bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unique genetic and environmental determinants of
prolonged fatigue: a twin study
Authors: HICKIE I. , KIRK K. , MARTIN N. 
Published: July 2002

Background. Prolonged fatigue syndromes have been proposed
as prevalent and disabling forms of
distress that occur independently of conventional notions of anxiety and
depression.Methods. To investigate the genetic and environmental antecedents
of common forms of
psychological and somatic distress, we measured fatigue, anxiety, depression
and psychological
distress in 1004 normal adult twin pairs (533 monozygotic (MZ), 471 dizygotic
(DZ)) over 50 years
of age.Results. Familial aggregation of psychological distress, anxiety
and fatigue appeared to be due
largely to additive genetic factors (MZ[ratio ]DZ ratios of 2·12–2·69).
The phenotypic correlations
between the psychological measures (distress, anxiety and depression) were
moderate (0·67–0·79)
and higher than that between fatigue and psychological distress (0·38).
Multivariate genetic
modelling revealed a common genetic factor contributing to the development
of all the observed
phenotypes (though most strongly for the psychological forms), a second
independent genetic factor
also influenced anxiety and depression and a third independent genetic
factor made a major
contribution to fatigue alone. In total, 44% (95% CI 25–60%) of the
genetic variance for fatigue
was not shared by the other forms of distress. Similarly, the environmental
factor determining
psychological distress made negligible contributions to fatigue, which
was underpinned largely by
its own independent environmental factor.Conclusion. This study supports the aetiological independence
of prolonged fatigue and, therefore,
argues strongly for its inclusion in classification systems in psychiatry.
Is disabling fatigue in childhood influenced by genes?
Authors: FARMER A. , SCOURFIELD J. , MARTIN N. , CARDNO A. , McGUFFIN P. 
Published: July 2002

Background. Medically unexplained chronic fatigue in childhood
may cause considerable disability
and (by definition) its cause remains unclear. A study of fatigue in healthy
twins has been
undertaken to examine whether or not genetic factors play a part.Method. A questionnaire survey of the main carers of an epidemiological
population-based sample
of 670 twin pairs who were asked about periods of unexplained and disabling
fatigue in their twins.
Out of 1340 individuals a period of disabling fatigue was reported for
92 (6·9%). Thirty-three
(2·5%) reported disabling fatigue for more than 1 month. Zygosity
could be confidently assigned
in 98% of the sample providing 278 monozygotic (MZ) and 378 dizygotic (DZ)
pairs. These data
were analysed using a structural equation modelling approach.Results. The results showed that disabling fatigue in childhood
is highly familial with an MZ
tetrachoric correlation (rMZ) of 0·81 and a DZ tetrachoric correlation
(rDZ) of 0·59, for fatigue
lasting at least a week. The most acceptable model using Akaike's
information criteria, was one
containing additive genetic effects (A) and shared environment (C) plus
residual (or non-shared)
environment (E). For fatigue lasting at least a month rMZ was 0·75
and rDZ 0·47. The most
acceptable model included just A and E. However, the role of shared environment
could not be
conclusively rejected.Conclusions. Unexplained disabling fatigue in childhood is
substantially familial. Both genetic and
shared environmental factors are worth further exploration in a search
for the causes.
Schizophrenia, temporal lobe epilepsy and psychosis:
an in vivo magnetic resonance spectroscopy and
imaging study of the hippocampus/amygdala
complex
Authors: MAIER M. , MELLERS J. , TOONE B. , TRIMBLE M. , RON M. A. 
Published: July 2002

Background. We have used proton magnetic resonance imaging and spectroscopy to measure
hippocampus/amygdala volumes and anterior hippocampal metabolite concentrations (N-acetyl
aspartate (NAA), creatine/phosphocreatine and choline) in subjects with temporal lobe epilepsy
(TLE), schizophrenia and in normal controls.Method. Four groups of right-handed patients were selected: 12 with TLE and psychosis (EP), 12
with TLE and no psychosis (ENP), 26 with schizophrenia, and 38 normal controls. Imaging and
spectroscopy were performed with a 1.5T Signa GE scanner.Results. The schizophrenia group showed a significant left-sided reduction in all metabolites. In the
epilepsy groups NAA was reduced bilaterally. The NAA reduction in the EP group was greater than
in the ENP group, especially on the left, although the result did not reach significance. Total
hippocampus/amygdala volumes showed no significant differences in any of the groups when
compared with normal controls. When compared with controls significant, specific regional volume
reductions were present bilaterally in the EP group and in the left hippocampus/amygdala in
schizophrenia. The regional volume reduction found in schizophrenia was also present in EP but
not in ENP.Conclusion. Spectroscopic abnormalities were more pronounced in the epilepsy groups and were
bilateral, and abnormalities in schizophrenia were left sided. Specific regional hippocampus/amygdala
volume reductions were more marked in the EP group and were bilateral. Left-sided
regional volume reduction identified in the dominant hemisphere of schizophrenics was also present
in EP patients, but not in ENP, suggesting that this region in the left temporal lobe may be
significant in the aetiology of psychosis. This is further supported by the predominantly left-sided
NAA reduction in schizophrenia. High resolution morphometric studies may identify specific
regions of the brain associated with the development of psychosis.
Elevated circulatory level of GABAA – antagonistic neurosteroids in
patients with combat-related post-traumatic stress disorder
Authors: SPIVAK B. , MAAYAN R. , KOTLER M. , MESTER R. , GIL-AD I. , SHTAIF B. , WEIZMAN A. 
Published: July 2002

Background. Post-traumatic stress disorder (PTSD) is a multisystem neurobiological disorder with chronic alterations in various neurochemical systems. Levels of the GABAA – antagonistic neurosteroids plasma dehydroepiandrosterone (DHEA) and its sulphate derivate, dehydro-epiandrosterone sulphate (DHEAS) may be relevant to depressive and anxiety disorders, including PTSD.Methods. We assessed the circulatory levels of morning plasma DHEA and DHEAS in 21 male out-patients with untreated chronic combat-related PTSD (CR-PTSD), and 18 healthy control male subjects.Results. Compared with the control subjects, the PTSD patients showed significantly higher plasma DHEA and DHEAS levels.Conclusions. Chronic CR-PTSD may be associated with increased circulatory level of neuroactive steroids with inhibitory activity at the GABAA receptors. Neurosteroid-induced decreased GABA-ergic tone may be relevant to the symptomatology and pathophysiology of chronic PTSD, as well as to the frequent co-morbidity of PTSD with depression and anxiety disorders.
Validation of the prospective NIMH-Life-Chart Method (NIMH-LCMTM-p) for longitudinal assessment of bipolar illness
Authors: DENICOFF K. D. , LEVERICH G. S. , NOLEN W. A. , RUSH A. J. , McELROY S. L. , KECK P. E. , SUPPES T. , ALTSHULER L. L. , KUPKA R. , FRYE M. A. , HATEF J. , BROTMAN M. A. , POST R. M. 
Published: July 2002

Background. Systematic and accurate depiction of a patient's course of illness is crucial for
assessing the efficacy of maintenance treatments for bipolar disorder. This need to rate the long-term prospective course of illness led to the development of the National Institute of Mental Health
prospective Life Chart Methodology (NIMH-LCMTM-p or LCM). The NIMH-LCMTM-p allows for
the daily assessment of mood and episode severity based on the degree of mood associated
functional impairment. We have previously presented preliminary evidence of the reliability and
validity of the LCM, and its utility in clinical trials. This study is a further and more extensive
validation of the clinician rated NIMH-LCMTM-p.Methods. Subjects included 270 bipolar patients from the five sites participating in the Stanley
Foundation Bipolar Network. Daily prospective LCM ratings on the clinician form were initiated
upon entry, in addition to at least monthly ratings with the Inventory of Depressive
Symptomatology-clinician rated (IDS-C), the Young Mania Rating Scale (YMRS) and the Global
Assessment of Functioning (GAF). We correlated appropriate measures and time domains of the
LCM with the IDS-C, YMRS and GAF.Results. Severity of depression on the LCM and on the IDS-C were highly correlated in 270 patients
(r = −0·785, P < 0·001). Similarly, a strong correlation was found between LCM mania and the
YMRS (r = 0·656, P < 0·001) and between the LCM average severity of illness and the GAF
(r = −0·732, P < 0·001).Conclusions. These data further demonstrate the validity and potential utility of the NIMH-
LCMTM-p for the detailed daily longitudinal assessment of manic and depressive severity and
course, and response to treatment.
Is physical deconditioning a perpetuating factor in
chronic fatigue syndrome? A controlled study on
maximal exercise performance and relations with
fatigue, impairment and physical activity
Authors: BAZELMANS E. , BLEIJENBERG G. , VAN DER MEER J. W. M. , FOLGERING H. 
Published: July 2002

Background. Chronic fatigue syndrome (CFS) patients often complain that physical exertion
produces an increase of complaints, leading to a greater need for rest and more time spent in bed.
It has been suggested that this is due to a bad physical fitness and that physical deconditioning is
a perpetuating factor in CFS. Until now, studies on physical deconditioning in CFS have shown
inconsistent results.Methods. Twenty CFS patients and 20 matched neighbourhood controls performed a maximal
exercise test with incremental load. Heart rate, blood pressure, respiratory tidal volume, O2
saturation, O2 consumption, CO2 production, and blood-gas values of arterialized capillary blood
were measured. Physical fitness was quantified as the difference between the actual and predicted
ratios of maximal workload versus increase of heart rate. Fatigue, impairment and physical activity
were assessed to study its relationship with physical fitness.Results. There were no statistically significant differences in physical fitness between CFS patients
and their controls. Nine CFS patients had a better fitness than their control. A negative relationship
between physical fitness and fatigue was found in both groups. For CFS patients a negative
correlation between fitness and impairment and a positive correlation between fitness and physical
activity was found as well. Finally, it was found that more CFS patients than controls did not
achieve a physiological limitation at maximal exercise.Conclusions. Physical deconditioning does not seem a perpetuating factor in CFS.
Fatigue and psychiatric disorder: different or the same?
Authors: VAN DER LINDEN G. , CHALDER T. , HICKIE I. , KOSCHERA A. , SHAM P. , WESSELY S. 
Published: July 2002

Background. Fatigue and psychiatric symptoms are common in the community, but their
association and outcome are sparsely studied.Method. A total of 1177 patients were recruited from UK primary care on attending their general
practitioner. Fatigue and psychiatric disorder was measured at three time points with the 12-item
General Health Questionnaire and the 11-item Fatigue Questionnaire.Results. Total scores for fatigue and psychiatric disorder did not differ between the three time
points and were closely correlated (r around 0·6). The association between non-co-morbid (‘pure’)
fatigue and developing psychiatric disorder 6 months later was the same as that for being well and
subsequent psychiatric disorder. Similarly, having non-co-morbid psychiatric disorder did not
predict having fatigue any more than being well 6 months previously. Between 13 and 15% suffered
from non-co-morbid fatigue at each time point and 2·5% suffered from fatigue at two time points
6 months apart. Less than 1% of patients suffered from non-co-morbid fatigue at all three time
points.Conclusions. The data are consistent with the existence of ‘pure’ independent fatigue state.
However, this state is unstable and the majority (about three-quarters) of patients become well or
a case of psychiatric disorder over 6 months. A persistent, independent fatigue state lasting for 6
months can be identified in the primary-care setting, but it is uncommon – of the order of 2·5%.
Non-co-morbid (pure) fatigue did not predict subsequent psychiatric disorder.
The waking-to-dreaming continuum and the effects of emotion
Authors: Hartmann Ernest 
Published: July 2002

The three-dimensional “AIM model” proposed by Hobson et al. is imaginative. However, many kinds of data suggest that the “dimensions” are not orthogonal, but closely correlated. An alternative view is presented in which mental functioning is considered as a continuum, or a group of closely linked continua, running from focused waking activity at one end, to dreaming at the other. The effect of emotional state is increasingly evident towards the dreaming end of the continuum.[Hobson et al.; Nielsen; Solms]
Nielsen's concept of covert REM sleep is a path toward a more realistic view of sleep psychophysiology
Authors: Pace-Schott Edward F. 
Published: July 2002

Nielsen's concept of “covert REM sleep” accounts for more of the complexity in sleep psychophysiology than its conceptual predecessors such as the tonic-phasic model. With new neuroimaging findings, such concepts lead to more precise sleep psychophysiology including both traditional polysomnographic signs and neuronal activity in greater proximity to the actual point sources and distributed networks which generate dreaming.[Hobson et al.; Nielsen]
Bratteli–Vershik models for Cantor minimal systems: applications to Toeplitz flows
Authors: GJERDE RICHARD , JOHANSEN ØRJAN 
Published: July 2002

We construct Bratteli–Vershik models for Toeplitz flows and characterize a class of properly ordered Bratteli diagrams corresponding to these flows. We use this result to extend by a novel approach—using basic theory of dimension groups—an interesting and non-trivial result about Toeplitz flows, first shown by Downarowicz. (Williams had previously obtained preliminary results in this direction.) The result states that to any Choquet simplex $K$, there exists a $0$–$1$ Toeplitz flow $(Y,\psi)$, so that the set of invariant probability measures of $(Y,\psi)$ is affinely homeomorphic to $K$. Not only do we give a conceptually new proof of this result, we also show that we may choose $(Y,\psi)$ to have zero entropy and to have full rational spectrum.Furthermore, our Bratteli–Vershik model for a given Toeplitz flow explicitly exhibits the factor map onto the maximal equicontinuous (odometer) factor. We utilize this to give a simple proof of the existence of a uniquely ergodic 0–1 Toeplitz flow of zero entropy having a given odometer as its maximal equicontinuous factor and being strongly orbit equivalent to this factor. By the same token, we show the existence of 0–1 Toeplitz flows having the 2-odometer as their maximal equicontinuous factor, being strong orbit equivalent to the same, and assuming any entropy value in $[0,\ln 2)$.Finally, we show by an explicit example, using Bratteli diagrams, that Toeplitz flows are not preserved under Kakutani equivalence (in fact, under inducing)—contrasting what is the case for substitution minimal systems. In fact, the example we exhibit is an induced system of a 0–1 Toeplitz flow which is conjugate to the Chacon substitution system, thus it is prime, i.e. it has no non-trivial factors.The thrust of our paper is to demonstrate the relevance and usefulness of Bratteli–Vershik models and dimension group theory for the study of minimal symbolic systems. This is also exemplified in recent papers by Forrest and by Durand, Host and Skau, treating substitution minimal systems, and by papers by Boyle, Handelman and by Ormes.
MEASURING COSTS IN COST-UTILITY ANALYSES
Authors: Stone Patricia W. , Chapman Richard H. , Sandberg Eileen A. , Liljas Bengt , Neumann Peter J. 
Published: July 2002

Objectives: Although cost-utility analysis (CUA) has been
recommended by some experts as the preferred technique for economic
evaluation, there is controversy regarding what costs should be included and
how they should be measured. The purpose of this study was to: a) identify the
cost components that have been included in published CUAs; b) catalogue the
sources of valuation used; c) examine the methods employed for estimating
costs; and d) explore whether methods have changed over time.Methods: We conducted a comprehensive search of the published
literature and systematically collected data on the cost estimation of CUAs.
We audited the cost estimates in 228 CUAs.Results: In most studies (99%), analysts included some direct
healthcare costs. However, the inclusion of direct non-healthcare and time
costs (17%) was generally lacking, as was productivity costs (8%). Only 6% of
studies considered future costs in added life-years. In general, we found
little evidence of change in methods over time. The most frequently used
source for valuation of healthcare services was published estimates (73%). Few
studies obtained utilization data from RCTs (10%) or relied on other primary
data (23%). About two-thirds of studies conducted sensitivity analyses on cost
estimates.Conclusions: We found wide variations in the estimation of costs
in published CUAs. The study underscores the need for more uniformity and
transparency in the field, and continued vigilance over cost estimates in CUAs
on the part of analysts, reviewers, and journal editors.
EXTRACORPOREAL SHOCK WAVE THERAPY IN ORTHOPEDICS
Authors: Wild Claudia , Khene Mahmoud , Wanke Stefan 
Published: July 2002

Objective: Extracorporeal shock wave therapy (ESWT) as an emerging
technology in orthopedics has been assessed in Austria with the objective to
establish a scientific basis for pending and pressing health policy decisions.
Despite encouraging results within some indications and the promising prospect
of a noninvasive treatment for some orthopedic diseases, it seemed crucial to
assess this new field of application in the light of evidence-based standards,
without forgetting the reality of healthcare decisions. This article presents
the results of the abovementioned assessment in the context of the
policy-making process in Germany, Austria, and Switzerland.Methods: The study is based on an overview of the already existing
reviews on the effectiveness of ESWT as carried out by different actors
(health insurances and orthopedists), and on an overview of additional
literature covering all relevant aspects (mode of action, recommendations,
economic estimates). Orthopedic societies, several institutions involved in
health technology assessment, and health insurance agencies were contacted in
search of further relevant literature, ongoing studies, and assessments.Results: Until now, clear evidence has not been available on the
effectiveness of ESWT in four currently recommended indications (tendinosis
calcarea of the shoulder, epicondylopathia humeri radialis, calcaneal spur,
and pseudarthrosis), although a substantial body of literature has been
produced. Despite encouraging results in some indications, the lack of
coherent therapy schemes and the poor quality in the design of clinical
studies has been serious enough to hinder the drawing of reasonable
conclusions.Conclusions: Due to the rapid diffusion of ESWT and the pressure
on reimbursement agencies to prove the ineffectiveness of ESWT, the policy
option of a pragmatic approach is recommended to controll the diffusion of an
uncertain health technology, alongside active research that would allow a more
comprehensive appraisal of this potentially interesting treatment strategy in
orthopedics.
Effect of moonlight on the foraging behaviour of a megachiropteran bat Cynopterus sphinx
Authors: Elangovan V. , Marimuthu G. 
Published: July 2002

AbstractWe studied the influence of moonlight upon the foraging activity pattern of the fruit bat Cynopterus sphinx. We observed the bats when foraging on the fruits of Calophyllum inophyllum and on the leaves of Mimusops elengi and Cassia fistula for 31, 27 and 28 days, respectively at the botanical garden in the Madurai Kamaraj University campus. The number of feeding bouts was recorded every hour between 18:00 and 05:00. A feeding bout involves a bat landing on the tree and collecting a part (or whole) of the fruit or a leaf. The total number of feeding bouts was negatively correlated with per cent moonlight each night. The number of feeding bouts decreased during the waxing phases of the moon. During the period of new moon the mean number of feeding bouts was significantly higher compared to the periods of other phases. During the first quarter and the last quarter phases, feeding occurred more during the dark part of the night, especially when the bats foraged upon M. elengi and C. fistula. While cloud cover enhanced the foraging activity, lightning and thunder suppressed it. Our study indicates that moonlight influences the foraging activity of C. sphinx.
On the geographic distribution of Loxodes rex (Protozoa, Ciliophora) and other alleged endemic species of ciliates
Authors: Esteban Genoveva F. , Finlay Bland J. , Charubhun Nuntaporn , Charubhun Bawpit 
Published: July 2002

AbstractThere is no consensus on the question of whether or not free‐living protist species have biogeographies, with the strongest disagreement coming from advocates of the hypothesis that the extraordinary abundance of protists drives their ubiquitous dispersal. If the probability of a species being ubiquitous is a function of its absolute global abundance, then the species that are least likely to be ubiquitous are those with relatively small global populations, i.e. the largest species. Among the free‐living ciliated protozoa, a prime candidate for such an organism must be the large (∼1200 μm long), unmistakable, fragile, non‐encysting karyorelictid Loxodes rex. This ciliate was known only from fresh waters in tropical Africa and it was long considered to be a rare example of an endemic ciliate. Here it is reported that Loxodes rex is thriving in a pond in Thailand. The status of other alleged endemic ciliate species is discussed.
Female genitalia in Pityohyphantes phrygianus, a spider with a skewed sex ratio
Authors: Uhl Gabriele , Gunnarsson Bengt 
Published: July 2002

AbstractThe functioning of female genitalia in many arthropods, especially the site and mode of sperm storage, may have a strong impact on the pattern of sperm usage, leading to differential male fertilization success and even varying offspring sex ratios. The female genital morphology of the linyphiid spider Pityohyphantes phrygianus was investigated, as this species was shown to possess an intriguing mechanism of sex ratio determination, possibly related to genital morphology. By means of SEM and serial semi‐thin sectioning, two distinctly different spermathecae plus an additional sperm sac, equipped with several valves, were found on each side of the genital apparatus. Sperm is stored under different conditions, as one of the spermathecae exhibits large gland cells of different types that discharge their products into the spermatheca through long secretory ducts, whereas the other spermatheca is surrounded by a simpler type of gland cell. Furthermore, there are folds instead of closed ducts leading to the spermathecae, and from the spermathecae to the oviduct. The latter fertilization‐fold runs inside the copulatory chamber and enters the oviduct from the outside. The mechanisms for sex ratio bias in spiders are discussed. The occurrence of two types of spermatheca of which one is twisted, provides good evidence for the involvement of female genital morphology in sex ratio control of P. phrygianus offspring. Data are compiled on species for which information is available on sex ratio and female genital morphology. We put forward a hypothesis that in species with a skewed sex ratio, there is interaction between female genital morphology and behaviour, i.e. change of body position before, during or immediately after sperm transfer.