting. The clinical appropriateness of orders entered was comparable even when supported by automated recommendations.

Physician Usage and Acceptance of a Machine Learning Recommender System for Simulated Clinical Order Entry

Clinical decision support tools that automatically disseminate patterns of clinical orders have the potential to improve patient care by reducing errors of omission and streamlining physician workflows. However, it is unknown if physicians will accept such tools or how their behavior will be affected. In this randomized controlled study, we exposed 34 licensed physicians to a clinical order entry interface and five simulated emergency cases, with randomized availability of a previously developed clinical order recommender system. With the recommender available, physicians spent similar time per case (6.7 minutes), but placed more total orders (17.1 vs. 15.8). The recommender demonstrated superior recall (59% vs 41%) and precision (25% vs 17%) compared to manual search results, and was positively received by physicians recognizing workflow benefits. Further studies must assess the potential clinical impact towards a future where electronic health records automatically anticipate clinical needs.

Direct measurement of shear properties of microfibers

As novel fibers with enhanced mechanical properties continue to be synthesized and developed, the ability to easily and accurately characterize these materials becomes increasingly important. Here we present a design for an inexpensive tabletop instrument to measure shear modulus (G) and other longitudinal shear properties of a micrometer-sized monofilament fiber sample, such as nonlinearities and hysteresis. This automated system applies twist to the sample and measures the resulting torque using a sensitive optical detector that tracks a torsion reference. The accuracy of the instrument was verified by measuring G for high purity copper and tungsten fibers, for which G is well known. Two industrially important fibers, IM7 carbon fiber and Kevlar(®) 119, were also characterized with this system and were found to have G = 16.5 ± 2.1 and 2.42 ± 0.32 GPa, respectively.

Role of the QuantiFERON®-TB Gold In-Tube test in the diagnosis of intrathoracic childhood tuberculosis

SETTING

Tertiary care hospitals in India.

OBJECTIVE

To compare the performance of the QuantiFERON®-TB Gold In-Tube test (QFT-GIT) with that of the tuberculin skin test (TST) in the diagnosis of intrathoracic childhood tuberculosis (TB).

METHODS

Children with intrathoracic TB were enrolled in a randomised controlled trial studying micronutrient supplementation in intrathoracic TB. They underwent TST and QFT-GIT before starting daily anti-tuberculosis treatment.

RESULTS

Of 362 children (median age 115.5 months, IQR 73-144, 55% girls) enrolled in the study, microbiological confirmation of TB was obtained in 128 (35%). The TST was positive in 337 (93%, 95%CI 90-95.5) and QFT-GIT in 297 (82%, 95%CI 77.8-85.6). Sensitivity of TST and QFT-GIT in culture-confirmed TB cases was respectively 90.5% (95%CI 84.1-94.5) and 82.6% (95%CI 74.9-88.4). QFT-GIT positivity rate correlated with TST induration (P < 0.001). TST was influenced by the disease spectrum (P = 0.004) and the age of the children (P = 0.002); QFT-GIT remained unaffected by these factors. Bacille Calmette-Guérin immunisation status, weight-for-age Z-scores and microbiological confirmation of Mycobacterium tuberculosis did not influence the performance of either test.

CONCLUSION

In high-burden countries, QFT-GIT is comparable to TST and offers no added advantage in the diagnosis of childhood intrathoracic TB.

Effect of micronutrient deficiency on QuantiFERON-TB Gold In-Tube test and tuberculin skin test in diagnosis of childhood intrathoracic tuberculosis

BACKGROUND/OBJECTIVES

Data on performance of QuantiFERON-TB Gold In-Tube test (QFT) and tuberculin skin test (TST) in children with active tuberculosis from high burden countries in the context of micronutrient deficiency are scarce. The objective of this study was to evaluate the effect of micronutrient deficiency on the performance of TST and QFT in children with intrathoracic tuberculosis.

SUBJECTS/METHODS

Children with probable intrathoracic tuberculosis underwent TST, QFT, gastric lavages and induced sputum examination for AFB (Acid-Fast Bacilli) smear and culture. Zinc, copper, ferritin and vitamin D were measured on stored serum samples. The study used cross-sectional data at initiation of anti-tubercular therapy.

RESULTS

Three hundred and sixty-two children (median age 115.5 months (interquartile range: 73, 144), 200 (55.3%) girls) were enrolled in the study. Microbiological confirmation of tuberculosis could be obtained in 128 patients. TST and QFT were positive in 337 (93%) and 297 (82%) children, respectively. Performance of both the tests was unaffected by weight-for-age and height-for-age 'z-scores' or by serum copper levels. TST was not affected by serum zinc and ferritin levels. Children with negative QFT results had lower mean serum zinc level (P=0.01) and higher ferritin levels (P=0.007) as compared to those with positive test. Higher proportion of children with positive TST were vitamin D deficient/insufficient (P=0.003).

CONCLUSION

Micronutrient status, especially serum levels of zinc, may influence the performance of QFT in children with intrathoracic tuberculosis. Considering the high prevalence of zinc deficiency in developing countries, QFT should be used cautiously for diagnosing tuberculosis.

A gender-based analysis of high school athletes using computerized electrocardiogram measurements

BACKGROUND

The addition of the ECG to the preparticipation examination (PPE) of high school athletes has been a topic for debate. Defining the difference between the high school male and female ECG is crucial to help initiate its implementation in the High School PPE. Establishing the different parameters set for the male and female ECG would help to reduce false positives. We examined the effect of gender on the high school athlete ECG by obtaining and analyzing ECG measurements of high school athletes from Henry M. Gunn High School.

METHODS

In 2011 and 2012, computerized Electrocardiograms were recorded and analyzed on 181 athletes (52.5% male; mean age 16.1 ± 1.1 years) who participated in 17 different sports. ECG statistics included intervals and durations in all 3 axes (X, Y, Z) to calculate 12 lead voltage sums, QRS Amplitude, QT interval, QRS Duration, and the sum of the R wave in V5 and the S Wave in V2 (RS Sum).

RESULTS

By computer analysis, we demonstrated that male athletes had significantly greater QRS duration, Q-wave duration, and T wave amplitude. (P<0.05). By contrast, female athletes had a significantly greater QTc interval. (P<0.05).

CONCLUSION

The differences in ECG measurements in high school athletes are strongly associated with gender. However, body size does not correlate with the aforementioned ECG measurements. Our tables of the gender-specific parameters can help facilitate the development of a more large scale and in-depth ECG analysis for screening high school athletes in the future.

Protective role of Trigonella foenum graceum extract against oxidative stress in hyperglycemic rats

BACKGROUND AND OBJECTIVES

"In all things of nature there is something of the marvelous". In the present study the anti-hyperglycemic and anti-oxidative potential of aqueous extract of Trigonella foenum graceum (TFG), a traditional medicinal herb was assessed in liver and WBC of alloxan induced diabetic rats. Free radicals can cause oxidative damage, which is balanced by the antioxidants. This has been implicated in aging, and diseases such as diabetes and other chronic conditions.

MATERIAL AND METHODS

TFG extract was administered orally [500 (LM) and 1000 mg/kg body weight (HM)] for six weeks. The effect of TFG on blood glucose were studied and the levels of lipid peroxidation [MDA (Malondialdehyde)] and antioxidant enzymes [SOD (Superoxide dismutase), GPx (Reduced Glutathione peroxidase)] were estimated and compared with standard drugs glibenclamide and insulin.

RESULTS

Treatment with TFG, insulin and glibenclamide resulted in significantly reduced blood glucose in LM (8.71%) and HM (3.87%) in comparison with normal controls. There was a significant decrease in lipid peroxidation in liver and white blood cells (WBC) in both low and high doses [liver LM (49%), HM (57.25%)], [WBC LM (54.28%), HM (62.5%)] and increase in antioxidant enzymes SOD [liver LM (33.59%), HM (58.7%)] [WBC LM (44.9%)] HM (58.7%) and GPx [Liver LM (58.55%), HM (40.20%)], [WBC LM (55.46%), HM (56.4%)] when compared to diabetic controls.

DISCUSSION

Potency of TFG in restoring several parameters to normal values is comparable to glibenclamide, though not as efficient as insulin, an indication of its antihyperglycemic and antioxidant effect.

Oleanolic Acid, a plant triterpenoid, significantly improves survival and function of islet allograft

BACKGROUND.: Oleanolic acid (OA) is a ubiquitous triterpenoid, with potent antioxidant and anti-inflammatory properties. Here, we tested whether these combined properties of OA can prevent nonimmunologic primary nonfunctioning and immunologic phenomena ascribed to graft rejection hence prolong islet allograft survival. METHODS.: Islet transplants were performed under kidney capsule of streptozotocin-induced diabetic C57BL/6 mice with BALB/c islets. Recipients were treated with 0.5 mg/day of OA intraperitoneally, and serum samples were collected once in 2 days and used for luminex, ELISA, and donor-specific antibody screening. Transplanted mice were killed at different time intervals to obtain splenocytes and kidney samples for ELISPOT, mixed leukocyte reaction, and immunohistochemical studies. RESULTS.: After transplantation, the decrement of blood glucose was significantly faster in mice receiving OA less than 2+/-1 days compared with untreated (4+/-2 days). OA prolonged survival of transplanted islets up to 23+/-3 days and reversed diabetes even with 250 islets. Treatment group showed increased serum interleukin (IL)-10 (twofold) and decreased inducible protein-10 and IL-4 (threefold) in luminex. Significantly reduced frequency of interferon-gamma (4.5-fold), IL-4 (3.5-fold), IL-2 (2.3-fold), and IL-17 (fourfold) producing T-cell populations were found in ELISPOT. OA-treated grafts had significant reduced and delayed infiltration of CD4+ and CD8+ T cells. OA also delayed donor-specific antibody generation up to 19 days after transplantation. Combined treatment with cyclosporine A, OA further prolonged the islet allograft survival to 34+/-3 days. CONCLUSIONS.: In conclusion, OA is an attractive, dietary nontoxic plant triterpenoid, which suppresses the production of proinflammatory cytokines and delays graft-specific immune responses to prolong islet allograft survival.

Particle Size and Charge Distribution Analysis of Pharmaceutical Aerosols Generated by Inhalers

Aerosol particles generated by inhalers for respiratory drug delivery acquire electrostatic charge during the dispersion process. The electrostatic charge distribution of the particles can affect the efficiency of drug delivery by influencing both the transport and deposition of inhaled particles in the human lung. To analyze the electrostatic charge acquired by the aerosol particles, two sets of metered-dose inhaler (MDI) and dry powder inhaler (DPI) devices were investigated. Both the particle size and charge distributions were measured simultaneously by using an electrical single-particle aerodynamic relaxation time (E-SPART) analyzer. The analyzer was calibrated with particles of known size, which were generated by a vibrating orifice aerosol generator (TSI Inc.) and charge using the Faraday cup method. The charge distributions of the pharmaceutical aerosols from both the DPI and MDI devices were bipolar in nature. Although the net charge-to-mass ratio was less than 0.2 microC/g, the individual particles were charged with a relatively high charge: -2 to + 2 microC/g. The count mean aerodynamic diameter of the aerosols generated from these devices was 3-5 microm.

Activated effector and memory T cells contribute to circulating sCD30: potential marker for islet allograft rejection

T-cell activation up-regulates CD30 resulting in an increase in serum soluble CD30 (sCD30). CD4+ T cells, a major source for sCD30, play a significant role in the pathogenesis of rejection. In this study, sCD30 was measured pre- and posttransplant in mouse islet allograft models and human islet allograft recipients. sCD30 was measured by ELISA in diabetic C57BL/6, CD4Knockout (KO) and CD8KO islet allograft recipients. sCD30 increased significantly prior to rejection (1.8 +/- 1 days) in 80% of allograft recipients. Sensitization with donor splenocytes, or a second graft, further increased sCD30 (282.5 +/- 53.5 for the rejecting first graft vs. 374.6 +/- 129 for the rejecting second graft) prior to rejection suggesting memory CD4+ T cells contribute to sCD30. CD4KO failed to reject islet allograft and did not demonstrate sCD30 increase. CD8KO showed elevated (227 +/- 107) sCD30 (1 day) prior to rejection. High pretransplant sCD30 (>20 U/ml) correlated with poor outcome in human islet allograft recipients. Further, increase in sCD30 posttransplant preceded (3-4 months) loss of islet function. We conclude that sCD30 is released from activated CD4 T cells prior to islet allograft rejection and monitoring sCD30 can be a valuable adjunct in the follow-up of islet transplant recipients.

Class Level Test Case Generation in Object Oriented Software Testing

Object-oriented programming consists of several different levels of abstraction, namely, the algorithmic level, class level, cluster level, and system level. In this article, we discuss a testing technique to generate test cases at class level for object-oriented programs. The formal object oriented class specification is used to develop a test model. This test model is based on finite state machine specification. The class specification and the test model is analyzed to select a set of test data for each method of the class, and finally the test cases can be generated using other testing techniques like finite-state testing or data-flow testing.

Simplified dispatch-assisted CPR instructions outperform standard protocol

OBJECTIVE

Dispatch-assisted chest compressions only CPR (CC-CPR) has gained widespread acceptance, and recent research suggests that increasing the proportion of compression time during CPR may increase survival from out-of-hospital cardiac arrest. We created a simplified CC-CPR protocol to reduce time to start chest compressions and to increase the proportion of time spent delivering chest compressions. This simplified protocol was compared to a published protocol, Medical Priority Dispatch System (MPDS) Version 11.2, recommended by the National Academies of Emergency Dispatch.

METHODS

Subjects were randomized to the MPDS v11.2 protocol or a simplified protocol. Data was recorded from a Laerdal Resusci Anne Skillreporter manikin. A simulated emergency medical dispatcher, contacted by cell phone, delivered standardized instructions for both protocols. Outcomes included chest compression rate, depth, hand position, full release, overall proportion of compressions without error, time to start of CPR and total hands-off chest time. Proportions were analyzed by Wilcoxon's Rank Sum tests and time variables with Welch ANOVA and Wilcoxon's Rank Sum test. All tests used a two-sided alpha-level of 0.05.

RESULTS

One hundred and seventeen subjects were randomized prospectively, 58 to the standard protocol and 59 to the simplified protocol. The average age of subjects in both groups was 25 years old. For both groups, the compression rate was equivalent (104 simplified versus 94 MPDS, p = 0.13), as was the proportion with total release (1.0 simplified versus 1.0 MPDS, p = 0.09). The proportion to the correct depth was greater in the simplified protocol (0.31 versus 0.03, p < 0.01), as was the proportion of compressions done without error (0.05 versus 0.0, p = 0.16). Time to start of chest compressions and total hands-off chest time were better in the simplified protocol (start time 60.9s versus 78.6s, p < 0.0001; hands-off chest time 69 s versus 95 s, p < 0.0001). The proportion with correct hand position, however, was worse in the simplified protocol (0.35 versus 0.84, p < 0.01).

CONCLUSIONS

The simplified protocol was as good as, or better than the MPDS v11.2 protocol in every aspect studied except hand position, and the simplified protocol resulted in significant time savings. The protocol may need modification to ensure correct hand position. Time savings and improved quality of CPR achieved by the new set of instructions could be important in strengthening critical links in the cardiac chain of survival.

Dosimetric evaluation of a variable field electron beam applicator

A commercially available variable electron beam applicator designed for the Phillips SL-75/20 linear accelerator was tested for possible clinical use. The basic design of this collimator consists of four movable L-shaped stainless steel blades forming the corners. In addition, four smaller fixed blades of the same material and thickness fill in the sides. Film placed in polystyrene phantoms were exposed in all experiments. Field size, field flatness, beam homogeneity and penumbra measurements, all indicated that the applicator is acceptable for clinical use. However, for use with large field sizes and/or high energy electron beams some minor modifications are suggested.