bluuebunny/crossref_metadata_2025 huggingface dataset:
Microvasculature in gingivitis and chronic periodontitis: Disruption of vascular networks with protracted inflammation
Authors: Zoellner Hans , Chapple Cheryl C. , Hunter Neil
Published: August 2002

Gingivitis occurring when bacterial plaque accumulates in the gingival crevice provides a convenient and interesting model for chronic inflammation in humans. In some patients, gingivitis progresses to the destructive lesion of periodontitis, involving the formation of periodontal pockets. The basis for pocket formation and progression is not as yet clear, although neutrophilic polymorphonuclear leukocytes (PMN) appear to play a protective role. Vascular changes appear to either facilitate or inhibit PMN function with the effect of either protecting from, or stimulating, periodontitis. Contrary to most circumstances, high endothelial cells in periodontitis are involved with PMN rather than lymphocyte emigration. Expansion of the microvasculature through increased vascular diameter and tortuosity as well as the development of high endothelial cells appears to protect from periodontitis by increasing the supply of both plasma defense factors and PMN to the tissues. Vascular changes that may oppose this and promote periodontitis are the formation of perivascular hyaline material and accumulation of basement membrane rests. The inadequate tissue turnover that accumulation of these vascular products represents can be argued as a vascular response to a chronic inflammation that has failed to eliminate the irritant. It is suggested that these vascular changes may account for the highly localized and burst‐like pattern of pocket formation in periodontitis. Finally, it is possible that the recent observation that periodontitis is an independent risk factor for systemic vascular disease may reflect stimulation of acute phase protein synthesis by cytokines released by periodontal high endothelial cells. Microsc. Res. Tech. 56:15–31, 2002. © 2002 Wiley‐Liss, Inc.
Localization of metals in cells of pterygote insects
Authors: Ballan‐Dufrançais Christiane
Published: August 2002

Insects maintain the equilibrium of their internal milieu by diffusion mechanisms, but more frequently by a substantial storage of metals in the cells of numerous organs: digestive tract, Malpighian tubules, fat body, integument, and genital organs. This storage implies the precipitation, of numerous cations (Ca, Mg, K, Mn, Fe, Zn, Cu) in a structure called the spherocrystal, which originates from the endoplasmic reticulum–Golgi complex: elements precipitate on a glycosaminoglycan nucleus in thin peripheral strata. Some spherocrystals contain exclusively mineral compounds, frequently phosphates, whereas others may contain organic compounds such as urates. In some species mineralized lysosomes store Ca, Fe, Zn, and Cu. When fed additional metals found in the environment, insects such as cockroach and ant are able to stay alive and to trap the metals (Cd or Pb, for example) in the peripheral strata of spherocrystals; the cytoplasm is not altered. It seems that these insects are able to resist exposures to high levels of toxic metals. The lysosomes are able to retain toxic heavy metals (Cd or Hg, for example) within metallothionein‐like proteins. Microsc. Res. Tech. 56:403–420, 2002. © 2002 Wiley‐Liss, Inc.
Sexual dimorphism in the neuronal circuits of the quail preoptic and limbic regions
Authors: Panzica Giancarlo , Viglietti‐Panzica Carla , Balthazart Jacques
Published: August 2002

A sexually dimorphic nucleus is located in the preoptic area of Japanese quail and plays a key role in the activation of male copulatory behavior. The medial preoptic nucleus (POM) is significantly larger in adult male than in adult female quail. Its volume is steroid‐sensitive in adulthood and consequently decreases after castration but is restored to normal levels by a treatment with exogenous testosterone. This volumetric difference appears to result only from a sex difference in the adult hormonal milieu and is not affected by embryonic treatments that permanently modify sexual behavior (no organizational effects). In contrast, some cytoarchitectonic features of the POM such as the size of neurons in the dorso‐lateral part of nucleus appear to be irreversibly affected by embryonic steroids. The POM is characterized by the presence of a wide variety of neurotransmitters, neuropeptides, and receptors and can be specifically identified by the presence of a dense cluster of aromatase‐immunoreactive cells, by a high density of neurotensin‐immunoreactive cells and fibers and by a dense vasotocinergic innervation. Some of these neurochemical markers of the dimorphic nucleus are themselves modulated by steroids. Many of these neurochemical changes appear to play a causal role in the control of male sexual behavior. The quail POM thus represents an excellent model for the analysis of steroid‐induced brain plasticity in a behaviorally relevant context. Microsc. Res. Tech. 54:364–374, 2001. © 2001 Wiley‐Liss, Inc.
Phylogeny of natural cytotoxicity: Cytotoxic activity of coelomocytes of the purple sea urchin, Arbacia punctulata
Authors: Lin Wenyu , Zhang Haiyan , Beck Gregory
Published: August 2002

Coelomocyte‐mediated nonspecific cell cytotoxic activity against human and murine target cells by the purple sea urchin Arbacia punctulata was investigated in vitro. Cytotoxic activity toward target cells was shown to be mediated by different coelomocyte populations isolated by discontinuous density gradient centrifugation. The population of phagocytic amebocytes showed the strongest cytotoxic activity and the highest binding to human NK markers by cytometry analysis. Our immunophenotypic studies showed that A. punctulata phagocytic amebocytes are CD14+, CD56+, CD158b+, CD3–, CD4–, CD8–, and CD16–. The cytotoxic activity was independent of experimental incubation temperatures, required viable effector cells, and required cell‐cell contact between the effector and target cells. Sodium azide significantly decreased coelomocyte cytotoxicity, indicating that cytotoxicity is metabolically dependent, and EDTA reduction of cytotoxic activity is consistent with the involvement of divalent cations in the cytotoxic process. These data describe a population of sea urchin coelomocytes (the phagocytic amebocyte) that are CD14+, CD56+, and CD158b+, with cytotoxic activities. J. Exp. Zool. 290:741–750, 2001. © 2001 Wiley‐Liss, Inc.
Landau's inequalities for tournament scores and a short proof of a theorem on transitive sub‐tournaments
Authors: Brualdi Richard A. , Shen Jian
Published: August 2002

Ao and Hanson, and Guiduli, Gyárfás, Thomassé and Weidl independently, proved the following result: For any tournament score sequence S = (s1, s2, … ,sn) with s1≤s2 ≤ … ≤ sn, there exists a tournament T on vertex set {1,2, …, n} such that the score of each vertex i is si and the sub‐tournaments of T on both the even and the odd indexed vertices are transitive in the given order; that is, i dominates j whenever i > j and i ≡ j (mod 2). In this note, we give a much shorter proof of the result. In the course of doing so, we show that the score sequence of a tournament satisfies a set of inequalities which are individually stronger than the well‐known set of inequalities of Landau, but collectively the two sets of inequalities are equivalent. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 244–254, 2001
Utopianism in psychology: The case of Wilhelm Reich
Authors: Pietikainen Petteri
Published: August 2002

This article examines utopian elements in Wilhelm Reich's writings in his American phase (1939–1957) in order to illustrate utopian sources of dynamic psychology. Although there are scholars who have used the term “psychological utopia” and applied it to individual thinkers (Reich, Marcuse, Fromm) and to specific psychological disciplines (psychoanalysis, behaviorism, cognitive psychology), the term itself has remained elusive and vague. Furthermore, there have been few attempts to systematically examine utopian elements in twentieth‐century psychology in general and the basic assumptions of psychological utopianism in particular. While pointing out that Reich's orgonomic theories have no scientific merit, this article argues for the relevancy of his ideas for understanding the nature of utopianism in dynamic psychology. © 2002 Wiley Periodicals, Inc.
Enterprise across the digital divide: information systems and rural microenterprise in Botswana
Authors: Duncombe Richard , Heeks Richard
Published: August 2002

This paper focuses on the role of information and information‐handling technologies within the many rural microenterprises that currently lack access to ICTs. On the basis of field research in Botswana, it finds that poor rural entrepreneurs rely heavily on informal, social and local information systems. While highly appropriate in many ways, these systems can also be constrained and insular. Priorities for breaking this insularity will be greater access to shared telephone services. ICTs may play a supplementary role. They will need to be based in intermediary organizations that can provide complementary inputs of finance, skills, knowledge and other resources. Copyright © 2002 John Wiley & Sons, Ltd.
Reproducibility of left ventricular mass measurement using a half‐Fourier black‐blood single‐shot fast spin‐echo sequence within a single breath hold: Comparison with a conventional multiple breath‐hold segmented gradient echo technique in patients
Authors: Vignaux Olivier , Duboc Denis , Coste Joel , Argaud Christophe , Carlier Pierre , Le Roux Patrick , Weber Simon , Legmann Paul
Published: August 2002

Purpose

To compare the reproducibility of left ventricular (LV) mass measurements using a black‐blood half‐Fourier single‐shot fast spin‐echo (SSFSE) and a segmented gradient echo magnetic resonance (MR) pulse sequence.

Material and Methods

Breath‐hold SSFSE and segmented gradient echo cardiac MR examinations were performed twice in 32 patients and manual detection of the LV endocardium and epicardium was applied by two blinded reviewers. The SSFSE pulse sequence allowed whole‐heart coverage in a single breath hold, while multiple breath holds were required using the segmented gradient echo sequence. Spatial presaturation slabs were used with the SSFSE pulse sequence to reduce the field of view (FOV) and thereby achieve higher spatial resolution.

Results

Intraclass correlation coefficients were higher with the SSFSE pulse sequence than with the segmented gradient echo pulse sequence: intraobserver reproducibility reached 0.999 vs. 0.991; interobserver reproducibility: 0.997 vs. 0.981; and interstudy reproducibility: 0.998 vs. 0.936. These higher levels of reproducibility were confirmed on Bland and Altman plots.

Conclusion

LV mass measurements can be assessed more reproducibly with the single breath‐hold SSFSE technique than with the standard multiple breath‐hold segmented gradient echo method. J. Magn. Reson. Imaging 2002;15:654–660. © 2002 Wiley‐Liss, Inc.
Measurement of vessel wall strain using cine phase contrast MRI
Authors: Wedding Kristin L. , Draney Mary T. , Herfkens Robert J. , Zarins Christopher K. , Taylor Charles A. , Pelc Norbert J.
Published: August 2002

Purpose

To determine the feasibility of using magnetic resonance imaging (MRI) to non‐invasively measure strain in the aortic wall.

Materials and Methods

Cine phase contrast MRI was used to measure the velocity of the aortic wall and calculate changes in circumferential strain over the cardiac cycle. A deformable vessel phantom was used for initial testing and in vitro validation. Ultrasonic sonomicrometer crystals were attached to the vessel wall and used as a gold standard.

Results

In the in vitro validation, MRI‐calculated wall displacements were within 0.02 mm of the sonomicrometer measurements when maximal displacement was 0.28 mm. The measured maximum strain in vitro was 0.02. The in vivo results were on the same order as prior results using ultrasound echo‐tracking.

Conclusion

Results of in vivo studies and measurement of cyclic strain in human thoracic and abdominal aortas demonstrate the feasibility of the technique.J. Magn. Reson. Imaging 2002;15:418–428. © 2002 Wiley‐Liss, Inc.
TrueFISP: Assessment of accuracy for measurement of left ventricular mass in an animal model
Authors: Fieno David S. , Jaffe Wyatt C. , Simonetti Orlando P. , Judd Robert M. , Finn J. Paul
Published: August 2002

Purpose

To test the accuracy of a high performance true fast imaging with steady‐state precession (TrueFISP) pulse sequence for the assessment of left ventricular (LV) mass in a large animal model on 1.5‐T scanners.

Materials and Methods

We imaged dogs (N = 10) on a clinical 1.5‐T clinical scanner using electrocardiogram (ECG)‐gated TrueFISP. In all animals, contiguous segmented k‐space cine images were acquired from base to apex (in‐plane resolution 1 × 1 mm2, slice thickness 5 mm, TR = 4.8 msec, TE = 1.6 msec) during repeated breath‐holds. In nine of the 10 animals, single‐shot images gated to end‐diastole were also acquired from base to apex in a single breath‐hold (in‐plane resolution 1 × 1 mm2, slice thickness 5 mm, TR = 3.2 msec, TE = 1.6 msec). After imaging, animals were killed, the left ventricle was isolated, and the true mass of the left ventricle (free wall and septum) was determined. Independently, two observers blinded to the post‐mortem results computed LV masses based on analysis of the magnetic resonance (MR) images.

Results

Comparison of the computed LV mass using TrueFISP to the actual mass showed excellent agreement. Cine‐systole was the most accurate technique (mass = 98.6% ± 4.5% actual, bias = 1.2 ± 3.4 g) followed by cine‐diastole (mass = 97.9% ± 5.3% actual, bias = 1.8 ± 4.1 g) and single shot (mass = 94.7% ± 7.9% actual, bias = 4.2 ± 6.3 g). Inter‐ and intra‐observer variabilities were low (5.8% ± 7.1% and 0.4% ± 4.8%, respectively).

Conclusion

We conclude that TrueFISP imaging is an accurate, rapid method to determine ventricular mass. In single‐shot mode, TrueFISP requires only one breath‐hold to estimate the mass of the heart within 6% of the actual value, whereas the segmented k‐space implementation measured LV mass to within 3% of the true value. J. Magn. Reson. Imaging 2002;15:526–531. © 2002 Wiley‐Liss, Inc.
Short echo time MR spectroscopic imaging of the lung parenchyma
Authors: Gold Garry E. , Pauly John M. , Leung Ann N. , Block Walter F. , Meyer Craig H. , Sze Raymond , Macovski Albert , Stark Paul
Published: August 2002

Purpose

To perform short echo time MR spectroscopic imaging of the lung parenchyma on normal volunteers.

Materials and Methods

A short echo time projection‐reconstruction spectroscopic imaging sequence was implemented on a commercial 1.5T whole body MRI scanner. Images and spectra of the lung parenchyma were obtained from five normal volunteers. Breath‐held spectroscopic imaging was also performed.

Results

Spectroscopic imaging of short‐T2* species allows visualization of different anatomic structures based upon their frequency shifts. A characteristic peak from the parenchyma was seen at three ppm from water frequency.

Conclusion

Short echo time MR spectroscopic imaging of the lung parenchyma was demonstrated in normal volunteers. This method may improve proton imaging of the lungs and add specificity to the diagnosis of pulmonary disease. J. Magn. Reson. Imaging 2002;15:679–684. © 2002 Wiley‐Liss, Inc.
A comparison of conventional spin‐echo and fast spin‐echo in the detection of multiple sclerosis
Authors: Patola Wayne B. , Coulter Bruce A. , Chipperfield Patricia M. , Lingawi Sattam S.
Published: August 2002

Fast spin‐echo (FSE) pulse sequences enable T2‐weighted imaging in a fraction of the time required for T2‐weighted conventional spin‐echo (CSE) imaging. Due to concerns that the altered contrast characteristics of FSE may interfere with the visualization of multiple sclerosis (MS) lesions, the sensitivity of T2‐weighted FSE sequences was compared to comparably weighted CSE sequences in the imaging of the brain in 100 patients with clinically suspected MS. The proton‐density FSE sequence revealed more MS lesions than its CSE counterpart, while the T2‐weighted CSE sequences were found to be more sensitive than the T2‐weighted FSE sequence. Contrast‐to‐noise ratios and signal‐to‐noise ratios compared favorably between sequences. Overall, there was little difference in the specificity between FSE and CSE in the diagnosis of MS. The higher sensitivity and the reduction in time attainable through the use of FSE warrants its replacement of CSE when imaging the brain in patients with clinically suspected MS. J. Magn. Reson. Imaging 2001;13:657–667. © 2001 Wiley‐Liss, Inc.
Visualization of flow patterns distal to aortic valve prostheses in humans using a fast approach for cine 3D velocity mapping
Authors: Kozerke Sebastian , Hasenkam J. Michael , Pedersen Erik M. , Boesiger Peter
Published: August 2002

The fluid dynamic performance of mechanical heart valves differs from normal valves and thus is considered related to late clinical complications in patients. Since flow patterns evolving around heart valves are complex in space and time, flow visualization based on time‐resolved 3D velocity data might add important information regarding the performance of specific valve designs in vivo. However, previous cine 3D techniques for three‐directional phase‐contrast velocity mapping suffer from long scan duration and therefore might hamper assessment in patients. A hybrid 3D phase‐contrast sequence combining segmented k‐space acquisition with short EPI readout trains is presented with its validation in vitro. The technique was applied to study flow patterns downstream from a bileaflet aortic prosthesis in six patients. Navigator echoes were incorporated for respiratory motion compensation. Before flow visualization, spurious phase errors due to concomitant gradient fields and eddy currents were corrected. Flow visualization was based on particle paths and animated velocity vector plots. Dedicated algorithms for particle path integration were implemented to account for the considerable motion of the ascending aorta during the cardiac cycle. A distinct flow pattern reflecting the valve design was observed closest to the valve during early flow acceleration. Reverse flow occurred adjacent to high velocity jets and above the hinge housings. Later in systole, flow became confined to the central vessel area and reverse flow along the inner aortic curvature developed. Further downstream from the valve, flow patterns varied considerably among patients, indicating the impact of varying aortic anatomy in vivo. It is concluded that MR velocity mapping is a potential tool for studying 3D flow patterns evolving around heart valve prostheses in humans. J. Magn. Reson. Imaging 2001;13:690–698. © 2001 Wiley‐Liss, Inc.
Combined MR imaging and CFD simulation of flow in the human descending aorta
Authors: Wood Nigel B. , Weston Simon J. , Kilner Philip J. , Gosman A. David , Firmin David N.
Published: August 2002

A combined MR and computational fluid dynamics (CFD) study is made of flow in the upper descending thoracic aorta. The aim was to investigate further the potential of CFD simulations linked to in vivo MRI scans. The three‐dimensional (3D) geometrical images of the aorta and the 3D time‐resolved velocity images at the entry to the domain studied were used as boundary conditions for the CFD simulations of the flow. Despite some measurement uncertainties, comparisons between simulated and measured flow structures at the exit from the domain demonstrated encouraging levels of agreement. Moreover, the CFD simulation allowed the flow structure throughout the domain to be examined in more detail, in particular the flow separation region in the distal aortic arch and its influence on the downstream flow during late systole. Additional information such as relative pressure and wall shear stress, which could not be measured via MRI, were also extracted from the simulation. The results have encouraged further applications of the methods described. J. Magn. Reson. Imaging 2001;13:699–713. © 2001 Wiley‐Liss, Inc.
Successful treatment of recurrent vulvar intraepithelial neoplasia resistant to interferon and isotretinoin with cidofovir
Authors: Koonsaeng Suphannee , Verschraegen Claire , Freedman Ralph , Bossens Michel , Kudelka Andrzej , Kavanagh John , Sittisomwong Tul , DeClercq Erik , Snoeck Robert
Published: August 2002

Vulvar intraepithelial neoplasias are difficult to eradicate completely without extensive surgical intervention. Cidofovir, a deoxycytidine monophosphate analog, may have a therapeutic role in this disease. A 43‐year‐old woman with a 20‐year history of genital warts presented with extensive vulvar intraepithelial neoplasia III, and refused surgical resection. Topical cidofovir 1% in Beeler base completely eradicated the lesion. Successive treatment applications, however, were necessary. Cidofovir is a promising topical antiviral compound for HPV induced vulvar intraepithelial neoplasia. J. Med. Virol. 64:195–198, 2001. © 2001 Wiley‐Liss, Inc.
Screening for possible failure of herpes simplex virus PCR in cerebrospinal fluid for the diagnosis of herpes simplex encephalitis
Authors: Puchhammer‐Stöckl Elisabeth , Presterl Elisabeth , Croÿ Cornelia , Aberle Stefan , Popow‐Kraupp Therese , Kundi Michael , Hofmann Hanns , Wenninger Ursula , Gödl Irene
Published: August 2002

The objectives of this study were to evaluate the reliability of herpes simplex virus (HSV) PCR testing in cerebrospinal fluid (CSF) for the detection of herpes simplex encephalitis. This was done by examining retrospectively the clinical follow‐up of a large group of patients tested routinely by HSV‐PCR. In addition, an attempt was made to assess the incidence of herpes simplex encephalitis in a central European population. CSF samples from 1,427 patients from all Vienna hospitals were submitted for HSV‐PCR testing during a period of 4 years and 8 months. Herpes simplex encephalitis was detected by PCR in 12 cases and by serological methods in one additional patient. Retrospective analysis of the course of disease, which was possible in 799 PCR‐negative patients, led to the identification of three additional cases in which herpes simplex encephalitis appears to have occurred despite negative PCR results. Failure of the PCR in these patients is most likely due to the time of obtaining CSF during the course of disease. A high specificity of the assay was demonstrated by the lack of false positive results in any of the 708 cases in which other causes for the neurological symptoms had been identified in the follow‐up. The incidence of herpes simplex encephalitis in the population of Vienna was between 1 case/469,000–577,000 individuals/year. The highest annual incidence was detected in the age group between 3 months and 3 years, which, however, could not be confirmed statistically. J. Med. Virol. 64:531–536, 2001. © 2001 Wiley‐Liss, Inc.
Detection and genotyping of human papillomavirus DNA by SPF10 and MY09/11 primers in cervical cells taken from women attending a colposcopy clinic
Authors: Perrons Chris , Kleter Bernhard , Jelley Rosanne , Jalal Hamid , Quint Wim , Tedder Richard
Published: August 2002

Human papillomavirus (HPV) is the main etiological agent of cervical cancer. There is a large number of HPV genotypes and therefore a need to distinguish the high risk HPV genotypes associated with invasive cancer from the low risk. Because persistence of high risk HPV infection is necessary for progression of a pre‐invasive cervical change one needs to identify the individual genotype to see if it persists. PCR amplification of HPV DNA is described using two consensus primer systems from cervical cells. Amplified HPV DNA was genotyped using a reverse hybridization line probe assay (LiPA). HPV DNA was amplified from 42% of samples by MY09/11 and from 80% by SPF10. In 42 samples HPV DNA was detected by both primer sets and in 38 samples only the SPF10 primers detected HPV DNA. The LiPA detected 21 different HPV genotypes (13 high risk) in this cohort of samples. Forty‐three percent contained a single HPV genotype and 24% contained multiple infections (2–5 genotypes). Overall, high risk HPV genotypes were detected in 48% of the cervical samples, the most frequent types were 16, 18, 31, and 51. The proportion of high risk HPV genotypes increased with more severe cytological abnormalities. This study demonstrates that the SPF10 primer set is more sensitive than the MY09/11 primer set and that genotyping by LiPA tells us if the HPV infection is caused by a high risk type and if the infection is mixed. Additionally LiPA provides information about the individual genotype when looking for persistence of infection. HPV DNA detection and genotyping is therefore a useful tool in the colposcopy clinic, used in conjunction with cytology. J. Med. Virol. 67:246–252, 2002. © 2002 Wiley‐Liss, Inc.
Optical, electrical and thermal analysis for GaN semiconductor lasers
Authors: Hatakoshi Gen‐ichi , Onomura Masaaki , Ishikawa Masayuki
Published: August 2002

Device characteristics of GaN‐based semiconductor lasers have been analysed by numerical calculation. Anti‐guide‐like behaviour of the waveguide mode appears in InGaN laser structures where the cladding layers have insufficient thickness. Such phenomena are peculiar to laser structures with GaN material systems. The layer structure should be designed so as to suppress the anti‐guide mode. Carrier overflow is also a significant problem for GaN lasers. A high acceptor concentration for the p‐type cladding layer and the reduction of the active layer volume have a large effect on the reduction of such carrier overflow. In regard to the temperature characteristics, one of the restricting factors is the use of sapphire substrates which have relatively high thermal resistivity. The maximum operation temperature has been calculated based on the analysis for the thermal resistance of the device. It was shown that reduction in the stripe width as well as reduction in threshold current density and operation voltage is very important for improving the temperature characteristics of GaN semiconductor lasers. Copyright © 2001 John Wiley & Sons, Ltd.
Aminopeptidase N mediates the utilization of the GSH precursor CysGly by cultured neurons
Authors: Dringen Ralf , Gutterer Jan Mirko , Gros Claude , Hirrlinger Johannes
Published: August 2002

Neurons in culture rely on the supply of exogenous cysteine for their glutathione synthesis. After application of cysteine to neuron‐rich primary cultures, the glutathione content was doubled after a 4‐hr incubation. The dipeptide cysteinylglycine (CysGly) was able to substitute for cysteine as exogenous glutathione precursor. In kidneys, the ectopeptidase aminopeptidase N (ApN) has been reported to hydrolyze CysGly. Expression of mRNA of ApN in rat brain and cultured rat neurons was demonstrated by reverse transcriptase polymerase chain reaction and sequencing of the cDNA fragment obtained. In addition, the presence of ApN protein in cultured neurons was demonstrated by its immunocytochemical localization. In the presence of an activity‐inhibiting antiserum against ApN the utilization of CysGly as neuronal glutathione precursor was completely prevented, whereas that of cysteine plus glycine was not affected. The data presented demonstrates that cultured rat neurons express ApN and that this ectopeptidase participates in the utilization of CysGly as precursor for neuronal glutathione. © 2001 Wiley‐Liss, Inc.
Astrocytic and microglia cells reactivity induced by neonatal administration of glutamate in cerebral cortex of the adult rats
Authors: Martínez‐Contreras A. , Huerta M. , Lopez‐Perez S. , García‐Estrada J. , Luquín S. , Beas Zárate C.
Published: August 2002

Recent studies confirm that astrocytes and neurons are associated with the synaptic transmission, particularly with the regulation of glutamate (Glu) levels. Therefore, they have the capacity to modulate the Glu released from neurons into the extracellular space. It has also been demonstrated an intense astrocytic and microglia response to physical or chemical lesions of the central nervous system. However, the persistence of the response of the glial cells in adult brain had not been previously reported, after the excitotoxic damage caused by neonatal dosage of monosodium glutamate (MSG) to newborn rats. In this study, 4 mg/g body weight of MSG were administered to newborn rats at 1, 3, 5, and 7 days after birth, at the age of 60 days the astrocytes and the microglia cells were analyzed with immunohistochemical methods in the fronto‐parietal cortex. Double labeling to glial fibrillary acidic protein (GFAP) and BrdU, or isolectin‐B4 and BrdU identified astrocytes or microglia cells that proliferated; immunoblotting and immunoreactivity to vimentin served for assess immaturity of astrocytic intermediate filaments. The results show that the neonatal administration of MSG‐induced reactivity of astrocytes and microglia cells in the fronto‐parietal cortex, which was characterized by hyperplasia; an increased number of astrocytes and microglia cells that proliferated, hypertrophy; increased complexity of the cytoplasm extension of both glial cells and expression of RNAm to vimentin, with the presence of vimentin‐positive astrocytes. This glial response to neuroexcitotoxic stimulus of Glu on the immature brain, which persisted to adulthood, suggests that the neurotransmitter Glu could trigger neuro‐degenerative illnesses. © 2002 Wiley‐Liss, Inc.
Fibroblast growth factor‐2 converts PACAP growth action on embryonic hindbrain precursors from stimulation to inhibition
Authors: Lelievre Vincent , Hu Zhongting , Byun Ji‐Yun , Ioffe Yevgeniya , Waschek James A.
Published: August 2002

Pituitary adenylyl cyclase activating peptide (PACAP) has been shown either to stimulate or to inhibit neural cell proliferation depending on the origin of the cell population. We show here that, depending on the presence or absence of fibroblast growth factor‐2 (FGF‐2, also called basic FGF), PACAP may either stimulate or inhibit DNA synthesis in neural precursors isolated from embryonic day 10.5 mouse hindbrain. In the absence of FGF‐2, PACAP stimulated 3H‐thymidine incorporation in a dose‐dependent manner. This stimulatory action was unaffected by antagonists of protein kinases A and C but was abolished in the presence of the MEK1/2 antagonist PD98059. In contrast, when FGF‐2 was present, PACAP inhibited DNA synthesis. This inhibitory action was insensitive to PD98059 but was fully blocked by the protein kinase A (PKA) inhibitor H89. The differential blockades by MEK1/2 and PKA inhibitors indicate that the FGF‐2‐induced switch in PACAP action on DNA synthesis was accomplished by a change in PACAP signaling pathways. We hypothesize that the actions of PACAP in the specific parts of the developing nervous system are determined in part by the presence or absence of FGFs and other growth factors. © 2002 Wiley‐Liss, Inc.
Efficacy of methylprednisolone therapy for the injured rat spinal cord
Authors: Rabchevsky Alexander G. , Fugaccia Isabella , Sullivan Patrick G. , Blades Deborah A. , Scheff Stephen W.
Published: August 2002

Currently the synthetic glucocorticosteroid methylprednisolone sodium succinate (MPSS) is the standard therapy after acute spinal cord injury (SCI) in humans based on reported neurological improvements. The mechanisms for its beneficial actions are not entirely clear, but experimental evidence suggests MPSS affords some degree of neuroprotection. As many studies with rat models of SCI have been unable to demonstrate improved behavioral outcome or tissue sparing after MPSS treatment, we chose to stereologically assess whether it alters lesion volume and tissue sparing over time, as well as long‐term behavioral recovery. Adult rats subjected to contusion SCI with the NYU impactor were administered either MPSS or saline for 24 hr beginning 5 min post injury. Over time the lesion dimensions were extremely dynamic, such that by 6 weeks post injury the volumes were reduced to a third of those seen after the first week. MPSS marginally reduced lesion volumes across time vs. controls, but the amount of spared gray and white matter remained unaltered between the two groups. Behavioral results further showed that MPSS failed to improve recovery of hind‐limb function. These findings add to the emerging scrutiny of MPSS as the standard therapy for acute SCI, as well as indicate the existence of a therapeutic window for tissue sparing restricted to the first several days after this type of SCI in rats. Equally important, our results caution the use of lesion volume dimensions or percent tissue sparing at the epicenter as indicators of therapeutic efficacy because neither reflects the actual amount of tissue sparing. © 2002 Wiley‐Liss, Inc.
BDNF dependence in neuroblastoma
Authors: Feng Xuan , Jiang Hong , Baik John C. , Edgar Cory , Eide Fernette F.
Published: August 2002

Neuroblastomas are heterogeneous tumors arising from sympathetic precursors in the neural crest. Growth factor stimulation of neuroblastomas promote diverse biological responses (mitogenesis, differentiation, cell death) depending on the particular tumor studied. Here we show that brief treatment with retinoic acid (RA) rendered the human neuroblastoma lines SY5Y, NGP, SMS‐KCNR, and SK‐N‐SH dependent on brain‐derived neurotrophic factor (BDNF) for survival. The BDNF‐ and trkB‐expressing line SMS‐KCN was dependent on an autocrine BDNF/trkB survival without exposure to RA. We conclude that the BDNF/trkB pathway plays an important role in neuroblastoma survival and speculate on a possible role in tumor pathogenesis. J. Neurosci. Res. 64:355–363, 2001. © 2001 Wiley‐Liss, Inc.
A theoretical and empirical extension to the transformational leadership construct
Authors: Goodwin Vicki L. , Wofford J. C. , Whittington J. Lee
Published: August 2002

The contingent rewards subscale of the Multifactor Leadership Questionnaire (MLQ) was examined in an attempt to theoretically explain recent empirical results linking contingent rewards to transformational rather than transactional leadership. In Study 1, we supported the proposal that the items in the contingent rewards subscale represented two separate factors, an explicit and an implicit psychological contract. In addition, the implicit factor loaded with other transformational subscales and the explicit factor loaded with other transactional subscales. We confirmed these results in Study 2, and supported other hypotheses from transformational leadership theory using the contingent rewards revision. Implications for the transformational leadership construct are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
A multi‐rater assessment of organizational commitment: are self‐report measures biased?
Authors: Goffin Richard D. , Gellatly Ian R.
Published: August 2002

Most investigations of organizational commitment have been conducted using self‐report measures, however, the veracity of self‐reports is often questioned. In a sample of 79 public‐sector administrative staff, we assessed two types of organizational commitment (affective and continuance) from the perspective of three different sources of raters (self, peer, and supervisor) to test three explanations of the factors influencing self‐report measures (observational opportunities, simple defensiveness, and moderated defensiveness). The pattern of correlations among the measures, analysed using the composite direct product multitrait–multirater approach, suggested that self‐report commitment measures are affected mainly by observations or experiences of the self‐reporter rather than by systematic bias related to defensive responding. This increases our confidence that scores from self‐report measures of affective and continuance commitment are veridical. Further, self‐ and peer‐based measures of commitment were largely redundant in the prediction of a job‐performance criterion whereas supervisory measures added unique predictive variance. Implications are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Have streamflow droughts in Europe become more severe or frequent?
Authors: Hisdal Hege , Stahl Kerstin , Tallaksen Lena M. , Demuth Siegfried
Published: August 2002

Changes in the magnitude and frequency of droughts will have extensive impacts on water management, agriculture and aquatic ecosystems. With the projected global temperature increase, scientists generally agree that the global hydrological cycle will intensify and suggest that extremes will become or have already become more common. In this study, a pan‐European dataset of more than 600 daily streamflow records from the European Water Archive (EWA) was analysed to detect spatial and temporal changes in streamflow droughts. Four different time periods were analysed: 1962–1990, 1962–1995, 1930–1995 and 1911–1995. The focus was on hydrological droughts derived by applying the threshold level approach, which defines droughts as periods during which the streamflow is below a certain threshold. The Annual Maximum Series (AMS) of drought severity and the frequency of droughts in Partial Duration Series (PDS) were studied. Despite several reports on recent droughts in Europe, the non‐parametric Mann–Kendall test and a resampling test for trend detection showed that it is not possible to conclude that drought conditions in general have become more severe or frequent. The period analysed and the selection of stations strongly influenced the regional pattern. For most stations, no significant changes were detected. However, distinct regional differences were found. Within the period 1962–1990 examples of increasing drought deficit volumes were found in Spain, the eastern part of Eastern Europe and in large parts of the UK, whereas decreasing drought deficit volumes occurred in large parts of Central Europe and in the western part of Eastern Europe. Trends in drought deficit volumes or durations could, to a large extent, be explained through changes in precipitation or artificial influences in the catchment. Changes in the number of drought events per year were determined by the combined effect of climate and catchment characteristics such as storage capacity. The importance of the time period chosen for trend analysis is illustrated using two very long time series. Copyright © 2001 Royal Meteorological Society
Automated database of mesocyclones from the HIRLAM(INM)‐0.5° analyses in the western Mediterranean
Authors: Picornell M.A. , Jansà A. , Genovés A. , Campins J.
Published: August 2002

An automated procedure has been developed to detect and select mesoscale cyclones and describe their tracks by means of the numerical analysis model, the HIRLAM(INM)‐0.5°, operational at the Spanish Institute of Meteorology (INM). This procedure gives us a description of features of these cyclones, such as their frequency of appearance, geographical distribution and horizontal dimensions, and it also enables us to study the movement and the evolution of the cyclone centres. This procedure was developed in order to obtain an automated database of Mediterranean cyclones. To check the performance of this method, the distribution of cyclones was compared with the distribution obtained from a manual catalogue of mesoscale cyclones, and selected cases were studied using both methods. Some results obtained for the western Mediterranean are presented. A large number of cyclones are detected and most of them are located in specific zones, such as the Gulf of Genoa, south of the Pyrenees, south of the Iberian Peninsula and the Alboran Sea. The cyclones follow preferred tracks, which are different depending on the season. Copyright © 2001 Royal Meteorological Society
The role of eastern North Pacific tropical storms in the rainfall climatology of western Mexico
Authors: Englehart Phil J. , Douglas Arthur V.
Published: August 2002

This paper explores the role that tropical storms (TS) of the eastern North Pacific play in the rainfall climatology of western Mexico. It uses an 18‐station rainfall grid, along with a data base of storm tracks (1949–1997). TS rainfall is defined by a distance threshold, so that for each station in the grid, daily rainfall recorded when a TS is located within 550 km of the station is considered as TS‐derived; rainfall recorded in the absence of a TS or when a storm is beyond 550 km from a station is by default ‘non‐TS’ rainfall. A variety of statistics are presented to demonstrate the static associations that exist between TS activity and regional rainfall patterns. In sum, they clearly suggest that improved seasonal forecasts of TS activity in the eastern North Pacific will be critical to advancing seasonal climate prediction for Mexico. This study also addresses the interannual variability in TS and non‐TS rainfall. Principal component analysis is used to define the region's primary modes of rainfall variation. Considering the temporal behaviour of the rainfall modes, analyses reveal no statistically significant trends in TS rainfall. In contrast, non‐TS rainfall modes exhibit significant trends. This study provides support for the idea that these trends are partly tied to long‐period fluctuations in the ocean–atmosphere system. The results also indicate that while TS rainfall is not subject to trend behaviour, its year‐to‐year fluctuations, apparently, are linked to large‐scale processes like El Niño–Southern Oscillation (ENSO) and the state of North Pacific sea‐surface temperatures (SSTs). Copyright © 2001 Royal Meteorological Society
Trends in New Zealand daily temperature and rainfall extremes
Authors: Salinger M.J. , Griffiths G.M.
Published: August 2002

Trends in daily temperature and rainfall indices are described for New Zealand. Two periods were examined: 1951–1998, to describe significant trends in temperature and rainfall parameters; and 1930–1998, to ascertain the effects of two main circulation changes that have occurred in the New Zealand region around 1950 and 1976.

Indices examined included frequencies of daily maximum and minimum temperatures, above and below specified percentile levels and at those levels, as well as frequencies of these above and below fixed temperature thresholds. Extreme daily rainfall intensity and frequency above the 95th percentile and the length of consecutive dry day sequences were the rainfall indices selected.

There were no significant trends in maximum temperature extremes (‘hot days’) but a significant increase in minimum temperatures was associated with decreases in the frequency of extreme ‘cold nights’ over the 48‐year period. There was a non‐significant tendency for an increase in the frequency of maximum temperature extremes in the north and northeast of New Zealand. A decline occurred in frequency of the minimum temperature 5th percentile (‘cold nights’) of 10–20 days a year in many locations. Trends in rainfall indices show a zonal pattern of response, with the frequency of 1‐day 95th percentile extremes decreasing in the north and east, and increasing in the west over the 1951–1996 period.

Changes in the frequency of threshold temperatures above 24.9°C (25°C days) and below 0°C (frost days) are strongly linked to atmospheric circulation changes, coupled with regional warming. From 1930–1950 more south to southwest anomalous flow occurred relative to later years. In this period, 25°C days were less frequent in all areas except the northeast, and there was markedly more frost days in all but inland areas of the South Island compared with the 1951–1975 period. There was more airflow from the east and northeast from 1951 to 1975, the frequency of 25°C days increased and frost days decreased in many areas of New Zealand. In the final period examined (1976–1998), more prevalent airflow from the west and southwest was accompanied by more anticyclonic conditions. Days with a temperature of 25°C increased in the northeast only. Frost day frequencies decreased between 5 and 15 days a year in many localities, with little change in the west of the South Island and at higher elevation locations. Copyright © 2001 Royal Meteorological Society
Optical absorption and emission spectral studies of phthalocyanine molecules in DMF
Authors: KUMAR G. A. , THOMAS J. , UNNIKRISHNAN N. V. , NAMPOORI V. P. N. , VALLABHAN C. P. G.
Published: August 2002

Optical absorption and emission spectral studies of various phthalocyanine ( Pc ) molecules in dimethyl formamide (DMF) solvent are reported in this paper. Measurements have been done for free base, Eu , Fe , Mn , Sm , Cu , Zn , Nd and La Pc - s . The principal optical transitions viz B and Q are identified and some of the important spectral parameters such as molar extinction coefficient (ε), absorption cross section (σa), dipole strength (q) and oscillator strength (f) are evaluated for the prominent Q-band. The measured radiative parameters viz emission cross section (σe), fluorescence bandwidth (Δλ) and optical gain (G) show wide variation among different systems. The results obtained are compared with other solid matrices such as glass and polymer.
Synthesis, spectroscopy and electrochemistry of octaphenoxyphthalocyaninato silicon complexes
Authors: MAREE M. DAVID , NYOKONG TEBELLO
Published: August 2002

A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by ( OPh )8 PcSi ( X )2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1 H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.
Syntheses and photochemical properties of octasubstituted phthalocyaninato zinc complexes
Authors: MAREE SUZANNE E. , NYOKONG TEBELLO
Published: August 2002

In this work a selection of octasubstituted phthalocyaninato zinc complexes were synthesized and their photochemistry studied. The substituents included cholesterol (3a), estrone (3b), naphthol (3c) and phenoxy groups substituted with CH3 (3d), C ( CH 3)3 (at two positions, 3e), C ( CH 3)3 (3f), NO2 (3g), NH 2 (3h), COH (3i), COOH (3j), and H (3k). In general, complexes containing electron-donating groups attached to the phenoxy ring (e.g. 3e and 3f) were found to be photochemically unstable with photobleaching quantum yields of the order of 10-3. In the presence of electron-withdrawing groups (3g, 3i, and 3j) the photobleaching quantum yields were of the order of 10-6 to 10-5. Singlet oxygen quantum yields (ΦΔ) ranged from 0.01 to 0.73. The lowest ΦΔ was observed for the highly aggregated complex 3c. All the complexes showed aggregation at high concentrations. Electrochemical reduction using a thin-layer spectroelectrochemistry cell showed that the complexes become more monomeric following reduction.