bluuebunny/crossref_metadata_2025 huggingface dataset:
Defining a common region of deletion at 13q21 in human cancers
Authors: Chen Ceshi , Brabham Will W. , Stultz Brian G. , Frierson Henry F. , Barrett J. Carl , Sawyers Charles L. , Isaacs John T. , Dong Jin‐Tang
Published: September 2002

Previous molecular genetic analyses identified a region of deletion at 13q21 in a variety of human cancers, suggesting the existence of a tumor suppressor gene(s) at this locus. In our earlier study on prostate cancer, the region of deletion was confined to a 3.1 cM interval between D13S152 and D13S162. At present, however, no known gene located in this interval has been firmly implicated in cancer, and the region remains too large for gene identification. To fine‐map the area of interest, we established a contig of bacterial artificial chromosome (BAC) clones, narrowed the region of deletion by loss of heterozygosity (LOH) and homozygosity‐mapping‐of‐deletion (HOMOD) analyses in different types of cancers, and tested a candidate gene from the region for mutation and alteration of expression in prostate cancers. The contig consisted of 75 overlapping BAC clones. In addition to the generation of 47 new sequence‐tagged‐site (STS) markers from the ends of BAC inserts, 76 known STS and expressed sequence tag markers were mapped to the contig (25 kb per marker on average). The minimal region of deletion was further defined to be about 700 kb between markers D13S791 and D13S166 by LOH analysis of 42 cases of prostate cancer, and by HOMOD analysis of eight prostate cancer cell lines/xenografts and 49 cell lines from cancers of the breast, ovary, endometrium, and cervix, using 18 microsatellite markers encompassing the deletion region. A gene that is homologous to the WT1 tumor suppressor gene, AP‐2rep (KLF12), was mapped in this region and was analyzed for its expression and genetic mutation. In addition to low levels of expression in both normal and neoplastic cells of the prostate, this gene did not have any mutations in a group of aggressive prostate cancers and cell lines/xenografts, as assessed by the methods of polymerase chain reaction‐single strand conformational polymorphism analysis and direct sequencing. These studies suggest that a 700 kb interval at 13q21 harbors a tumor suppressor gene(s) that seems to be involved in multiple types of cancer, and that the AP‐2rep gene is unlikely to be an important tumor suppressor gene in prostate cancer. The BAC contig and high‐resolution physical map of the defined region of deletion should facilitate the cloning of a tumor suppressor gene(s) at 13q21. © 2001 Wiley‐Liss, Inc.
Allelic loss on chromosome bands 13q11‐q13 in esophageal squamous cell carcinoma
Authors: Li Guang , Hu Nan , Goldstein Alisa M. , Tang Ze‐Zhong , Roth Mark J. , Wang Quan‐Hong , Dawsey Sanford M. , Han Xiao‐You , Ding Ti , Huang Jing , Giffen Carol , Taylor Philip R. , Emmert‐Buck Michael R.
Published: September 2002

Allelic loss on chromosome 13 occurs frequently in esophageal squamous cell carcinoma. However, studies of the two known tumor suppressor genes located on 13q, RB1 and BRCA2, have shown few mutations, suggesting that other genes are likely to be involved in the development of this tumor type. To identify a minimal deletion interval, we first analyzed 42 microsatellite markers spanning chromosome bands 13q11‐q13 in 56 esophageal squamous cell carcinoma patients, including 34 with a family history of upper gastrointestinal cancer and 22 without a family history of cancer. Lifestyle risk factors and clinical/pathologic characteristics were also collected. Two commonly deleted regions were identified: one was located on band 13q12.11, between markers D13S787 and D13S221; the other was located on bands 13q12.3‐q13.1 from markers D13S267 to D13S219. We observed higher allelic loss frequencies for eight of the microsatellite markers in those patients with a family history of upper gastrointestinal cancer compared to patients without such a history. This study suggests that one or more unidentified tumor suppressor genes are located on chromosome arm 13q that play a role in the development of esophageal squamous cell carcinoma. © 2001 Wiley‐Liss, Inc.
An ethnoarchaeological study of chemical residues in the floors and soils of Q'eqchi' Maya houses at Las Pozas, Guatemala
Authors: Fernández Fabián G. , Terry Richard E. , Inomata Takeshi , Eberl Markus
Published: September 2002

This ethnoarchaeological study at the Q'eqchi' Maya village of Las Pozas, Guatemala, aimed to refine the understanding of the relationship between soil chemical signatures and human activities for archaeological applications. The research involved phosphorus, exchangeable ion (calcium, potassium, magnesium, sodium), and trace element analysis of soils and earth floors extracted by Mehlich II, ammonium acetate, and DTPA chelate solutions, respectively. The results showed high levels of phosphorus, potassium, magnesium, and pH in food preparation areas, as well as high phosphorus concentrations and low pH in food consumption areas. The traffic areas exhibited low phosphorus and trace element contents, whereas refuse disposal areas were enriched. These results provide important information for the understanding of space use in ancient settlements. © 2002 Wiley Periodicals, Inc.
Amphotericin B potentiates the activation of inducible nitric oxide synthase and causes nitric oxide‐dependent mitochondrial dysfunction in cytokine‐treated rodent astrocytes
Authors: Trajkovic Vladimir , Markovic Milos , Samardzic Tatjana , Miljkovic Djordje J. , Popadic Dusan , Stojkovic Marija Mostarica
Published: September 2002

Because the neurotoxic effects of the antifungal drug amphotericin B (AMB) closely resemble those ascribed to the highly reactive gaseous free radical nitric oxide (NO), we investigated the effect of AMB on NO production in rodent astrocytes. AMB caused a dose‐dependent increase of NO generation in interferon‐γ (IFN‐γ)‐stimulated rat and mouse astrocytes, as well as in IFN‐γ + tumor necrosis factor‐α (TNF‐α)‐activated rat astrocytoma cell line C6. Treatment of rat astrocytes with AMB markedly potentiated IFN‐γ‐triggered expression of mRNA for iNOS, but not for its transcription factor IRF‐1. The activation of transcription factor NF‐κB was apparently required for AMB‐induced iNOS mRNA expression, as the latter was abolished by NF‐κB inhibitors: pyrrolidine dithiocarbamate and MG132. AMB‐mediated enhancement of astrocyte NO production was partly dependent on endogenous IL‐1, as shown by partial inhibition of AMB effect with IL‐1 receptor antagonist. IFN‐γ + AMB treatment led to reduction of astrocyte mitochondrial respiration (measured by MTT assay) that has been completely reverted by selective iNOS inhibitor aminoguanidine. AMB toxicity toward IFN‐γ‐stimulated astrocytes was dependent on both AMB and NO action, since AMB and NO‐releasing substance SNP synergized in inducing astrocyte mitochondrial dysfunction. These results suggest that the enhancement of cytokine‐induced iNOS activation in astrocytes and the subsequent release of high amounts of NO might be at least partly responsible for AMB neurotoxicity. GLIA 35:180–188, 2001. © 2001 Wiley‐Liss, Inc.
Macrophage depletion impairs oligodendrocyte remyelination following lysolecithin‐induced demyelination
Authors: Kotter Mark R. , Setzu Anna , Sim Fraser J. , Van Rooijen Nico , Franklin Robin J.M.
Published: September 2002

An association between macrophages and remyelination efficiency has been observed in a variety of different models of CNS demyelination. In order to test whether this association is causal or coincidental, we have examined the effects of macrophage depletion on the rate of remyelination of lysolecithin‐induced demyelination in the spinal cord of young adult female rats. Macrophage depletion was achieved by reducing the monocyte contribution to the macrophages within the lesion using the clodronate‐liposome technique. This technique not only resulted in a decrease in Ox‐42–positive cells in the spleen of treated animals but also in the levels of macrophage scavenger receptor type B mRNA expression within the demyelinating lesion. In animals treated with clodronate‐liposomes throughout the remyelination process, there was a significant decrease in the extent of oligodendrocyte remyelination at 3 weeks after lesion induction, but no effect on Schwann cell remyelination. If macrophage depletion was delayed until the second half of the remyelination phase, then there was no effect on the repair outcome, implying that macrophages are required for the early stages of CNS remyelination. The results of this study indicate that the macrophage response is an important component of successful CNS remyelination and that approaches to the treatment of demyelinating disease based on inhibition of the inflammatory response may also impair regenerative events that follow demyelination. GLIA 35:204–212, 2001. © 2001 Wiley‐Liss, Inc.
Continuous interleukin‐6 application in vivo via macroencapsulation of interleukin‐6–expressing COS‐7 cells induces massive gliosis
Authors: Tilgner Johannes , Volk Benedikt , Kaltschmidt Christian
Published: September 2002

The inflammatory cytokine interleukin‐6 (IL‐6) was found in senile plaques of Alzheimer's patients and might be involved in the pathology of Parkinson's disease and multiple sclerosis. Interestingly, an astocytosis is also found in these neurodegenerative disorders. To evaluate the direct effects of IL‐6 in vivo on glial cells, we created a new in vivo model. IL‐6 and mock‐transfected (control group) COS‐7 cells were encapsulated in a poly‐acryl‐nitril membrane for implantation into the rat striatum. Afterward, the host immune reaction to the membrane without encapsulated cells and the biological action of IL‐6–producing capsules was evaluated. Animals with an implanted membrane without cells showed a moderate astrocytosis 5 days after the operation. Furthermore, microglia and T‐cells could be detected and after 30 days the astrocytosis decreased to a small layer around the membrane. In comparison to the control group, which received a sham operation, our results demonstrate that the response of glial cells is caused by the mechanical damage of the surgical procedure itself rather than due to the introduced membrane material. In contrast, we found a massive proliferation and activation of astrocytes and microglia after 10 days by IL‐6–secreting capsules, indicating that IL‐6 is involved in the induction of gliosis. Control animals that received encapsulated mock‐transfected COS‐7 cells showed only a weak response. These data point to an involvement of IL‐6 in the proliferation and activation of glial cells as seen in neurodegenerative disorders. GLIA 35:234–245, 2001. © 2001 Wiley‐Liss, Inc.
Multiple compartments with different metabolic characteristics are involved in biosynthesis of intracellular and released glutamine and citrate in astrocytes
Authors: Waagepetersen Helle S. , Sonnewald Ursula , Larsson Orla M. , Schousboe Arne
Published: September 2002

The metabolism of glucose and lactate was investigated in cultured mouse cerebellar astrocytes, a culture preparation consisting of a homogeneous population of cells, by incubating the cells in a medium containing either [U‐13C]glucose or [U‐13C]lactate in combination with unlabeled lactate and glucose, respectively. After the incubation, cell extracts and media were analyzed by GC/MS (gas chromatography/mass spectrometry) for labeling patterns in aspartate, glutamate, and glutamine, as well as the tricarboxylic acid (TCA) cycle constituents citrate and fumarate. Triple labeling of extracellular citrate exceeded that of double labeling from [U‐13C]glucose. This was not the case when lactate was the labeled precursor. These results indicate that pyruvate carboxylation in biosynthesis of releasable citrate was less prominent from lactate compared with glucose. As observed in the case of extracellular citrate, triple labeling of intracellular aspartate was higher than double labeling when [U‐13C]glucose was the precursor, but not with [U‐13C]lactate as precursor. The pattern of labeling in citrate was different intra‐ and extracellularly and the extent of labeling extracellularly was 10 times higher using [U‐13C]glucose compared with [U‐13C]lactate. However, the intracellular citrate labeling from [U‐13C]glucose only exceeded that originating from labeled lactate by a factor of two. This is in contrast to the labeling pattern obtained for glutamine, since intracellularly this was equally prominent using [U‐13C]glucose and [U‐13C]lactate as substrates. Moreover, extracellularly the labeling was only slightly higher when using [U‐13C]glucose compared with [U‐13C]lactate. Intracellular glutamate and extracellular glutamine exhibited similar incorporation patterns with regard to double compared with triple labeling and the extent of incorporation of label from [U‐13C]lactate compared with [U‐13C]glucose. It should be noted that the main intracellular pools of citrate and glutamine were compartmentalized; i.e., releasable citrate and glutamine exhibited a labeling pattern distinctly different from that of their intracellular pools. Moreover, carboxylation of pyruvate using glucose as the precursor was more important for biosynthesis of releasable glutamine and citrate, compared with their intracellular pools. Based on the results a model of multiple compartments is suggested. The compartments differ with regard to utilization of lactate and glucose, synthetic pathways for TCA cycle intermediates and amino acids, particularly citrate and glutamine, as well as the contents of different metabolites. GLIA 35:246–252, 2001. © 2001 Wiley‐Liss, Inc.
Kinetic study on debromination of vic‐dibromides with trivalent phosphorus compounds
Authors: Yasui Shinro , Itoh Kenji , Ohno Atsuyoshi
Published: September 2002

Various types of trivalent phosphorus compounds (1) brought about reductive debromination of vic‐dibromides (2) to afford olefins. The reaction was accelerated by either electron‐releasing substituents on the phosphorus of 1 or electron‐withdrawing substituents on the α‐carbon of 2. The substituent effects, along with the stereochemistry of the reaction, are consistent with an E1CB‐like mechanism for the elimination of the two bromine atoms. That is, 1 initially undergoes nucleophilic attack upon a bromine of 2. At the transition state, a fractional positive charge is developed on the phosphorus of 1 and a fractional negative charge on the carbon of 2. This mechanism suggests the importance of an electronic character of the vic‐dibromide in determining the relative ease of bromophilicity, carbophilicity, and basicity of the phosphorus of a trivalent phosphorus compound in a reaction with the dibromide. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:217–222, 2001
Interconversion of cyclotrimetallenes and dihalocyclotrimetallanes consisting of group 14 elements
Authors: Ya. Lee Vladimir , Matsuno Tadahiro , Ichinohe Masaaki , Sekiguchi Akira
Published: September 2002

The 1‐ and 2‐disilagermirenes and cyclotrisilene were reacted with carbon tetrachloride or 1,2‐dibromoethane to give almost quantitatively the corresponding dihalocyclotrimetallane derivatives. The crystal structure of 1,2‐dichloro‐1,2,3,3‐tetrakis[di‐tert‐butyl(methyl)silyl]‐1,2‐disilagermirane showed a trans arrangement of the two chlorine atoms in the three‐membered ring system. Reduction of the dihalocyclotrimetallanes with t‐Bu3SiNa quantitatively produced the corresponding starting cyclotrimetallenes. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:223–226, 2001
The Modern Campus
Authors: Langenberg Donald N. , Spicer Donald Z.
Published: September 2002

The modern campus is a learning environment of unprecedented flexibility and effectiveness that respects and treasures the academic values and traditions of the past while embracing the technological tools of the present.
Appropriate and inappropriate instructional behaviors for international training
Authors: Burba Fengjiao Ji , Petrosko Joseph M. , Boyle Mike A.
Published: September 2002

Samples of university students from the United States, Eastern cultures, and Western cultures rated thirty‐one classroom instructional behaviors for appropriateness in their culture. U.S. students had significantly higher appropriateness ratings than Eastern students on clarity of presentation, enthusiasm, classroom interaction, and spatial‐behavioral communication behaviors. Western students exceeded Eastern students in all areas except spatial‐behavioral communication behaviors; ratings of non‐U.S. students were predicted by field of study and age.
The relationship between organizational support, employee development, and organizational commitment: An empirical study
Authors: Tansky Judith W. , Cohen Debra J.
Published: September 2002

An empirical study conducted in a major midwestern hospital found that organizational commitment and perceived organizational support were significantly correlated with satisfaction with career development. Results suggested that when organizations make efforts to develop their managers, the managers become more committed to the organization and also more likely to develop their employees.
Fundamental analysis of boiling heat transfer of magnetic fluids in a magnetic field
Authors: Xu L. , Peng X.F.
Published: September 2002

A theoretical investigation was conducted to explore boiling characteristics of magnetic fluids, including the effects of a magnetic field on the surface characteristics of magnetic fluids, the significance of body force and the stress induced. Emphasis was placed on aspects of nucleation, bubble behavior and dynamics. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 69–75, 2002; DOI 10.1002/htj.10012
Heat transfer in high‐aspect‐ratio rectangular passage with skewed ribs
Authors: Okamura Takanari , Koga Akinori , Kawagishi Hiroyuki
Published: September 2002

The heat transfer characteristics and flow behavior in a rectangular passage with two opposite 45° skewed ribs for turbine rotor blade have been investigated for Reynolds numbers from 7800 to 19,000. In this blade, the spanwise coolant passage at the trailing edge region whose thickness is very thin is chosen, so the channel aspect ratio (=width/height of channel) is extremely high, 4.76. Therefore the heat transfer experiment in the high‐aspect‐ratio cooling channel was performed using thermochromic liquid crystal and thermocouples. Furthermore, the calculation of flow and heat transfer was carried out using CFD analysis code to understand the heat transfer experimental results. The enhanced heat transfer coefficients on the smooth side wall at the rib's leading end were the same level as those on the rib‐roughened walls. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 89–104, 2002; DOI 10.1002/htj.10018
Heat transfer for Marangoni‐driven boundary layer flow
Authors: Christopher David M. , Wang Buxuan
Published: September 2002

Marangoni convection induced by variation of the surface tension with temperature along a surface influences crystal growth melts and other processes with liquid–vapor interfaces, such as boiling in both microgravity and normal gravity in some cases. This paper presents the Nusselt number for Marangoni flow over a flat surface calculated using a similarity solution for both the momentum equations and the energy equation assuming developing boundary layer flow along a surface. Solutions are presented for the surface velocity, the total flow rate, and the Nusselt number for various temperature profiles, Marangoni numbers, and Prandtl numbers. For large bubbles, the predicted boundary layer thickness would be less than the bubble diameter, so the curvature effects could be neglected and this analysis could be used as a first estimate of the effect of Marangoni flow around a vapor bubble. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 105–116, 2002; DOI 10.1002/htj.10019
Past expectations, present disappointments, future hopes or psychopathology as the rate‐limiting step of progress in psychopharmacology
Authors: Van Praag H. M
Published: September 2002

In 1974 I published a paper in which we predicted that biological depression research would lead to new, innovative antidepressants, to more sophisticated prescription of antidepressants and ultimately to ‘functional psychopharmacology’. These expectations have not materialized. The reasons why are discussed and the conclusion is reached that there are reasons to believe that, belated, they will come true. I consider it no bold venture to uphold them. Copyright © 2001 John Wiley & sons, Ltd.
How valuable are animal models in defining antidepressant activity?
Authors: Bourin M , Fiocco A. J , Clenet F
Published: September 2002

Animal models of depression have been utilised to screen novel compounds with antidepressant potential although uncertainty lingers concerning their clinical relevance. In order for a model to be considered of any value, it must possess predictive validity (does drug action in the model correspond to that in the clinic?), face validity (are there phenomenological similarities between the model and the clinic?) and construct validity (does the model possess a strong theoretical rationale?). On the one hand, there are models based on stress such as the learned helplessness model, the forced swimming test and the chronic mild stress model and, on the other hand, models based on neuronal deficits such as the olfactory bulbectomy model. To date, among models more frequently used in depression, none of them meet all these criteria. Moreover, improvements to tests are often poorly validated and estimating time of onset of action of antidepressants remains a major challenge in animal model research. Finally, reproducing the tests outside the laboratory of origin continues to be problematic and leads to variability in results. Although animal models of depression fail to be unequivocally valid, they represent the best tool to define potential antidepressant activity of drugs, to investigate their mechanism of action and, to a greater extent, explore this complex heterogeneous illness. Copyright © 2001 John Wiley & Sons, Ltd.
Imidazoline receptors: possible involvement in the pathophysiology and treatment of depression
Authors: Halaris Angelos , Piletz John E
Published: September 2002

Imidazoline receptors (IR), a novel family of non‐adrenergic receptors, are present in brain, especially the limbic system, and platelets among other organs. Their functions include central mediation of blood pressure control and possibly modulation of affective symptomatology. Studies of unipolar depressed patients have revealed consistent up‐regulation of the I1 subtype on the platelet. Treatment with cyclic antidepressants is accompanied by down‐regulation in responders. Treatment with the non‐cyclic bupropion produced similar findings. Studies of human post‐mortem brain show changes in depressed subjects but the protein fragments assessed are of different molecular weights than in the platelet. Plasma agmatine is believed to be a putative endogenous ligand for I receptors. Thus, IR may be useful state markers of affective disorders. Copyright © 2001 John Wiley & Sons, Ltd.
Are CRF receptor antagonists potential antidepressants?
Authors: O'Brien Donna , Skelton Kelly H , Owens Michael J , Nemeroff Charles B
Published: September 2002

Corticotropin‐releasing factor (CRF) is the major regulator of the hypothalamic‐pituitary‐adrenal (HPA) axis, and plays a key role in coordinating the endocrine, as well as autonomic and behavioral responses of an organism to stress. Direct CNS administration of CRF to laboratory animals produces an aggregate of effects that mimic the mammalian stress response. Impeding CRF function with CNS administration of a peptidergic CRF antagonist can block these manifestations of the stress response whether produced by exogenous CRF or occurring naturally in response to a stressor. A role for hypersecretion of CRF in the pathophysiology of depression is suggested by the finding that CNS administration of CRF mirrors many of the signs and symptoms utilized as diagnostic criteria for major depression. In addition, a large body of clinical evidence points to excess hypothalamic secretion of CRF and an accompanying HPA axis hyperactivity in patients with major depression. The recent development of selective, small molecule CRF1 receptor antagonists, which block the effects of CRF both in vitro and in vivo, suggest that these compounds may be effective in the treatment of affective and anxiety disorders. Early evidence indicates that these agents possess anxiolytic and antidepressant activity in animal behavioral models. Copyright © 2001 John Wiley & Sons, Ltd.
Novel approaches to the treatment of depression by modulating the hypothalamic – pituitary – adrenal axis
Authors: Dinan TimothyG
Published: September 2002

Many patients with major depression show evidence of over‐activation of the hypothalamic – pituitary – adrenal axis (HPA), as evidenced by hypercortisolism and adrenal hyperplasia. Such over‐activity is associated with increased corticotropin releasing factor (CRF) reactivity in the CSF and blunted release of ACTH in response to CRF infusion. Recent evidence suggests a switch from CRF to AVP regulation of the axis during depression, with depressed patients showing enhanced response to ddAVP infusion. The HPA provides multiple potential sites for antidepressant development. The use of glucocorticoid antagonists, cortisol synthesis inhibitors, CRF and AVP antagonists have been suggested. Copyright © 2001 John Wiley & Sons, Ltd.
Dose‐response effects of zaleplon as compared with triazolam (0·25 mg) and placebo in chronic primary insomnia
Authors: Drake Christopher L , Roehrs Timothy A , Mangano Richard M , Roth Thomas
Published: September 2002

The effects of two nights of treatment with the short‐acting benzodiazepine receptor agonist zaleplon, triazolam, or placebo was assessed in chronic primary insomniacs using two concurrent, multi‐center, randomized, double‐blind, Latin Square crossover studies. Study 1 (n = 47) compared zaleplon (10 and 40 mg) to triazolam (0·25 mg) and placebo. Study 2 (n = 36) compared zaleplon (20 and 60 mg) to triazolam (0·25 mg) and placebo. For each study, polysomnographically recorded sleep parameters and patient reports of sleep quality were collected during baseline and two consecutive nights during the four treatment phases in each study. All doses of zaleplon produced significant decreases in latency to persistent sleep. Although no minimally effective dose could be determined, dose‐response effects were apparent. Triazolam 0·25 mg produced a decrease in latency to persistent sleep that was comparable to that of zaleplon 10 mg. Only the triazolam dose and the 60 mg dose of zaleplon produced significant increases in total sleep time over placebo. Zaleplon 40 and 60 mg and triazolam produced decreases in the percentage of REM sleep compared to placebo. Patient reports of efficacy were consistent with objective findings. In addition, all doses of zaleplon tended to increase while triazolam decreased the percentage of stage 3/4 sleep. There was no evidence of residual daytime impairment for any of the zaleplon doses, however, triazolam administration produced significant impairment in performance on a digit copying test. A higher number of adverse events were seen with the 40 and 60 mg doses of zaleplon compared to triazolam (0·25) and placebo. At higher doses, zaleplon is more effective than triazolam at reducing latency to persistent sleep in chronic insomnia and is not associated with the decrease in slow‐wave sleep or residual impairment observed with triazolam. However, increases in total sleep time were apparent only at doses which produced concomitant increases in the number of adverse events. In contrast, triazolam (0·25 mg) produced increases in total sleep time (˜25 min) and decreases in latency to persistent sleep at a dose of 0·25 mg. Copyright © 2000 John Wiley & Sons, Ltd.
Habitual caffeine consumption and its relation to memory, attention, planning capacity and psychomotor performance across multiple age groups
Authors: Hameleers P. A. H. M , Van Boxtel M. P. J , Hogervorst E , Riedel W. J , Houx P. J , Buntinx F , Jolles J
Published: September 2002

The present study evaluated the association between habitual caffeine intake via coffee and tea and cognitive performance. This was done as part of a larger research programme into the determinants of cognitive ageing (the Maastricht Aging Study: MAAS). Possible withdrawal effects that may have explained in part the positive association between performance and intake in an earlier study were controlled for. In addition, all cognitive tests in this study were administered under strict laboratory conditions. A group of 1875 healthy adults, stratified for age (range 24 – 81 years), sex, and general ability, were screened for habitual intake of coffee and tea and took part in extensive cognitive testing. Multiple regression analysis with control for age, sex, socio‐demographic variables, and substance use showed that habitual caffeine consumption was significantly related to better long‐term memory performance and faster locomotor speed. No relationships were found between habitual caffeine consumption and short‐term memory, information processing, planning, and attention as measured with the Stroop Test. Moreover, no difference in sensitivity to caffeine intake between different age groups was found, suggesting that caffeine intake did not counteract age‐related cognitive decline. Several recommendations are made to improve the design of future studies in this field. Copyright © 2000 John Wiley & Sons, Ltd.
Fenfluramine challenge in anxious children
Authors: Sallee Floyd R , Vrindavanam Nandagopal S , Liu Hong , Sethuraman Gopalan , Sine Lauren
Published: September 2002

The study objective was to determine if serotonergic challenge with oral racemic fenfluramine would differentiate between childhood anxiety disorders in comparison to normal controls. Subjects were 24 children with anxiety diagnoses (DSM‐IIIR) by structured interview, and 14 normal controls (ages 7 – 14 years) matched for age and sex. All subjects were given a standard challenge dose of d,1‐fenfluramine (1 mg/kg) followed by serial assessments of cardiovascular, neurohormonal, and mood parameters over a five hour period. In response to fenfluramine, controls demonstrated increases in subjective anxiety and systolic blood pressure relative to anxious subjects. Fenfluramine was safely tolerated and did not induce panic symptoms in any subject. Exaggerated prolactin response to fenfluramine differentiated an obsessive – compulsive disorder (OCD) subset from both controls and other anxiety disorders. Fenfluramine challenge differentiates anxious children from healthy controls by elevated anxiety ratings and systolic blood pressure in controls. Increased prolactin response to fenfluramine discriminates children with obsessive – compulsive disorder from both healthy children and children with other anxiety diagnoses. As adults with OCD appear to demonstrate a blunted prolactin response to fenfluramine challenge, the serotonin pathways involved may differ between ‘early’ and ‘late’ onset disorder, or the serotonin substrates tapped by this challenge may change over time. Copyright © 2000 John Wiley & Sons, Ltd.
Moxonidine versus placebo as an aid in smoking cessation
Authors: Levine Louise R , Tonneson Philip , Wennike Poul , Faries Douglas
Published: September 2002

This study assessed the effects of moxonidine as an aid in smoking cessation in 166 heavily addicted smokers who were motivated to quit smoking completely. Recruitment was via advertisement. Patients were randomly allocated to receive double‐blind placebo or moxonidine (0·1 mg once or twice daily) for 6 weeks. Brief counseling was provided. An encouragement letter was sent prior to the quit date. Success was defined as not smoking any cigarettes during weeks 3 – 6, an expired carbon monoxide level of < 10 ppm, and a plasma cotinine level of < 25 ng/ml. The study failed to demonstrate a statistically significant effect for moxonidine on either nicotine withdrawal symptoms or smoking cessation. Reported side effects were not different with moxonidine than with placebo, however. Copyright © 2000 John Wiley & Sons, Ltd.
Serum trace elements in animal models and human depression: Part III. Magnesium. Relationship with copper
Authors: Zieba Andrzej , Kata Renata , Dudek Dominika , Schlegel‐zawadzka Malgorzata , Nowak Gabriel
Published: September 2002

In the present study we report the results of investigations into the serum magnesium levels in a clinical study of 19 patients with unipolar depression; 16 normal controls and in three animal models of depression: chronic severe stress (CSS), chronic mild stress (CMS) and olfactory bulbectomy (OB) in rats. There was no alteration in the values found in the rat models of depression. Unipolar depressed patients exhibit significantly lower serum magnesium levels than the appropriate controls (depression 19·1±2·2 mg/l; control 21·0 mg/l). There is no correlation between serum magnesium levels and the severity of depression. A significant positive correlation between serum magnesium/copper ratio and the severity of depression indicates a clear relationship between alterations of the homeostasis of these two ions in human depression. Copyright © 2000 John Wiley & Sons, Ltd.
Investigating mechanisms of stormflow generation by natural tracers and hydrometric data: a small catchment study in the Black Forest, Germany
Authors: Hangen E. , Lindenlaub M. , Leibundgut Ch. , von Wilpert K.
Published: September 2002

The importance and interaction of various hydrological pathways and identification of runoff source areas involved in solute transport are still under considerable debate in catchment hydrology. To reveal stormflow generating areas and flow paths, hydrometric behaviour of throughfall, soil water from various depths, runoff, and respective concentrations of the environmental tracers 18O, Si, K, SO4 and dissolved organic carbon were monitored for a 14‐week period in a steep headwater catchment in the Black Forest Mountains, Germany.

Two stormflow hydrographs were selected and, based on 18O and Si, chemically separated into three flow components. Their sources were defined using mixing diagrams. Additional information about stormflow generating mechanisms was derived from recession analyses of the basin's complete 5‐year hydrograph record. By providing insight into storage properties and residence times of outflowing reservoirs of the basin, recession analysis proved to be a valuable tool in runoff model conceptualization. Its results agreed well with hydrometric and hydrochemical data. Supported by evaluation of 30 hillslope soil profiles a coherent concept of stormflow generation could be derived: whereas in many steeply sloped basins in the temperate region soil water from hillslopes appears to have an immediate effect on the shape of the stormflow hydrograph, its role at this basin is basically restricted to the recharge of the groundwater reservoir in the near‐channel area. Storm hydrograph peaks appear to be derived from a small direct runoff component supplemented by a fast delivery of baseflow from the groundwater reservoir in the valley bottom. Copyright © 2001 John Wiley & Sons, Ltd.
The impact of peat harvesting and natural regeneration on the water balance of an abandoned cutover bog, Quebec
Authors: Van Seters Tim E. , Price Jonathan S.
Published: September 2002

Harvested sites rarely return to functional ecosystems after abandonment because drainage and peat extraction lower the water table and expose relatively decomposed peat, which is hydrologically unsuitable for Sphagnum moss re‐establishment. Some natural regeneration of Sphagnum has occurred in isolated pockets on traditionally harvested (block‐cut) sites, for reasons that are poorly understood, but are related to natural functions that regulate runoff and evaporation. This study evaluates the water balance of a naturally regenerated cutover bog and compares it with a nearby natural bog of similar size and origin, near Riviere du Loup, Quebec. Water balance results indicated that evapotranspiration was the major water loss from the harvested bog, comprising 92 and 84% of total outputs (2·9 mm day−1) during the 1997 and 1998 seasons, respectively. Despite denser tree cover at the harvested site, evapotranspiration from the natural bog was similar, although less spatially variable. At the harvested site, evaporative losses ranged from 1·9 mm day−1 on raised baulks and roads to 3·6 mm day−1 from moist surfaces with Sphagnum. Although about half of the ditches were inactive or operating at only a fraction of their original efficiency, runoff was still significant at 12 and 24% of precipitation during the 1997 and 1998 study seasons, respectively. This compares with negligible rates of runoff at the natural bog. Thus the cutover bog, although abandoned over 25 years ago, has not regained its hydrological function. This is both a cause and effect of its inability to support renewed Sphagnum regeneration. Without suitable management (e.g. blocking ditches), this site is not likely to improve for a very long time. Copyright © 2001 John Wiley & Sons, Ltd.
The cycle of instability: stress release and fissure flow as controls on gully head retreat
Authors: Collison A. J. C.
Published: September 2002

Gully head and wall retreat has commonly been attributed to fluvial scour and head collapse as a result of soil saturation, sapping or piping. The empirical evidence to substantiate these conceptual models is sparse, however, and often contradictory. This paper explores the hydrological and mechanical controls on gully head and wall stability by modelling the hydrology, stability and elastic deformation of a marl gully complex in Granada Province, south‐east Spain. The hydrological and slope‐stability simulations show that saturated conditions can be reached only where preferential fissure flow channels water from tension cracks into the base of the gully head, and that vertical or subvertical heads will be stable unless saturation is achieved. Owing to the high unsaturated strengths of marl measured in this research, failure in unsaturated conditions is possible only where the gully head wall is significantly undercut. Head retreat thus requires the formation of either a tension crack or an undercut hollow. Finite‐element stress analysis of eroding slopes reveals a build up of shear stress at the gully head base, and a second stress anomaly just upslope of the head wall. Although tension cracks on gully heads have often been attributed to slope unloading, this research provides strong evidence that the so called ‘sapping hollow’ commonly found in the gully headwall base is also a function of stress release. Although further research is needed, it seems possible that ‘pop out’ failures in river channels may be caused by the same process. The hydrological analysis shows that, once a tension crack has developed, throughflow velocity in the gully headwall will increase by an order of magnitude, promoting piping and enlargement of this weakened area. It is, therefore, possible to envisage a cycle of gully expansion in which erosion, channel incision or human action unloads the slope below a gully head, leading to stress patterns that account for the tension crack and a stress‐release hollow. The tension crack promotes faster throughflow, encouraging hollow enlargement and piping, which undercut the gully head. The tension crack permits the development of positive pore‐water pressures behind the gully head, leading either to failure or contributing to toppling. Finally the debris may be eroded by fluvial action, unloading a new section of slope and completing the cycle of gully head retreat. Copyright © 2001 John Wiley & Sons, Ltd.
Bank‐toe processes in incised channels: the role of apparent cohesion in the entrainment of failed bank materials
Authors: Wood Anna L. , Simon Andrew , Downs Peter W. , Thorne Colin R.
Published: September 2002

Numerous processes may instigate bank retreat and the consequent collection of failed cohesive materials at the bank toe. Cohesion between the failed material and the substrate can provide additional strength to resist direct fluvial entrainment. Failed, cohesive material can act as a form of natural bank‐toe protection by consuming and diverting flow energy that may otherwise be used to further scour the basal zone of incising channels.

Investigations in Goodwin Creek, Mississippi, have revealed the existence of apparent cohesion between failed, cohesive blocks and their underlying surface. The method used to assess this cohesion involved a pulley system mounted on a tripod and supporting a load cell. Mean and maximum apparent‐cohesion values of 1·08 kPa and 2·65 kPa, respectively, were measured in this way, identifying a source that bonds blocks to the underlying surface. Cohesion values and types vary spatially and temporally. Tensiometric tests beneath blocks suggest that cohesion resulting from matric suction alone may be as much as 3·5 kPa in summer and 1·8 kPa in winter.

Apparent cohesion is believed to have been sufficient to help prevent removal of the largest blocks by a peak flow of 66·4m3/s on 23 September 1997. Maximum excess shear stress required to entrain a D75 block can be augmented by as much as 97% by the presence of apparent cohesion at the block–substrate interface when compared with a condition with zero apparent cohesion at the block underside. Given these findings, it is no longer sufficient to estimate block entrainment in the basal area from block size or bed roughness alone, as in a Shields‐type approach. Copyright © 2001 John Wiley & Sons, Ltd.
A three‐component end‐member analysis of streamwater hydrochemistry in a small Japanese forested headwater catchment
Authors: Katsuyama Masanori , Ohte Nobuhito , Kobashi Sumiji
Published: September 2002

Intensive water sampling in conjunction with hydrological observations was conducted during three different rainstorms in order to understand the effects of rainfall events on the temporal variation of streamwater chemistry in a small headwater forest catchment. Concentrations of Na+ and SO42− decreased as the discharge rate increased. Hydrograph separation of the components was made using the three‐component model based on the end‐members mixing analysis (EMMA). The three end‐members were:

the groundwater in the saturated zone that prescribes the chemistry of the baseflow;

the throughfall that dilutes the streamwater;

the groundwater in the transient saturated zone prescribed, which was dependent on the groundwater level.

When the groundwater level was lower, only the two components, groundwater in the saturated zone and throughfall, affected the streamwater chemistry. When the groundwater level rose and the saturated zone spread, the groundwater in the transient saturated zone became the third component. When the groundwater in the transient saturated zone contributed to the discharge, this component became the dominant source and the streamwater chemistry was affected by the groundwater chemistry in the transient saturated zone. When this component was discharged as the saturation overland flow, the streamwater chemistry was greatly affected by this component. Copyright © 2001 John Wiley & Sons, Ltd.
Chemical and isotopic methods for confirming the roles of wadis in regional groundwater recharge in a regional arid environment: a case study in Al Ain, UAE
Authors: Tang Changyuan , Machida Isao , Shindo Shizuo , Kondoh Akihiko , Sakura Yasuo
Published: September 2002

In arid environments groundwater may represent the most important source of water for sustaining life. The timing and nature of precipitation may induce infiltration and recharge on a small scale. The Al Ain region, UAE was chosen and from 1996 to 1997 studies were conducted to illustrate spatial distribution of recharge for groundwater by using chemical and isotopic methods. According to the field survey, UAE can be hydrogeologically classified into five parts: mountain area, wadis, sand dunes, inland sabkhas and coastal sabkhas, respectively. In this report, we studied a typical wadi, Wadi Mieshiq area. Upstream of the wadi, it was found that the groundwaters were characterized by low salinity. Stable isotopes of groundwaters in the wadi were lighter than those of the stream waters in the mountain area, since stream water was affected by evaporation before it infiltrated into the ground. The isotopes of recharged water into the wadi must have isotopically light values. From the results above, groundwater along the wadi was mainly derived from not only water from the mountain area but also infiltrated water during the flood period. Wadis are an important recharge region for groundwater. Copyright © 2001 John Wiley & Sons, Ltd.
Subsurface runoff characteristics from a forest hillslope soil profile including macropores, Hitachi Ohta, Japan
Authors: Noguchi Shoji , Tsuboyama Yoshio , Sidle Roy C. , Hosoda Ikuhiro
Published: September 2002

Subsurface flow within forest hillslopes is not well understood. A soil pit containing macropores was prepared and instrumented for subsurface flow measurements at the Hitachi Ohta Experimental Watershed. The subsurface flow from the soil profile was divided into five groups: the porous (including macropores) organic‐rich soil layer; three macropore groups in the mineral soil layer; and the mineral soil matrix excluding visible macropores. The outflow from the organic‐rich soil layer coincided with rainfall and depended strongly on rainfall intensity. Such a response is related to the location of the organic‐rich layer in the uppermost portion of the soil profile. One macropore in the mineral soil was connected directly to a hydraulically active fracture in the bedrock. Therefore, the flow from this macropore group was high and delayed relative to rainfall even though the group is located in the upper left portion of the mineral soil layer. Most of the hillslope discharge occurred from the soil matrix excluding visible macropores. Preferential flow pathways in the mineral soil, as evidenced by staining tests, contributed to stormflow. The flow from two macropores just above bedrock was generally very low and responded gradually to rainfall inputs. This minor outflow was influenced by preferential flow above bedrock. Four macropores in the upper right portion of the mineral soil layer did not connect to preferential flow pathways. Therefore, outflow from this group was measured only when large rain events occurred. Soil moisture, amounts and intensities of rainfall, and bedrock topography affected heterogeneous outflow from the soil profile. The expansion and extension of macropore networks might contribute to stormflow. Results indicate that hydrometric measurements are needed to support inferences derived from end member mixing analysis and topographic‐based hydrologic models related to complex preferential flow pathways in forest catchments. Copyright © 2001 John Wiley & Sons, Ltd.