bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of the leukocyte common antigen (CD45) in mature B‐cell malignancies
Authors: Hendrickx Ann , Bossuyt Xavier
Published: September 2002

CD45 is a glycoprotein expressed on all lymphohematopoietic cells. Its expression increases during normal B‐cell differentiation and remains stable on mature cells. Although it is widely known that CD45 antigen expression is decreased in B‐acute lymphocytic leukemia (ALL), only scarce and contradictory information is available on CD45 expression on mature B‐cell malignancies. In healthy adults (n = 15), CD45 expression on B lymphocytes was lower than that on T cells. In patients with chronic lymphocytic leukemia (CLL; n = 22), CD45 expression on malignant cells was lower than that on the whole lymphocyte population of healthy adults (n = 28) and on normal B lymphocytes (n = 15). In 6 of the 22 CLL patients, the malignant cell population could be separated from the normal lymphocyte population on the CD45‐side scatter (SSC) plot. In 16 CLL patients, there was some degree of overlap between the malignant and normal cells with respect to CD45 expression. For these patients, there was an inverse correlation between CD45 expression on the whole lymphocyte population and the percentage of malignant cells in this population. In two patients with mantle cell lymphoma (MCL), CD45 expression on the malignant cells appeared lower than that on normal B cells and on the whole lymphocyte population. In six patients with hairy cell leukemia (HCL), CD45 expression on hairy cells was comparable to that on the whole lymphocyte population of healthy adults, but slightly higher than that of normal B cells. Evaluation of CD45 expression may help to characterize mature B‐cell malignancies. Cytometry (Comm. Clin. Cytometry) 46:336–339, 2001. © 2001 Wiley‐Liss, Inc.
P2 receptors in cerebellar neurons: Molecular diversity of ionotropic ATP receptors in Purkinje cells
Authors: García‐Lecea Marta , Sen Raquel P. , Soto Florentina , Miras‐Portugal Ma Teresa , Castro Enrique
Published: September 2002

ATP is now recognized as a fast neurotransmitter after the demonstration of synaptic transmission mediated by ATP in the medial habenula, locus coeruleus, spinal cord, and hippocampus. We focused on the postnatal rat cerebellum as a model territory and studied the role of ATP neurotransmission using cultured cells. Cerebellar Purkinje neurons in culture express ionotropic P2X receptors. We have shown that Ca2+ signals mediated by ATP in Purkinje cells present pharmacological profile characteristics of ATP receptors formed by P2X2 subunits. However, the complete range of known P2X subunits are expressed in the cerebellum. With the aid of the RT‐PCR technique we identified mRNA for P2X1–4 and P2X6 subunits in the rat cerebellum during the first postnatal week. These results have been confirmed by Southern blotting of PCR products using selective P2X probes. This opens the question of the relative contribution of each subunit to functional channels. Immunocytochemical labeling using anti‐P2X antibodies reveal that several P2X subunits colocalize to the same Purkinje cell. This raises the possibility of extensive hetero‐oligomerization of P2X subunits. Patch‐clamping of Purkinje cells in culture indicates the presence of two subpopulations of ATP receptors: a fast and rapidly desensitizing receptor and a nondesensitizing receptor with slower kinetics. Our results suggest that both receptors may be formed by co‐assembly of dissimilar P2X subunits. Drug Dev. Res. 52:104–113, 2001. © 2001 Wiley‐Liss, Inc.
Load voltage compensation using series–shunt power converter
Authors: Takeshita Takaharu , Hayashi Yuji , Matsui Nobuyuki , Fujita Hideki
Published: September 2002

This paper presents a method of amplitude control and unbalance compensation of the load voltage using a series–shunt power converter. The series power converter works to obtain a constant balanced sinusoidal load voltage. The shunt converter regulates the DC link voltage and compensates for the reactive current of the source within the rated current of the converter. To design the required capacity for the series–shunt power converter, the relation between the converter capacity and the load power factor at constant compensation voltage is introduced. The required capacity of the series–shunt power converter is reduced by more than 50% compared with that of a conventional series power converter. The effectiveness of the proposed load voltage compensation technique using the series–shunt power converter is verified by experiments. © 2001 Scripta Technica, Electr Eng Jpn, 136(3): 39–48, 2001
Influence of capacitor properties on irregular ignition of discharge circuit using a thyristor
Authors: Miyairi Keiichi , Itoh Eiji , Morimitsu Norimasa , Ishikawa Makoto , Hagiwara Katsuo
Published: September 2002

A misfire phenomenon taking place in a discharge circuit composed of a capacitor and thyristor has been investigated. This circuit was operated at a frequency of up to 198 Hz. A misfire was observed in a circuit with a PET capacitor at low temperatures, while no misfire was observed with a PP capacitor under any conditions. Transient currents in the range of 40 A to 1 mA were measured with a digital oscilloscope. In the case of a PET capacitor, the current initially decreased exponentially at a given time constant, but exhibited a slow decay which caused the misfire. This current is associated with residual charges trapped in the bulk of the PET film. © 2001 Scripta Technica, Electr Eng Jpn, 137(2): 1–7, 2001
Corporate environmental management and information technology
Authors: Rikhardsson Pall M.
Published: September 2002

Information technology has changed, is changing and will continue to change the face of business as we further enter the Information Society. Today it would be difficult for a company to function effectively without the aid of various information technologies, such as accounting software, production software, the Internet, computer networks and telecommunications devices.

Information technology also has an impact on how companies perform environmental management. This paper looks at the relations between corporate environmental management and information technology. First it presents a framework for mapping information technology. Using this framework it focuses on the use of information technology in corporate environmental management and describes the market for standard environmental management information systems and implementation experiences from one large international company. Copyright © 2001 John Wiley & Sons, Ltd. and ERP Environment
Tests on low‐ductility RC frames under high‐ and low‐frequency excitations
Authors: Quek Ser‐Tong , Bian Chengmei , Lu Xilin , Lu Wensheng , Xiong Haibei
Published: September 2002

The response of low‐ductility reinforced concrete (RC) frames, designed typically for a non‐seismic region, subjected to two frequencies of base excitations is studied. Five half‐scaled, two‐bay, two‐storey, RC frames, each approximately 5 m wide by 3.3 m high, were subjected to both horizontal and/or vertical base excitations with a frequency of 40 Hz as well as a lower frequency of about 4 Hz (close to the fundamental frequency) using a shake table. The imposed acceleration amplitude ranged from 0.2 to 1.2g. The test results showed that the response characteristics of the structures differed under high‐ and low‐frequency excitations. The frames were able to sustain high‐frequency excitations without damage but were inadequate for low‐frequency excitations, even though the frames exhibited some ductility. Linear‐elastic time‐history analysis can predict reasonably well the structural response under high‐frequency excitations. As the frames were not designed for seismic loads, the reinforcement detailing may not have been adequate, based on the crack pattern observed. The effect of vertical excitation can cause significant additional forces in the columns and moment reversals in the beams. The ‘strong‐column, weak‐beam’ approach for lateral load RC frame design is supported by experimental observations. Copyright © 2001 John Wiley & Sons, Ltd.
Do starvation diets lead to irreversible lung changes?
Authors: Key Adrienne , Lacey J. Hubert , Nussey Stephen
Published: September 2002

Animal research has demonstrated specific, irreversible, structural and functional changes in the lungs of starved rats. The effect of starvation on lung compliance in anorexia nervosa has not been studied. This case‐study and series review offer evidence of similar changes occurring specifically in the lungs of younger patients with very severe anorexia nervosa. They also raise the possibility that the younger the patient, the greater the risk of permanent damage. We conducted a detailed comparison of 13 cases. Copyright © 2001 John Wiley & Sons, Ltd and Eating Disorders Association.
Improving Public Communication in Environmental Impact Assessments
Authors: Ligon Daisy M. , Deason Jonathan P.
Published: September 2002

A recent research project investigated the potential application of computer‐aided tools as a means of
improving and enhancing public communication of environmental impact assessments (EIAs) of federal
facilities. This article focuses on one aspect of the research project: a survey that asked how environmental
impacts should be measured and in what form the results should be presented in order to improve the
communication process. The responses to the survey supported the importance of selecting appropriate
environmental measures and presenting the results in a way that can easily be understood. The survey also
provided insights on how EIAs could be expanded (e.g., in terms of how impacts should be quantified)
and whether all needed information can be derived (and presented) using interactive computer tools.
© 2001 John Wiley & Sons, Inc.
Filters for short non‐stationary sequences
Authors: Pollock D. S. G.
Published: September 2002

This paper describes a methodology for implementing bidirectional frequency‐selective filters in cases where the data sequence is short and non‐stationary. A simple method is proposed for dealing with the start‐up problem. The method has a firm theoretical basis and it is computationally efficient. Copyright © 2001 John Wiley & Sons, Ltd.
AN2/NG2 protein‐expressing glial progenitor cells in the murine CNS: Isolation, differentiation, and association with radial glia
Authors: Diers‐Fenger Marianne , Kirchhoff Frank , Kettenmann Helmut , Levine Joel M. , Trotter Jacqueline
Published: September 2002

During early neural development, the lineage specification of initially pluripotent progenitor cells is associated with proliferation, differentiation, and migration. Oligodendroglial progenitor cells migrate from their sites of origin to reach the axons that they will myelinate. We have described a cell‐surface protein, AN2, expressed by oligodendroglial progenitor cells in vitro and showed that antibodies against AN2 inhibited the migration of cultured primary oligodendroglial progenitor cells, suggesting that the AN2 antigen plays a role in their migration. Recently, results from MALDI mass spectroscopy showed that AN2 is the mouse homologue of the rat NG2 protein. In this study, we have analyzed cells staining with AN2 antibodies during development and in the adult murine central nervous system (CNS), carried out double stainings with antibodies against NG2, and investigated the differentiation potential of cells in vitro after isolation from early postnatal brain using AN2 antibodies. AN2 and NG2 antibodies stained totally overlapping populations of cells in the CNS. AN2/NG2 expressing cells in embryonic and postnatal brain expressed the PDGF‐α‐receptor and in postnatal brain exhibited electrophysiological properties typical of glial progenitor cells. Cells isolated from early postnatal brain using AN2 monoclonal antibody developed into oligodendrocytes in low serum medium or into astrocytes in the presence of fetal calf serum. In the embryonic spinal cord, cells staining with AN2 antibodies were found closely apposed to radial glial cells, suggesting that glial precursors, like neurons, may use radial glia as scaffolds for migration. GLIA 34:213–228, 2001. © 2001 Wiley‐Liss, Inc.
Endogenous opioids and oligodendroglial function: Possible autocrine/paracrine effects on cell survival and development
Authors: Knapp Pamela E. , Itkis Olga S. , Zhang Lixin , Spruce Barbara A. , Bakalkin Georgy , Hauser Kurt F.
Published: September 2002

Previous work has shown that oligodendrocytes (OLs) express both μ‐ and κ‐opioid receptors. In developing OLs, μ receptor activation increases OL proliferation, while the κ‐antagonist nor‐binaltorphimine (NorBNI) affects OL differentiation. Because exogenous opioids were not present in our defined culture medium, we hypothesized that NorBNI blocked endogenous opioids produced by the OLs themselves. To test this, intact and partially processed proenkephalin and prodynorphin‐derived peptides were assessed in OLs using immunocytochemistry or Western blot analysis, or both. Immature OLs possessed large amounts of intact and partially processed proenkephalin precursors, as well as posttranslational products of prodynorphin including dynorphin A (1–17). With maturation, however, intact or partially processed proenkephalin was expressed by only about 50% of OLs, while dynorphin A (1–17) was undetectable. To assess the function of OL‐derived opioids, the effect of κ‐agonists/antagonists on OL differentiation and death was explored. κ‐Agonists alone had no effect. In contrast, NorBNI significantly increased OL death. Additive OL losses were evident when NorBNI was paired with toxic levels of glutamate, suggesting that κ‐receptor blockade alone is sufficient to induce OL death. Thus, the results indicate that OLs express proenkephalin and prodynorphin peptides in a developmentally regulated manner, and further suggest that opioids produced by OLs modulate OL maturation and survival through local (i.e., autocrine and/or paracrine) mechanisms. GLIA 35:156–165, 2001. © 2001 Wiley‐Liss, Inc.
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

This 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

The 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

The 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

[(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

In 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

Various 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

Background

We 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.

Methods

Proportional hazards methods were applied to head and neck cancer patients whose treatment included surgery by the Johns Hopkins Otolaryngology service (n = 388).

Results

The 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).

Conclusions

Compared 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

A 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

An 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

A 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

Hippocampal 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

Declarative 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

Cytosine 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

We 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

A 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.
The effect of clozapine on blood glucose metabolism
Authors: Chae Beang‐Jin , Kang Byung‐Jo
Published: September 2002

The aim of this prospective study was to examine the effect of clozapine on blood glucose metabolism compared with haloperidol. Oral glucose tolerance tests were taken every week for 8 weeks to assess the prevalence of diabetes mellitus, impaired glucose tolerance and glycemic peak delay in 19 patients of the clozapine group compared with 15 patients of the haloperidol group. There were two dropouts in the clozapine group and five in the haloperidol group. Finally 17 patients in the clozapine group and 10 patients in the haloperidol group participated in this study. In the clozapine group, six patients (35%) had impaired glucose tolerance, and seven patients (41%) had glycemic peak delay. In the haloperidol group, no patient (0%) had impaired glucose tolerance, and one patient (10%) had glycemic peak delay. None of either group developed diabetes mellitus. In conclusion, the clozapine group had more impaired glucose tolerance and glycemic peak delay than the haloperidol group. However, this difference did not achieve statistical significance (p = 0.056, p = 0.189). Copyright © 2001 John Wiley & Sons, Ltd.
Chemical and isotopic evidence of nitrogen transformation in the Mississippi River, 1997–98
Authors: Battaglin William A. , Kendall Carol , Chang Cecily C. Y. , Silva Steven R. , Campbell D. H.
Published: September 2002

An Erratum has been published for this article in Hydrological Processes 16(5) 2002, 1129–1130.

Nitrate (NO3) and other nutrients discharged by the Mississippi River are suspected of causing a zone of depleted dissolved oxygen (hypoxic zone) in the Gulf of Mexico each summer. The hypoxic zone may have an adverse affect on aquatic life and commercial fisheries. The amount of NO3 delivered by the Mississippi River to the Gulf of Mexico is well documented, but the relative contributions of different sources of NO3, and the magnitude of subsequent in‐stream transformations of NO3, are not well understood. Forty‐two water samples collected in 1997 and 1998 at eight stations located either on the Mississippi River or its major tributaries were analysed for NO3, total nitrogen (N), atrazine, chloride concentrations and NO3 stable isotopes (δ15N and δ18O). These data are used to assess the magnitude and nature of in‐stream N transformation and to determine if the δ15N and δ18O of NO3 provide information about NO3 sources and transformation processes in a large river system (drainage area 2 900 000 km2) that would otherwise be unavailable using concentration and discharge data alone.

Results from 42 samples indicate that the δ15N and δ18O ratios between sites on the Mississippi River and its tributaries are somewhat distinctive, and vary with season and discharge rate. Of particular interest are two nearly Lagrangian sample sets, in which samples from the Mississippi River at St Francisville, LA, are compared with samples collected from the Ohio River at Grand Chain, II, and the Mississippi River at Thebes, IL. In both Lagrangian sets, mass‐balance calculations indicate only a small amount of in‐stream N loss. The stable isotope data from the samples suggest that in‐stream N assimilation and not denitrification accounts for most of the N loss in the lower Mississippi River during the spring and early summer months. Published in 2001 by John Wiley & Sons, Ltd.
Chemical weathering and runoff chemistry in a steep headwater catchment
Authors: Anderson Suzanne Prestrud , Dietrich William E.
Published: September 2002

We present here deductions about the location, rate, and mechanisms of chemical weathering in a small catchment based on a catchment‐scale sprinkling experiment. In this experiment demineralized water was applied at an approximately steady rate in the CB1 catchment in the Oregon Coast Range to reach and maintain a quasi‐steady discharge for a period of 4 days. Because of nearly steady flow conditions within the catchment, the contribution to solute fluxes from soil and bedrock could be partitioned. One half of the solute flux from the catchment derived from colluvial soil, and one half from weathering in bedrock. This implies more intense weathering in the thin colluvium mantling the catchment than in the thick underlying weathered bedrock. The annual solute flux from the catchment, scaled to the annual runoff from the catchment, is 32 ± 10 t km−2 year−1, equivalent to published chemical denudation rates for nearby rivers with drainage areas 106 times greater than the experiment site. Soil waters sampled during the sprinkling experiment had steady compositions following a period of transient water flow conditions, implying steady‐state chemical evolution in the soil. The waters leached ‘organic’ anions from shallow depths in the soil, which solubilized aluminium and iron, indicating that podzolization is occurring in these soils. Carbonate dissolution appears to be an important source of solutes from the bedrock, despite being present as only a minor phase in the rock. Water balance suggests that the residence time of water in the catchment is about 2 months, and that typical 24 h storms displace only a fraction of the stored water. A consequence is that runoff chemistry is dominated by old water, which imposes strong limits on the variability of runoff composition. Copyright © 2001 John Wiley & Sons, Ltd.
Generation of stemflow volume and chemistry in a mature Japanese cypress forest
Authors: Koichiro Kuraji , Yuri Tanaka , Nobuaki Tanaka , Isamu Karakama
Published: September 2002

Long‐term monitoring of rainfall, throughfall and stemflow was conducted in a mature Japanese cypress forest at the University Forest in Chiba, Boso Peninsula, Japan. Two stemflow collectors were installed in a tree at 19·1 m (just under the tree crown) and at 1·3 m above the ground to determine the processes controlling the generation, volume and quality of stemflow at the stem, leaves and branches. The canopy‐only stemflow and stem‐only stemflow for this tree, and the canopy‐and‐stem stemflow for three other trees, were measured and sampled for chemical analysis. Total stemflow increased after installation of the 19·1 m collector just under the tree crown, suggesting a large water storage capacity of the bark. All ion concentrations in stemflow except H+ were highest in the first sample collected during a rain event and declined thereafter. Hydrogen ion concentrations of canopy‐only stemflow and canopy‐and‐stem stemflow were nearly balanced with the charge balance deficit (CBD) concentrations for all samples. Following comparison of ion concentrations among canopy‐only stemflow, canopy‐and‐stem stemflow and throughfall, the ions were categorized into four groups (NO3−, SO42−, H+, CBD), (Na+, Cl−), (Mg2+, Ca2+) and (K+, NH4+). The groupings were based on differences in stemflow and throughfall chemistry generation processes between and among the groups. Copyright © 2001 John Wiley & Sons, Ltd.
A new empirical weighted monetary aggregate for the UK
Authors: Drake Leigh , Mills Terence C.
Published: September 2002

This paper utilizes an approach to long‐run modelling proposed by Pesaranet al. (1996. Testing for the existence of a long run relationship. Mimeo, University of Cambridge) to develop an empirical weighted broad monetary aggregate for the UK. The properties of this new aggregate are contrasted with those of the corresponding simple sum and Divisia aggregates. The new weighted monetary aggregate is found to be highly stable and conforms well with standard money demand properties. The aggregate also displays sensible impulse response and persistence profiles to monetary shocks in the context of a VECM framework. Finally, the empirical weighted aggregate displays superior information content in respect of nominal income when contrasted with simple sum and Divisia aggregates using a series of St. Louis equations. Copyright © 2001 John Wiley & Sons, Ltd.
Modelling the conditional volatility of commodity index futures as a regime switching process
Authors: Fong Wai Mun , See Kim Hock
Published: September 2002

Commodity index futures offer a versatile tool for gaining different forms of exposure to commodity markets. Volatility is a critical input in many of these applications. This paper examines issues in modelling the conditional variance of futures returns based on the Goldman Sachs Commodity Index (GSCI). Given that commodity markets tend to be ‘choppy’ (Webb, 1987), a general econometric model is proposed that allows for abrupt changes or regime shifts in volatility, transition probabilities which vary explicitly with observable fundamentals such as the basis, GARCH dynamics, seasonal variations and conditional leptokurtosis. The model is applied to daily futures returns on the GSCI over 1992–1997. The results show clear evidence of regime shifts in conditional mean and volatility. Once regime shifts are accounted for, GARCH effects are minimal. Consistent with the theory of storage, returns are more likely to switch to the high‐variance state when the basis is negative than when the basis is positive. The regime switching model also performs well in forecasting the daily volatility compared to standard GARCH models without regime switches. The model should be of interest to sophisticated traders who base their trading strategies on short‐term volatility movements, managed commodity funds interested in hedging an underlying diversified portfolio of commodities and investors of options and other derivatives tied to GSCI futures contracts. Copyright © 2001 John Wiley & Sons, Ltd.
Testing of seasonal fractional integration in UK and Japanese consumption and income
Authors: Gil‐Alaña L. A. , Robinson P. M.
Published: September 2002

The seasonal structure of quarterly UK and Japanese consumption and income is examined by means of fractionally based tests proposed by Robinson (1994). These series were analysed from an autoregressive unit root viewpoint by Hylleberg, Engle, Granger and Yoo (HEGY, 1990) and Hylleberg, Engle, Granger and Lee (HEGL, 1993). We find that seasonal fractional integration, with amplitudes possibly varying across frequencies, is an alternative plausible way of modelling these series. Copyright © 2001 John Wiley & Sons, Ltd.