A Distinct Arabidopsis Latent Virus 1 Isolate Was Found in Wild Brassica hirta Plants and Bees, Suggesting the Potential Involvement of Pollinators in Virus Spread

During our search for aphid-pathogenic viruses, a comovirus was isolated from wild asymptomatic Brassica hirta (white mustard) plants harboring a dense population of Brevicoryne brassicae aphids. The transmission-electron-microscopy visualization of purified virions revealed icosahedral particles. The virus was mechanically transmitted to plants belonging to Brassicaceae, Solanaceae, Amaranthaceae, and Fabaceae families, showing unique ringspot symptoms only on B. rapa var. perviridis plants. The complete viral genome, comprised of two RNA segments, was sequenced. RNA1 and RNA2 contained 5921 and 3457 nucleotides, respectively, excluding the 3' terminal poly-adenylated tails. RNA1 and RNA2 each had one open-reading frame encoding a polyprotein of 1850 and 1050 amino acids, respectively. The deduced amino acids at the Pro-Pol region, delineated between a conserved CG motif of 3C-like proteinase and a GDD motif of RNA-dependent RNA polymerase, shared a 96.5% and 90% identity with the newly identified Apis mellifera-associated comovirus and Arabidopsis latent virus 1 (ArLV1), respectively. Because ArLV1 was identified early in 2018, the B. hirta comovirus was designated as ArLV1-IL-Bh. A high-throughput-sequencing-analyses of the extracted RNA from managed honeybees and three abundant wild bee genera, mining bees, long-horned bees, and masked bees, sampled while co-foraging in a Mediterranean ecosystem, allowed the assembly of ArLV1-IL-Bh, suggesting pollinators' involvement in comovirus spread in weeds.

Plant size, latitude, and phylogeny explain within-population variability in herbivory

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

Trait-based approaches to predicting biological control success: challenges and prospects

Identifying traits that are associated with success of introduced natural enemies in establishing and controlling pest insects has occupied researchers and biological control practitioners for decades. Unfortunately, consistent general relationships have been difficult to detect, preventing a priori ranking of candidate biological control agents based on their traits. We summarise previous efforts and propose a series of potential explanations for the lack of clear patterns. We argue that the quality of current datasets is insufficient to detect complex trait-efficacy relationships and suggest several measures by which current limitations may be overcome. We conclude that efforts to address this elusive issue have not yet been exhausted and that further explorations are likely to be worthwhile.

Analysis of apocarotenoid volatiles from lettuce (Lactuca sativa) induced by insect herbivores and characterization of carotenoid cleavage dioxygenase gene

Plant apocarotenoids have been shown to have a diverse biological role in herbivore-plant interactions. Despite their importance, little is known about herbivores' effect on apocarotenoid emissions in Lactuca sativa. In this study, we examined changes in apocarotenoid emissions in lettuce leaves after infestation by two insects, viz., Spodoptera littoralis larvae and Myzus persicae aphids. We found that β-ionone and β-cyclocitral showed higher concentrations than the other apocarotenoids, with a significant increase as per the intensity of infestation of both herbivore species. Furthermore, we performed functional characterization of Lactuca sativa carotenoid cleavage dioxygenase 1 (LsCCD1) genes. Three LsCCD1 genes were overexpressed in E. coli strains, and recombinant proteins were assayed for cleavage activity on an array of carotenoid substrates. The LsCCD1 protein cleaved β-carotene at the 9,10 (9',10') positions producing β-ionone. The transcript analysis of LsCCD1 genes revealed differential expression patterns under varying levels of herbivores' infestation, but the results were inconsistent with the pattern of β-ionone concentrations. Our results suggest that LsCCD1 is involved in the production of β-ionone, but other regulatory factors might be involved in its induction in response to herbivory. These results provide new insights into apocarotenoid production in response to insect herbivory in lettuce.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03511-4.

Bedrock may dictate the distribution of the fire salamander in the southern border of its global range

Understanding the factors that determine the spatial distribution of species is crucial for conservation planning. In this short communication, we review previous distribution models of the fire salamander (Salamandra infraimmaculata) in northern Israel, produced by the group of the late Prof. Leon Blaustein, while suggesting a biologically-informed reinterpretation of their main predictions. We argue for the prime importance of bedrock, specifically hard limestone, because it is tightly associated with the availability of karstic formations that are key to adult survival throughout the summer. Furthermore, we suggest that the spatial distribution of limestone bedrock also determines large-scale inter-population connectivity, and may explain the observed genetic differentiation among populations, as well as the southernmost limit of the species’ global distribution.

Metatranscriptome Analysis of Sympatric Bee Species Identifies Bee Virus Variants and a New Virus, Andrena-Associated Bee Virus-1

Bees are important plant pollinators in agricultural and natural ecosystems. High average annual losses of honey bee (Apis mellifera) colonies in some parts of the world, and regional population declines of some mining bee species (Andrena spp.), are attributed to multiple factors including habitat loss, lack of quality forage, insecticide exposure, and pathogens, including viruses. While research has primarily focused on viruses in honey bees, many of these viruses have a broad host range. It is therefore important to apply a community level approach in studying the epidemiology of bee viruses. We utilized high-throughput sequencing to evaluate viral diversity and viral sharing in sympatric, co-foraging bees in the context of habitat type. Variants of four common viruses (i.e., black queen cell virus, deformed wing virus, Lake Sinai virus 2, and Lake Sinai virus NE) were identified in honey bee and mining bee samples, and the high degree of nucleotide identity in the virus consensus sequences obtained from both taxa indicates virus sharing. We discovered a unique bipartite + ssRNA Tombo-like virus, Andrena-associated bee virus-1 (AnBV-1). AnBV-1 infects mining bees, honey bees, and primary honey bee pupal cells maintained in culture. AnBV-1 prevalence and abundance was greater in mining bees than in honey bees. Statistical modeling that examined the roles of ecological factors, including floral diversity and abundance, indicated that AnBV-1 infection prevalence in honey bees was greater in habitats with low floral diversity and abundance, and that interspecific virus transmission is strongly modulated by the floral community in the habitat. These results suggest that land management strategies that aim to enhance floral diversity and abundance may reduce AnBV-1 spread between co-foraging bees.

Disease, contagious cannibalism, and associated population crash in an omnivorous bug, Geocoris pallens

Disease and cannibalism are two strongly density-dependent processes that can suppress predator populations. Here we show that California populations of the omnivorous predatory bug Geocoris pallens are subject to infection by a pathogen, as yet unidentified, that elicits elevated expression of cannibalism. Laboratory experiments showed that the pathogen is moderately virulent, causing flattened abdomens, elevated nymphal mortality, delayed development, and reduced body size of adult females. Infection furthermore increases the expression of cannibalism. Field populations of Geocoris spp. declined strongly in association with sharp increases in the expression of egg cannibalism by adult G. pallens. Increased cannibalism was accompanied by a strongly bimodal distribution of cannibalism expression, with some females (putatively uninfected) expressing little cannibalism and others (putatively infected) consuming most or all of the eggs present. Highly cannibalistic females did not increase their consumption of Ephestia cautella moth eggs, suggesting that the high cannibalism phenotype reflected a specific loss of restraint against eating conspecifics. Highly cannibalistic females also often exhibited reduced egg laying, consistent with a virulent pathogen; less frequently, more cannibalistic females exhibited elevated egg laying, suggesting that cannibalism might also facilitate recycling of nutrients in eggs. Elevated cannibalism was not correlated with reduced prey availability or elevated field densities of G. pallens. Geocoris pallens population crashes appear to reflect the combined consequences of direct virulence-adverse pathogen effects on the infected host's physiology-and indirect virulence-mortality of both infected and uninfected individuals due to elevated cannibalism expression by infected individuals.

A Pyrus communis gene for p-hydroxystyrene biosynthesis, has a role in defense against the pear psylla Cacopsylla biden

Styrene analogs are known to be naturally synthesized in the leaves of pears and in other plant species, including several trees in the Styracaceae family. Styrene analogs are potential contributors to the aroma of wine, perfumes, pharmaceuticals, and other fermented foods and beverages. In addition, styrene analogs perform important ecological functions such as insecticidal and antifeedant activities against insects. We showed here that exogenous applications of styrene and p-hydroxystyrene caused a dramatic reduction the number of eggs laid by psylla and of subsequent nymph survival. Despite their importance specific reactions that lead to the biosynthesis of the styrene analogs in pear are unknown. To identify genes involved in the synthesis of these metabolites, existing genome databases of the Rosaceae were screened for pear genes with significant sequence similarity to bacterial phenolic acid decarboxylase. Herein described are the isolation and characterization of a pear phenolic acid decarboxylase, designated PyPAD1, which catalyzed the decarboxylation of p-coumaric acid and ferulic acid to p-hydroxystyrene and 3-methoxy-4-hydroxystyrene respectively. Its apparent Km values for p-coumaric acid and ferulic acid were 34.42 and 84.64 μM, respectively. The PyPAD1 preferred p-coumaric acid to ferulic acid as a substrate by a factor of 2.4 when comparing catalytic efficiencies in vitro. Expression analysis of PyPAD1 showed that the gene was transcribed in all five pear genotypes examined. However, transcript abundance was increased in correlation with the presence of p-hydroxystyrene in resistant cultivars Py-701 and Py-760 and in the sensitive cultivar Spadona when grafted on these resistant cultivars. Thus, PyPAD1 appears to be responsible for the decarboxylation of the p-coumaric acid, and for the production of metabolites that are active against pear psylla.

The effects of a windborne pollen-provisioning cover crop on the phytoseiid community in citrus orchards in Israel

BACKGROUND

Several phytoseiid species can potentially control the citrus rust mite (CRM). Their effectiveness varies, however, as do their intraguild interactions. Under laboratory conditions, Euseius stipulatus, E. scutalis and Iphiseius degenerans preyed effectively on CRM, whereas Amblyseius swirskii and Typhlodromus athiasae had no effect on CRM. In combination with A. swirskii, Euseius numbers were reduced due to intraguild predation, and consequently CRM suppression was less effective. In the field, predatory mite species can be variably provisioned by windborne pollen released from cover crops such as Rhodes grass (RG). We aimed to determine the effects of RG on the phytoseiid community in two field experiments, on different cultivars (pomelo and Shamouti orange). We also tested these communities for negative interspecific abundance relationships that are expected if their respective laboratory-observed intraguild interactions are manifested in the field.

RESULTS

Overall, on pomelo, we observed a dominance of A. swirskii, relatively low E. stipulatus and high CRM abundances. Amblyseius swirskii and E. stipulatus abundances were both elevated near RG, despite apparent intraguild predation by A. swirskii. Conversely, T. athiasae abundances were lower near RG, likely due to predation by A. swirskii. On Shamouti, E. stipulatus abundances were much higher than on pomelo and were not negatively related to A. swirskii abundances. There, RG increased E. stipulatus abundance, and CRM was reduced.

CONCLUSION

RG cover cropping can enhance CRM control, depending on variation in intraguild interactions among phytoseiids, particularly between A. swirskii and E. stipulatus. These may be modulated by climatic and/or cultivar effects. © 2018 Society of Chemical Industry.

The epidemiology and evolution of parasite transmission through cannibalism

Cannibalism is a widespread behavior, and evidence is abundant for transmission from infected victims to susceptible cannibals in many parasite-host systems. Current theory suggests that cannibalism generally impedes disease spread, because each victim is usually consumed by a single cannibal. Thus, cannibalism merely transfers pathogens from one individual to another without spreading infections to additional hosts. This assumes that cannibalism is the only mode of transmission and that the host population is homogenous. However, host developmental stages are a key determinant of both cannibal-victim and host-pathogen interactions. We suggest that multiple modes of pathogen transmission can interact through host stage structure. We show theoretically that cannibalism can enhance disease spread by consistently transferring infections from low quality to high quality hosts that are more infectious via horizontal transmission. We review empirical evidence for the generality of key conditions required for this process, and analyze the implications for the evolution of transmission through cannibalism. More generally, our theory promotes the consideration of multiple transmission pathways when studying parasite-host systems, and advances a useful intuition for assessing whether or not such pathways may be mutually augmentative.

Cannibalism amplifies the spread of vertically transmitted pathogens

Cannibalism is a widespread behavior. Abundant empirical evidence demonstrates that cannibals incur a risk of contracting pathogenic infections when they consume infected conspecifics. However, current theory suggests that cannibalism generally impedes disease spread, because each victim is usually consumed by a single cannibal, such that cannibalism does not function as a spreading process. Consequently, cannibalism cannot be the only mode of transmission of most parasites. We develop simple, but general epidemiological models to analyze the interaction of cannibalism and vertical transmission. We show that cannibalism increases the prevalence of vertically transmitted pathogens whenever the host population density is not solely regulated by cannibalism. This mechanism, combined with additional, recently published, theoretical mechanisms, presents a strong case for the role of cannibalism in the spread of infectious diseases across a wide range of parasite-host systems.

Ethephon induced oxidative stress in the olive leaf abscission zone enables development of a selective abscission compound

BACKGROUND

Table olives (Olea europaea L.), despite their widespread production, are still harvested manually. The low efficiency of manual harvesting and the rising costs of labor have reduced the profitability of this crop. A selective abscission treatment, inducing abscission of fruits but not leaves, is crucial for the adoption of mechanical harvesting of table olives. In the present work we studied the anatomical and molecular differences between the three abscission zones (AZs) of olive fruits and leaves.

RESULTS

The fruit abscission zone 3 (FAZ3), located between the fruit and the pedicel, was found to be the active AZ in mature fruits and is sensitive to ethephon, whereas FAZ2, between the pedicel and the rachis, is the flower active AZ as well as functioning as the most ethephon induced fruit AZ. We found anatomical differences between the leaf AZ (LAZ) and the two FAZs. Unlike the FAZs, the LAZ is characterized by small cells with less pectin compared to neighboring cells. In an attempt to differentiate between the fruit and leaf AZs, we examined the effect of treating olive-bearing trees with ethephon, an ethylene-releasing compound, with or without antioxidants, on the detachment force (DF) of fruits and leaves 5 days after the treatment. Ethephon treatment enhanced pectinase activity and reduced DF in all the three olive AZs. A transcriptomic analysis of the three olive AZs after ethephon treatment revealed induction of several genes encoding for hormones (ethylene, auxin and ABA), as well as for several cell wall degrading enzymes. However, up-regulation of cellulase genes was found only in the LAZ. Many genes involved in oxidative stress were induced by the ethephon treatment in the LAZ alone. In addition, we found that reactive oxygen species (ROS) mediated abscission in response to ethephon only in leaves. Thus, adding antioxidants such as ascorbic acid or butyric acid to the ethephon inhibited leaf abscission but enhanced fruit abscission.

CONCLUSION

Our findings suggest that treating olive-bearing trees with a combination of ethephon and antioxidants reduces the detachment force (DF) of fruit without weakening that of the leaves. Hence, this selective abscission treatment may be used in turn to promote mechanized harvest of olives.

Consistent high prevalence of Exophiala dermatitidis, a neurotropic opportunist, on railway sleepers

Environmental isolation of black yeasts potentially causing human disorders is essential for understanding ecology and routes of infection. Several Exophiala species show prevalence for man-made environments rich in monoaromatic compounds, such as creosote-treated or petroleum-stained railway sleepers. Ambient climatic conditions play a role in species composition in suitable habitats. Therefore, the aim of the present study was to establish the composition of Exophiala species in railway stations as a potential source of human infections in a subtropical region with evaluation of their antifungal susceptibility profiles. We examined 150 railway samples using cotton swabs moistened with sterile physiological saline. Black yeasts and relatives were selected on theirs colony morphology and identified based on ITS rDNA sequencing. Overall, 36 (24%) of samples were positive for black yeast-like fungi, i.e., Exophiala dermatitidis (n=20, 55.6%) was predominant, followed by E. phaeomuriformis (n=9, 25%), E. heteromorpha (n=5, 13.9%), and E. xenobiotica (n=2, 5.6%). Massive contaminations of E. dermatitidis were seen on railway sleepers on creosoted oak wood at the region close to the sea level, while in cold climates were primarily contaminated with clinically insignificant or rare human opportunists (E. crusticola). It seems that, high temperature and humidity are significant effect on species diversity. Moreover, the MIC results for all E. dermatitidis and E. phaeomuriformis strains revealed the widest range and the highest MICs to caspofungin (range 1-16mg/L, Geometric mean 4.912mg/L), and the lowest MIC for posaconazole (0.016-0.031mg/L, G mean 0.061mg/L). However, their clinical effectiveness in the treatment of Exophiala infections remains to be determined.

Oviposition responses of two mosquito species to pool size and predator presence: varying trade-offs between desiccation and predation risks

Natural selection is predicted to favor females that can detect risks of desiccation and predation when choosing among temporary pools for oviposition. Pool size may serve both as a cue for desiccation risk and as a predictor for future colonization by predators or for the probability of present, undetected predators. Therefore, oviposition responses to pool size are expected to interact with the presence of predators that can be detected. We measured oviposition by two mosquito species, Culiseta longiareolata and Culex laticinctus, in a mesocosm experiment, crossing two pool surface sizes with presence or absence of the hemipteran predator, Notonecta maculata, which is chemically detectable by mosquitoes. Both mosquito species strongly avoided Notonecta pools. Using a mechanistic statistical model, we accounted for the higher encounter rate of females with larger pools, and determined their true oviposition preferences for pool size. C. laticinctus showed a clear preference for larger pools, but C. longiareolata, a species with larvae more vulnerable to predation, showed no significant preference for pool size. This study confirms the importance of risk of predation in explaining oviposition patterns, and suggests a possible inter-specific variation in the trade-off between predation and desiccation risks.

Pattern of Sleep in Infants and Toddlers Visiting at a Teaching Hospital in Lalitpur

Introduction: Sleep is an integral part in a child’s health and development. During different stages of development, there are aberrations in normal physiology of sleep which make children more susceptible to various types of sleep problems. This study was conducted to identify sleep pattern and sleep problems in Nepalese children using Nepali translation of Brief Infant Sleep Questionnaire (BISQ) screening tool.Materials and Methods: This was a descriptive cross-sectional study. Data were collected from parents of children aged 6 to 36 months attending paediatric out-patient clinic for general health check-up from July 2013 to December 2013. Nepali translation of the BISQ was used as a screening tool for sleep problems in this study.Results: The study included 553 children (52.4% boys). Mothers completed the questionnaire in 92% of children. Mean total duration of sleep in 24 hours was 11.7 ±1.7 hours. Respondents reported sleep problem in 16.9% of children whereas 20.3% of children had sleep problems according to BISQ criteria. As per this criteria, 2.7% of children had total sleep duration less than 9 hours, 5.9% of children had total night awakening duration of more than one hour, 13.9% of children had night waking >3 times. These BISQ sleep parameters differed significantly in children with and without sleep problems (p<0.001). In addition, children with sleep problem took longer time to sleep than children without sleep problems (p<0.001).Conclusion: Sleep problems are common in Nepalese infants and toddlers according to the BISQ. Screening for sleep problems is highly recommended during health care visits given the prevalence of sleep problems identified by this study to reduce their potential adverse impact.J Nepal Paediatr Soc 2015;35(1):24-30

Compensatory development and costs of plasticity: larval responses to desiccated conspecifics

Understanding constraints on phenotypic plasticity is central to explaining its evolution and the evolution of phenotypes in general, yet there is an ongoing debate on the classification and relationships among types of constraints. Since plasticity is often a developmental process, studies that consider the ontogeny of traits and their developmental mechanisms are beneficial. We manipulated the timing and reliability of cues perceived by fire salamander larvae for the future desiccation of their ephemeral pools to determine whether flexibility in developmental rates is constrained to early ontogeny. We hypothesized that higher rates of development, and particularly compensation for contradictory cues, would incur greater endogenous costs. We found that larvae respond early in ontogeny to dried conspecifics as a cue for future desiccation, but can fully compensate for this response in case more reliable but contradictory cues are later perceived. Patterns of mortality suggested that endogenous costs may depend on instantaneous rates of development, and revealed asymmetrical costs of compensatory development between false positive and false negative early information. Based on the results, we suggest a simple model of costs of development that implies a tradeoff between production costs of plasticity and phenotype-environment mismatch costs, which may potentially underlie the phenomenon of ontogenetic windows constraining plasticity.

Sol−Gel-Derived Composite Antimony-Doped, Tin Oxide-Coated Clay−Silicate Semitransparent and Conductive Electrodes

A new form of conductive and transparent porous composite electrode is introduced. The electrode material is composed of antimony-doped, tin oxide (ATO)-coated mica platelets imbedded in sol-gel-derived silicate or methyl silicate network. The platelet clays self-align in a layered structure within the silicate film, an anisotropic construction that minimizes the ATO loading required to achieve electric percolation. Transparency and resistance as a function of clay loading is reported with typical values of 100 k Omega/square and 1.5 OD for a 20-microm-thick film. The transparency is lower as compared to sputtered ATO glasses, but this is, as far as we know, the best method for the low-temperature preparation of transparent, porous, and electrically conductive (as opposed to the amply reported ionically conductive) electrode materials. Permselectivity induced by the silicate and clay ingredients is demonstrated by permeation of positively charged methyl viologen compared to negatively charged ferricyanide. Prussian blue-modified ATO-coated platelets dispersed in sol-gel-derived silicate were used to demonstrate feasibility of a transparent and electrically conductive porous electrochromic material.

Sleep patterns and sleep disruptions in kindergarten children

Assessed sleep patterns and sleep disruptions in kindergarten children and investigated the relation between sleep measures derived from objective and subjective evaluation methods. The sleep patterns of 59 normal kindergarten children (mean age = 5.5 years) were monitored for 4 to 5 consecutive nights by means of activity monitors (actigraph) and by means of parental daily sleep logs. The correlation between the actigraphic measures and the daily parental logs indicated that parents were accurate reporters of sleep schedule measures. However, parents were less accurate in assessing sleep quality measures, significantly underestimating the number of night-wakings and overestimating the quality of their children's sleep. Fragmented sleep was found, by means of activity monitoring, in 41% of the children.

Sleep patterns and sleep disruptions in school-age children

This study assessed the sleep patterns, sleep disruptions, and sleepiness of school-age children. Sleep patterns of 140 children (72 boys and 68 girls; 2nd-, 4th-, and 6th-grade students) were evaluated with activity monitors (actigraphs). In addition, the children and their parents completed complementary sleep questionnaires and daily reports. The findings reflected significant age differences, indicating that older children have more delayed sleep onset times and increased reported daytime sleepiness. Girls were found to spend more time in sleep and to have an increased percentage of motionless sleep. Fragmented sleep was found in 18% of the children. No age differences were found in any of the sleep quality measures. Scores on objective sleep measures were associated with subjective reports of sleepiness. Family stress, parental age, and parental education were related to the child's sleep-wake measures.

Sleep patterns and sleep disruptions in school-age children

This study assessed the sleep patterns, sleep disruptions, and sleepiness of school-age children. Sleep patterns of 140 children (72 boys and 68 girls; 2nd-, 4th-, and 6th-grade students) were evaluated with activity monitors (actigraphs). In addition, the children and their parents completed complementary sleep questionnaires and daily reports. The findings reflected significant age differences, indicating that older children have more delayed sleep onset times and increased reported daytime sleepiness. Girls were found to spend more time in sleep and to have an increased percentage of motionless sleep. Fragmented sleep was found in 18% of the children. No age differences were found in any of the sleep quality measures. Scores on objective sleep measures were associated with subjective reports of sleepiness. Family stress, parental age, and parental education were related to the child's sleep-wake measures.

Attention deficit/hyperactivity disorder children with a 7-repeat allele of the dopamine receptor D4 gene have extreme behavior but normal performance on critical neuropsychological tests of attention

An association of the dopamine receptor D4 (DRD4) gene located on chromosome 11p15.5 and attention deficit/hyperactivity disorder (ADHD) has been demonstrated and replicated by multiple investigators. A specific allele [the 7-repeat of a 48-bp variable number of tandem repeats (VNTR) in exon 3] has been proposed as an etiological factor in attentional deficits manifested in some children diagnosed with this disorder. In the current study, we evaluated ADHD subgroups defined by the presence or absence of the 7-repeat allele of the DRD4 gene, using neuropsychological tests with reaction time measures designed to probe attentional networks with neuroanatomical foci in D4-rich brain regions. Despite the same severity of symptoms on parent and teacher ratings for the ADHD subgroups, the average reaction times of the 7-present subgroup showed normal speed and variability of response whereas the average reaction times of the 7-absent subgroup showed the expected abnormalities (slow and variable responses). This was opposite the primary prediction of the study. The 7-present subgroup seemed to be free of some of the neuropsychological abnormalities thought to characterize ADHD.

Instability of sleep patterns in children with attention-deficit/hyperactivity disorder

OBJECTIVE

To compare the stability of the sleep-wake system of children with attention-deficit/hyperactivity disorder (ADHD) and controls by objective and subjective measures.

METHOD

Thirty-eight school-age boys with diagnosed ADHD and 64 control school-age boys were examined using actigraphic monitoring and sleep diaries, over 5 consecutive nights.

RESULTS

Increased instability in sleep onset, sleep duration, and true sleep were found in the ADHD group compared with the control group. Discriminant analysis revealed that children's classification (ADHD versus control) could be significantly predicted on the basis of their sleep measures.

CONCLUSIONS

The findings support the hypothesis that instability of the sleep-wake system is a characteristic of children with ADHD. Given the potential negative effects of disturbed or unstable sleep on daytime functioning, it is recommended that a thorough sleep assessment be conducted when a sleep disturbance is suspected or when symptoms associated with daytime sleepiness or decreased arousal level are present.

Estimating sleep patterns with activity monitoring in children and adolescents: how many nights are necessary for reliable measures?

STUDY OBJECTIVES

This study provides estimates of reliability for aggregated values from 1 to 7 recording nights for five commonly used actigraphic measures of sleep patterns, reliability as a function of night type (weeknight or weekend night), and stability of measures over several months.

DESIGN AND SETTING

Data are from three studies that obtained 7 nights of actigraph data (using Mini Motionlogger actigraphs and associated validated algorithms [ASA]) on children and adolescents living at home on self-selected sleep-wake schedules.

PARTICIPANTS

Participants were 169 children aged 12-60 months, and 55 adolescents aged 11-16 years.

MEASUREMENTS AND RESULTS

Up to 28% of weekly recordings may be unacceptable for analysis in young participants because of illness, technical problems, and participant noncompliance; studies aiming to collect 5 nights of actigraph data should record for at least 1 full week. Reliability estimates for values aggregated over any 5 nights were adequate (> or = .70) for sleep start time, wake minutes, and sleep efficiency. Measures of sleep minutes and sleep period were less reliable and may require 7 or more nights for estimates of stable individual differences. Reliability for 1- or 2-night aggregates were poor for all measures. We found significant and high correlations between summer and fall session measures for all five variables when weekend nights were included.

CONCLUSIONS

Five or more nights of usable recordings are required to obtain reliable actigraph measures of sleep for children and adolescents.

Sleep and pulmonary function in children with well-controlled, stable asthma

The aim of this study was to assess sleep and pulmonary function in asthmatic and control children. Forty children with well-controlled, stable asthma, and 34 controls (age range: 8.2 to 15.4 years) were monitored with wrist actigraphs and peak-flow meters for 3 consecutive days. In addition, asthma severity was assessed by subjective parental and self-rating scale and symptom checklist. Asthmatic children had poorer sleep quality in comparison to their controls, as manifested in lower percentages of quiet sleep (p < .05) and increased activity level during sleep (p < .05). As expected, asthmatic children had reduced morning peak expiratory flow measures (p < .01) and a higher evening-to-morning drop in peak expiratory flow (p < .005). Peak-flow measures were significantly correlated with subjective and objective sleep measures. In the asthmatic group, sleep measures were also correlated with subjective asthma severity indices and symptom checklists. We conclude that poorer sleep is associated with reduced pulmonary function. The reduced sleep quality, coupled with subjective reports of increased fatigue and reduced alertness found in asthmatic children, suggest that these children are at risk for developing neurobehavioral deficits associated with chronic sleep loss.

Sleep quality in children with attention deficit hyperactivity disorder: an actigraphic study

The aim of the present study was to compare the sleep of 12 children with attention deficit hyperactivity disorder (ADHD) with that of 12 normal controls. The children were examined in their natural environment, using continuous actigraphic monitoring over several consecutive nights, as well as undergoing subjective parental reports. It was hypothesized that children diagnosed with ADHD would suffer from reduced sleep quality than children without ADHD. This hypothesis was supported by the actigraphic measures, but not supported by the subjective parental reports. It was also found that the sleep quality of the two groups differed over the course of the night, which suggests a difference in sleep architecture. Various possible explanations for these findings, their implications regarding the relationship between sleep and ADHD, and the resulting treatment ramifications are discussed, and suggestions for further research are provided.

Sleep and melatonin in infants: a preliminary study

Sleep-wake patterns of 20 normal, healthy infants (16 girls and four boys; age range: 26-37 weeks) were recorded for a period of 1 week with a miniature activity monitor. Urine samples were extracted from the infants' disposable diapers that were collected during a 60-hour period to determine the levels of 6-sulphatoxymelatonin (aMT6s, a melatonin metabolite) using a radioimmunoassay test. Infants with "mature" secretion patterns (i.e. with an adult-like circadian rhythm) had a significantly delayed sleep-wake cycle in comparison to those with "immature" patterns. The onset of their nocturnal-sleep episode was delayed by almost 1 hour (22.1 vs. 21.2 hours; p < 0.05). Higher secretion rates of aMT6s during the evening hours (6:00-10:00 p.m.) were associated with earlier onset of nocturnal sleep (r = 0.51; p < 0.05). A delayed peak of melatonin was associated with more fragmented sleep during the night (e.g. r = 0.49; p < 0.05; for lower sleep percent). These findings suggest that melatonin plays an important role in the evolution of the sleep-wake system.

Evaluating night wakings in sleep-disturbed infants: a methodological study of parental reports and actigraphy

The aim of this study was to investigate the use of objective and subjective sleep measures in diagnostic assessment of night-waking problems during infancy. Infant sleep-wake measures obtained from parental daily logs were compared with objective sleep measures derived from activity monitoring during a week-long period in 66 referred infants. Reported sleep measures were significantly correlated with objective sleep measures and showed a significant level of day-to-day stability. Parents were accurate reporters of sleep-schedule measures (e.g. sleep onset, r = 0.88; sleep duration, r = 0.74; p < 0.0001). However, parents were less accurate in assessing sleep quality measures, significantly overestimating the time that their infants spent in actual sleep and underestimating the number of their night-wakings (r = 0.41 and r = 0.60, respectively; P < 0.001). It is suggested that subjective and objective measures should play a complementary role in the clinical assessment of night-waking problems in early childhood.

Newborns' sleep-wake patterns: the role of maternal, delivery and infant factors

OBJECTIVE

The purpose of this study was to assess the sleep-wake patterns of fullterm (> or = 37 weeks) newborns and to evaluate the effects of specific factors including maternal gestational diabetes, infant size and anthropometric measures, gender, gestational age and delivery variables.

METHODS

Two-hundred twenty newborns were studied in the hospital nursery for a continuous 24-h period with miniature activity monitors attached to the infants' ankles. The sample consisted of 102 infants of gestational diabetic mothers (IGDM) and 118 controls. Anthropometric measurements were obtained and maternal and infant characteristics were recorded.

RESULTS

The newborns had a discernible diurnal sleep pattern and slept twice as much during the nighttime as daytime hours (P < 0.001). Higher skinfold measurements correlated significantly with increased quiet and motionless sleep (P < 0.05) for the IGDM but not for controls. Sleep of infants born at later gestational ages was characterized by increased percent of quiet and motionless sleep (P < 0.0001). No direct gender effects were identified.

CONCLUSIONS

Multiple factors were associated with the sleep-wake patterns of the newborns on our study cohort including maternal glucose values during pregnancy, increased measures of adiposity in IGDM, increased gestational age, mode of delivery and delivery Sequence. Investigation of the sleep-wake characteristics of neonates using activity monitors is a noninvasive method for gaining new understanding of the relationships between sleep wake activity patterns and infant characteristics.

The effect of nasolacrimal occlusion on drug-induced mydriasis

BACKGROUND

Nasolacrimal occlusion has been shown to improve the efficacy of some topically applied ocular drugs. The aim of this study was to investigate the effect of nasolacrimal occlusion on tropicamide-induced mydriasis.

METHODS

We compared pupillary dilatation by 0.125% tropicamide with and without nasolacrimal occlusion in 40 healthy volunteers.

RESULTS

Analysis of variance with repeated measures failed to show any advantage due to nasolacrimal occlusion in drug-induced mydriasis.

CONCLUSION

Nasolacrimal occlusion did not increase the mydriasis obtained with 0.125% tropicamide.

Sleep and psychological characteristics of children on a psychiatric inpatient unit

OBJECTIVE

To assess the association of objective measures of sleep-wake patterns and psychological status and abuse history of children hospitalized in a psychiatric inpatient unit.

METHOD

Thirty-nine inpatient children participated in the study. They were monitored for one to three consecutive nights with miniature wrist activity monitors for objective assessment of sleep-wake patterns. In addition, a thorough psychiatric and psychosocial assessment was completed with each child and the parents.

RESULTS

Children's self-ratings of depression, hopelessness, and low self-esteem were significantly correlated with objective sleep measures indicating poorer sleep quality. No significant correlations between intelligence scores and sleep measures were found. Nonabused and sexually abused children had better sleep quality than physically abused children.

CONCLUSIONS

Sleep quality during hospitalization is strongly associated with self experiences of depression, hopelessness, and low self-esteem in children with severe behavior disorders.

Case study: sleep and aggressive behavior in a blind, retarded adolescent. A concomitant schedule disorder?

Blind people are prone to suffer from sleep-wake schedule disorders. This report describes 2 months of monitoring of sleep patterns and aggressive behaviors in a totally blind, severely retarded adolescent boy, hospitalized in a psychiatric hospital. The documented sleep-wake patterns seem to portray a sleep-wake schedule disorder with a monthly periodicity. Aggressive behaviors seem to echo the same periodicity, suggesting that a common or linked biobehavioral timing mechanism may underlie both sleep and episodic aggressive outbursts. The need to consider sleep schedule disorders as a primary process underlying some psychopathological disorders, and the related risks of misdiagnosis and mistreatment, are highlighted.

The role of actigraphy in the evaluation of sleep disorders

This paper, which has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association, provides the background for the Standards of Practice Committee's parameters for the practice of sleep medicine in North America. The growing use of activity-based monitoring (actigraphy) in sleep medicine and sleep research has enriched and challenged traditional sleep-monitoring techniques. This review summarizes the empirical data on the validity of actigraphy in assessing sleep-wake patterns and assessing clinical and control groups ranging in age from infancy to elderly. An overview of sleep-related actigraphic studies is also included. Actigraphy provides useful measures of sleep-wake schedule and sleep quality. The data also suggest that actigraphy, despite its limitations, may be a useful, cost-effective method for assessing specific sleep disorders, such as insomnia and schedule disorders, and for monitoring their treatment process. Methodological issues such as the proper use of actigraphy and possible artifacts have not been systematically addressed in clinical research and practice.

Assessment of intervention for infant night waking: parental reports and activity-based home monitoring

Sleep patterns of 50 infants (aged 9-24 months) with sleep disturbances were studied by using an activity monitor (actigraph) and parental reports during the baseline and intervention periods. Two behavioral intervention methods were used to treat the multiple or prolonged night-waking problems. Infant sleep significantly improved during the period of intervention as measured by both actigraphic and parental monitoring. The discrepancy between parental and actigraphic measures increased over time, as did the number of omitted items from the parental daily logs. The results highlight some of the advantages as well as some of the limitations of actigraphic and parental monitoring of infant sleep, and they suggest that the two methods may have complementary roles in assessing intervention efficacy in this field.

Activity-based sleep-wake identification: an empirical test of methodological issues

The effects of actigraph placement and device sensitivity on actigraphic automatic sleep-wake scoring were assessed using concomitant polysomnographic and wrist actigraphic data from dominant and nondominant hands of 20 adults and 16 adolescents during 1 laboratory night. Although activity levels differed between dominant and nondominant wrists during periods of sleep (F = 4.57; p < 0.05) and wake (F = 15.5; p < 0.0005), resulting sleep-wake scoring algorithms were essentially the same and were equally explanatory (R2 = 0.64; p < 0.0001). When the sleep-wake scoring algorithm derived from the nondominant hand was used to score the nondominant data for sleep-wake, overall agreement rates with polysomnography scoring ranged between 91 and 93% for the calibration and validation samples. Results obtained with the same algorithm for the dominant-wrist data were within the same range. Agreement for sleep scoring was consistently higher than for wake scoring. Statistical manipulation of activity levels before applying the scoring algorithm indicated that this algorithm is quite robust toward moderate changes in activity level. Use of "twin-wrist actigraphy" enables identification of artifacts that may result from breathing-related motions.

Assessment of intervention for infant night waking: parental reports and activity-based home monitoring

Sleep patterns of 50 infants (aged 9-24 months) with sleep disturbances were studied by using an activity monitor (actigraph) and parental reports during the baseline and intervention periods. Two behavioral intervention methods were used to treat the multiple or prolonged night-waking problems. Infant sleep significantly improved during the period of intervention as measured by both actigraphic and parental monitoring. The discrepancy between parental and actigraphic measures increased over time, as did the number of omitted items from the parental daily logs. The results highlight some of the advantages as well as some of the limitations of actigraphic and parental monitoring of infant sleep, and they suggest that the two methods may have complementary roles in assessing intervention efficacy in this field.

Somatic, cognitive and emotional characteristics of abused children in a psychiatric hospital

A systematic review of medical records of one hundred consecutive admissions to a children's psychiatric inpatient unit was conducted to assess specific somatic, cognitive and emotional characteristics that distinguish sexually abused children from other hospitalized children. Sexually abused children were characterized by: a lower performance IQ, higher incidence of parasomnia prior to admission, longer length of hospital stay, and comparatively small physical stature.

Effects of methylphenidate on sleep in children with attention-deficient hyperactivity disorder. An activity monitor study

OBJECTIVE

To assess the effects of methylphenidate hydrochloride on sleep patterns in children diagnosed as having attention-deficit hyperactivity disorder (ADHD).

DESIGN

A double-blind, controlled drug-placebo cross-over design.

SETTING

Home.

SUBJECTS

Ten children (aged 6 years 9 months to 12 years & months) diagnosed as having ADHD were consecutively recruited and compared with age- and sex-matched normal controls.

TREATMENT

Methylphenidate hydrochloride (0.3 to 0.4 mg/kg) or placebo was administered at 7:30 AM.

MEASUREMENTS AND RESULTS

Each child underwent activity monitoring at home during 6 days of no treatment (baseline) followed by placebo and methylphenidate treatment. The results of the three trial stages, as well as those of the 20 age- and sex-matched normal controls, were compared. A shorter total sleep duration was evident during the methylphenidate treatment compared with that of baseline and placebo treatment. The amount of quiet sleep was lower (however, not significantly) among the study group compared with controls, whereas no such difference was noted during methylphenidate treatment. Night-to-night sleep pattern stability was found. No other differences were found either between children with ADHD and controls or between on and off stages of methylphenidate treatment.

CONCLUSIONS

These results support the notion that ADHD is a centrally generated disorder attributable to hypoarousal, which subsequently stimulates motor overactivity. Methylphenidate does not appear to affect sleep patterns adversely and possibly normalizes them in patients with ADHD.

Infant-parent co-sleeping in an evolutionary perspective: implications for understanding infant sleep development and the sudden infant death syndrome

Evidence suggests that infant-parent co-sleeping represents the species-wide pattern of sleep in which human infant physiology evolved. The hypothesis evaluated in this manuscript is that the co-sleeping environment may foster development of optimal sleep patterning in infants and confer other benefits, including reducing the risk of the sudden infant death syndrome (SIDS). These postulations by McKenna are considered from different perspectives by the coauthors. Using evolutionary, cross-species, crosscultural, physiological and behavioral data, our objective was to present a conceptual framework for assessing the developmental consequences of solitary sleeping and infant-parent co-sleeping.

Sleep characteristics of asthmatics in the first four years of life: a comparative study

The association between asthma and sleep disturbances was assessed as part of a community survey of sleep patterns in children aged 4-48 months. A questionnaire covering the area of past and present sleep and settling behaviour, as well as health history and demographic data, was administered to 752 mothers of children visiting 14 well baby clinics. Fifty one (6.8%) of the children who were diagnosed as having asthma by their paediatricians were compared with the remaining healthy controls (children with perinatal problems, other chronic illnesses, developmental problems, or repeat admissions to hospital were excluded). Thirty nine per cent of the children with asthma and 38% of the normal controls were identified as regular wakers. The number of interrupted nights each week, settling time, and sleep duration were comparable. In the children with asthma an uninterrupted night's sleep was acquired later than in the control group. Parental perception of the severity of the sleep problem was similar in the two groups, as were the calming techniques. It is concluded that this study does not support a significantly increased prevalence of sleep disturbances among young children with asthma compared with their healthy peers.

Parental and relationship representations and experiences of depression in college students

Young adults' descriptions of their parents and their relationships with their parents were used to reexamine the relations between object representation and depressive experience. One hundred eight students completed (a) four open-ended descriptions, including two written descriptions of the parents (mother and father, separately), and two written descriptions of the relationships with the parents; and (b) the Depressive Experience Questionnaire. Each of the four open-ended descriptions was rated on seven scales. Factor analysis yielded four distinct factors from the 28 dimensions of the descriptions. These factors were related to: (a) the degree of elaboration and investment, (b) the structural level of the descriptions, (c) the affective tone of the description of the father, and (d) the affective tone of the description of the mother. Significant differences and interactions were found regarding the interplay between the specific significant other represented (father or mother) and the specific framework of representation (parent description or relationship description). Measures derived from parents' and relationship descriptions significantly predicted depressive experiences of self-criticism and dependency. The results indicate the advantages of a joint exploration of the representation of distinct significant others (mother and father) and the use of two modes of relatedness (describe parent and describe relationship with parent) in the process of personality assessment.

The effects of illness on sleep behaviour in infants

For the purpose of evaluating the association between health problems and sleep disturbances as part of a community survey of sleep patterns in childhood, a questionnaire was administered to 752 mothers of children between the ages of 4 months and 4 years, and to the nurses at their regular baby clinics. The questionnaire covered the areas of past and present sleep and settling behaviour, as well as health history and demographic data. The study group consisted of 66 (8.9%) children who had either chronic medical problems, or history of an illness requiring hospitalisation. Regular night waking was reported in 35% and 34% of the group with and without history of illness, respectively. The mean number of interrupted nights per week was similar in both groups and so were the sleep problems perceived by the mothers. We conclude that in this age group the results do not support an association between health problems and prolonged sleep disturbances.

Toddlers' sleep and temperament: reporting bias or a valid link? A research note

Objective sleep measures derived from a computerized movement detector attached to the child's leg, were obtained for a group of 31 toddlers (mean age: 18.5 months). The monitored sleep parameters were compared with maternal assessment of the child's sleep and her perception of his temperament. The validity of maternal diaries as a measure of the child's sleep was not supported. Nevertheless, a link between both subjective and objective sleep measures with temperament dimensions was indicated. The modest association between sleep and temperament may suggest either a continuity between some aspects of day- and night-time functioning or, alternatively, the influence of the child's sleep behavior in shaping the mother's perceptions of her toddler's temperament.

Increased motor activity and recurrent manic episodes: predictors of rapid relapse in remitted bipolar disorder patients after lithium discontinuation

Ten patients with remitted bipolar illness on lithium maintenance therapy underwent placebo-controlled lithium discontinuation. Clinical ratings and recording of sleep-wake activity using wrist-worn actigraphs were carried out before and after lithium discontinuation. Seven patients experienced relapse into mania or hypomania within the first 3 months after lithium discontinuation. Actigraphic recordings revealed that patients who relapsed had higher baseline levels of daytime motor activity than patients without relapse. This may suggest that motor activity can be a sensitive marker of subclinical manic tendencies and early relapse following lithium discontinuation.