bluuebunny/crossref_metadata_2025 huggingface dataset:
Neocortical neurogenesis in humans is restricted to development
Authors: Bhardwaj Ratan D. , Curtis Maurice A. , Spalding Kirsty L. , Buchholz Bruce A. , Fink David , Björk-Eriksson Thomas , Nordborg Claes , Gage Fred H. , Druid Henrik , Eriksson Peter S. , Frisén Jonas
Published: August 2006

Stem cells generate neurons in discrete regions in the postnatal mammalian brain. However, the extent of neurogenesis in the adult human brain has been difficult to establish. We have taken advantage of the integration of
14
C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral neocortex. Together with the analysis of the neocortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that, whereas nonneuronal cells turn over, neurons in the human cerebral neocortex are not generated in adulthood at detectable levels but are generated perinatally.
Prenatal exposure to ultrasound waves impacts neuronal migration in mice
Authors: Ang Eugenius S. B. C. , Gluncic Vicko , Duque Alvaro , Schafer Mark E. , Rakic Pasko
Published: August 2006

Neurons of the cerebral neocortex in mammals, including humans, are generated during fetal life in the proliferative zones and then migrate to their final destinations by following an inside-to-outside sequence. The present study examined the effect of ultrasound waves (USW) on neuronal position within the embryonic cerebral cortex in mice. We used a single BrdU injection to label neurons generated at embryonic day 16 and destined for the superficial cortical layers. Our analysis of over 335 animals reveals that, when exposed to USW for a total of 30 min or longer during the period of their migration, a small but statistically significant number of neurons fail to acquire their proper position and remain scattered within inappropriate cortical layers and/or in the subjacent white matter. The magnitude of dispersion of labeled neurons was variable but systematically increased with duration of exposure to USW. These results call for a further investigation in larger and slower-developing brains of non-human primates and continued scrutiny of unnecessarily long prenatal ultrasound exposure.
Transfer of learning in avoiding false memory: The roles of warning, immediate feedback, and incentive
Authors: Jou Jerwen , Foreman Joseph
Published: August 2006

Participants learned semantic associates and were tested in the Deese–Roediger–McDermott (DRM) paradigm. A multiple-trial learning procedure with warning, feedback, and monetary incentive was employed to reduce false memory. Results showed that there was a progressive reduction of false memory over the trials as well as a generalization of learning to new lists of words in avoiding the critical nonpresented words attributable to explicit warning, feedback, and incentive, respectively. Both the feedback and the monetary incentive had an effect beyond what an explicit warning could obtain. In addition, participants were found to achieve false-memory reduction by enhancing the activation of the critical words and the monitoring process, rather than by strengthening the verbatim processing of the list words. It was concluded that false memory may not be as impervious to correction as was believed insofar as an effective training method is applied.
On polyharmonic operators with limit-periodic potential in dimension two
Authors: Karpeshina Yulia , Lee Young-Ran
Published: August 2006

This is an announcement of the following results. We consider a polyharmonic operator

H
=
(
−
Δ

)
l

+
V
(
x
)

H=(-\Delta )^l+V(x)

in dimension two with

l
≥
6

l\geq 6

and

V
(
x
)

V(x)

being a limit-periodic potential. We prove that the spectrum of

H
H

contains a semiaxis and there is a family of generalized eigenfunctions at every point of this semiaxis with the following properties. First, the eigenfunctions are close to plane waves at the high-energy region. Second, the isoenergetic curves in the space of momenta corresponding to these eigenfunctions have the form of slightly distorted circles with holes (Cantor-type structure). Third, the spectrum corresponding to the eigenfunctions (the semiaxis) is absolutely continuous.
An initial map of insertion and deletion (INDEL) variation in the human genome
Authors: Mills Ryan E. , Luttig Christopher T. , Larkins Christine E. , Beauchamp Adam , Tsui Circe , Pittard W. Stephen , Devine Scott E.
Published: August 2006

Although many studies have been conducted to identify single nucleotide polymorphisms (SNPs) in humans, few studies have been conducted to identify alternative forms of natural genetic variation, such as insertion and deletion (INDEL) polymorphisms. In this report, we describe an initial map of human INDEL variation that contains 415,436 unique INDEL polymorphisms. These INDELs were identified with a computational approach using DNA re-sequencing traces that originally were generated for SNP discovery projects. They range from 1 bp to 9989 bp in length and are split almost equally between insertions and deletions, relative to the chimpanzee genome sequence. Five major classes of INDELs were identified, including (1) insertions and deletions of single-base pairs, (2) monomeric base pair expansions, (3) multi-base pair expansions of 2–15 bp repeat units, (4) transposon insertions, and (5) INDELs containing random DNA sequences. Our INDELs are distributed throughout the human genome with an average density of one INDEL per 7.2 kb of DNA. Variation hotspots were identified with up to 48-fold regional increases in INDEL and/or SNP variation compared with the chromosomal averages for the same chromosomes. Over 148,000 INDELs (35.7%) were identified within known genes, and 5542 of these INDELs were located in the promoters and exons of genes, where gene function would be expected to be influenced the greatest. All INDELs in this study have been deposited into dbSNP and have been integrated into maps of human genetic variation that are available to the research community.
Identification of potential regulatory motifs in odorant receptor genes by analysis of promoter sequences
Authors: Michaloski Jussara S. , Galante Pedro A.F. , Malnic Bettina
Published: August 2006

Mouse odorant receptors (ORs) are encoded by >1000 genes dispersed throughout the genome. Each olfactory neuron expresses one single OR gene, while the rest of the genes remain silent. The mechanisms underlying OR gene expression are poorly understood. Here, we investigated if OR genes share common cis-regulatory sequences in their promoter regions. We carried out a comprehensive analysis in which the upstream regions of a large number of OR genes were compared. First, using RLM-RACE, we generated cDNAs containing the complete 5′-untranslated regions (5′-UTRs) for a total number of 198 mouse OR genes. Then, we aligned these cDNA sequences to the mouse genome so that the 5′ structure and transcription start sites (TSSs) of the OR genes could be precisely determined. Sequences upstream of the TSSs were retrieved and browsed for common elements. We found DNA sequence motifs that are overrepresented in the promoter regions of the OR genes. Most motifs resemble O/E-like sites and are preferentially localized within 200 bp upstream of the TSSs. Finally, we show that these motifs specifically interact with proteins extracted from nuclei prepared from the olfactory epithelium, but not from brain or liver. Our results show that the OR genes share common promoter elements. The present strategy should provide information on the role played by cis-regulatory sequences in OR gene regulation.
Common inheritance of chromosome Ia associated with clonal expansion of Toxoplasma gondii
Authors: Khan Asis , Böhme Ulrike , Kelly Krystyna A. , Adlem Ellen , Brooks Karen , Simmonds Mark , Mungall Karen , Quail Michael A. , Arrowsmith Claire , Chillingworth Tracey , Churcher Carol , Harris David , Collins Matthew , Fosker Nigel , Fraser Audrey , Hance Zahra , Jagels Kay , Moule Sharon , Murphy Lee , O'Neil Susan , Rajandream Marie-Adele , Saunders David , Seeger Kathy , Whitehead Sally , Mayr Thomas , Xuan Xuenan , Watanabe Junichi , Suzuki Yutaka , Wakaguri Hiroyuki , Sugano Sumio , Sugimoto Chihiro , Paulsen Ian , Mackey Aaron J. , Roos David S. , Hall Neil , Berriman Matthew , Barrell Bart , Sibley L. David , Ajioka James W.
Published: August 2006

Toxoplasma gondii is a globally distributed protozoan parasite that can infect virtually all warm-blooded animals and humans. Despite the existence of a sexual phase in the life cycle, T. gondii has an unusual population structure dominated by three clonal lineages that predominate in North America and Europe, (Types I, II, and III). These lineages were founded by common ancestors ~10,000 yr ago. The recent origin and widespread distribution of the clonal lineages is attributed to the circumvention of the sexual cycle by a new mode of transmission—asexual transmission between intermediate hosts. Asexual transmission appears to be multigenic and although the specific genes mediating this trait are unknown, it is predicted that all members of the clonal lineages should share the same alleles. Genetic mapping studies suggested that chromosome Ia was unusually monomorphic compared with the rest of the genome. To investigate this further, we sequenced chromosome Ia and chromosome Ib in the Type I strain, RH, and the Type II strain, ME49. Comparative genome analyses of the two chromosomal sequences revealed that the same copy of chromosome Ia was inherited in each lineage, whereas chromosome Ib maintained the same high frequency of between-strain polymorphism as the rest of the genome. Sampling of chromosome Ia sequence in seven additional representative strains from the three clonal lineages supports a monomorphic inheritance, which is unique within the genome. Taken together, our observations implicate a specific combination of alleles on chromosome Ia in the recent origin and widespread success of the clonal lineages of T. gondii.
Uneven chromosome contraction and expansion in the maize genome
Authors: Bruggmann Rémy , Bharti Arvind K. , Gundlach Heidrun , Lai Jinsheng , Young Sarah , Pontaroli Ana C. , Wei Fusheng , Haberer Georg , Fuks Galina , Du Chunguang , Raymond Christina , Estep Matt C. , Liu Renyi , Bennetzen Jeffrey L. , Chan Agnes P. , Rabinowicz Pablo D. , Quackenbush John , Barbazuk W. Brad , Wing Rod A. , Birren Bruce , Nusbaum Chad , Rounsley Steve , Mayer Klaus F.X. , Messing Joachim
Published: August 2006

Maize (Zea mays or corn), both a major food source and an important cytogenetic model, evolved from a tetraploid that arose about 4.8 million years ago (Mya). As a result, maize has extensive duplicated regions within its genome. We have sequenced the two copies of one such region, generating 7.8 Mb of sequence spanning 17.4 cM of the short arm of chromosome 1 and 6.6 Mb (25.6 cM) from the long arm of chromosome 9. Rice, which did not undergo a similar whole genome duplication event, has only one orthologous region (4.9 Mb) on the short arm of chromosome 3, and can be used as reference for the maize homoeologous regions. Alignment of the three regions allowed identification of syntenic blocks, and indicated that the maize regions have undergone differential contraction in genic and intergenic regions and expansion by the insertion of retrotransposable elements. Approximately 9% of the predicted genes in each duplicated region are completely missing in the rice genome, and almost 20% have moved to other genomic locations. Predicted genes within these regions tend to be larger in maize than in rice, primarily because of the presence of predicted genes in maize with larger introns. Interestingly, the general gene methylation patterns in the maize homoeologous regions do not appear to have changed with contraction or expansion of their chromosomes. In addition, no differences in methylation of single genes and tandemly repeated gene copies have been detected. These results, therefore, provide new insights into the diploidization of polyploid species.
Transcriptional Regulation of Gibberellin Metabolism Genes by Auxin Signaling in Arabidopsis
Authors: Frigerio Martín , Alabadí David , Pérez-Gómez José , García-Cárcel Laura , Phillips Andrew L. , Hedden Peter , Blázquez Miguel A.
Published: August 2006

Auxin and gibberellins (GAs) overlap in the regulation of multiple aspects of plant development, such as root growth and organ expansion. This coincidence raises questions about whether these two hormones interact to regulate common targets and what type of interaction occurs in each case. Auxins induce GA biosynthesis in a range of plant species. We have undertaken a detailed analysis of the auxin regulation of expression of Arabidopsis (Arabidopsis thaliana) genes encoding GA 20-oxidases and GA 3-oxidases involved in GA biosynthesis, and GA 2-oxidases involved in GA inactivation. Our results show that auxin differentially up-regulates the expression of various genes involved in GA metabolism, in particular several AtGA20ox and AtGA2ox genes. Up-regulation occurred very quickly after auxin application; the response was mimicked by incubations with the protein synthesis inhibitor cycloheximide and was blocked by treatments with the proteasome inhibitor MG132. The effects of auxin treatment reflect endogenous regulation because equivalent changes in gene expression were observed in the auxin overproducer mutant yucca. The results suggest direct regulation of the expression of GA metabolism genes by Aux/IAA and ARF proteins. The physiological relevance of this regulation is supported by the observation that the phenotype of certain gain-of-function Aux/IAA alleles could be alleviated by GA application, which suggests that changes in GA metabolism mediate part of auxin action during development.
Interaction between Rice MYBGA and the Gibberellin Response Element Controls Tissue-Specific Sugar Sensitivity of α-Amylase Genes
Authors: Chen Peng-Wen , Chiang Chih-Ming , Tseng Tung-Hi , Yu Su-May
Published: August 2006

Expression of α-amylase genes during cereal grain germination and seedling growth is regulated negatively by sugar in embryos and positively by gibberellin (GA) in endosperm through the sugar response complex (SRC) and the GA response complex (GARC), respectively. We analyzed two α-amylase promoters, αAmy3 containing only SRC and αAmy8 containing overlapped SRC and GARC. αAmy3 was sugar-sensitive but GA-nonresponsive in both rice (Oryza sativa) embryos and endosperms, whereas αAmy8 was sugar-sensitive in embryos and GA-responsive in endosperms. Mutation of the GA response element (GARE) in the αAmy8 promoter impaired its GA response but enhanced sugar sensitivity, and insertion of GARE in the αAmy3 promoter rendered it GA-responsive but sugar-insensitive in endosperms. Expression of the GARE-interacting transcription factor MYBGA was induced by GA in endosperms, correlating with the endosperm-specific αAmy8 GA response. αAmy8 became sugar-sensitive in MYBGA knockout mutant endosperms, suggesting that the MYBGA–GARE interaction overrides the sugar sensitivity of αAmy8. In embryos overexpressing MYBGA, αAmy8 became sugar-insensitive, indicating that MYBGA affects sugar repression. α-Amylase promoters active in endosperms contain GARE, whereas those active in embryos may or may not contain GARE, confirming that the GARE and GA-induced MYBGA interaction prevents sugar feedback repression of endosperm α-amylase genes. We demonstrate that the MYBGA–GARE interaction affects sugar feedback control in balanced energy production during seedling growth and provide insight into the control mechanisms of tissue-specific regulation of α-amylase expression by sugar and GA signaling interference.
Impaired megakaryopoiesis in patients with chronic idiopathic neutropenia is associated with increased transforming growth factor β1 production in the bone marrow
Authors: Psyllaki Maria , Damianaki Athina , Gemetzi Claudia , Pyrovolaki Katerina , Eliopoulos George D. , Papadaki Helen A.
Published: August 2006

Patients with chronic idiopathic neutropenia (CIN) display relatively low peripheral blood platelet counts and hypo‐lobulated megakaryocytes in the bone marrow (BM). The underlying pathogenetic mechanismswere probed by studying the reserves and clonogenic potential of BM megakaryocytic progenitor cells using flow‐cytometry and a collagen‐based clonogenic assay for the identification of megakaryocyte colony‐forming units (CFU‐Meg). Thrombopoietin (TPO) and transforming growth factor‐β1 (TGFβ1) levels were also evaluated in long‐term BM culture supernatants using an enzyme‐linked immunosorbent assay. CIN patients (n = 39) showed a low proportion of BM CD34+/CD61+ megakaryocytic progenitor cells and low frequency of early and mixed CFU‐Meg in the BM mononuclear, but not CD34+, cell fraction, compared with healthy controls (n = 20). TPO and TGFβ1 levels were significantly higher in patients compared with controls. TPO levels inversely correlated with platelet counts whereas TGFβ1 values correlated inversely with CD34+/CD61+ and CFU‐Meg megakaryocytic progenitor cell numbers and positively with TPO levels. The addition of an anti‐TGFβ1 neutralising antibody significantly increased the numbers of CFU‐Meg in CIN patients but not in controls, compared with baseline. These data suggest that increased local production of TGFβ1 probably affects the BM megakaryocytic progenitor cell growth in CIN whereas the compensatory production of TPO finally balances the TGFβ1‐induced inhibitory effect.
Spectators & spectacles: nurses, midwives and visuality
Authors: Barnard Alan G. , Sinclair Marlene
Published: August 2006

Aim.  In this paper we reflect on how linear perspective vision influences the practice of nurses and midwives and to advance understanding of clinical practice in technologically intensive environments through examination of drawings by nurses and midwives and through critical analysis.

Background.  There is increasing emphasis on vision in Western culture, and both nurses and midwives spend a great deal of time observing their clinical environment(s). Healthcare practitioners work increasingly in image‐based realities and nurses rely on visual skills. Vision and visual representation are central to our practice and are important to examine because we look often at technology to assess people and care.

Discussion.  The world in which we practise is one of meaning(s). Technological development is transformative in nature and produces changes that alter the way(s) we give care. Amongst all this change, it is unclear how we practise in environments characterized by increasing technology and it is unknown how nursing and midwifery practice alter as a result.

Conclusion.  Simple drawings included in this paper highlight an important and shared experience of clinical practice(s). They emphasize the importance and scope of the visual sense and expose practitioner behaviour that has enormous implications for current and future professional development and person‐focussed care provision. Experiences described in this paper require further examination and highlight substantial changes to nurse–patient relationships, health care and the way we practise.
Male nurses’ experiences of providing intimate care for women clients
Authors: Inoue Madoka , Chapman Rose , Wynaden Dianne
Published: August 2006

Aim.  This paper reports a study of male nurses’ experiences of providing intimate care for women clients.

Background.  The number of men entering the nursing profession has increased worldwide. As a consequence of the move to a more gender‐balanced profession, debate has ensued over how intimate care should be performed when this requires male nurses to be physically close to women clients. As there was little previous work on this topic, we wished to provide nurses, clients and other healthcare professionals with a better understanding of male nurses’ experiences of working with women clients and within a healthcare system where they often feel excluded.

Method.  Semi‐structured, open‐ended interviews were conducted with male nurses working in various clinical settings in Western Australia. Latent content analysis was used to analyse the interviews, which were carried out between June and July 2004.

Findings.  Three themes were identified: the definition of intimate care, the emotional experience associated with providing intimate care and strategies used to assist in the delivery of intimate care for women clients. Providing intimate care for women clients was a challenging experience for male nurses. Participants described how it required them to invade these clients’ personal space. Consequently, they often experienced various negative feelings and used several strategies to assist them during care delivery.

Conclusions.  Nurse educators should assist male nurses to be better prepared to interact with women clients in various settings. Furthermore, workplace environments need to provide additional support and guidance for male nurses to enable them to develop effective coping strategies to manage challenging situations.
Nurses’ opportunistic interventions with patients in relation to smoking
Authors: Whyte Rosemary E. , Watson Hazel E. , McIntosh Jean
Published: August 2006

Aim.  This paper reports a study exploring nurses’ provision of opportunistic health education on smoking for hospital patients.

Background.  Smoking cessation guidelines recommend assessment of patients’ smoking habits and provision of smoking cessation advice when possible, and highlight the importance of the role of nurses in health promotion and health education. In the past, nurses have been criticized for lack of knowledge, skills and confidence in relation to health education and the perception that it is additional to, rather than integrated with, nursing care.

Methods.  A qualitative case study design was selected to explore the health education practice of 12 nurses working in acute wards in three general hospitals in Scotland. Data were collected in 2000 through non‐participant observation, semi‐structured interviews and the use of a radio‐microphone to record nurse–patient interactions. The data analysis was guided by four key elements of health education practice: ‘the teachable moment’, ‘readiness to learn’, ‘the provision of health information’ and ‘oral communication’.

Findings.  Smoking was part of the nurses’ agenda, as most recognized opportunities to introduce health education on smoking during nursing care, suggesting a tentative move towards the integration of health education with nursing care. Evidence from patients’ interactions indicated ample opportunity for nurses to provide smoking‐related health information. However, the content of nurses’ interactions on smoking was variable, with some limited by poor communication skills and inadequate knowledge of smoking and smoking cessation. The context of the interactions was also important in understanding some of the restrictions on conversational progress.

Conclusions.  Nurses require the knowledge and skills to perform a health education role, and the inclusion of smoking cessation guidelines in nursing curricula would contribute to this. Where patients are in hospitals for short periods of time, opportunistic health education on smoking needs to be introduced as the basis for more specialist intervention.
Psychometric properties of the Arabic version of Quality of Life Index
Authors: Halabi Jehad O.
Published: August 2006

Aim. This paper reports a study to translate the English language version of the Quality of Life Index into Arabic and estimate its reliability and content validity.

Background. Quality of life has become an important concern in health care and social policy. It is a difficult construct to define and measure, as it is determined by cultural, ethical, personal and religious values. The generic Ferrans and Powers Quality of Life Index was developed to measure quality of life of healthy individuals. Specific versions of the index were developed for particular diseases, such as diabetes, cancer and end‐stage kidney disease. The instruments were initially developed for English‐speaking clients and were later translated into several languages and used within a variety of cultures. However, there were no Arabic versions of the tool available to measure the quality of life of general populations or of people with particular diseases.

Method. The Quality of Life Index was translated into Arabic using two of the techniques suggested in the literature for translation – back translation and bilingual technique. The same process was followed in the translation of the original scale and various disease‐specific versions of the instrument. The work took place between 1995 and 2004.

Findings. The translated Arabic Quality of Life Index demonstrated a high degree of accuracy of translation and estimates of content validity. Subsequent to the translation of the original scale into Arabic, 13 disease‐related versions of the instrument were translated and are ready for use with clients who speak Arabic. Four of the versions have been used to collect data from clients. The results revealed high estimates of reliability for the generic, diabetes, cancer and dialysis versions.

Conclusion. The Arabic version of the Quality of Life Index is highly reliable and has sufficient content validity for measuring quality of life of Arabic‐speaking clients.
Learning‐dependent changes in sleep spindles and Stage 2 sleep
Authors: FOGEL STUART M. , SMITH CARLYLE T.
Published: August 2006

It has become increasingly clear that sleep is necessary for efficient memory consolidation. Recently, it has been found that Stage 2 sleep disruption impairs procedural memory performance, and that memory performance is correlated with the duration of Stage 2 sleep; but the mechanisms involved in synaptic plasticity for procedural memory during sleep have not been identified. The present study examined the learning‐dependent changes in sleep, including Stage 2 sleep spindles. Following an intense period of simple motor procedural learning, the duration of Stage 2 sleep and spindle density increased. There were no changes observed in the duration of any other stage of sleep or in the density of rapid eye movements. These findings support the hypothesis that sleep spindles are involved in the off‐line reprocessing of simple motor procedural memory during Stage 2 sleep.
Duration of sleep and breast cancer risk in a large population‐based case–control study
Authors: McELROY JANE A. , NEWCOMB POLLY A. , TITUS‐ERNSTOFF LINDA , TRENTHAM‐DIETZ AMY , HAMPTON JOHN M. , EGAN KATHLEEN M.
Published: August 2006

One important function of sleep may be its contribution to the maintenance of the immune system and regulation of the circadian rhythms by melatonin. Researchers have speculated that disruption of immune functions involving cortisol levels and natural killer cell activity may increase breast cancer risk whereas increased melatonin exposure may protect against breast cancer. We conducted a multistate population‐based case–control study of 4033 women with invasive breast cancer and 5314 community women without breast cancer in which we inquired about women's sleep habits in the recent past and during adult lifetime. Relative to women who slept 7.0–7.9 h/night, the multivariate odds ratio for developing breast cancer among women who slept an average of 9 h or more per night approximately 2 years prior to interview was 1.13 (95% CI 0.93–1.37). The multivariate‐adjusted odds ratio for the continuous term was 1.06 (95% CI 1.01–1.11), suggesting a 6% increase in risk for every additional hour of sleep. Similar patterns were observed for average lifetime adult sleep duration. We found little evidence that sleeping few hours per night was associated with breast cancer risk. The results of this study suggest that increasing sleep duration is modestly associated with an increased breast cancer risk. In contrast, short duration of sleep (<7 h/night) is not substantially associated with increased risk. Further research in this area is warranted.
Dry mouth upon awakening in obstructive sleep apnea
Authors: OKSENBERG ARIE , FROOM PAUL , MELAMED SAMUEL
Published: August 2006

The aim was to assess the significance of dry mouth upon awakening as a symptom of obstructive sleep apnea (OSA). The participants were 668 consecutive adults referred for polysomnographic evaluation (PSG) because of snoring and suspected OSA, and 582 adults who were attending a general health check‐up. Data were obtained from self‐administered questionnaires and PSG evaluation. The participants were asked to answer the following question: ‘During the last month, did you experience waking up in the morning with a dry mouth?’. The response scale consisted of five categories: ‘never’, ‘rarely’, ‘sometimes’, often’, or ‘almost always’. We classified patients as having dry mouth upon awakening complaint only if they reported experiencing the symptom ‘almost always’. The prevalence of dry mouth upon awakening was twofold higher in patients with OSA (31.4%) than in primary snorers (16.4%, P < 0.001), and increased linearly from 22.4%, to 34.5%, and 40.7% in mild, moderate, and severe OSA respectively (P < 0.001). The prevalence of dry mouth upon awakening in the control group was 3.2%. Logistic regression results indicated that this symptom significantly differentiated OSA patients from primary snorers after adjusting for age, BMI, gender, hypertension, and other classical OSA symptoms (OR 2.33, 95% CI 1.34–4.07). Dry mouth upon awakening appears as a significant symptom of OSA. We suggest that increased sleep time spent with an open mouth is a likely explanation for these findings.
What predicts patients’ perceptions of improvement in insomnia?
Authors: VINCENT NORAH , PENNER STEPHANIE , LEWYCKY SAMANTHA
Published: August 2006

Although there has been considerable research into the effectiveness of individual cognitive behavioral treatment for chronic insomnia, less is known about patients’ perceptions of what constitutes actual improvement. This study utilized 70 outpatients (mean age = 49.7 years, SD = 12.0) with insomnia who completed a 6‐week cognitive behavioral group for sleep. Participants completed a number of primary (Pittsburgh Sleep Quality Index) and secondary measures (the Dysfunctional Beliefs about Sleep Scale, Insomnia Severity Index, Beck Depression Inventory, Penn State Worry Questionnaire) at pre‐ and post‐treatment. Perceived improvement was measured using the Clinical Global Improvement Scale (CGI). Results were analyzed using a combination of Logistic Regression analysis and receiver operating curve characteristic analysis (ROC). Results demonstrated that sleep quality and sleep duration were the most sensitive primary measures, or best predicted perceived improvement, whereas sleep efficiency was the most specific primary measure, or best predicted perceived lack of improvement (defined as only mild improvement). Of the secondary measures, results showed that daytime impairment was the most sensitive predictor of perceived improvement and that mood was the most specific predictor of perceived lack of improvement. Implications of these findings are that sleep quality, sleep duration, and sleep efficiency may offer different types of information and the choice of measure for predicting global improvement in insomnia will depend on the needs of the researcher/clinician.
Epidemiological aspects of self‐reported sleep onset latency in Japanese junior high school children
Authors: ALEXANDRU GAINA , MICHIKAZU SEKINE , SHIMAKO HAMANISHI , XIAOLI CHEN , HITOMI KANAYAMA , TAKASHI YAMAGAMI , ROBERT WILLIAMS W. , SADANOBU KAGAMIMORI
Published: August 2006

The purpose of this study was to investigate the relationships between sleep onset latency (SOL) and other sleep–wake patterns and media use habits in Japanese schoolchildren. A total of 9718 junior high school children responded (12.8 years) and 9199 questionnaires were used in the present analyses. The questionnaire assessed sleep–wake patterns, TV viewing and videogame habits. Overall, 72.1% of the subjects reported short SOL (≤20 min). Long SOL subjects (>20 min) were strongly associated with disturbed sleep manifested especially by increased risk of night awakenings, decreased sleep depth, and bad sleep in general (overall sleep quality). Prolonged SOL was also associated with daytime sleepiness, difficulties in falling asleep, bad morning feeling and sleep insufficiency. We found a U‐shaped relationship between sleep period and SOL. Increase in bedtime was accompanied by increased risk of prolonged SOL. The impact of ultra‐short and ultra‐long SOL (≤5 and ≥40 min) was also analysed. Long durations of watching television and playing videogame were significantly associated with prolonged SOL. After adjustment for sex, girls presented significantly higher risk of prolonged SOL. Body mass index adjustment did not reveal any significant results. SOL presents a significant component of sleep–wake habits; poor sleep hygiene and insufficient sleep time significantly increase SOL. Parents, healthcare practitioners and children themselves should be aware of the potentially negative influence of prolonged SOL. Additionally, the optimal coherent sleep–wake schedule must be promoted in parallel with the limitation on the viewing TV and game practices.
Sleep in healthy seniors: a diary study of the relation between bedtime and the amount of sleep obtained
Authors: MONK TIMOTHY H. , THOMPSON WESLEY K. , BUYSSE DANIEL J. , HALL MARTICA , NOFZINGER ERIC A. , REYNOLDS CHARLES F.
Published: August 2006

The aim of this study was to determine whether naturally occurring inter‐individual and intra‐individual differences in bedtime selection in the elderly might be lawfully related to the amount of sleep that is obtained. A total of 128 seniors (63f, 65m) aged 70–92 years each provided a week of sleep diary data yielding a total of 896 subject‐nights for analysis. From each subject‐night the diary was used to derive measures of time in bed (TIB) and total sleep time (TST). These measures were used as dependent variables in mixed‐effect linear models (nights nested within subjects) with the independent variable being bedtime for that subject‐night, arbitrarily expressed as minutes since 19:00 hours. Although there were strong inter‐individual and intra‐individual differences, for both genders, bedtime had a statistically significant effect (P < 0.001) on both TIB and TST. We observed that later bedtimes were associated with less time in bed and less time asleep. On average between 7 and 8 min of less TIB and TST were associated with each 10‐min delay in bedtime from 19:00 hours. These results are interpreted in terms of increases in sleep being derived from living in a better harmony with an earlier peaking circadian pacemaker characteristic of older age, although other possible mechanisms are also considered (e.g. age‐dependent alterations in phase angle and homeostatic sleep need).
Effects of two nights sleep deprivation and two nights recovery sleep on response inhibition
Authors: DRUMMOND SEAN P. A. , PAULUS MARTIN P. , TAPERT SUSAN F.
Published: August 2006

This study examined the effects of two nights of total sleep deprivation (TSD) and two nights of recovery sleep on response inhibition. Thirty‐eight young, healthy adults performed a Go‐NoGo task at 14 : 00 after: (1) a normal night of sleep; (2) each of two consecutive nights of TSD; and (3) each of two consecutive nights of recovery sleep; they also performed the task at 05 : 00 during the first night of sleep deprivation. We hypothesized that TSD would lead to an impaired ability to withhold a response that would be reversed with recovery sleep. Subjects did experience a significant increase in false positive responses throughout all of TSD, errors of omission (i.e. missed ‘go’ targets) were not significant until after the second night of TSD. Both components (withholding a response and automatic responding) of the task returned to baseline levels after one night of recovery sleep. These data suggest that individuals experience difficulty in withholding an inappropriate response during TSD, even when they are able to attend to the incoming stimuli and respond accurately to appropriate stimuli.
Sleep bruxism is associated to micro‐arousals and an increase in cardiac sympathetic activity
Authors: HUYNH N. , KATO T. , ROMPRÉ P. H. , OKURA K. , SABER M. , LANFRANCHI P. A. , MONTPLAISIR J. Y. , LAVIGNE G. J.
Published: August 2006

Sleep bruxism (SB) subjects show a higher incidence of rhythmic masticatory muscle activity (RMMA) than control subjects. RMMA is associated with sleep micro‐arousals. This study aims to: (i) assess RMMA/SB episodes in relation to sleep cycles; (ii) establish if RMMA/SB and micro‐arousals occur in relation to the slow wave activity (SWA) dynamics; (iii) analyze the association between RMMA/SB and autonomic cardiac activity across sleep cycles. Two nights of polygraphic recordings were made in three study groups (20 subjects each): moderate to high SB, low SB and control. RMMA episodes were considered to occur in clusters when several groups of RMMA or non‐specific oromotor episodes were separated by less than 100 s. Correlations between sleep, RMMA/SB index and heart rate variability variables were assessed for the first four sleep cycles of each study group. Statistical analyses were done with SYSTAT and SPSS. It was observed that 75.8% of all RMMA/SB episodes occurred in clusters. Micro‐arousal and SB indexes were highest during sleep cycles 2 and 3 (P < 0.001). Within each cycle, micro‐arousal and RMMA/SB indexes showed an increase before each REM sleep (P ≤ 0.02). The cross‐correlation plot for micro‐arousal index showed positive association from 4 min preceding SB onset in the moderate to high SB subjects (P ≤ 0.06). The cross‐correlation plot revealed that SWA decreases following SB onset (P ≤ 0.05). Further cross‐correlation analysis revealed that a shift in sympatho‐vagal balance towards increased sympathetic activity started 8 min preceding SB onset (P ≤ 0.03). In moderate to severe SB subjects, a clear increase in sympathetic activity precedes SB onset.
Development of the Sleep Quality Scale
Authors: YI HYERYEON , SHIN KYUNGRIM , SHIN CHOL
Published: August 2006

Sleep quality affects health and the overall quality of life. As the factors that influence sleep quality and their relative importance vary among individuals, a self‐report method is essential. Although various questionnaires have been used to assess sleep quality, few all‐inclusive assessment scales have been developed. Therefore, the purpose of this study was to develop an instrument for measuring sleep quality and to study its validity and reliability. A Sleep Quality Scale (SQS) was developed using item analysis and factor analysis on items with content validity. SQS, composed of 28 items and six factors, accounted for 62.6% of the total variance. The difference of SQS score between insomniacs and normal subjects confirmed the construct validity (t = −13.8, P = 0.000). Concurrent validity was identified by the significant correlation of SQS with the Pittsburgh Sleep Quality Index (r = 0.72, P = 0.000). The Cronbach's alpha coefficient was 0.92 for internal consistency and the correlation coefficient was 0.81 for test–retest reliability at a 2‐week interval. The developed SQS was therefore confirmed to be a valid and reliable instrument for the comprehensive assessment of sleep quality.
Frequent lapses of responsiveness during an extended visuomotor tracking task in non‐sleep‐deprived subjects
Authors: PEIRIS MALIK T. R. , JONES RICHARD D. , DAVIDSON PAUL R. , CARROLL GRANT J. , BONES PHILIP J.
Published: August 2006

We investigated the occurrence of lapses of responsiveness (lapses) in 15 non‐sleep‐deprived subjects performing a 1D continuous tracking task during normal working hours. Tracking behaviour, facial video, and electroencephalogram (EEG) were recorded simultaneously during two 1‐h sessions. Rate and duration were estimated for lapses identified by a tracking flat spot and/or video sleep. Fourteen of the 15 subjects had one or more lapses, with an overall rate of 39.3 ± 12.9 lapses per hour (mean ± SE) and a lapse duration of 3.4 ± 0.5 s. We also found that subjects’ performance improved towards the end of the 1‐h long session, even though no external temporal cues were available. Spectral power was found to be higher during lapses in the delta, theta, and alpha bands, and lower in the beta, gamma, and higher bands, but correlations between changes in EEG power and lapses were low. In conclusion, lapses are a frequent phenomenon in normal subjects – even when not sleep‐deprived – engaged in an extended monotonous continuous visuomotor task. This is of particular importance to the transport sector in which there is a need to maintain sustained attention for extended periods of time and in which lapses can lead to multiple‐fatality accidents.
Measurements of gastric emptying of low‐ and high‐nutrient liquids using 3D ultrasonography and scintigraphy in healthy subjects
Authors: Gentilcore D. , Hausken T. , Horowitz M. , Jones K. L.
Published: August 2006

Abstract  Scintigraphy represents the ‘gold standard’ for the measurement of gastric emptying. Recent studies suggest that three‐dimensional (3D) ultrasonography may allow a precise measure of gastric emptying, given the capacity for accurate volume calculations of the stomach. The aim of this study was to compare measurements of gastric emptying of both low‐ and high‐nutrient drinks by 3D ultrasonography with scintigraphy. Ten healthy young subjects (6M, 4F, age 23.5 ± 1.5 years) were studied on 2 days. Concurrent measurements of gastric emptying by scintigraphy and 3D ultrasonography were performed after ingestion of 500 mL beef soup (12 kcal) or 300 ml dextrose (25% w/v) (314 kcal) labelled with 20 MBq 99mTc‐sulphur colloid. There was no significant difference between scintigraphic and ultrasonographic 50% emptying times (T50s) (soup: 27.7 ± 4.8 min vs 23.8. ± 4.8 min; dextrose: 122.2 ± 13.3 min vs 131.9 ± 10.2 min). There was a close correlation between scintigraphic and ultrasonographic T50s for both soup (r = 0.92, P = 0.0005) and dextrose (r = 0.88, P = 0.0007). For the T50s, the limits of agreement were −15.2 min and +8.1 min for the soup (mean difference −3.6 min) and −35.3 min and +47.6 min for dextrose (mean difference +6.2 min). 3D ultrasonography provides a valid measure of gastric emptying of liquid meals in healthy subjects.
Expression of ABA 8′‐hydroxylases in relation to leaf water relations and seed development in bean
Authors: Yang Seung Hwan , Zeevaart Jan A.D.
Published: August 2006

In plants, the level of abscisic acid (ABA) is determined by synthesis and catabolism. Hydroxylation of ABA at the 8′ position is the key step in ABA catabolism. This reaction is catalyzed by ABA 8′‐hydroxylase, a cytochrome P450 (CYP). The cDNAs of PvCYP707A1 and PvCYP707A2 were isolated from bean (Phaseolus vulgaris L.) axes treated with (+)‐ABA and that of PvCYP707A3 from dehydrated bean leaves. The recombinant PvCYP707A proteins expressed in yeast were biochemically characterized. Yeast strains over‐expressing any of the three PvCYP707As were able to convert ABA to phaseic acid (PA). The microsomal fractions from these yeast strains also exhibited ABA 8′‐hydroxylase activity. Expression of PvCYP707A3 in primary leaves was strongly increased by water stress, whereas PvCYP707A1 and PvCYP707A2 mRNA levels were rapidly increased by rehydration of water‐stressed leaves. Northern blot analysis of PvCYP707As in bean showed a high level of expression in the mature fruits, senescent leaves, roots, seed coats and axes. All three PvCYP707As were expressed at varying intensities throughout seed development. Imbibed seeds also had high PvCYP707A mRNA levels. Thus, expression of PvCYP707As is both environmentally and developmentally regulated. Transgenic Nicotiana sylvestris plants over‐expressing PvCYP707As displayed a wilty phenotype, and had reduced ABA levels and increased PA levels. These results demonstrate that expression of PvCYP707As is the major mechanism by which ABA catabolism is regulated in bean.
Visualization of PtdIns3P dynamics in living plant cells
Authors: Vermeer Joop E.M. , van Leeuwen Wessel , Tobeña‐Santamaria Rafa , Laxalt Ana M. , Jones David R. , Divecha Nullin , Gadella Theodorus W.J. , Munnik Teun
Published: August 2006

To investigate PtdIns3P localization and function in plants, a fluorescent PtdIns3P‐specific biosensor (YFP–2xFYVE) was created. On lipid dot blots it bound specifically and with high affinity to PtdIns3P. Transient expression in cowpea protoplasts labelled vacuolar membranes and highly motile structures undergoing fusion and fission. Stable expression in tobacco BY‐2 cells labelled similar motile structures, but labelled vacuolar membranes hardly at all. YFP–2xFYVE fluorescence strongly co‐localized with the pre‐vacuolar marker AtRABF2b, partially co‐localized with the endosomal tracer FM4‐64, but showed no overlap with the Golgi marker STtmd–CFP. Treatment of cells with wortmannin, a PI3 kinase inhibitor, caused the YFP–2xFYVE fluorescence to redistribute into the cytosol and nucleus within 15 min. BY‐2 cells expressing YFP–2xFYVE contained twice as much PtdIns3P as YFP‐transformed cells, but this had no effect on cell‐growth or stress‐induced phospholipid signalling responses. Upon treatment with wortmannin, PtdIns3P levels were reduced by approximately 40% within 15 min in both cell lines. Stable expression of YFP–2xFYVE in Arabidopsis plants labelled different subcellular structures in root compared with shoot tissues. In addition labelling the motile structures common to all cells, YFP–2xFYVE strongly labelled the vacuolar membrane in leaf epidermal and guard cells, suggesting that cell differentiation alters the distribution of PtdIns3P. In dividing BY‐2 cells, YFP–2xFYVE‐labelled vesicles surrounded the newly formed cell plate, suggesting a role for PtdIns3P in cytokinesis. Together, these data show that YFP–2xFYVE may be used as a biosensor to specifically visualize PtdIns3P in living plant cells.
The evolution of cooperation and altruism – a general framework and a classification of models
Authors: Lehmann L. , Keller L.
Published: August 2006

One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories.