bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confidence of primary care physicians in assessing the suicidality of geriatric patients
Authors: Kaplan Mark S. , Adamek Margaret E. , Martin Jennifer L. 
Published: September 2002

AbstractThis study examined the confidence levels of physicians in assessing the risk of suicide among older adults in clinical settings. Of the 300 physicians who were selected from a population of 4980 family practice, internal medicine, and geriatric physicians in Illinois, 63% responded to the mail survey. Several categorical items inquired about specific assessment and treatment approaches, referral resources used, barriers to meeting the mental health needs of older patients, and sources of training in suicide risk assessment. All the training items (suicide assessment in medical school, residency, and CME courses; rating of medical school training; and insufficient training in geriatric mental health) were significantly (p < 0.01) associated with confidence in assessing suicidality. The overall model consisting of six variables explained 57% of the variation in confidence scores [F (6, 130) = 28.48, p < 0.001]. Three variables accounted for 50% of the explained variance: confidence in diagnosing depression, residency training in the assessment of suicide risk, and assessment of the intentional misuse of medication. Confidence in diagnosing depression (β = 0.38, p < 0.001) was the strongest predictor. More effective mental health care will require specific preparation in treating geriatric patients through the full spectrum of medical training, including medical school, residency, and CME courses. Improved prevention of elderly suicide hinges on the enhancement of clinical skills in diagnosing and treating geriatric depression. Copyright © 2001 John Wiley & Sons, Ltd.
Secondary prevention of depressive symptoms in elderly inhabitants of residential homes
Authors: Cuijpers Pim , Lammeren Paula van 
Published: September 2002

AbstractThe effects of a multifaceted secondary prevention intervention in residential homes in the Netherlands were examined, using a quasi‐experimental design. In five experimental residential homes, the caregivers received three training sessions on detecting depression and on supporting depressed residents. Furthermore, an information session was organized for all personnel, a further session was organized for residents and their relatives, and several group interventions were offered. 213 residents participated in the study. 211 residents of five other residential homes, matched on basic variables, served as a comparison group. Effects on depressive symptoms (geriatric depression scale) and health related quality of life (MOS‐SF‐36) were measured at pretest and after the intervention, one year later. Because the drop‐out rate was high and drop‐outs differed significantly from the remaining population, the scores of drop‐outs were imputed. Since we used a quasi‐experimental design, we controlled for confounding variables. Regression analyses resulted in significant effects of the intervention on the GDS and on role functioning in the total population. When the analyses were limited to those scoring high on the GDS at pretest, significant effects were found on the GDS, and on four domains of health‐related quality of life: psychological distress, role functioning, pain and social functioning. The improvement in GDS scores in GDS cases was significantly larger than in other subjects. Our results suggest that general approaches aimed at a residential home are capable of influencing depressive symptoms in inhabitants. Possibly, it may not be necessary to wait until depressive symptoms have escalated and inhabitants need extensive treatment. Copyright © 2001 John Wiley & Sons, Ltd.
Comparative electrophysiological and hemodynamic measures of neural activation during memory‐retrieval
Authors: Düzel Emrah , Picton Terence W. , Cabeza Roberto , Yonelinas Andrew P. , Scheich Henning , Heinze Hans‐Jochen , Tulving Endel 
Published: September 2002

AbstractThe spatial and temporal characteristics of the brain processes underlying memory retrieval were studied with both event‐related potentials (ERP) and positron emission tomography (PET) techniques. Subjects studied lists of 20 words and then performed episodic (old/new judgment) or semantic (living/nonliving decision) retrieval tasks on multiple four‐item test lists, each lasting 10 sec. The PET and ERP measurements at test were assessed in relation to both the task (episodic vs. semantic) and the item (old vs. new or living vs. nonliving). Episodic retrieval was associated with increased blood flow in the right frontal lobe (Brodmann Area 10) and a sustained, slowly developing positive ERP shift recorded from the right frontopolar scalp. Semantic retrieval was associated with increased blood flow in the left frontal (Area 45) and temporal (Area 21) lobes but no clear ERP concomitant. The two retrieval tasks also differed from each other in the ERPs to single items in an early (300–500 ms) time window. Item‐related comparisons yielded convergent results mainly if the retrieved information was relevant to the given task (e.g., old/new items during episodic retrieval and living/nonliving items during semantic retrieval). Episodically retrieved old items were associated with increased blood flow in the left medial temporal lobe and a transient increase in the amplitude of the late positive component (500–700 ms) of the ERP. Semantically retrieved living items were associated with increased blood flow in the left frontal cortex and anterior cingulate and a transient late frontal slow wave (700–1,500 ms) in the ERPs. These results indicate that the brain regions engaged in memory retrieval are active in either a sustained or transient manner. They map task‐related processes to sustained and item‐related processes to transient neural activity. But they also suggest that task‐related factors can transiently affect early stages of item processing. Hum. Brain Mapping 13:104–123, 2001. © 2001 Wiley‐Liss, Inc.
Synthesis and properties of group 15 element porphyrin peroxides
Authors: Satoh Wataru , Masumoto Shuji , Yamamoto Yohsuke , Akiba Kin‐ya 
Published: September 2002

Abstract[(Por)M(R)(OOR′)]+Y− (Por: TPP [tetraphenylporphyrin], OEP [octaethylporphyrin]; M: Sb, As, P; R: Me, Et, Ph; R′: H, C(=O)m‐ClC6H4, t‐Bu) were prepared from [(Por)M(R)(X)]+Y− (X: OTf, Br). The reactivities of the peroxide porphyrins toward nucleophiles such as triphenylphosphine increased in the order of ‐OOt‐Bu, m‐CPBA, and ‐OOH derivatives. Phosphorus (P‐OOH) and arsenic hydroperoxide (As‐OOH) were much more reactive than the corresponding antimony hydroperoxide (Sb‐OOH). The higher reactivity of phosphorus and arsenic peroxides can be explained by the stability of the M=O (M=P, As) bonding system in the intermediates of the oxidation reactions. An X‐ray structural analysis of [(TPP)Sb‐(Me)(OOt‐Bu)]+PF6− is presented. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:431–443, 2001
The effect of variable health insurance deductibles on the demand for physician visits
Authors: Schellhorn Martin 
Published: September 2002

AbstractIn order to contain cost in the health care sector, the introduction of consumer incentives in health insurance has been suggested and realized in many countries. The Swiss health system reform of 1996 introduced a choice of deductible for health services in the mandatory basic health insurance. This paper estimates the effect of this choice on physician service utilization. A generalized method of moments (GMM) estimator is applied to take account of the endogeneity of the choice of the deductible in the estimation of the number of physician visits. This paper finds that most of the observed reduction in the number of physician visits among individuals who choose a higher deductible seems to be a result of self‐selection of individuals into the respective insurance contracts, and not to induced changes in utilization behaviour. Copyright © 2001 John Wiley & Sons, Ltd.
Live long, live well: quantifying the health of heterogeneous populations
Authors: Mullahy John 
Published: September 2002

AbstractVarious health, quality, utility and disability adjusted life years or life expectancy (HALY, QALY, DALY; HALE, QALE, DALE) measures have become gold standards for defining outcomes in technology evaluation, population health monitoring, and other evaluative efforts. As such, the analytical framework within which these measures are used for descriptive and evaluative purposes should be theoretically consistent and statistically rigorous. For instance, widely accepted definitions of cost‐effectiveness ratios and other technology evaluation criteria that are based on expectations of the respective cost and outcome measures must, as such, be defined in terms of expected HALYs or QALYs. Similarly, measures like HALEs or QALEs used for population health monitoring are typically concerned with population expectations of such measures (or their corresponding totals). This paper demonstrates that estimation of such expectations necessitates consideration of the population variation in, and covariation between, quality and longevity. From the perspective of several different environments characterizing such heterogeneity, quantification or estimation of measures like QALYs is reconsidered. An empirical example of the central issues is provided by means of an analysis of the years of healthy life (YHL) measure drawn from the US National Health Interview Survey. Copyright © 2001 John Wiley & Sons, Ltd.
The American Society of Anesthesiologists' class as a comorbidity index in a cohort of head and neck cancer surgical patients
Authors: Reid Britt C. , Alberg Anthony J. , Klassen Ann C. , Koch Wayne M. , Samet Jonathan M. 
Published: September 2002

AbstractBackgroundWe assessed the American Society of Anesthesiologists' (ASA) class, as a measure of comorbidity in comparison to the commonly used Charlson index for prognostic ability in a HNCA population.MethodsProportional hazards methods were applied to head and neck cancer patients whose treatment included surgery by the Johns Hopkins Otolaryngology service (n = 388).ResultsThe Charlson index and ASA class were modestly correlated (Spearman 0.36, p < .001). Compared with patients with ASA class 1 or 2, those with ASA class 3 or 4 had a two‐fold elevated mortality rate (Relative Hazard (RH) = 2.00, 95% CI, 1.38–2.89). This association was stronger than observed for a Charlson index score of 1 or more compared with 0 (RH = 1.59, 95% CI, 1.17–2.17). Both the Charlson index and ASA class adjusted RHs displayed dose‐response patterns (p value for trend < .001).ConclusionsCompared with the Charlson index, the ASA class had comparable if not greater prognostic ability for mortality in this elderly HNCA population. © 2001 John Wiley & Sons, Inc. Head Neck 23: 985–994, 2001.
Hippocampal synaptic plasticity is modulated by theta rhythm in the fascia dentata of adult and aged freely behaving rats
Authors: Orr G. , Rao G. , Houston F.P. , McNaughton B.L. , Barnes C.A. 
Published: September 2002

AbstractA modulatory role for the hippocampal theta rhythm in synaptic plasticity is suggested by the observations that theta occurs during exploratory behaviors, spatial learning is impaired when the theta rhythm is disrupted, and excitation of hippocampal principal cells is phase‐coupled to the theta wave. The theta phase affects the nature of the plasticity induced in urethane‐anesthetized rats and in the carbachol‐treated in vitro slice preparation, but these oscillations are phenomenologically different from natural theta, and the effects of theta phase on plasticity under natural conditions have not been reported. We therefore examined the effects of theta phase on the magnitude of long‐term potentiation (LTP) in awake rats running on a linear track for a food reward. Twelve adult and 10 aged F344 male rats were implanted with a stimulating electrode in the perforant path and a recording electrode in the hilus of the fascia dentata. Stimuli were delivered at the peak or trough of the hilar theta rhythm. In both adult and aged, memory‐impaired rats, LTP lasting at least 48 h was induced when stimuli were delivered at the positive theta peak, whereas LTP was not induced when stimuli were delivered at the negative troughs. Consistent with the finding that the threshold for LTP induction is increased at this synapse in old rats, the magnitude of LTP induced at the peak of theta rhythm was significantly lower in old animals. These data confirm that LTP can be modulated by locomotion‐induced theta, and that this modulation is at least qualitatively preserved across age. Hippocampus 2001;11:647–654. © 2001 Wiley‐Liss, Inc.
Adaptive anterior hippocampal responses to oddball stimuli
Authors: Strange Bryan A. , Dolan Raymond J. 
Published: September 2002

AbstractAn efficient memory system requires the ability to detect and preferentially encode novel stimuli. Human electrophysiological recordings demonstrate differential hippocampal responses to novel vs. familiar stimuli, as well as to oddball stimuli. Although functional imaging experiments of novelty detection have demonstrated hippocampal activation, oddball‐evoked hippocampal activation has not been demonstrated. Here we use event‐related functional magnetic resonance imaging (fMRI) to measure hippocampal responses to three types of oddball words: perceptual, semantic, and emotional. We demonstrate left anterior hippocampal sensitivity to all three oddball types, with adaptation of responses across multiple oddball presentations. This adaptive hippocampal oddball response was not modulated by depth of processing, suggesting a high degree of automaticity in the underlying process. However, an interaction with depth of encoding for semantic oddballs was evident in a more lateral left anterior hippocampal region. We conclude that the hippocampal response to oddballs demonstrates a second‐order novelty effect, being sensitive to the “novelty of novelty” of oddball stimuli. The data provide support for a more general theory that a function of the anterior hippocampus is to register mismatches between expectation and experience. Hippocampus 2001;11:690–698. © 2001 Wiley‐Liss, Inc.
Bilateral hippocampal pathology impairs topographical and episodic memory but not visual pattern matching
Authors: Spiers Hugo J. , Burgess Neil , Hartley Tom , Vargha‐Khadem Faraneh , O'Keefe John 
Published: September 2002

AbstractA virtual reality environment was used to test memory performance for simulated “real‐world” spatial and episodic information in a 22‐year‐old male, Jon, who has selective bilateral hippocampal pathology caused by perinatal anoxia. He was allowed to explore a large‐scale virtual reality town and was then tested on his memory for spatial layout and for episodes experienced. Topographical memory was tested by assessing his ability to navigate, recognize previously visited locations, and draw maps of the town. Episodic memory was assessed by testing the retrieval of simulated events which consisted of collecting objects from characters while following a route through the virtual town. Memory for the identity of objects, as well as for where they were collected, from whom, and in what order, was also tested. While the first task tapped simple recognition memory, the latter three tested memory for context. Jon was impaired on all topographical tasks and on his recall of the context‐dependent questions. However, his recognition of objects from the virtual town, and of “topographical” scenes (as evaluated by standard neuropsychological tests), was not impaired. These findings are consistent with the view that the hippocampus is involved in navigation, recall of long term allocentric spatial information and context‐dependent episodic memory, but not visual pattern matching. Hippocampus 2001;11:715–725. © 2001 Wiley‐Liss, Inc.
Rhythmic hippocampal slow oscillation characterizes REM sleep in humans
Authors: Bódizs Róbert , Kántor Sándor , Szabó Gábor , Szûcs Anna , Erõss Lóránd , Halász Péter 
Published: September 2002

AbstractHippocampal rhythmic slow activity (RSA) is a well‐known electrophysiological feature of exploratory behavior, spatial cognition, and rapid eye movement (REM) sleep in several mammalian species. Recently, RSA in humans during spatial navigation was reported, but systematic data regarding human REM sleep are lacking. Using mesio‐temporal corticography with foramen ovale electrodes in epileptic patients, we report the presence of a 1.5–3‐Hz synchronous rhythmic hippocampal oscillation seemingly specific to REM sleep. This oscillation is continuous during whole REM periods, is clearly observable by visual inspection, and appears in tonic and phasic REM sleep episodes equally. Quantitative analysis proved that this 1.5–3‐Hz frequency band significantly differentiates REM sleep from waking and slow‐wake sleep (SWS). No other frequency band proved to be significant or showed this high rhythmicity. Even in temporo‐lateral surface recordings, although visually much less striking, the relative power of the 1.5–3‐Hz frequency band differentiates REM sleep from other states with statistical significance. This could mean that the 1.5–3‐Hz hippocampal RSA spreads over other cortical areas in humans as in other mammals. We suggest that this oscillation is the counterpart of the hippocampal theta of mammalian REM sleep, and that the 1.5–3‐Hz delta EEG activity is a basic neurophysiological feature of human REM sleep. Hippocampus 2001;11:747–753. © 2001 Wiley‐Liss, Inc.
Perceptual learning, awareness, and the hippocampus
Authors: Manns Joseph R. , Squire Larry R. 
Published: September 2002

AbstractDeclarative memory depends on the hippocampus and related medial temporal lobe and diencephalic structures. Declarative memory has usually been found to be available to conscious recollection. A recent study (Chun and Phelps, Nat Neurosci 1999;2:844–847) found that damage to the medial temporal lobe (including the hippocampus) impaired performance on a perceptual learning task, yet the learning was accomplished in the absence of memory for the stimuli. This finding raised the possibility that some hippocampus‐dependent tasks may be inaccessible to awareness and may be performed without evoking conscious memory processes. Using the same task, we show that when damage is confined largely to the hippocampal formation, perceptual learning is intact. Thus, the available data suggest that damage limited to the hippocampal formation does not impair nonconscious (nondeclarative) memory. Further, the data do not contradict the idea that hippocampus‐dependent memory is accessible to conscious recollection. Finally, perceptual learning was impaired in patients, with extensive damage to the medial temporal lobe and with additional variable damage to lateral temporal cortex. Hippocampus 2001;11:776–782. Published 2001 Wiley‐Liss, Inc.
The role of purine analogue combinations in the management of acute leukemias
Authors: Frewin R. J. , Johnson S. A. 
Published: September 2002

AbstractCytosine arabinoside plays a pivotal role in the therapy of acute myeloid leukemias with the concentration of its active metabolite, ara‐CTP, being positively correlated with improved clinical outcome. Both in vitro studies and ex vivo studies have confirmed the ability of the purine analogues to enhance ara‐CTP accumulation within leukemic cells via the stimulation of deoxycytidine kinase. Clinical studies have confirmed the efficacy of these combination regimes in the treatment of acute leukemias. The basis of the biochemical rationale for the development of combination chemotherapy regimes with purine analogues for acute leukemias is reviewed along with clinical studies of their effectiveness and toxicity. Copyright © 2001 John Wiley & Sons, Ltd.
The association between risk factors for tardive dyskinesia and phenylalanine‐induced abnormal movements in schizophrenia
Authors: Schultz S. K. , Ellingrod V. , Fleming F. W. , Andreasen N. C. 
Published: September 2002

AbstractWe examined whether an oral challenge dose of the amino acid phenylalanine (a dopamine precursor) exacerbates the abnormal movements of tardive dyskinesia (TD). We also examined age, gender, treatment duration, and baseline movement severity in relation to phenylalanine‐induced changes in movements. Lastly, we assessed the influence of fasting amino acid levels on phenylalanine‐induced movements. In a placebo‐controlled fashion, the abnormal involuntary movement scale (AIMS) was obtained on 25 patients before and after a phenylalanine challenge drink. A general linear model determined the relative effects of age, gender, treatment duration, and fasting amino acid levels on the magnitude of induced movements. Age and treatment duration did not affect phenylalanine‐induced movements. Lower fasting levels of phenylalanine were associated with greater movements after controlling for age, F = 11.89, p < 0.003. The severity of abnormal movements at baseline also predicted response to phenylalanine, F = 8.62, p = 0.0079. Brain amino acid and neurotransmitter pools are influenced by changes in dietary protein, which may have implications in the development and prevention of movement disorders. This study suggests that fasting amino acid levels may predict differences in vulnerability to movements during an influx of neurotransmitter precursors, perhaps due to long‐term compensatory changes in receptor sensitivity. Copyright © 2001 John Wiley & Sons, Ltd.
The pharmacokinetics of THC in fat and brain: resulting functional responses to marihuana smoking
Authors: Nahas Gabriel G. 
Published: September 2002

AbstractA pleasant sensory perception (PSP), the high of THC or of marihuana consumption, is a consistent functional response to this drug only manifested by man, and which occurs concurrently with an increased heart rate. However, it has not been possible to relate consistently magnitude and duration of these functional markers to THC plasma concentration, whatever the route of administration. A re‐analysis of all the available clinical and experimental data reporting the pharmacokinetics and storage of THC in tissues in function of time, have indicated that the discrepancies between functional responses and plasma molecular THC concentration may be accounted for by the pharmacokinetics of THC. The instant uptake and unlimited storage of THC by neutral fat limits the molecular concentration of the drug present in the plasma to a level which does not exceed 6 × 1014 molecules/ml. The physicochemical nature of the membrane lipid bilayer (of the blood–brain barrier) will restrict the access of THC into the bilayer receptors and its: reactive enzymes. The PSP and increased heart rate of marihuana is correlated with the molecular concentration of THC in the bilayer (blood–brain barrier) of the order of 1012–1014 molecules/ml. This number in turn would be related to the number of functional THC receptor sites in the lipid bilayer. THC would exert its functional properties on PSP and heart rate through a molecular transmission to specific receptor site and bilipid layer physicochemical interations. Rapid uptake and slow release of THC in fat associated with a rate‐limited uptake into brain may be a general philogenetic mechanism which would protect brain function from prolonged exposure to xenobiotics like THC and other fat soluble drugs. Copyright © 2001 John Wiley & Sons, Ltd.