Olfactory detection of viruses shapes brain immunity and behavior in zebrafish

Olfactory sensory neurons (OSNs) are constantly exposed to pathogens, including viruses. However, serious brain infection via the olfactory route rarely occurs. When OSNs detect a virus, they coordinate local antiviral immune responses to stop virus progression to the brain. Despite effective immune control in the olfactory periphery, pathogen-triggered neuronal signals reach the CNS via the olfactory bulb (OB). We hypothesized that neuronal detection of a virus by OSNs initiates neuroimmune responses in the OB that prevent pathogen invasion. Using zebrafish ( Danio rerio ) as a model, we demonstrate viral-specific neuronal activation of OSNs projecting into the OB, indicating that OSNs are electrically activated by viruses. Further, behavioral changes are seen in both adult and larval zebrafish after viral exposure. By profiling the transcription of single cells in the OB after OSNs are exposed to virus, we found that both microglia and neurons enter a protective state. Microglia and macrophage populations in the OB respond within minutes of nasal viral delivery followed decreased expression of neuronal differentiation factors and enrichment of genes in the neuropeptide signaling pathway in neuronal clusters. Pituitary adenylate-cyclase-activating polypeptide ( pacap ), a known antimicrobial, was especially enriched in a neuronal cluster. We confirm that PACAP is antiviral in vitro and that PACAP expression increases in the OB 1 day post-viral treatment. Our work reveals how encounters with viruses in the olfactory periphery shape the vertebrate brain by inducing antimicrobial programs in neurons and by altering host behavior.

Npas4a expression in the teleost forebrain is associated with stress coping style differences in fear learning

Learning to anticipate potentially dangerous contexts is an adaptive behavioral response to coping with stressors. An animal's stress coping style (e.g. proactive-reactive axis) is known to influence how it encodes salient events. However, the neural and molecular mechanisms underlying these stress coping style differences in learning are unknown. Further, while a number of neuroplasticity-related genes have been associated with alternative stress coping styles, it is unclear if these genes may bias the development of conditioned behavioral responses to stressful stimuli, and if so, which brain regions are involved. Here, we trained adult zebrafish to associate a naturally aversive olfactory cue with a given context. Next, we investigated if expression of two neural plasticity and neurotransmission-related genes (npas4a and gabbr1a) were associated with the contextual fear conditioning differences between proactive and reactive stress coping styles. Reactive zebrafish developed a stronger conditioned fear response and showed significantly higher npas4a expression in the medial and lateral zones of the dorsal telencephalon (Dm, Dl), and the supracommissural nucleus of the ventral telencephalon (Vs). Our findings suggest that the expression of activity-dependent genes like npas4a may be differentially expressed across several interconnected forebrain regions in response to fearful stimuli and promote biases in fear learning among different stress coping styles.

Differential effects of ethanol on behavior and GABAA receptor expression in adult zebrafish (Danio rerio) with alternative stress coping styles

Variation in stress responses between individuals are linked to factors ranging from stress coping styles to sensitivity of neurotransmitter systems. Many anxiolytic compounds (e.g. ethanol) can increase stressor engagement through modulation of neurotransmitter systems and are used to investigate stress response mechanisms. There are two alternative suites of correlated behavioral and physiological responses to stressors (stress coping styles) that differ in exploration tendencies: proactive and reactive stress coping styles. By chronically treating individuals differing in stress coping style with ethanol, a GABA-acting drug, we assessed the role of the GABAergic system on the behavioral stress response. Specifically, we investigated resulting changes in stress-related behavior (i.e. exploratory behavior) and whole-brain GABAA receptor subunits (gabra1, gabra2, gabrd, & gabrg2) in response to a novelty stressor. We found that ethanol-treated proactive individuals showed lower stress-related behaviors than their reactive counterparts. Proactive individuals showed significantly higher expression of gabra1, gabra2, and gabrg2 compared to reactive individuals and ethanol treatment resulted in upregulation of gabra1 and gabrg2 in both stress coping styles. These results suggest that impacts of ethanol on stress-related behaviors vary by stress coping style and that expression of select GABAA receptor subunits may be one of the underlying mechanisms.

Differences in stress reactivity between zebrafish with alternative stress coping styles

Animals experience stress in a variety of contexts and the behavioural and neuroendocrine responses to stress can vary among conspecifics. The responses across stressors often covary within an individual and are consistently different between individuals, which represent distinct stress coping styles (e.g. proactive and reactive). While studies have identified differences in peak glucocorticoid levels, less is known about how cortisol levels differ between stress coping styles at other time points of the glucocorticoid stress response. Here we quantified whole-body cortisol levels and stress-related behaviours (e.g. depth preference, movement) at time points representing the rise and recovery periods of the stress response in zebrafish lines selectively bred to display the proactive and reactive coping style. We found that cortisol levels and stress behaviours are significantly different between the lines, sexes and time points. Further, individuals from the reactive line showed significantly higher cortisol levels during the rising phase of the stress response compared with those from the proactive line. We also observed a significant correlation between individual variation of cortisol levels and depth preference but only in the reactive line. Our results show that differences in cortisol levels between the alternative stress coping styles extend to the rising phase of the endocrine stress response and that cortisol levels may explain variation in depth preferences in the reactive line. Differences in the timing and duration of cortisol levels may influence immediate behavioural displays and longer lasting neuromolecular mechanisms that modulate future responses.

Neurotranscriptome profiles of multiple zebrafish strains

Behavioral displays or physiological responses are often influenced by intrinsic and extrinsic mechanisms in the context of the organism's evolutionary history. Understanding differences in transcriptome profiles can give insight into adaptive or pathological responses. We utilize high throughput sequencing (RNA-sequencing) to characterize the neurotranscriptome profiles in both males and females across four strains of zebrafish (Danio rerio). Strains varied by previously documented differences in stress and anxiety-like behavioral responses, and generations removed from wild-caught individuals. Here we describe detailed methodologies and quality controls in generating the raw RNA-sequencing reads that are publically available in NCBI's Gene Expression Omnibus database (GSE61108).

Characterizing the neurotranscriptomic states in alternative stress coping styles

Background

Animals experience stress in many contexts and often successfully cope. Individuals exhibiting the proactive versus reactive stress coping styles display qualitatively different behavioral and neuroendocrine responses to stressors. The predisposition to exhibiting a particular coping style is due to genetic and environmental factors. In this study we explore the neurotranscriptomic and gene network biases that are associated with differences between zebrafish (Danio rerio) lines selected for proactive and reactive coping styles and reared in a common garden environment.

Results

Using RNA-sequencing we quantified the basal transcriptomes from the brains of wild-derived zebrafish lines selectively bred to exhibit the proactive or reactive stress coping style. We identified 1953 genes that differed in baseline gene expression levels. Weighted gene coexpression network analyses identified one gene module associated with line differences. Together with our previous pharmacological experiment, we identified a core set of 62 genes associated with line differences. Gene ontology analyses reveal that many of these core genes are implicated in neurometabolism (e.g. organic acid biosynthetic and fatty acid metabolic processes).

Conclusions

Our results show that proactive and reactive stress coping individuals display distinct basal neurotranscriptomic states. Differences in baseline expression of select genes or regulation of specific gene modules are linked to the magnitude of the behavioral response and the display of a coping style, respectively. Our results expand the molecular mechanisms of stress coping from one focused on the neurotransmitter systems to a more complex system that involves an organism’s capability to handle neurometabolic loads and allows for comparisons with other animal taxa to uncover potential conserved mechanisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1626-x) contains supplementary material, which is available to authorized users.

Limited sex-biased neural gene expression patterns across strains in Zebrafish (Danio rerio)

Background

Male and female vertebrates typically differ in a range of characteristics, from morphology to physiology to behavior, which are influenced by factors such as the social environment and the internal hormonal and genetic milieu. However, sex differences in gene expression profiles in the brains of vertebrates are only beginning to be understood. Fishes provide a unique complement to studies of sex differences in mammals and birds given that fish show extreme plasticity and lability of sexually dimorphic characters and behaviors during development and even adulthood. Hence, teleost models can give additional insight into sexual differentiation. The goal of this study is to identify neurotranscriptomic mechanisms for sex differences in the brain.

Results

In this study we examined whole-brain sex-biased gene expression through RNA-sequencing across four strains of zebrafish. We subsequently conducted systems level analyses by examining gene network dynamics between the sexes using weighted gene coexpression network analysis. Surprisingly, only 61 genes (approximately 0.4% of genes analyzed) showed a significant sex effect across all four strains, and 48 of these differences were male-biased. Several of these genes are associated with steroid hormone biosynthesis. Despite sex differences in a display of stress-related behaviors, basal transcript levels did not predict the intensity of the behavioral display. WGCNA revealed only one module that was significantly associated with sex. Intriguingly, comparing intermodule dynamics between the sexes revealed only moderate preservation. Further we identify sex-specific gene modules.

Conclusions

Despite differences in morphology, physiology, and behavior, there is limited sex-biased neural gene expression in zebrafish. Further, genes found to be sex-biased are associated with hormone biosynthesis, suggesting that sex steroid hormones may be key contributors to sexual behavioral plasticity seen in teleosts. A possible mechanism is through regulating specific brain gene networks.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-905) contains supplementary material, which is available to authorized users.

Behavioral and neurogenomic transcriptome changes in wild-derived zebrafish with fluoxetine treatment

Background

Stress and anxiety-related behaviors are seen in many organisms. Studies have shown that in humans and other animals, treatment with selective serotonin reuptake inhibitors (e.g. fluoxetine) can reduce anxiety and anxiety-related behaviors. The efficacies and side effects, however, can vary between individuals. Fluoxetine can modulate anxiety in a stereospecific manner or with equal efficacy regardless of stereoisomer depending on the mechanism of action (e.g. serotonergic or GABAergic effects). Zebrafish are an emerging and valuable translational model for understanding human health related issues such as anxiety. In this study we present data showing the behavioral and whole brain transcriptome changes with fluoxetine treatment in wild-derived zebrafish and suggest additional molecular mechanisms of this widely-prescribed drug.

Results

We used automated behavioral analyses to assess the effects of racemic and stereoisomeric fluoxetine on male wild-derived zebrafish. Both racemic and the individual isomers of fluoxetine reduced anxiety-related behaviors relative to controls and we did not observe stereospecific fluoxetine effects. Using RNA-sequencing of the whole brain, we identified 411 genes showing differential expression with racemic fluoxetine treatment. Several neuropeptides (neuropeptide Y, isotocin, urocortin 3, prolactin) showed consistent expression patterns with the alleviation of stress and anxiety when anxiety-related behavior was reduced with fluoxetine treatment. With gene ontology and KEGG pathway analyses, we identified lipid and amino acid metabolic processes, and steroid biosynthesis among other terms to be over-enriched.

Conclusion

Our results demonstrate that fluoxetine reduces anxiety-related behaviors in wild-derived zebrafish and alters their neurogenomic state. We identify two biological processes, lipid and amino acid metabolic synthesis that characterize differences in the fluoxetine treated fish. Fluoxetine may be acting on several different molecular pathways to reduce anxiety-related behaviors in wild-derived zebrafish. This study provides data that could help identify common molecular mechanisms of fluoxetine action across animal taxa.

Localizing brain regions associated with female mate preference behavior in a swordtail

Female mate choice behavior is a critical component of sexual selection, yet identifying the neural basis of this behavior is largely unresolved. Previous studies have implicated sensory processing and hypothalamic brain regions during female mate choice and there is a conserved network of brain regions (Social Behavior Network, SBN) that underlies sexual behaviors. However, we are only beginning to understand the role this network has in pre-copulatory female mate choice. Using in situ hybridization, we identify brain regions associated with mate preference in female Xiphophorus nigrensis, a swordtail species with a female choice mating system. We measure gene expression in 10 brain regions (linked to sexual behavior, reward, sensory integration or other processes) and find significant correlations between female preference behavior and gene expression in two telencephalic areas associated with reward, learning and multi-sensory processing (medial and lateral zones of the dorsal telencephalon) as well as an SBN region traditionally associated with sexual response (preoptic area). Network analysis shows that these brain regions may also be important in mate preference and that correlated patterns of neuroserpin expression between regions co-vary with differential compositions of the mate choice environment. Our results expand the emerging network for female preference from one that focused on sensory processing and midbrain sexual response centers to a more complex coordination involving forebrain areas that integrate primary sensory processing and reward.

Identifying context-specific gene profiles of social, reproductive, and mate preference behavior in a fish species with female mate choice

Sensory and social inputs interact with underlying gene suites to coordinate social behavior. Here we use a naturally complex system in sexual selection studies, the swordtail, to explore how genes associated with mate preference, receptivity, and social affiliation interact in the female brain under specific social conditions. We focused on 11 genes associated with mate preference in this species (neuroserpin, neuroligin-3, NMDA receptor, tPA, stathmin-2, β-1 adrenergic receptor) or with female sociosexual behaviors in other taxa (vasotocin, isotocin, brain aromatase, α-1 adrenergic receptor, tyrosine hydroxylase). We exposed females to four social conditions, including pairings of differing mate choice complexity (large males, large/small males, small males), and a social control (two females). Female mate preference differed significantly by context. Multiple discriminant analysis (MDA) of behaviors revealed a primary axis (explaining 50.2% between-group variance) highlighting differences between groups eliciting high preference behaviors (LL, LS) vs. other contexts, and a secondary axis capturing general measures distinguishing a non-favored group (SS) from other groups. Gene expression MDA revealed a major axis (68.4% between-group variance) that distinguished amongst differential male pairings and was driven by suites of “preference and receptivity genes”; whereas a second axis, distinguishing high affiliation groups (large males, females) from low (small males), was characterized by traditional affiliative-associated genes (isotocin, vasotocin). We found context-specific correlations between behavior and gene MDA, suggesting gene suites covary with behaviors in a socially relevant context. Distinct associations between “affiliative” and “preference” axes suggest mate preference may be mediated by distinct clusters from those of social affiliation. Our results highlight the need to incorporate natural complexity of mating systems into behavioral genomics.

Estradiol, reproductive cycle and preference behavior in a northern swordtail

Estrogen is associated with female sexual behaviors, particularly receptive behaviors during the reproductive cycle. Less is known about the relationship between estrogen and female preference behaviors that may precede receptivity and copulation. Separating the mechanisms underlying preference from receptivity is often confounded by the tightly coupled cycle- or estrogen-dependent expression of female sexual behaviors. Here we utilize a live-bearing poeciliid (Xiphophorus nigrensis), a model species for studying the evolution of female mate choice that can store sperm over multiple brood cycles. We assayed estradiol along with preference, receptivity and locomotor behaviors in gestating females and then re-tested these females on days 1, 7, 14, 21, and 28 post-parturition. With a posteriori reproductive cycle assessment, we asked whether reproductive state predicts differences in (i) estradiol levels, and (ii) behaviors (preference, receptivity, and general locomotor activity). We then examined if estradiol levels (independent of reproductive state) explain any variation in these behaviors. We found that endogenous estradiol levels vary across the reproductive cycle: gestating females had lower estradiol levels than those undergoing vitellogenesis/fertilization. In contrast, receptivity and preference behaviors did not vary over the reproductive cycle. Estradiol levels did not predict variation in receptive behavior, but were associated with increased locomotion. While individual female preference behaviors were consistent across the reproductive cycle, there was a small negative relationship between estradiol and preference behaviors explaining between 3% and 10% of the inter-female variation in preference behavior. Our data indicate X. nigrensis females may exhibit a facultatively dissociated reproductive system.

The primary care physician and Alzheimer's disease: an international position paper

This paper aims to define the role of the primary care physician (PCP) in the management of Alzheimer's disease (AD) and to propose a model for a work plan. The proposals in this position paper stem from a collaborative work of experts involved in the care of AD patients. It combines evidence from a literature review and expert's opinions who met in Paris, France, on July 2009 during the International Association of Geriatrics and Gerontology (IAGG) World Congress. The PCP's intervention appears essential at many levels: detection of the onset of dementia, diagnostic management, treatment and follow-up. The key role of the PCP in the management of AD, as care providers and care planners, is consolidated by the family caregiver's confidence in their skills. In primary care practice the first step is to identify dementia. The group proposes a "case finding" strategy, in target situations in which dementia should be detected to allow, secondarily, a diagnosis of AD, in certain cases. We propose that the PCP identifies 'typical' cases. In typical cases, among older subjects, the diagnosis of "probable AD" can be done by the PCP and then confirm by the specialist. While under-diagnosis of AD exists, so does under-disclosure. Disclosure to patient and family should be done by both specialist and PCP. Then, the PCP has a central role in management of the disease with the general objectives to detect, prevent and treat, when possible, the complications of the disease (falls, malnutrition, behavioural and psychological symptoms of dementia). The PCP needs to give basic information to the caregiver on respite care and home support services in order to prevent crisis situations such as unplanned institutionalisation and "emergency" hospital admission. Finally, therapeutic research must be integrated in the daily practice of PCP. It is a matter of patients' right to benefit from access to innovation and clinical research whatever his age or diseases, while of course fully respecting the rules and protective measures that are in force.

Sexual and social stimuli elicit rapid and contrasting genomic responses

Sensory physiology has been shown to influence female mate choice, yet little is known about the mechanisms within the brain that regulate this critical behaviour. Here we examine preference behaviour of 58 female swordtails, Xiphophorus nigrensis, in four different social environments (attractive and unattractive males, females only, non-attractive males only and asocial conditions) followed by neural gene expression profiling. We used a brain-specific cDNA microarray to identify patterns of genomic response and candidate genes, followed by quantitative PCR (qPCR) examination of gene expression with variation in behaviour. Our microarray results revealed patterns of genomic response differing more between classes of social stimuli than between presence versus absence of stimuli. We identified suites of genes showing diametrically opposed patterns of expression: genes that are turned ‘on’ while females interact with attractive males are turned ‘off’ when interacting with other females, and vice versa. Our qPCR results identified significant predictive relationships between five candidate genes and specific mate choice behaviours (preference and receptivity) across females exposed to males, with no significant patterns identified in female or asocial conditions or with overall locomotor activity. The identification of stimulus- and behaviour-specific responses opens an exciting window into the molecular pathways associated with social behaviour and mechanisms that underlie sexual selection.

Electrical and behavioral courtship displays in the mormyrid fish Brienomyrus brachyistius

Mormyrid electric fish rely on the waveform of their electric organ discharges (EODs) for communicating species, sex, and social status, while they use the sequences of pulse intervals (SPIs) for communicating rapidly changing behavioral states and motivation. Little is known of electric signaling during courtship behavior because of two major difficulties: (1) the fish are not easily bred in captivity and (2) there is no reliable means of separating electric signals from several individuals in natural communication settings. Through simulating artificial rain conditions, we have successfully induced courtship and succeeded in breeding a mormyrid electric fish (Brienomyrus brachyistius) in the laboratory. We have also developed a system of video recording and editing combined with cross correlation analysis to precisely record and view behavior and separate EODs from two individuals in non-breeding and breeding contexts. Knowing the electrical and motor patterns during courtship allows for further exploration of topics such as mate choice and neural basis of pattern generation in these fish. Here we describe nine common motor displays and 11 SPIs. Analysis of frequency of occurrences suggests that some SPI patterns are sex and season specific. We also observed electrical duetting called ;rasp matching' during courtship signaling among pairs; males and females exchange ;rasps' and ;bursts', respectively, in alternation. Our study employs new techniques to separate and document SPIs in the context of courtship. We show that some SPIs correlate with specific behavioral acts around the time of spawning.

Food sampling practice in the United Kingdom

As an integral part of the UK food surveillance scheme, routine food sampling is undertaken by officers at local councils. One of the main purposes of the food sampling programme is to detect food contaminants before they are sold to the public. This paper investigated the current UK food sampling activity undertaken by the local Environmental Health Departments and examined the effectiveness of the food programme. A national survey was undertaken by means of a questionnaire sent to 439 UK local authorities and a response rate of 39.2% (172 LAs) was achieved. Thirty-nine per cent of replies indicated that ensuring food safety and hygiene was the most important aim of sampling. Less than half of the returns suggested that their food programmes contributed to the prevention of foodborne illness. However, over three-quarters agreed that the current food sampling system could be improved upon. This study concluded that current UK food sampling is marginalized by financial constraints. In order to design an effective routine food programme, it should be based on an overall co-ordinated approach from local to European levels. Future work towards a statistically validated approach to the design will improve the effectiveness of food sampling programme.

The responsibilities and activities of internal medicine clerkship directors

PURPOSE

To characterize the responsibilities, activities, and scholarly productivity of internal medicine clerkship directors (CDs).

METHODS

In 1999, internal medicine CDs from 122 U.S. medical schools and one Canadian medical school were surveyed. The instrument asked about the CDs' demo-graphics, workloads, clerkship characteristics, and scholarly productivity.

RESULTS

The response rate was 89%; 72% of the respondents were men. Mean age was 45 years, mean time as CD was 6.5 years, and 58% of the CDs had completed fellowship training. The CDs spent 28% of their professional time on the clerkship, three half days weekly in clinic, and three months on inpatient services. The CDs had published a mean of 2.2 (range 0-20) articles and received a mean of 0.7 (range 0-4) grants. Similar factors were associated with publishing articles and receiving grants; gender (men), < or = three clinic half days weekly, fellowship training, having a faculty development program, teaching other courses, and discussing expectations with their department chairs. In a multivariate analysis, fellowship training, clinic half days, teaching other courses, and discussing expectations explained 22% of the variance for papers published. For grants received, a model with gender, clinic half days, a faculty development program, discussing expectations, and teaching other courses explained 35% of the variance.

CONCLUSIONS

An internal medicine CD invests significant effort administering the clerkship and contributing to clinical and educational activities. The factors associated with successful scholarship may be useful for fostering CDs' academic careers.

Identification of benzethonium chloride in commercial grapefruit seed extracts

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission [PIXE] analysis). The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other topical applications. This compound comprised 8.03% (n = 2) of the liquid GSE sample. Higher amounts of benzethonium chloride were found in powder GSE samples.

Fear of hypoglycaemia among insulin-treated Hong Kong Chinese patients: implications for diabetes patient education

This study investigated fear of hypoglycaemia among insulin-treated Chinese patients in Hong Kong. The study employed a cross-sectional descriptive design. Using structured-interviews, the authors collected data from 120 insulin-treated adults attending a diabetes centre. Results showed that although hypoglycaemic attacks were generally mild, they were common amongst one-third of patients. Fear was predominantly low, however 15% of respondents reported high fear. In addition, fear correlated positively with time since insulin-treatment, frequency of hospitalization due to hypoglycaemia, and frequency of hypoglycaemia affecting working life. Results also showed that although all respondents were insulin-treated, 40% had undesirable metabolic control. No statistically significant differences were found between the respondents' rating of adequacy of their diabetes knowledge among three groups of respondents who had completed, defaulted or were attending an education programme. Implications for diabetes patient education and further study are discussed.

Accuracy, precision and user-acceptability of self blood glucose monitoring machines

The performance of six self-monitoring blood glucose (SMBG) machines (Accutrend, Reflolux S, Companion 2, Glucometer GX, Glucometer IV and One Touch II) were examined using venous blood samples from 88 patients. Whole blood glucose (BG) values were measured by four machines from each brand. Machine-generated whole blood glucose (BG) values were corrected before comparison with laboratory plasma glucose values, measured by a glucose oxidase method. Based on error grid analysis, most of the corrected machine-generated BG values were clinically acceptable. Accutrend, Glucometer IV and Companion 2 showed the greatest consistency between machines of the same brand. Over 80% of corrected BG values generated by Glucometer IV fell within +/-10% of the reference values. One Touch II yielded the most reproducible results with a mean CV of 2.7% and was considered the most user friendly machine. More studies are required to examine the performance of these machines in the hands of patients.

Use of a single lumen endotracheal tube and continuous CO2 insufflation in transthoracic endoscopic sympathectomy

BACKGROUND

Transthoracic endoscopic sympathectomy (TES) is an accepted standard surgical treatment for palmar hyperhidrosis. For anesthetic management, a double lumen endobronchial tube is usually used to deflate the lung on the operative side. Recently we have applied continuous insufflation of carbon dioxide (CO2) into the pleural cavity to merely compress one lung while ventilating both lungs with a conventional single lumen endotracheal tube.

METHODS

We have studied 45 patients (ASA I and II) who underwent bilateral TES, Thirty-three were ventilated by single lumen tube and the other 12 by double lumen endobronchial tube with one lung ventilation. In both groups I and II, CO2 was insufflated slowly through the scope to a intrapleural pressure of 20 cm H2O. Both lungs were ventilated with peak pressure of less than 20 cmH2O at tidal volume of 5-12 ml/kg at 10-16 beats/min.

RESULTS

In these patients, no CO2 retention was noted. Oxygenation and cardiovascular stability were maintained and there were no complications. In the double lumen series, we found that oxygen saturation was less uniform and less stable than those in the single lumen series.

CONCLUSIONS

It is concluded that the use of single lumen endotracheal tube with continuous insufflation of CO2 in TES is easy, simple and safe.

Changes in acute myocardial infarction risk and patterns of practice for patients older and younger than 70 years, 1987-90

OBJECTIVE

To evaluate temporal changes in risk and patterns of hospital practice for acute myocardial infarction (AMI).

DESIGN/PATIENTS

Retrospective analysis of age-related medical therapy and outcome of 342 consecutive patients (132 at least 70 years old and 210 younger than 70) with AMI between July 1, 1989, and June 30, 1990, and comparison with data from two previous analyses of AMI practice in 1987 (n = 207) and 1988-89 (n = 402).

SETTING

Tertiary care medical centre.

INTERVENTIONS

No direct interventions; results of the two previous AMI practice pattern analyses, however, were propagated during the practice time of the most recent analysis.

RESULTS

In 1989-90, hospital mortality was higher (19%) among patients at least 70 years old compared with patients younger than 70 (8%) (P less than 0.01). Therapies proven by repeated clinical trials to be effective in reducing AMI risk were all used less frequently in patients aged at least 70 years: thrombolysis (20 versus 43%); beta-blockers (41 versus 62%); acetylsalicylic acid (71 versus 87%); and nitrates (86 versus 97%). Qualitatively, these age-specific patterns of AMI mortality and therapy were similar to previous studies. Quantitatively, however, comparing 1987 with 1989-90 demonstrated parallel and marked increases in the use of all proven medications in both age groups, ranging from 42 to 230% (P less than 0.01). There was also a significant overall decrease in mortality from the 1987 patient cohort (20%) to the 1989-90 cohort (13%) (P less than 0.05). The decrease in mortality was entirely due to decreased mortality within the group 70 years or older; 35% in 1987 versus 19% in 1989-90 (P less than 0.05). Mortality in the AMI patients younger than 70 years old remained unchanged from 1987 to 1989-90.

CONCLUSIONS

Pattern of practice analyses were associated with, and may have contributed to, improved patient care and outcomes in AMI. Increased use of effective AMI medical therapy had a greater benefit in elderly higher risk AMI patients than lower risk younger patients. Persisting age-specific differences in AMI therapy may respond to more direct quality improvement measures, such as critical path management.

Comparison of risk and patterns of practice in patients older and younger than 70 years with acute myocardial infarction in a two-year period (1987-1989)

To further evaluate contemporary risk and practice patterns in acute myocardial infarction (AMI), 402 consecutive patients with AMI between July 1, 1988, and June 30, 1989 were studied. The clinical investigations, medical therapy and outcome of patients aged greater than or equal to 70 years (n = 132; group 1) were compared with patients aged less than 70 years (n = 270; group 2). In group 1, 20% of patients had no typical cardiac pain versus 6% in group 2 (p less than 0.01). History of previous AMI, Q-wave AMI and peak creatine kinase were not different in the 2 groups. In-hospital mortality was markedly higher in group 1 (27%) than in group 2 (8%), p less than 0.01. Multivariate analysis revealed previous AMI, presentation without typical pain and age greater than or equal to 70 years to be independently associated with the greatest relative risk. Post-AMI exercise testing, ejection fraction calculations and coronary angiography were all performed less often (p less than 0.01); proven effective medical therapies, including thrombolysis, beta blockers, acetylsalicylic acid and nitrates were all used less frequently (p less than 0.01). The very high mortality and less aggressive management of elderly patients with AMI confirm similar data from our 1987 AMI patient cohort and other recently reported AMI patient outcome analyses. However, it remains uncertain why older patients with AMI are investigated and treated differently from younger patients. Further studies are warranted.

The use of methylmethacrylate in primary total knee replacements with large tibial defects

Bone defects in the tibial plateau present technical problems in primary knee replacement surgery. A variety of techniques is available to solve these problems. Of 59 patients treated with a cement fill and followed an average of 7.1 years (range, five to 11 years), there was only one failure requiring revision. Overall, knee scores averaged 78 points and roentgenogram scores averaged 85 points. Radiolucent lines were noted in 43 of the 59 patients, but none were progressive except in the one failure. There was no clinical correlation between the presence of radiolucent lines and clinical symptoms. Good long-term results might be expected from the cement fill when the bone defects are smaller than 20 mm and affect less than 50% of either plateau.

Revised Absolute Configurations of Latifolic Acid and the Pyrrolizidine Alkaloid Latifoline

The absolute stereochemistry of (+)- latifolk acid has been determined by single-crystal X-ray crystallographic analysis to be (2S,3R,4R)-3- hydroxy-2,4-dimethyl-5-oxotetrahydrofuran-3-carboxylic acid. The configuration of the three chiral centres is opposite to that presently recorded in the literature. Accordingly, the configuration of the pyrrolizidine alkaloid, latifoline, which includes a latifolic acid side chain, must be revised.

Transposition of Tn1000: in vivo properties

Transposition mediated by the Tn1000 transposase was investigated by using transposon variants carrying synthetic or wild-type termini but no intact Tn1000 genes. Transposon Tn1001, whose only homologies to Tn1000 are in its 38-base-pair terminal inverted repeats, transposed at the same rate as Tn1005, an artificial construct carrying wild-type Tn1000 termini and approximately 1 kilobase of flanking Tn1000 DNA at each end, when transposase was supplied in trans. The majority of the transpositions into pOX38 gave rise to cointegrates, but approximately 10% of the products expressed phenotypes of direct transpositions. The expression and temperature dependence of the tnpA gene product were examined by studying transposition of Tn1001 to bacteriophage lambda. The temperature optimum for transposition was 37 degrees C, and the transposase was stable for up to 2 h at this temperature.

Stress fracture as a cause of chronic pain following revision total hip arthroplasty. Report of two cases

Femoral stress fractures following revision total hip arthroplasty developed about a cortical window in two patients. These cases differ from previously reported fractures in that there was no significant trauma, the pain was gradual in onset, and there was no displacement at the fracture site. Tomograms and radionuclide bone scans were necessary to reveal the fracture. One femur healed with hip spica immobilization, while the other required bone grafting. Femoral stress fractures should be considered in the differential diagnosis of patients with thigh pain after revision total hip arthroplasty, particularly if a cortical window had been necessary.

Rotational isomerism about the 17(20)-bond of steroids and euphoids as shown by the crystal structures of euphol and tirucallol

The influence of configuration at C-20 on rotation about the 17(20)-bond in steroids and euphoids was examined by x-ray crystallographic studies of the C-20 epimers euphol and tirucallol. The H atom on C-20 was in back next to C-18 in the crystal structures of both of the compounds, and C-22 was found to be cis-oriented ("left-handed") to C-13 in euphol and trans-oriented to it ("right-handed") in tirucallol. The results, which are consistent with the known left-handed crystal structure of 24(25)-dihydroeuphol and right-handed crystal structure of cholesterol and other natural sterols, lend further credence to the earlier suggestion that rotational isomerism at the 17(20)-bond can arise in C-20 epimers and that there is preference for an arrangement with the 20-H atom adjacent to C-18.

Quinones and quinone methides. X. The crystal structure of a dimeric oxidation product from 2,4-Bis(1,1-dimethylethyl)-6-[(4-methoxyphenyl)methyl]phenol

The molecular structure of a minor oxidation product of the insect sterilant 2,4-bis(1,1-dimethylethyl) 6-[(4-methoxyphenyl)methyl]phenol has been established as (�)-cis-1,3,6,8-tetrakis(1,1-dimethyl-ethyl)-4b,9b-bis(4-methoxyphenyl)-4b,9b-dihydrobenzofuro[3,2-b]benzofuran by means of X-ray crystallographic analysis.

Diarylheptanoid and other phenolic constituents of Centrolobium species

The heartwood of a specimen of Centrolobium tomentosum Benth (Leguminosae) has given (–)-centrolobine (1a), (–)-de-O-methylcentrolobine (1b), (–)-centrolobol (2), piceatannol (3)and the isoflavone formononetin (4). The heartwood of a second Centrolobium species, which could not be identified further at the U.S. Forest Products Laboratory, yielded (+)-centrolobine, (+)-de-O-methylcentrolobine, (+)-centrolobol, formononetin, 4',7-dihydroxyflavanone (5), 3-hydroxy-9-methoxypterocarpan (6) and minor amounts of a new dihydric phenol. This was identified by n.m.r. and X-ray diffraction measurements as 2-(2'-hydroxy-4'-methoxyphenyl)benzofuran-6-ol (8).

New quinolinone and bis-quinolinone alkaloids from Euxylophora paraensis

Three quinolin-2-one alkaloids were isolated from the heartwood of Euxylophora paraensis andidentified by spectroscopic methods as 2,3,3-trimethyl-2,3,4,5-tetrahydrofurano[3,2-c]quinolin-4-one(2a), its N-methyl derivative (2b), and 3-(1,2-dimethyl-2-hydroxypropyl)-4-hydroxy-1-methylquinolin-2(1 H)-one (3). Four new dimers, E, F, G and B, were also isolated and identified as the bisquinolin-2-ones (5c), (5d), (6) and (9). The unsaturated dimer G and an isomer have been prepared by oxidationof paraensidimerin A and C.

The structures of paraensidimerin A and C, two bisquinolinone alkaloids from Euxylophora paraensis

Single-crystal X-ray diffraction studies and n.m.r. spectral measurements have now shown structure of paraensidimerin A, a bisquinolinone alkaloid from the heartwood of Euxylophora paraensis (Rutaceae), to be (6aα,7β,15β,16aα)-(�-6,6,9,15,18-pentamethyl-6,6a,7,9,15,16,16a,18-octahydro-7,15-methano-8H,17H-quino[3',4' :5',6'] pyrano[3',4':5,6] oxocino[3,2-c] quinoline-8,17-dione (8). Paraensidimerin C is a stereoisomer, (6aα,7β,15β,16aβ)-(�)-6,6,9,15,18-pentamethyl-9,15,16,16a,18-octahydro-7,15-methano-8H,17H-quino [3',4':5',6'] pyrano [3',4': 5,6] oxocino [3,2-quinoline-8,17-dione (9). Possible biosynthetic routes to these and other dimeric quinolinone alkaloids are suggested.

Quinones and quinone methides. VIII. Oxidation products of the screwworm chemosterilant, 2,4-Bis(1,1-dimethylethyl)-6-(4-methoxyphenylmethyl)phenol

The title compound is oxidized by silver oxide in acetone to a complex mixture of products, including the benzophenone derivative (7), a benzylic alcohol, isolated as its methyl ether (15), and two spiro cyclohexadienone benzopyran dimers (17) and (19). A colourless dimer was shown by single-crystal X-ray diffraction measurements to be a 2,3- dihydrobenzofuran derivative (22).

Quinones and quinone methides. IX. Oxidation of 2,4-Bis(1,1-dimethylethyl)-6-(4-methoxyphenylmethyl)phenol in alcoholic solvents: Monomeric products and the crystal structure of an unusual dimes, 2-[3,5-Bis(1,1-dimethylethyl)-2-{methoxy-(4-methoxyphenyl)methoxy} phenoxyl-1,5-bis(1,1-dimethylethyl)-3-[methoxy-(4-methoxyphenyl)methyl]benzene

Oxidation of the title benzylphenol (1) with silver oxide in alcoholic media forms benzylic ethers of type (5) in high yields; e.g. oxidation in methanol yields 2,4-bis(1,1-dimethylethyl)-6-[methoxy(4- methoxyphenyl)methyl]phenol(5a) together with an unusual dimer, the structure of which was shown by X-ray crystallographic analysis to be 2-[3,5-bis(1,1-dimethylethyl)-2-{methoxy(4-methoxyphenyl)- methoxy}phenoxy]-1,5-bis(1,1-dimethylethy)-3-[methoxy(4- methoxyphenyl)methyl]benzene (6). The benzylic ethers (5) are convenient intermediates for the syntheses of a variety of compounds related to (1).

New quinolinone alkaloids from the heartwood of, Euxylophora paraensis

The heartwood of Euxylophora paraensis Hub. (Rutaceae) has given N-methylflindersine (2),spectabiline (3), skimmianine (4) and two new alkaloids, identified from spectroscopic data as 4-hydroxy-2,2,6-trimethyl-3,4,5,6-tetrahydro-2H-pyrano[3,2-c]quinolin-5-one (5) and 4-(2,3-dihydroxy-3-methylbutoxy)-1-methylquinolin-2(1H)-one (6). Five new dimeric quinolinone alkaloids, C30H30N2O4, were isolated. The structure of one of these, paraensidimerin D, has now been shown by single-crystal X-ray diffraction methods to be (11), viz. (6aα,7α,14aα)-6,6,9,16- tetramethyl-7-(2-methylprop-1-enyl)-6,6a,7,9,14a,16-hexahydro-8H,15H- quino[3'',4'':5',6'] pyrano [2',3':4,5] pyrano-[3,2-c]quinoline-8,15- dione.

Quinones and quinone methides. VI. Reactions of 2-Arylmethyl- and 2-(1-Arylethyl)- 1,4-benzoquinones with 4-hydroxy-2H-1-benzopyran-2-one

In alcoholic potassium hydroxide 2-methoxy-5-(4-methoxyphenylmethyl)- 1,4-benzoquinone (I) reacts with 4-hydroxy-2H-1-benzopyran-2-one (7) to yield the quinol (8a). In pyridine, however,(1) tautomerizes to the ortho-quinone methide which combines with (7) to yield (17a). 2-(1- Arylethyl-1,4-benzoquinones yield quinols related to (8a) in both alcoholic potassium hydroxide and pyridine solutions; this indicates that quinones methides which might be formed from these quinones are relatively unreactive to nucleophiles.

Drowning and near-drowning involving children: a five-year total population study from the City and County of Honolulu

A study of all serious childhood immersion accidents (both drowned and near-drowned cases) is reported from Hawaii. This is a total population-based survey of 140 consecutive cases (0--15 years) occurring during the five-year period (1973--1977. Age-specific, sex-specific, and osmolality-specific (salt versus fresh water) data are presented both for survivors and fatalities. The overall annual drowning rate of 3.1 per 100,000 children at risk is low, for a water-oriented society. The survival rate following loss of consciousness in the water is 73 per cent. There is no evidence from this study that osmolality affected the probability of survival. The rank order of importance of drowning sites is swimming pools, surf, sheltered salt water bathing, domestic bath tubs, fresh water streams, salt water canals, and garden fish ponds. Specific accident rates, by sex, outcome, and site of immersion are also presented. No secular trend in the rate of drowning was observed in this study. Comparison with the only other available total population survey (Australia) of childhood immersions reveals common epidemiological and demographic patterns in modern urban societies and suggests that safety regulations play a role in reducing swimming accidents and fatalities in children.

Performance comparison of scene matching techniques

The problem of matching two images of the same scene, taken by different sensors under different viewing geometries, is a challenging problem in the field of image processing and pattern recognition. The scenes are usually transformed so drastically by the different viewing geometries and sensor characteristics that it is extremely difficult, if not impossible, to match the original images without the proper data processing. Geometric and intensity transformations must be performed to bring the matching elements and their intensity into a one-to-one correspondence. Objects of interest represented by subimages of one scene were located in the other using scene matching techniques with intensity difference and edge features as measurement features. Performance characteristics of the matches by these techniques are presented in terms of the probability of a match as a function of the probability of false fix.

Toxaphene insecticide: a complex biodegradable mixture

Adsorption and gas-liquid chromatography separate toxaphene into at least 175 polychlorinated 10-carbon compounds including Cl(6), Cl(7), Cl(8), Cl(9), and Cl(10) derivatives. One toxic component is 2,2,5-endo,6-exo,8,9,10-heptachlorobornane. Rats metabolically dechlorinate toxaphene, removing about half of the chlorine from the technical insecticide and from each of seven subfractions of varying composition and toxicity.