Comparing Deep Learning Approaches for Understanding Genotype × Phenotype Interactions in Biomass Sorghum

We explore the use of deep convolutional neural networks (CNNs) trained on overhead imagery of biomass sorghum to ascertain the relationship between single nucleotide polymorphisms (SNPs), or groups of related SNPs, and the phenotypes they control. We consider both CNNs trained explicitly on the classification task of predicting whether an image shows a plant with a reference or alternate version of various SNPs as well as CNNs trained to create data-driven features based on learning features so that images from the same plot are more similar than images from different plots, and then using the features this network learns for genetic marker classification. We characterize how efficient both approaches are at predicting the presence or absence of a genetic markers, and visualize what parts of the images are most important for those predictions. We find that the data-driven approaches give somewhat higher prediction performance, but have visualizations that are harder to interpret; and we give suggestions of potential future machine learning research and discuss the possibilities of using this approach to uncover unknown genotype × phenotype relationships.

Immunization stress-related response - Redefining immunization anxiety-related reaction as an adverse event following immunization

The Council for the International Organizations of Medical Sciences (CIOMS) and WHO working group on pharmacovigilance defines five cause specific AEFI which includes an immunization anxiety-related reaction. Historically this term has been used to describe a range of symptoms and signs that may arise after immunization that are related to "anxiety" about the immunization. However, the term "anxiety" does not adequately capture all the elements of this cause specific AEFI. In 2015, the Global Advisory Committee for Vaccine Safety convened an expert working group with the purpose of redefining, preventing and managing this particular AEFI. The term "Immunization Stress-Related Response" is proposed to replace the former terminology. We present a manual that redefines this AEFI and present a framework for prevention, diagnosis and management in both an individual and also when such events occur as clusters and affect multiple individuals. Since such mass events can result in cessation of immunization programmes and/or a loss of public confidence, a communication response is essential.

High-throughput phenotyping with deep learning gives insight into the genetic architecture of flowering time in wheat

BACKGROUND

Measurement of plant traits with precision and speed on large populations has emerged as a critical bottleneck in connecting genotype to phenotype in genetics and breeding. This bottleneck limits advancements in understanding plant genomes and the development of improved, high-yielding crop varieties.

RESULTS

Here we demonstrate the application of deep learning on proximal imaging from a mobile field vehicle to directly estimate plant morphology and developmental stages in wheat under field conditions. We developed and trained a convolutional neural network with image datasets labeled from expert visual scores and used this "breeder-trained" network to classify wheat morphology and developmental stages. For both morphological (awned) and phenological (flowering time) traits, we demonstrate high heritability and very high accuracy against the "ground-truth" values from visual scoring. Using the traits predicted by the network, we tested genotype-to-phenotype association using the deep learning phenotypes and uncovered novel epistatic interactions for flowering time. Enabled by the time-series high-throughput phenotyping, we describe a new phenotype as the rate of flowering and show heritable genetic control for this trait.

CONCLUSIONS

We demonstrated a field-based high-throughput phenotyping approach using deep learning that can directly measure morphological and developmental phenotypes in genetic populations from field-based imaging. The deep learning approach presented here gives a conceptual advancement in high-throughput plant phenotyping because it can potentially estimate any trait in any plant species for which the combination of breeder scores and high-resolution images can be obtained, capturing the expert knowledge from breeders, geneticists, pathologists, and physiologists to train the networks.

High-throughput phenotyping with deep learning gives insight into the genetic architecture of flowering time in wheat

BACKGROUND

Measurement of plant traits with precision and speed on large populations has emerged as a critical bottleneck in connecting genotype to phenotype in genetics and breeding. This bottleneck limits advancements in understanding plant genomes and the development of improved, high-yielding crop varieties.

RESULTS

Here we demonstrate the application of deep learning on proximal imaging from a mobile field vehicle to directly estimate plant morphology and developmental stages in wheat under field conditions. We developed and trained a convolutional neural network with image datasets labeled from expert visual scores and used this "breeder-trained" network to classify wheat morphology and developmental stages. For both morphological (awned) and phenological (flowering time) traits, we demonstrate high heritability and very high accuracy against the "ground-truth" values from visual scoring. Using the traits predicted by the network, we tested genotype-to-phenotype association using the deep learning phenotypes and uncovered novel epistatic interactions for flowering time. Enabled by the time-series high-throughput phenotyping, we describe a new phenotype as the rate of flowering and show heritable genetic control for this trait.

CONCLUSIONS

We demonstrated a field-based high-throughput phenotyping approach using deep learning that can directly measure morphological and developmental phenotypes in genetic populations from field-based imaging. The deep learning approach presented here gives a conceptual advancement in high-throughput plant phenotyping because it can potentially estimate any trait in any plant species for which the combination of breeder scores and high-resolution images can be obtained, capturing the expert knowledge from breeders, geneticists, pathologists, and physiologists to train the networks.

Longitudinal Outcomes in the 2014 Acute Flaccid Paralysis Cluster in Canada

We describe the presenting features and long-term outcome of an unusual cluster of pediatric acute flaccid paralysis cases that occurred in Canada during the 2014 enterovirus D68 outbreak. Children (n = 25; median age 7.8 years) presenting to Canadian centers between July 1 and October 31, 2014, and who met diagnostic criteria for acute flaccid paralysis were evaluated retrospectively. The predominant presenting features included prodromal respiratory illness (n = 22), cerebrospinal fluid lymphocytic pleocytosis (n = 18), pain in neck/back (n = 14) and extremities (n = 10), bowel/bladder dysfunction (n = 9), focal central gray matter lesions found in all regions of the spinal cord within the cohort (n = 16), brain stem lesions (n = 8), and bulbar symptoms (n = 5). Enterovirus D68 was detectable in nasopharyngeal specimens (n = 7) but not in cerebrospinal fluid. Acute therapies (corticosteroids, intravenous immunoglobulins, plasmapheresis) were well tolerated with few side effects. Fourteen of 16 patients who were followed beyond 12 months post onset had neurologic deficits but showed ongoing clinical improvement and motor recovery.

Global alignment of immunization safety assessment in pregnancy - The GAIA project

Immunization in pregnancy provides a promising contribution to globally reducing neonatal and under-five childhood mortality and morbidity. Thorough assessment of benefits and risks for the primarily healthy pregnant women and their unborn babies is required. The GAIA project was formed in response to the call of the World Health Organization for a globally concerted approach to actively monitor the safety of vaccines and immunization in pregnancy programs. GAIA aims to improve the quality of outcome data from clinical vaccine trials in pregnant women with a specific focus on the needs and requirements for safety monitoring in LMIC. In the first year of the project, a large and functional network of experts was created. The first outputs include a guidance document for clinical trials of immunization in pregnancy, a basic data collection guide, ten case definitions of key obstetric and neonatal health outcomes, an ontology of key terms and a map of pertinent disease codes. The GAIA Network is designed as an open and growing forum for professionals sharing the GAIA vision and aim. Based on the initial achievements, tools and services are developed to support investigators and strengthen immunization in pregnancy programs with specific focus on LMIC.

Contributions and challenges for worldwide vaccine safety: The Global Advisory Committee on Vaccine Safety at 15 years

In 1999, the Global Advisory Committee on Vaccine Safety (GACVS) was established by the World Health Organization (WHO) to provide independent scientific advice on issues relating to the safety of vaccines and immunization. Fifteen years onward, we conducted a multi-faceted review to evaluate the impact, reach and challenges facing GACVS, including the role GACVS plays in informing global, regional and WHO member state vaccine policy. The methods included measures of organizational structure, citation impact, themes approached, and a discussion by previous and current members to evaluate past, present and future challenges. Given the increasing range of data sources and the deployment of many new vaccines, the Committee is facing the complex task of identifying the best available evidence for recommendations on vaccine safety. To help meet the increased demand for public transparency in decision making, GACVS-structured methodology for evidence-based decisions is evolving. GACVS also promotes best practices and capacity building for timely and accurate risk assessment; risk communications; outreach to help countries maintain and, if needed, rebuild public trust in vaccines; and advocacy for bridging the major gaps in vaccine safety capacity globally.

Webcams, Crowdsourcing, and Enhanced Crosswalks: Developing a Novel Method to Analyze Active Transportation

INTRODUCTION

Active transportation opportunities and infrastructure are an important component of a community's design, livability, and health. Features of the built environment influence active transportation, but objective study of the natural experiment effects of built environment improvements on active transportation is challenging. The purpose of this study was to develop and present a novel method of active transportation research using webcams and crowdsourcing, and to determine if crosswalk enhancement was associated with changes in active transportation rates, including across a variety of weather conditions.

METHODS

The 20,529 publicly available webcam images from two street intersections in Washington, DC, USA were used to examine the impact of an improved crosswalk on active transportation. A crowdsource, Amazon Mechanical Turk, annotated image data. Temperature data were collected from the National Oceanic and Atmospheric Administration, and precipitation data were annotated from images by trained research assistants.

RESULTS

Summary analyses demonstrated slight, bi-directional differences in the percent of images with pedestrians and bicyclists captured before and after the enhancement of the crosswalks. Chi-square analyses revealed these changes were not significant. In general, pedestrian presence increased in images captured during moderate temperatures compared to images captured during hot or cold temperatures. Chi-square analyses indicated the crosswalk improvement may have encouraged walking and biking in uncomfortable outdoor conditions (P < 0.5).

CONCLUSION

The methods employed provide an objective, cost-effective alternative to traditional means of examining the effects of built environment changes on active transportation. The use of webcams to collect active transportation data has applications for community policymakers, planners, and health professionals. Future research will work to validate this method in a variety of settings as well as across different built environment and community policy initiatives.

Abstract 2316: Fasting protects mice from lethal DNA damage by promoting small intestinal stem cell survival and by inhibiting acute inflammation

Short-term fasting in mice has been shown to increase survival from lethal doses of chemotherapy; however, the route of protection in these animals is unknown. In this study we demonstrate that fasting prior to chemotherapy protects small intestinal (SI) stem cells in mice exposed to high dose etoposide. Histologic and in vitro crypt culture analyses show nearly all SI stem cells were lost when fed mice were treated with high dose etoposide but high numbers of stem cells survived when fasted mice were similarly treated. In fasted mice treated with etoposide, multiple stem cell populations marked by Lgr5, Bmi1 or HopX expression contributed to maintaining small intestinal architecture and function as identified by lineage tracing analysis. We found fasting did not impact plasma etoposide clearance; consequently, etoposide treatment induced similar levels of DNA double strand breaks (DSBs) in stem cells of both fed and fasted mice through γH2AX immunofluorescence staining. Expression analysis of enriched populations of SI stem/progenitor cells isolated from etoposide-treated treated mice revealed that DNA repair and DNA damage response genes were elevated in response to fasting. Expression results correlated with faster resolution of DNA DSBs, as measured by loss of γH2AX staining and with reduced apoptosis, as measured by cleaved caspase-3 staining in stem/progenitors cells of fasted mice. Strikingly, large numbers of neutrophils infiltrated into the SI of fed mice within 48 h of etoposide treatment resulting in complete separation of crypts from their corresponding villi. By contrast, inflammatory cell infiltrates were not observed in the SI of fasted mice following similar treatment. These results suggest that fasting preserves small intestinal architecture and barrier function by increasing DNA repair capacity in SI stem cells and by preventing pro-inflammatory responses following exposure to high dose chemotherapy. Fasting may therefore be useful as a prophylactic treatment to reduce host toxicity in patients undergoing dose intensive chemotherapy. Future work will focus on delineating the molecular mechanism of fasting-induced SI stem cell protection.

Citation Format: Kelsey L. Tinkum, Kristina M. Stemler, Lynn S. White, Andrew J. Loza, Sabrina Jeter-Jones, Basia M. Michalski, Catherine E. Kuzmicki, Robert Pless, Thaddeus Stappenbeck, David Piwnica-Worms, Helen Piwnica-Worms. Fasting protects mice from lethal DNA damage by promoting small intestinal stem cell survival and by inhibiting acute inflammation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2316. doi:10.1158/1538-7445.AM2015-2316

Safety of immunization during pregnancy: a review of the evidence of selected inactivated and live attenuated vaccines

Vaccine-preventable infectious diseases are responsible for significant maternal, neonatal, and young infant morbidity and mortality. While there is emerging scientific evidence, as well as theoretical considerations, indicating that certain vaccines are safe for pregnant women and fetuses, policy formulation is challenging because of perceived potential risks to the fetus. This report presents an overview of available evidence on pregnant women vaccination safety monitoring in pregnant women, from both published literature and ongoing surveillance programs. Safety data were reviewed for vaccines against diseases which increase morbidity in pregnant women, their fetus or infant as well as vaccines which are used in mass vaccination campaigns against diseases. They include inactivated seasonal and pandemic influenza, mono- and combined meningococcal polysaccharide and conjugated vaccines, tetanus toxoid and acellular pertussis combination vaccines, as well as monovalent or combined rubella, oral poliomyelitis virus and yellow fever vaccines. No evidence of adverse pregnancy outcomes has been identified from immunization of pregnant women with these vaccines.

Two cloud-based cues for estimating scene structure and camera calibration

We describe algorithms that use cloud shadows as a form of stochastically structured light to support 3D scene geometry estimation. Taking video captured from a static outdoor camera as input, we use the relationship of the time series of intensity values between pairs of pixels as the primary input to our algorithms. We describe two cues that relate the 3D distance between a pair of points to the pair of intensity time series. The first cue results from the fact that two pixels that are nearby in the world are more likely to be under a cloud at the same time than two distant points. We describe methods for using this cue to estimate focal length and scene structure. The second cue is based on the motion of cloud shadows across the scene; this cue results in a set of linear constraints on scene structure. These constraints have an inherent ambiguity, which we show how to overcome by combining the cloud motion cue with the spatial cue. We evaluate our method on several time lapses of real outdoor scenes.

Principal component analysis of dynamic relative displacement fields estimated from MR images

Non-destructive measurement of acceleration-induced displacement fields within a closed object is a fundamental challenge. Inferences of how the brain deforms following skull impact have thus relied largely on indirect estimates and course-resolution cadaver studies. We developed a magnetic resonance technique to quantitatively identify the modes of displacement of an accelerating soft object relative to an object enclosing it, and applied it to study acceleration-induced brain deformation in human volunteers. We show that, contrary to the prevailing hypotheses of the field, the dominant mode of interaction between the brain and skull in mild head acceleration is one of sliding arrested by meninges.

Pandemic (H1N1) 2009 outbreak at Canadian Forces cadet camp

We conducted a case-control study to describe the clinical and epidemiologic characteristics of an outbreak of pandemic (H1N1) 2009 at a Canadian military cadet training center. We found that asthma and obesity confer greater risk for infection. Viral shedding was detected by PCR up to 18 days after symptom onset.

Chapter 16. Two-photon microscopy and multidimensional analysis of cell dynamics

Two-photon (2P) microscopy is a high-resolution imaging technique that was initially applied by neurobiologists and developmental cell biologists but has subsequently been broadly adapted by immunologists. The value of 2P microscopy is that it affords an unparalleled view of single-cell spatiotemporal dynamics deep within intact tissues and organs. As the technology develops and new transgenic mice and fluorescent probes become available, 2P microscopy will serve as an increasingly valuable tool for assessing cell function and probing molecular mechanisms. Here we discuss the technical aspects related to 2P microscope design, explain in detail various tissue imaging preparations, and walk the reader through the often daunting process of analyzing multidimensional data sets and presenting the experimental results.

Monitoring of adverse events during the 2003 mass vaccination campaign with a trivalent meningococcal A/C/W135 polysaccharide vaccine in Burkina Faso

During a mass campaign with a newly licensed meningococcal polysaccharide ACW135 vaccine in Burkina Faso, adverse events following immunization (AEFI) were monitored up to 4 weeks after the campaign. Eighty-six AEFI cases (5.9 cases per 100,000 vaccine doses distributed) were reported. Among 22 serious events, 4 severe local reactions were considered very likely and 4 severe allergic reactions were considered probably related to the vaccination. One fatal case in a child followed protracted seizures of undetermined cause. In a setting with no prior surveillance system, adverse events were reported at rates comparable to documented rates for meningococcal polysaccharide vaccines in other settings. The findings confirm the benefits of the vaccine in the control of meningococcal meningitis.

Understanding vaccine safety information from the Vaccine Adverse Event Reporting System

The Vaccine Adverse Event Reporting System (VAERS) is administered by the Food and Drug Administration and CDC and is a key component of postlicensure vaccine safety surveillance. Its primary function is to detect early warning signals and generate hypotheses about possible new vaccine adverse events or changes in frequency of known ones. VAERS is a passive surveillance system that relies on physicians and others to voluntarily submit reports of illness after vaccination. Manufacturers are required to report all adverse events of which they become aware. There are a number of well-described limitations of such reporting systems. These include, for example, variability in report quality, biased reporting, underreporting and the inability to determine whether a vaccine caused the adverse event in any individual report. Strengths of VAERS are that it is national in scope and timely. The information in VAERS reports is not necessarily complete nor is it verified systematically. Reports are classified as serious or nonserious based on regulatory criteria. Reports are coded by VAERS in a uniform way with a limited number of terms using a terminology called COSTART. Coding is useful for search purposes but is necessarily imprecise. VAERS is useful in detecting adverse events related to vaccines and most recently was used for enhanced reporting of adverse events in the national smallpox immunization campaign. VAERS data have always been publicly available. However, it is essential for users of VAERS data to be fully aware of the strengths and weaknesses of the system. VAERS data contain strong biases. Incidence rates and relative risks of specific adverse events cannot be calculated. Statistical significance tests and confidence intervals should be used with great caution and not routinely. Signals detected in VAERS should be subjected to further clinical and descriptive epidemiologic analysis. Confirmation in a controlled study is usually required. An understanding of the system's defined objectives and inherent drawbacks is vital to the effective use of VAERS data in vaccine safety investigations.

Epidemiology of autoimmune reactions induced by vaccination

In order for vaccinations to 'work', the immune system must be stimulated. The concern that immunizations may lead to the development of autoimmune disease (AID) has been questioned. Since AID occur in the absence of immunizations, it is unlikely that immunizations are a major cause of AID. Epidemiological studies are needed, however, to assess whether immunizations may increase the risk in some susceptible individuals. This paper discusses the evidence for and against vaccination as a risk factor for AID. Evidence for immunizations leading to AID come from several sources including animal studies, single and multiple case reports, and ecologic association. However more rigorous investigation has failed to confirm most of the allegations. Unfortunately the question remains difficult to address because for most AIDs, there is limited knowledge of the etiology, background incidence and other risk factors for their development. This information is necessary, in the absence of experimental evidence derived from controlled studies, for any sort of adequate causality assessment using the limited data that are available. Several illustrative examples are discussed to highlight what is known and what remains to be explored, and the type of epidemiological evidence that would be required to better address the issues. Examples include the possible association of immunization and multiple sclerosis (and other demyelinating diseases), type 1 diabetes mellitus, Guillain-Barre Syndrome, idiopathic thrombocytopenic purpura, and rheumatoid arthritis.

Challenges and controversies in immunization safety

No vaccine is perfectly safe or effective. As diseases such as diphtheria and polio fade, vaccine safety concerns, especially alleged links between vaccinations and several chronic illnesses, have become increasingly prominent in the media and to the public. This article reviews the current scientific evidence on several recent vaccine safety controversies. It also provides information on how various safety research is conducted, some of the concurrent challenges, and finally, some guidance on communicating with patients on vaccine risks.

The Ouchi illusion as an artifact of biased flow estimation

A pattern by Ouchi has the surprising property that small motions can cause illusory relative motion between the inset and background regions. The effect can be attained with small retinal motions or a slight jiggling of the paper and is robust over large changes in the patterns, frequencies and boundary shapes. In this paper, we explain that the cause of the illusion lies in the statistical difficulty of integrating local one-dimensional motion signals into two-dimensional image velocity measurements. The estimation of image velocity generally is biased, and for the particular spatial gradient distributions of the Ouchi pattern the bias is highly pronounced, giving rise to a large difference in the velocity estimates in the two regions. The computational model introduced to describe the statistical estimation of image velocity also accounts for the findings of psychophysical studies with variations of the Ouchi pattern and for various findings on the perception of moving plaids. The insight gained from this computational study challenges the current models used to explain biological vision systems and to construct robotic vision systems. Considering the statistical difficulties in image velocity estimation in conjunction with the problem of discontinuity detection in motion fields suggests that theoretically the process of optical flow computations should not be carried out in isolation but in conjunction with the higher level processes of 3D motion estimation, segmentation and shape computation.

Monitoring signals for vaccine safety: the assessment of individual adverse event reports by an expert advisory committee. Advisory Committee on Causality Assessment

Monitoring vaccine safety is a complex and shared responsibility. It can be carried out in many ways, one of which is the reporting of individual cases of adverse reactions thought to be due to vaccination. The task is difficult because ascribing causality to an individual case report is fraught with challenges. A standardized evaluation instrument--known as the causality assessment form--was therefore developed for use by an expert advisory committee to facilitate the process. By following the several sections in this form, the members of the committee are taken through a series of points to establish causality. These points include the basic criteria for causation such as biological plausibility, the time elapsed between the vaccine administration and the onset of the adverse event, and whether other factors (drugs, chemicals or underlying disease) could account for the adverse symptoms. The form concludes with a consensus assessment of causality, a commentary about the assessment, and advice for further study or follow-up. This method of assessing the more serious cases of adverse reaction reported to vaccination has proven useful in evaluating ongoing safety of vaccines in Canada. Through analyses such as this, new signals can be identified and investigated further.

Reporting vaccine-associated adverse events

OBJECTIVE

To determine family physicians' awareness of the need to monitor and report vaccine-associated adverse events (VAAE) in Canada and to identify mechanisms that could facilitate reporting.

DESIGN

Mailed survey.

SETTING

Canadian family practices.

PARTICIPANTS

Random sample of 747 family physicians. Overall response rate was 32% (226 of 717 eligible physicians).

MAIN OUTCOME MEASURES

Access to education on VAAE; knowledge about VAAE monitoring systems, reporting criteria, and reporting forms; method of reporting VAAEs and reasons for not reporting them; and current experience with VAAEs.

RESULTS

Of 226 respondents, 55% reported observing VAAEs, and 42% reported the event. Fewer than 50% were aware of a monitoring system for VAAE, and only 39% had had VAAE-related education during medical training. Only 28% knew the reporting criteria. Reporting was significantly associated with knowledge of VAAE monitoring systems and reporting criteria (P < 0.01).

CONCLUSION

Physicians need more feedback and education on VAAE reporting and more information about the importance of reporting and about reporting criteria and methods.

Families of stationary patterns producing illusory movement: insights into the visual system

A computational explanation of the illusory movement experienced upon extended viewing of Enigma, a static figure painted by Leviant, is presented. The explanation relies on a model for the interpretation of three-dimensional motion information contained in retinal motion measurements. This model shows that the Enigma figure is a special case of a larger class of figures exhibiting the same illusory movement and these figures are introduced here. Our explanation suggests that eye movements and/or accommodation changes cause weak retinal motion signals, which are interpreted by higher-level processes in a way that gives rise to these illusions, and proposes a number of new experiments to unravel the functional structure of the motion pathway.

Drug-Related Mortality in Canada (1984-1994)

OBJECTIVE

To examine drug-related deaths due to adverse drug reactions between 1984 and 1994.

DATA SOURCE

Voluntary reports of deaths due to adverse events as reported to the Adverse Drug Reaction Monitoring Program, Drugs Directorate, Health Protection Branch, Health Canada.

METHODS

Drugs were classified according to the Anatomical, Therapeutic, Chemical (ATC) coding system. Descriptive statistics were utilized.

RESULTS

One thousand four hundred and seventeen drug-related deaths were reported (700 male, 685 female, 32 unknown). The mean+/-SD age of patients was 54.6+/-21.7 years (range 1 month-97 years). In total, 2131 medications were implicated as suspect drugs (1.5+/-1.0, range 1-7). The most commonly reported categories of suspect drugs were the nervous system agents (50.6%), followed by cardiovascular system agents (9.0%), general antiinfectives for systemic use (8.8%) and musculoskeletal system agents (8.3%). One thousand and eighty-six deaths were classified as non-suicides. For non-suicide deaths, the most commonly reported suspect drugs were classified as nervous system agents (37.9%), followed by general antiinfectives for systemic use (12.3%), musculoskeletal system (11.5%) and cardiovascular system agents (10.2%). Three hundred and thirty-one (23.3%) reports were identified as suicides. For suicides, the most commonly reported suspect drugs were the nervous system agents (81.1%), followed by the respiratory system agents (8.5%) and the cardiovascular system agents (6.0%).

CONCLUSION

Nervous system agents, musculoskeletal medications and general antiinfectives for systemic use figured prominently in deaths reported to HPB between 1984 and 1994.

Adverse events temporally associated with meningococcal vaccines

OBJECTIVE

To determine the incidence of severe adverse events temporally associated with meningococcal vaccines administered as part of a mass vaccination program.

DESIGN

Retrospective descriptive study of events reported to a passive provincial surveillance system.

SETTING

The province of Quebec.

PARTICIPANTS

The 1,198,751 individuals aged 6 months to 20 years who were vaccinated against meningococcal disease between Dec. 27, 1992, and Mar. 31, 1993.

OUTCOME MEASURES

Total numbers and rates of severe adverse events, including allergic reactions, anaphylactic reactions, neurological events (other than abnormal crying and screaming) and other serious or unusual events.

RESULTS

A total of 118 reports of severe adverse events were selected from the surveillance system. The most frequent were allergic reactions (9.2 per 100,000 doses). Few anaphylactic or neurologic reactions were reported (0.1 and 0.5 per 100,000 doses respectively). There were no reports of sequelae or of encephalopathy, meningitis or encephalitis.

CONCLUSION

Meningococcal vaccines seem to be associated with fewer adverse events than have previously been reported. Existing surveillance programs are useful for determining the incidence of adverse events temporally associated with vaccines.

How well do family physicians manage sexually transmitted diseases?

OBJECTIVE

To identify gaps in knowledge about sexually transmitted diseases (STDs) and evaluate practice.

DESIGN

We compared how 49 family physicians managed 249 episodes of STDs with the recommendations of the 1988-1989 Canadian STD management guidelines. (The study took place before revised guidelines were distributed in late 1992.)

SETTING

Family physicians' practices throughout Canada.

PARTICIPANTS

Physicians recruited by the National Research System from among the members of the College of Family Physicians of Canada. These physicians had been in practice for a mean of 9 years; 43 were Certificants of the College.

MAIN OUTCOME MEASURES

Family physicians' self-reported episodes of sexually transmitted disease evaluated in light of current Canadian guidelines.

RESULTS

Of the 249 episodes studied, 215 (86.3%) were treated effectively, and 34 (13.7%) were judged to have been treated ineffectively. Of the 215 effective treatments, 67 (31.2%) were not completely in agreement with current guidelines.

CONCLUSION

Experienced family physicians with postgraduate training usually manage STDs well. The number of ineffective treatments and effective treatments not following the 1988-1989 guidelines, especially for pelvic inflammatory disease, indicates that information on managing certain STDs and syndromes should be made available to all family physicians in a format that is easy to read and use.

Adverse events temporally associated with immunizing agents

In Canada during 1990, a total of 2832 reports of adverse events temporally associated with the administration of immunizing agents were received by the Childhood Immunization Division of the Laboratory Centre for Disease Control. This paper summarizes the data collected, describes the surveillance system, and demonstrates that, with more than 12,000,000 doses of vaccines distributed during 1990, the incidence of adverse events reported is very low.

Trends in bicycle helmet use in Ottawa from 1988 to 1991

OBJECTIVE

To determine the prevalence rates of helmet use by cyclists in Ottawa in September 1991 and to compare them with the rates in a baseline survey conducted in September 1988.

DESIGN

Observational survey.

SUBJECTS

A total of 3252 cyclists (commuters, recreational cyclists and students in primary, secondary and postsecondary schools) were observed. In the baseline study 1963 such cyclists had been surveyed.

RESULTS

In 1991, 1056 (32.5%) of the cyclists were observed wearing helmets. After the samples were standardized for varying size across the cyclist groups the total helmet use was found to have increased from 10.7% in 1988 to 32.2% in 1991. The highest increase in the rate of helmet use was found among the commuters (from 17.9% in 1988 to 44.6% in 1991); the rate had increased from 14.3% to 31.1% among the recreational cyclists and from 1.9% to 21.0% among the students. All of the trends were statistically significant (p less than 0.0001). When the student population was subdivided the rate of helmet use was found to be 25% among the elementary school children, 17% among the secondary school students and 20.2% among the postsecondary school students.

CONCLUSIONS

The use of bicycle helmets in Ottawa has increased dramatically. Our experience, as well as evidence from other centres, indicates that specific interventions such as media coverage, bulk-buying projects in schools and discount coupons can accelerate the rate of helmet adoption. Although less than half of cyclists are wearing helmets the trend has acquired considerable momentum, and major gains are expected in the next few years. Nevertheless, resistance among young adults and the cost of helmets for low-income groups may be problems. These challenges call for the refinement of future promotional strategies.

A 1H NMR study of the syn-anti dynamic equilibrium in adenine nucleosides and nucleotides with the aid of some synthetic model analogues with fixed conformations

The syn-anti equilibrium about the glycosidic bond in adenosine and some related analogues was studied by means of 1H NMR spectroscopy, with the aid of several model analogues fixed in given conformations either by intramolecular bonding, or by introduction of a bulky substituent. A model unambiguously and exclusively in the syn conformation is 8- (alpha-hydroxyisopropyl) adenosine; while one fixed in the anti conformation is 8,5'-anhydro-8-oxoadenosine. A new analogue, fixed in the high anti conformation, is 8,2-'O-isopropylidenearabinofuranosyladenine. Several additional new model compounds were synthesized and their properties are described. With the aid of these models, the syn-anti dynamic equilibrium was examined for adenosine and some related compounds in different solvent systems, and the conformer populations evaluated quantitatively. The validity of the procedure applied, and the accuracy of the results are critically examined, and compared with findings obtained by other procedures. Available literature data on the syn-anti equilibrium in other 8-substituted adenosines are re-analyzed in the light of the present results. An analysis is also presented of the interdependence of the various conformational parameter, i. e. conformation about the glycosidic bond and those of the sugar ring and exocyclic carbinol group, in adenosine and 2',3'-O-isopropylidenadenosine.