Multiple atopy phenotypes and their associations with asthma: similar findings from two birth cohorts.

BACKGROUND: Although atopic sensitization is one of the strongest risk factors for asthma, its relationship with asthma is poorly understood. We hypothesize that 'atopy' encompasses multiple sub-phenotypes that relate to asthma in different ways. METHODS: In two population-based birth cohorts (Manchester and Isle of Wight - IoW), we used a machine learning approach to independently cluster children into different classes of atopic sensitization in an unsupervised manner, based on skin prick and sIgE tests taken throughout childhood and adolescence. We examined the qualitative cluster properties and their relationship to asthma and lung function. RESULTS: A five-class solution best described the data in both cohorts, with striking similarity between the classes across the two populations. Compared with nonsensitized class, children in the class with sensitivity to a wide variety of allergens (~1/3 of children atopic by conventional definition) were much more likely to have asthma (aOR [95% CI0; 20.1 [10.9-40.2] in Manchester and 11.9 [7.3-19.4] in IoW). The relationship between asthma and conventional atopy was much weaker (5.5 [3.4-8.8] in Manchester and 5.8 [4.1-8.3] in IoW). In both cohorts, children in this class had significantly poorer lung function (FEV1 /FVC lower by 4.4% in Manchester and 2.6% in IoW; P < 0.001), most reactive airways, highest eNO and most hospital admissions for asthma (P < 0.001). CONCLUSIONS: By adopting a machine learning approach to longitudinal data on allergic sensitization from two independent unselected birth cohorts, we identified latent classes with strikingly similar patterns of atopic response and association with clinical outcomes, suggesting the existence of multiple atopy phenotypes.

Superiorized algorithm for reconstruction of CT images from sparse-view and limited-angle polyenergetic data.

Recent work in CT image reconstruction has seen increasing interest in the use of total variation (TV) and related penalties to regularize problems involving reconstruction from undersampled or incomplete data. Superiorization is a recently proposed heuristic which provides an automatic procedure to 'superiorize' an iterative image reconstruction algorithm with respect to a chosen objective function, such as TV. Under certain conditions, the superiorized algorithm is guaranteed to find a solution that is as satisfactory as any found by the original algorithm with respect to satisfying the constraints of the problem; this solution is also expected to be superior with respect to the chosen objective. Most work on superiorization has used reconstruction algorithms which assume a linear measurement model, which in the case of CT corresponds to data generated from a monoenergetic x-ray beam. Many CT systems generate x-rays from a polyenergetic spectrum, however, in which the measured data represent an integral of object attenuation over all energies in the spectrum. This inconsistency with the linear model produces the well-known beam hardening artifacts, which impair analysis of CT images. In this work we superiorize an iterative algorithm for reconstruction from polyenergetic data, using both TV and an anisotropic TV (ATV) penalty. We apply the superiorized algorithm in numerical phantom experiments modeling both sparse-view and limited-angle scenarios. In our experiments, the superiorized algorithm successfully finds solutions which are as constraints-compatible as those found by the original algorithm, with significantly reduced TV and ATV values. The superiorized algorithm thus produces images with greatly reduced sparse-view and limited angle artifacts, which are also largely free of the beam hardening artifacts that would be present if a superiorized version of a monoenergetic algorithm were used.

Hydrogen peroxide modulation of the respiratory burst of human neutrophils.

Addition of micromolar concentrations of hydrogen peroxide (H2O2) to human neutrophils resulted in a dose-dependent luminol-enhanced chemiluminescent response. Pretreatment of neutrophils with micromolar concentrations of H2O2 altered their response to the surface acting stimulants serum-treated zymosan (STZ) and formyl-methionyl-leucyl-phenylalanine (fMLP), but not to the intracellular stimulant phorbol myristate acetate (PMA). The alterations were partially reversible by catalase, but exacerbated by superoxide dismutase. These results suggest a modulatory role for H2O2 in the respiratory burst of neutrophils.

Improving trauma care in Trinidad and Tobago.

Identification of trauma as a major cause of morbidity and mortality in Trinidad and Tobago prompted the establishment of a training programme aimed at improving trauma care in this developing country. An Advanced Trauma Life Support (ATLS) programme for physicians, funded through the Canadian International Development Agency resulted in a statistically significant improvement of in-hospital trauma patient outcome at the Port-of-Spain General Hospital (observed to expected mortality ratio of 3.16 pre-ATLS compared to 1.94 post-ATLS). A recent analysis of all motor vehicle injuries for a shorter period did not confirm this positive impact of the ATLS programme, primarily because a large number of these patients died in the pre-hospital period. Pre-hospital trauma care therefore required urgent attention to complement the positive in-hospital impact of the ATLS programme. A second training programme (the Pre-Hospital Trauma Life Support or PHTLS) for paramedical personnel was thus instituted in 1990. Over 250 physicians have been trained in the ATLS programme and to date over 100 paramedical personnel have been trained in the PHTLS programme. Attempts have also been made to equip the ambulances with more appropriate resuscitative devices in order to improve pre-hospital care. The combination of the PHTLS and the ATLS programme should result in further improvement in the care of patients sustaining major injuries in Trinidad and Tobago.

Incorporating transcultural care education in allied health curricula.

A clinical skill recently identified as a necessary curricular component in allied health programs is transculturally competent care. It is imperative to teach allied health students transcultural care skills, first, because the population of the United States is becoming more ethnically, culturally, and racially diverse, and the allied health workforce must be prepared for this change. Second, Western medicine has historically reflected European values and traditions. Because other cultures view health and disease differently, health care workers must understand and be respectful of values and traditions that differ from their own. And finally, organizations that accredit health care facilities and academic programs, and licensing boards, are recognizing cultural competency as an important clinical skill for all health care workers. Based on existing literature on transcultural care education, which primarily comes from nursing, this article suggests a model for its incorporation in allied health curricula.

Allied health applications of a computerized clinical log database system.

Preliminary research in the development and use of computerized clinical log records began in 1987 in an allied health college at a midwestern academic health center. This article reviews development and implementation of a computerized system for managing clinical log records to improve and enhance allied health educational programs in the radiation sciences. These clinical log databases are used for quantitative and qualitative analyses of student participation in clinical procedures, and educational planning for each student. Collecting and recording data from clinical log records serves as a valuable instructional tool for students, with both clinical and didactic applications.

Review article: diagnosis and treatment of non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent condition affecting adults and children, leading to significant morbidity. It is often associated with the metabolic syndrome, although multiple pathogenetic mechanisms have been suggested. In the coming decades, it promises to be the leading cause of liver disease in industrial countries. AIM: To provide a comprehensive, updated review of diagnosis and management of NAFLD and to appraise the evolution of new modalities in these areas. METHODS: An Ovid MEDLINE search was performed to identify pertinent original research and review articles. Selected references in these articles were also evaluated. RESULTS: The diagnosis of hepatic steatosis and steatohepatitis or non-alcoholic steatohepatitis (NASH) is not yet possible without liver biopsy. This is impractical given the large numbers affected by the condition. Current therapy has focused on improving insulin resistance and mediators of inflammation, factors probably associated with disease progression. CONCLUSIONS: There are no proven non-invasive diagnostic modalities to distinguish NAFLD and NASH, but new biomarker panels are approximating the liver biopsy in accuracy. Therapeutic targets of drug development are in early stages, but a multifaceted approach will probably yield several treatment options in the years to come.

Photon migration of near-diffusive photons in turbid media: a Lagrangian-based approach.

We show that light transport in a turbid medium can be described by a path integral with a quasi-particle Lagrangian. The most probable trajectory over which photons can be found can be obtained from this Lagrangian. This approach extends the diffusion approximation to the near-diffusive regime, in which photons travel only a few transport mean free paths.

Omnidirectional reflection from a one-dimensional photonic crystal.

We demonstrate that one-dimensional photonic crystal structures (such as multilayer films) can exhibit complete reflection of radiation in a given frequency range for all incident angles and polarizations. We derive a general criterion for this behavior that does not require materials with very large indices. We perform numerical studies that illustrate this effect.

Nitrous oxide reduces the cost of intravenous anaesthesia.

One hundred and one women (ASA grades I and II) were anaesthetized for routine gynaecological surgery using an intravenous (i.v.) anaesthetic technique combining propofol and alfentanil. The patients were allocated randomly into groups. Group one received 33% oxygen in nitrous oxide and group two received 33% oxygen in air (total i.v. anaesthesia). The group receiving nitrous oxide required significantly less (P < 0.05) of the propofol and alfentanil mixture to maintain anaesthesia and this was found to reduce the mean cost of anaesthesia by 1.70 pounds, (P < 0.05). There was no significant difference in the incidence of postoperative complications between the two groups. We suggest that nitrous oxide may be used to reduce the cost of total i.v. anesthesia with propofol and alfentanil without causing any increase in post-operative morbidity in patients undergoing routine gynaecological surgery.

Comparison of performance 2 years after the old and new (interactive) ATLS courses.

BACKGROUND: We previously (1997) demonstrated superior clinical but similar cognitive performance after the new interactive compared to the old ATLS course. The present study is aimed at determining whether this difference was short term or maintained over time (2 years). MATERIALS AND METHODS: Two groups of 13 physicians out of the original 32 physicians were available for the study which compared performance in a 40-item MCQ examination on trauma topics and clinical performance in 4 trauma OSCE stations consisting of simulated trauma patients. Paired and unpaired t tests were used for within- and between-group comparisons, respectively, with P < 0.05 being considered statistically significant. Overall OSCE scores (maximum standard 20), adherence to priority scores (Priority, scale 1 to 7), and overall approach (Approach, scale 1 to 5) scores were analyzed. RESULTS: Values are means +/- SD; (+)-P < 0.05 compared to 1999; *P < 0.05 compared to old group [table in text]. CONCLUSIONS: Although knowledge base decreases similarly with time after both courses, the new interactive course participants maintained a consistently higher clinical skill performance level at 2 years.

A new device for measuring intrauterine temperature.

OBJECTIVE: We evaluated a new device that uses the intrauterine pressure catheter to measure the maternal temperature in patients who are in labor. STUDY DESIGN: The study was conducted at two medical centers, Christiana Hospital in Newark, Delaware, and Saint Louis University/St Mary's Health Center in St Louis, Missouri, from September 1, 1997, to May 2, 1998. An intrauterine pressure catheter with a thermistor sensor in the tip was placed into the uterus after spontaneous rupture of membranes. The intrauterine, oral, and tympanic temperatures were simultaneously obtained immediately after insertion of the intrauterine pressure catheter and then hourly until delivery or the initiation of amnioinfusion. RESULTS: The study comprised 97 patients and 404 temperature readings with a temperature range of 34.7 degrees C to 40.7 degrees C. The normal mean +/- SD for the oral, tympanic, and intrauterine temperatures was 36.7 degrees C +/- 0.5 degrees C, 36.8 degrees C +/- 0.5 degrees C, and 37.3 degrees C +/- 0.4 degrees C, respectively. There was a linear relationship among the oral, tympanic, and intrauterine temperatures. All three methods showed a significant increase in mean body temperature after epidural anesthesia. CONCLUSION: The new device, the intrauterine pressure-temperature catheter, provides a convenient and accurate means of continuously measuring uterine temperature in patients who are in labor and require intrauterine monitoring.

Effect of basic prehospital trauma life support program on cognitive and trauma management skills.

We tested the effectiveness of a basic prehospital trauma life support (PHTLS) program by assessing cognitive performance and trauma management skills among prehospital trauma personnel. Fourteen subjects who completed a standard PHTLS course (group I) were compared to a matched group not completing a PHTLS program (group II). Cognitive performance was assessed on 50-item multiple choice examinations, and trauma skills management was assessed with four simulated trauma patients. Pre-PHTLS multiple choice questionnaire scores were similar (45.8 +/- 9.4% vs. 48.8 +/- 8.9% for groups I and II, respectively), but the post-PHTLS scores were higher in group I (80.4 +/- 5.9%) than in group II (52.6 +/- 4.9%). Pre-PHTLS simulated trauma patient performance scores (standardized to a maximum total of 20 for each station) were similar at all four stations for both groups, ranging from 7.9 to 10.4. The post-PHTLS scores were statistically significantly higher at all four stations for group I (range 16.0-19.0) compared to those for group II (range 8.0-11.1). The overall mean pre-PHTLS score for all four stations was 8.3 +/- 2.1 for group I and 8.8 +/- 2.0 (NS) for group II; the group I post-PHTLS mean score for the four stations was 17.1 +/- 2.7 (p < 0.05) compared to 9.1 +/- 2.3 for group II. Pre-PHTLS Adherence to Priority scores on a scale of 1 to 7 were similar (1.1 +/- 0.9 for group I and 1.2 +/- 1.0 for group II). Post-PHTLS group I Priority scores increased to 5.9 +/- 1.1. Group II (1.1 +/- 1.0) did not improve their post-PHTLS scores. The pre-PHTLS Organized Approach scores in the simulated trauma patients on a scale of 1 to 5 were 2.1 +/- 1.0 for group I and 1.9 +/- 1.2 for group II (NS) compared to 4.2 +/- 0.9 (p < 0.05) in group I and 2.0 +/- 0.8 in group II after PHTLS. This study demonstrates improved cognitive and trauma management skills performance among prehospital paramedical personnel who complete the basic PHTLS program.

Comparison of performance of interns completing the old (1993) and new interactive (1997) Advanced Trauma Life Support courses.

BACKGROUND: The 1997 edition of the Advanced Trauma Life Support (ATLS) course emphasized interactivity as its major change. The impact of this change is assessed in this study. METHODS: We compared two matched groups of 16 interns completing either the old (group I) or new (group II) ATLS course. Cognitive skills (40 standard ATLS questions plus 10 additional questions on airway and shock) and clinical trauma management skills (four trauma objective structured clinical examinations [OSCEs] on simulated trauma patients) were tested. OSCE station scores (standardized to a maximum of 20), priority scores (graded 1-7), organized approach global passing grades (graded 1-5), and initial assessment test station scores (graded 1-5) were compared. RESULTS: Using ATLS criteria, three interns failed in each group. Post-ATLS examination question scores were similar (84.5+/-6.9 for group I, 85.9+/-7.1 for group II); scores for the airway and shock questions were higher but not different between the two groups. The four OSCE station mean scores varied between 13.9+/-2.0 and 15.4+/-2.1 for group I and were higher (p < 0.05) for group II (17.9+/-1.6 to 19.1+/-1.0). Priority scores were similar (group I, 6.3+/-1.1; group II, 6.4+/-1.2), but approach scores (3.9+/-0.1 for group I and 4.9+/-0.8 for group II) were lower in group I, as were the initial assessment test scores (2.9+/-0.2 for group I and 4.9+/-0.8 for group II). There were 8 honors grades in group I and 40 (p < 0.05) in group II. Interactive teaching, adult education principles, opportunities for discussion, provision of feedback, and stimulation of self-learning were rated more highly in the new course. CONCLUSION: Using standard ATLS pass criteria, performance after the new and old ATLS courses was similar. Superior performances were measured using OSCE methodology for clinical trauma management skills after the new compared with the old ATLS course in this population of interns.

Distribution of the paths of early-arriving photons traversing a turbid medium.

We describe experiments to measure the spatial and the temporal distribution of photons traversing a turbid medium in the early-arriving regime in which the photons are multiply scattered but are not completely randomized. The photon paths are resolved temporally by a streak camera and spatially by an adjustable absorbing screen with a small aperture. The results are compared with predictions of a theory based on path integrals (PIs) and with the standard diffusion approximation. The PI theory agrees with the data for both long and short times of flight; this agreement is in contrast to the diffusion approximation, which fails for short times. An alternative PI calculation, based on the use of an effective Lagrangian, also agrees with the experiments. PI theory succeeds because it preserves causality. The implications for optical tomography are discussed.

Attrition of cognitive and trauma management skills after the Advanced Trauma Life Support (ATLS) course.

OBJECTIVE: To test the attrition of cognitive and trauma management skills among practising physicians after the Advanced Trauma Life Support (ATLS) course. DESIGN, MATERIALS, AND METHODS: Sixty practising physicians who completed the ATLS course had comparative assessment of cognitive skills (with multiple choice questions, MCQ) pre-ATLS, immediately post-ATLS, at 6 months (group A), 2 years (group B), 4 years (group C), and 6 years (group D) after the course. Trauma management skills were also compared using eight Objective Structured Clinical Examination (OSCE) trauma stations completed by the four groups of physicians. MEASUREMENTS AND MAIN RESULTS: Pre-ATLS MCQ scores (54.2 +/- 4.2 to 59.8 +/- 5.3%) and immediately post-ATLS MCQ scores (85.9 +/- 5.1 to 87.7 +/- 5.3%) were similar in all four groups. Follow-up MCQ scores were 77.8 +/- 3.6% at 6 months 70.6. +/- 1.9% at 2 years, 69.4 +/- 1.7% at 4 years, and 68.9 +/- 2.0% at 6 years. OSCE scores out of a maximum of 20 were 16.8 +/- 0.3 at 6 months, 13.9 +/- 0.1 at 2 years, 12.0 +/- 0.1 at 4 years, and 11.9 +/- 0.1 at 6 years. Adherence-to-priorities scores (maximum, 7) were 6.6 +/- 0.2 at 6 months, 6.8 +/- 0.1 at 2 years, 6.6 +/- 0.1 at 4 years, and 6.6 +/- 0.1 at 6 years. Organized-approach scores (maximum, 5) were 4.8 +/- 0.1 at 6 months, 4.6 +/- 0.2 at 2 years, 4.7 +/- 0.2 at 4 years, and 4.6 +/- 0.2 at 6 years. Using the MCQ 80% pass mark criterion, at least 50% of physicians fail by 6 months and all fail this cognitive test thereafter. CONCLUSIONS: Whereas cognitive and trauma management skills decline after the ATLS, these skills are maintained at similar levels between 4 and 6 years after ATLS. A 50% failure rate occurs within 6 months and maximum attrition of cognitive skills occurs within 2 years of ATLS completion. Major principles of adherence to priorities and maintenance of an organized approach to trauma care are preserved for at least 6 years after ATLS.