bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in spinal cord regenerative ability through phylogenesis and development: Lessons to be learnt
Authors: Ferretti Patrizia , Zhang Fang , O'Neill Paul
Published: January 2003

Lower vertebrates, such as fish and amphibians, and developing higher vertebrates can regenerate complex body structures, including significant portions of their central nervous system. It is still poorly understood why this potential is lost with evolution and development and becomes very limited in adult mammals. In this review, we will discuss the current knowledge on the cellular and molecular changes after spinal cord injury in adult tailed amphibians, where regeneration does take place, and in developing chick and mammalian embryos at different developmental stages. We will focus on the recruitment of progenitor cells to repair the damage and discuss possible roles of changes in early response to injury, such as cell death by apoptosis, and of myelin‐associated proteins, such as Nogo, in the transition between regeneration‐competent and regeneration‐incompetent stages of development. A better understanding of the mechanisms underlying spontaneous regeneration of the spinal cord in vivo in amphibians and in the chick embryo will help to devise strategies for restoring function to damaged or diseased nervous tissues in mammals. Developmental Dynamics 226:245–256, 2003.© 2003 Wiley‐Liss, Inc.
Cnidarians: An evolutionarily conserved model system for regeneration?
Authors: Holstein T.W. , Hobmayer E. , Technau U.
Published: January 2003

Cnidarians are among the simplest metazoan animals and are well known for their remarkable regeneration capacity. They can regenerate any amputated head or foot, and when dissociated into single cells, even intact animals will regenerate from reaggregates. This extensive regeneration capacity is mediated by epithelial stem cells, and it is based on the restoration of a signaling center, i.e., an organizer. Organizers secrete growth factors that act as long‐range regulators in axis formation and cell differentiation. In Hydra, Wnt and TGF‐beta/Bmp signaling pathways are transcriptionally up‐regulated early during head regeneration and also define the Hydra head organizer created by de novo pattern formation in aggregates. The signaling molecules identified in Cnidarian regeneration also act in early embryogenesis of higher animals. We suppose that they represent a core network of molecular interactions, which could explain at least some of the mechanisms underlying regeneration in vertebrates. Developmental Dynamics 226:257–267, 2003.© 2003 Wiley‐Liss, Inc.
Regeneration‐specific expression pattern of three posterior Hox genes
Authors: Christen Bea , Beck Caroline W. , Lombardo Aurora , Slack Jonathan M.W.
Published: January 2003

Homeobox genes encode positional information during primary and secondary axis formation during development. For this reason, the Hox genes have attracted attention in regeneration research as well. At early stages of regeneration, Hox genes have been implicated in wound healing and the dedifferentiation process and at later stages in the patterning of the blastema. We studied the expression of three Abdominal B‐type Hox genes in Xenopus: XHoxc10, XHoxa13, and XHoxd13 during normal limb development and during regeneration of limbs and tails. We compared their expression with nonregenerating and with wounded limbs and tails, respectively. We show that the temporal and spatial control of these three Hox genes in blastemas differs from normal development. All three are specific to regeneration, XHoxc10 is up‐regulated at the right time and at the site where cells dedifferentiate and undifferentiated cells are recruited, whereas XHoxa13 is reexpressed slightly later in regeneration, when the blastemal cells proliferate and remains on during patterning of the blastema. XHoxd13 is not expressed until relatively late and appears to be involved only in patterning of the blastema. Developmental Dynamics 226:349–355, 2003.© 2003 Wiley‐Liss, Inc.
Regeneration of the urodele limb: A review
Authors: Nye Holly L.D. , Cameron Jo Ann , Chernoff Ellen A.G. , Stocum David L.
Published: January 2003

Urodele amphibians have been widely used for studies of limb regeneration. In this article, we review studies on blastema cell proliferation and propose a model of blastemal self‐organization and patterning. The model is based on local cell interactions that intercalate positional identities within circumferential and proximodistal boundaries that outline the regenerate. The positional identities created by the intercalation process appear to be reflected in the molecular composition of the cell surface. Transcription factors and signaling molecules involved in patterning are discussed within the context of the boundary/intercalation model. Developmental Dynamics 226:280–294, 2003. © 2003 Wiley‐Liss, Inc.
Urodele spinal cord regeneration and related processes
Authors: Chernoff Ellen A.G. , Stocum David L. , Nye Holly L.D. , Cameron Jo Ann
Published: January 2003

Urodele amphibians, newts and salamanders, can regenerate lesioned spinal cord at any stage of the life cycle and are the only tetrapod vertebrates that regenerate spinal cord completely as adults. The ependymal cells play a key role in this process in both gap replacement and caudal regeneration. The ependymal response helps to produce a different response to neural injury compared with mammalian neural injury. The regenerating urodele cord produces new neurons as well as supporting axonal regrowth. It is not yet clear to what extent urodele spinal cord regeneration recapitulates embryonic anteroposterior and dorsoventral patterning gene expression to achieve functional reconstruction. The source of axial patterning signals in regeneration would be substantially different from those in developing tissue, perhaps with signals propagated from the stump tissue. Examination of the effects of fibroblast growth factor and epidermal growth factor on ependymal cells in vivo and in vitro suggest a connection with neural stem cell behavior as described in developing and mature mammalian central nervous system. This review coordinates the urodele regeneration literature with axial patterning, stem cell, and neural injury literature from other systems to describe our current understanding and assess the gaps in our knowledge about urodele spinal cord regeneration. Developmental Dynamics 226:295–307, 2003. © 2003 Wiley‐Liss, Inc.
Regeneration of the ear after wounding in different mouse strains is dependent on the severity of wound trauma
Authors: Rajnoch Charissa , Ferguson Sharon , Metcalfe Anthony D. , Herrick Sarah E. , Willis Hayley S. , Ferguson Mark W.J.
Published: January 2003

The replacement and restoration of tissue mass after organ damage or injury in adult higher vertebrates is critical to the architecture and function of the organ. If replacement occurs with scar tissue, this often results in adverse effects on function and growth as well as an undesirable cosmetic appearance. However, certain mammals, such as the MRL/MpJ mouse, have shown a restricted capacity for regeneration, rather than scar tissue formation, after an excisional ear punch wound. To investigate the changes in tissue architecture leading to ear wound closure, initial ear wounding studies with a 2‐mm clinical biopsy punch were performed on MRL/MpJ mice, by using C57BL/6 mice as a nonregenerative control strain. In contrast to previously reported studies on mouse ear regeneration, we observed that C57BL/6 mice in fact showed a limited regenerative capacity. One explanation for this difference could be attributed to the method of wounding used; both previous studies on mouse ear regeneration used a thumb punch, whereas our approach was to use a clinical biopsy punch. This approach led us to further investigate whether the severity of trauma applied influenced the rate of wound healing. We, therefore, compared the effects of the sharp clinical biopsy punch with that of a cruder thumb punch, and introduced a third strain of mouse, Balb/c, known to be a slow‐healing strain. A new method to quantify ear punch hole closure was developed and a histologic investigation conducted up to 4 months after wounding. Image analysis data showed a reduction in original ear wound area of 85% in MRL/MpJ mice at 4 weeks and of 91.7% over 4 months by using a biopsy punch. In contrast, the crude thumb punch methodology resulted in an increase in wound area of up to 58% in Balb/c ears; thought to be due to increased necrosis of the wound site. All biopsy‐punched wound areas plateaued in healing between days 28 and 112. Only 5 of 80 MRL/MpJ mouse ears showed no residual holes macroscopically after 28 days. Histologically, all strains of mice healed their ear wounds in a similar manner involving re‐epithelialization, blastema‐like formation, dermal extension, blood vessel formation, chondrogenesis, folliculogenesis, and skeletal muscle and fat differentiation. However, all regenerative features were more pronounced and accelerated in MRL/MpJ mice when compared with C57BL/6 and Balb/c biopsy‐punched mouse ears. Developmental Dynamics 226:388–397, 2003. © 2003 Wiley‐Liss, Inc.
Matrix metalloproteinase activity correlates with blastema formation in the regenerating MRL mouse ear hole model
Authors: Gourevitch Dmitri , Clark Lise , Chen Pan , Seitz Alexander , Samulewicz Stefan J. , Heber‐Katz Ellen
Published: January 2003

The MRL mouse was proposed as a model of mammalian regeneration because it can close ear holes completely with the restoration of normal tissue. This regeneration process involves the formation of a blastema during healing, the re‐appearance of cartilage and hair follicles, and healing without scarring. Such a process requires extensive tissue remodeling. To characterize differences in ear wounding responses between regenerating and nonregenerating mice, we examined and compared the extracellular matrix remodeling and the matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) response in the MRL and C57BL/6 mouse strains after injury. We found a correlation between the MRL's ability to break down the basement membrane, form a blastema, and close ear hole wounds and an inflammatory response with neutrophils and macrophages seen in the ear after injury. These cells were positive for MMP‐2 and MMP‐9 as well as TIMP‐2 and TIMP‐3. Clear differences between the MRL and B6 response to injury were seen that could explain the differences in healing and blastema formation in the MRL and lack of it in the B6 mice. This finding was further supported by enzyme activity as determined by gelatin zymography. Developmental Dynamics 226:377–387, 2003. © 2003 Wiley‐Liss, Inc.
Role for keratins 6 and 17 during wound closure in embryonic mouse skin
Authors: Mazzalupo Stacy , Wong Pauline , Martin Paul , Coulombe Pierre A.
Published: January 2003

Injury to adult skin triggers a response designed to restore its vital barrier function. A conserved aspect of this response is a rapid switch in gene expression whereby the type II keratin 6 (K6) and type I keratins 16 and 17 (K16, K17) are induced in epithelial cells at the wound edge. This induction occurs at the expense of the keratins normally expressed during terminal differentiation and correlates with the activation of epithelial cells at the wound edge, ahead of their migration into the wound site. Here, we show that the capacity to enact this switch is already acquired in E11.5 stage mouse embryos. Such early timing is well ahead of the onset of differentiation‐specific gene expression (∼E13.5) and the acquisition of barrier formation by developing epidermis (∼E16.5). Induction of K6, K16, and K17 correlates with changes in the morphology of epithelial cells at the wound edge. The closure of embryonic wounds is significantly delayed in K17 null embryos, but not embryos null for K6. These observations significantly extend the correlation between K6, K16, and K17 expression and epithelial wound closure, and provide direct evidence that expression of these keratins, K17 in particular, is important for the timeliness of this process. Developmental Dynamics 226:356–365, 2003.© 2003 Wiley‐Liss, Inc.
Chromosome imbalances in thyroid follicular neoplasms: A comparison between follicular adenomas and carcinomas
Authors: Roque Lucia , Rodrigues Raquel , Pinto António , Moura‐Nunes Vasco , Soares Jorge
Published: January 2003

The underlying genetic events associated with follicular thyroid tumorigenesis are still ill defined. In this study, we performed a screening for chromosome imbalances by comparative genomic hybridization (CGH) in a group of 12 follicular adenomas (FAs) and 20 follicular carcinomas (FTCs) previously characterized by conventional cytogenetics and flow cytometry analysis. In general, a great similarity was observed between the CGH profiles of the FAs and FTCs. In both benign and malignant tumors, a combination of gains affecting 5, 7, 12, 17, 19, and 20 was observed. Chromosome 7 was the most frequently affected chromosome, with three regions of consensus gains: 7p11–12, 7q11.3–q21, and 7q31. Recurrent gains of chromosomes 5 and 12 involved 5p11, 5p15, 5q13–q22, 5q21–q23, 12p11, and 12q11–q12. DNA sequence losses were also observed in both tumor groups. Chromosomal arms deleted in at least five of the neoplasms were (in order of frequency): in adenomas, 15q, 2p/2q, 3q, 6p/6q, 11q, and 22q; and in FTCs, 3p, 2p, 8q, 1p, 2q, 3q, 6q, 8p, 9p, 11q, 13q, 6p, and 18q. The statistical evaluation of the CGH data demonstrated that 15q loss was significantly associated with FA. Two regions of minimal common loss were defined by CGH at 15: 15q11–q21 and 15q26‐qter. The identification of these regions provides a basis for further molecular studies. © 2003 Wiley‐Liss, Inc.
Comprehensive molecular cytogenetic characterization of cervical cancer cell lines
Authors: Harris Charles P. , Lu Xin Yan , Narayan Gopeshwar , Singh Bhuvanesh , Murty Vundavalli V. V. S. , Rao Pulivarthi H.
Published: January 2003

We applied a combination of molecular cytogenetic methods, including comparative genomic hybridization (CGH), spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH), to characterize the genetic aberrations in eight widely used cervical cancer (CC) cell lines. CGH identified the most frequent chromosomal losses including 2q, 3p, 4q, 6q, 8p, 9p, 10p, 13q, and 18q; gains including 3q, 5p, 5q, 8q, 9q, 11q, 14q, 16q, 17q, and 20q; and high‐level chromosomal amplification at 3q21, 7p11, 8q23–q24, 10q21, 11q13, 16q23–q24, 20q11.2, and 20q13. Several recurrent structural chromosomal rearrangements, including der(5)t(5;8)(p13;q23) and i(5)(p10); deletions affecting chromosome bands 5p11, 5q11, and 11q23; and breakpoint clusters at 2q31, 3p10, 3q25, 5p13, 5q11, 7q11.2, 7q22, 8p11.2, 8q11.2, 10p11.2, 11p11.2, 14q10, 15q10, 18q21, and 22q11.2 were identified by SKY. We detected integration of HPV16 sequences by FISH on the derivative chromosomes involving bands 18p10 and 18p11 in cell line C‐4I, 2p16, 5q21, 5q23, 6q, 8q24, 10, 11p11, 15q, and 18p11 in Ca Ski, and normal chromosome 17 at 17p13 in ME‐180. FISH analysis was also used further to determine the copy number changes of PIKA3CA and MYC. This comprehensive cytogenetic characterization of eight CC cell lines enhances their utility in experimental studies aimed at gene discovery and functional analysis. © 2003 Wiley‐Liss, Inc.
SIAH1 inactivation correlates with tumor progression in hepatocellular carcinomas
Authors: Matsuo Koichi , Satoh Seiji , Okabe Hiroshi , Nomura Akinari , Maeda Toshiki , Yamaoka Yoshio , Ikai Iwao
Published: January 2003

Accumulation of loss of heterozygosity (LOH) on chromosome 16 is frequently observed in human hepatocellular carcinomas (HCCs). To identify tumor‐suppressor genes (TSGs) involved in hepatocarcinogenesis, we performed deletion mapping of chromosome 16 in 59 HCCs. Three commonly deleted regions, located in 16q12.1, 16q22.1, and 16q24.2, were observed. Because there has been no study on LOH at locus 16q12.1 in HCCs, we focused on this region. By searching the Human Genome Database at the National Center for Biotechnology Information web site, we identified 14 known genes in 16q12.1 as TSG candidates. Among these, the expression of SIAH1 was markedly downregulated in HCCs, and inactivation of SIAH1 expression was associated with LOH at 16q12.1. A mutation analysis of SIAH1 revealed no somatic mutations, but one single nucleotide polymorphism was found among the 35 HCCs investigated. Subsequently, we evaluated the relation between SIAH1 expression, confirmed by semiquantitative RT‐PCR, and clinicopathological parameters in HCCs. SIAH1 was significantly downregulated in advanced HCCs, including poorly differentiated tumors, larger tumors, and tumors in advanced stages. These findings suggest that inactivation of SIAH1 plays an important role in HCC progression. © 2003 Wiley‐Liss, Inc.
Genetic markers useful for distinguishing between organ‐confined and locally advanced prostate cancer
Authors: Chu Lisa W. , Troncoso Patricia , Johnston Dennis A. , Liang Jan C.
Published: January 2003

Prostate cancer is one of the most commonly diagnosed cancers and the second leading cause of cancer deaths among men in the United States. In this study, we performed comparative genomic hybridization (CGH) on 45 primary prostate adenocarcinomas to determine genetic markers that could be useful for distinguishing between organ‐confined and locally advanced prostate cancer. Of these tumors, 24 were pT2 stage, 21 were pT3b; 20 had low Gleason scores (GS), 25 had high GS. The most common chromosomal alterations in all 45 tumors included losses on 8p (57.8%), 10q21→qter (40.0%), 16q (35.6%), 11q21→qter (28.9%), 16p (22.2%), 6q22→24 (22.2%), 10p (20.0%), 5q31→qter (17.8%), 6p (17.8%), 15q22→qter (15.6%), and 17p (15.6%) as well as gains on 7cen→p14 (20.0%), 7cen→q22 (20.0%), and Xcen→q21 (17.8%). Contingency table analysis showed that losses of 8p, 10q25→qter, 6p21, 6q24→qter, and 15q22→qter were significantly increased in frequency (P < 0.05) with increasing stage and/or GS. A model was created following multivariate logistic regression analysis that was predictive of tumor stage in approximately 90% of the tumors studied. This model suggests that loss of 8p is the most valuable predictor of stage. These findings suggest that chromosomal regions identified in this study may be useful for distinguishing between organ‐confined and locally advanced prostate tumors. © 2003 Wiley‐Liss, Inc.
Breakpoints at 1p36.3 in three MDS/AML(M4) patients with t(1;3)(p36;q21) occur in the first intron and in the 5′ region of MEL1
Authors: Xinh Phan Thi , Tri Nguyen Khanh , Nagao Hiromasa , Nakazato Hiroshi , Taketazu Fumitoshi , Fujisawa Shin , Yagasaki Fumiharu , Chen Ying Zhang , Hayashi Yasuhide , Toyoda Atsushi , Hattori Masahira , Sakaki Yoshiyuki , Tokunaga Katsushi , Sato Yuko
Published: January 2003

The recurrent translocation t(1;3)(p36;q21) is associated with myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML) characterized by trilineage dysplasia, especially dysmegakaryopoiesis and a poor prognosis. Recently, the two genes involved in this translocation have been identified: the MEL1 gene at 1p36.3, and the RPN1 gene at 3q21. The breakpoint in RPN1 is centromeric to the breakpoint cluster region of the inv(3) abnormality. Because the MEL1 transcript is detected only in leukemic cells with t(1;3)(p36;q21), ectopic expression of MEL1 driven by RPN1 at 3q21 is thought to contribute to the pathogenesis of t(1;3)(p36;q21) leukemia. However, the precise breakpoint in the patients has not yet been identified. With fluorescence in situ hybridization analysis by use of BAC/PAC probes, we identified the breakpoint at 1p36.3 in three MDS/AML patients with t(1;3)(p36;q21): within the first intron of the MEL1 gene (one patient) or within a 29‐kb region located in the 5′ region of MEL1 (two other patients). We detected several sizes of MEL1 transcript in two patients including the first patient, although we have not yet clarified whether MEL1 transcripts were different among the patients and whether a truncated MEL1 transcript was expressed in the first patient. This patient showed an unusual clinical profile, repeating progression to overt leukemia and conversion to MDS three times during the 29‐month survival period, which might be related to a different molecular mechanism in this patient. © 2003 Wiley‐Liss, Inc.
Optimal use of high‐resolution topographic data in flood inundation models
Authors: Bates P. D. , Marks K. J. , Horritt M. S.
Published: January 2003

In this paper we explore the optimum assimilation of high‐resolution data into numerical models using the example of topographic data provision for flood inundation simulation. First, we explore problems with current assimilation methods in which numerical grids are generated independent of topography. These include possible loss of significant length scales of topographic information, poor representation of the original surface and data redundancy. These are resolved through the development of a processing chain consisting of: (i) assessment of significant length scales of variation in the input data sets; (ii) determination of significant points within the data set; (iii) translation of these into a conforming model discretization that preserves solution quality for a given numerical solver; and (iv) incorporation of otherwise redundant sub‐grid data into the model in a computationally efficient manner. This processing chain is used to develop an optimal finite element discretization for a 12 km reach of the River Stour in Dorset, UK, for which a high‐resolution topographic data set derived from airborne laser altimetry (LiDAR) was available. For this reach, three simulations of a 1 in 4 year flood event were conducted: a control simulation with a mesh developed independent of topography, a simulation with a topographically optimum mesh, and a further simulation with the topographically optimum mesh incorporating the sub‐grid topographic data within a correction algorithm for dynamic wetting and drying in fixed grid models. The topographically optimum model is shown to represent better the ‘raw’ topographic data set and that differences between this surface and the control are hydraulically significant. Incorporation of sub‐grid topographic data has a less marked impact than getting the explicit hydraulic calculation correct, but still leads to important differences in model behaviour. The paper highlights the need for better validation data capable of discriminating between these competing approaches and begins to indicate what the characteristics of such a data set should be. More generally, the techniques developed here should prove useful for any data set where the resolution exceeds that of the model in which it is to be used. Copyright © 2002 John Wiley & Sons, Ltd.
Hydraulic modelling of fish habitat in urban rivers during high flows
Authors: Booker D. J.
Published: January 2003

In urban rivers, flow regime and channel morphology are the drivers of physical habitat quality for aquatic species. Peak discharges are increased at high flows as a result of impermeable catchments and channel engineering for flood protection schemes. Hazardous conditions and flashy hydrographs mean that measurement of velocities at high flows is a difficult task. This research uses a three‐dimensional computational fluid dynamics (3D‐CFD) model to simulate hydraulic patterns in two urban river channels. A 3D‐CFD code, called SSIIM, was used to simulate hydraulic conditions in two engineered river reaches of the River Tame, Birmingham, UK. These two sites represent channels with different levels of engineering. Models were calibrated and tested using field measurements. Results show that modelled water surface levels and velocity profiles are well simulated. Calibrated roughness heights are compared with those derived from field measurement of sediment size. Numerical experiments are used to assess the relationship between grid resolution in the vertical dimension and the form of the modelled velocity profiles. Biologists have used laboratory experiments to determine maximum sustainable swimming speeds (MSSS) of fish, often in order to assess what level of a particular pollutant may be tolerable. In this work, simulations of high‐flow hydraulic patterns are used to compare velocity patterns with fish MSSS. Results show that when the water levels rise to fill the first channel of the two‐stage channels at the sites, which occurred 16 times in 2000, MSSS are surpassed in the majority of available habitat, suggesting that excessive velocities at high flows are one factor that limits fish habitat. A comparison between the two reaches shows that there is less available habitat in the more modified reach. Conclusions suggest that an approach that integrates water quality issues and physical channel characteristics must be taken in river rehabilitation schemes, as improvements to water quality alone may not be sufficient to improve habitat quality to the desired level. Copyright © 2002 John Wiley & Sons, Ltd.
Measurements of rain splash on bench terraces in a humid tropical steepland environment
Authors: Van Dijk A. I. J. M. , Bruijnzeel L. A. , Wiegman S. E.
Published: January 2003

Soil loss continues to threaten Java's predominantly bench‐terraced volcanic uplands. Sediment transport processes on back‐sloping terraces with well‐aggregated clay‐rich oxisols in West Java were studied using two different techniques. Splash on bare, cropped, or mulched sub‐horizontal (2–3°) terrace beds was studied using splash cups of different sizes, whereas transport of sediment on the predominantly bare and steep (30–40/deg ) terrace risers was measured using a novel device combining a Gerlach‐type trough with a splash box to enable the separate measurement of transport by wash and splash processes. Measurements were made during two consecutive rainy seasons. The results were interpreted using a recently developed splash distribution theory and related to effective rainfall erosive energy. Splash transportability (i.e. transport per unit contour length and unit erosive energy) on the terrace risers was more than an order of magnitude greater than on bare terrace beds (0·39–0·57 versus 0·013–0·016 g m J−1). This was caused primarily by a greater average splash distance on the short, steep risers (>11 cm versus c. 1 cm on the beds). Splashed amounts were reduced by the gradual formation of a protective ‘pavement’ of coarser aggregates, in particular on the terrace beds. Soil aggregate size exhibited an inverse relationship with detachability (i.e. detachment per unit area and unit erosive energy) and average splash length, and therefore also with transportability, as did the degree of canopy and mulch cover. On the terrace risers, splash‐creep and gravitational processes transported an additional 6–50% of measured rain splash, whereas transport by wash played a marginal role. Copyright © 2002 John Wiley & Sons, Ltd.
Heterogeneity in ground water–surface water interactions in the hyporheic zone of a salmonid spawning stream
Authors: Malcolm I. A. , Soulsby C. , Youngson A. F. , Petry J.
Published: January 2003

Spatial and temporal variability in ground water–surface water interactions in the hyporheic zone of a salmonid spawning stream was investigated. Four locations in a 150‐m reach of the stream were studied using hydrometric and hydrochemical tracing techniques. A high degree of hydrological connectivity between the riparian hillslope and the stream channel was indicated at two locations, where hydrochemical changes and hydraulic gradients indicated that the hyporheic zone was dominated by upwelling ground water. The chemistry of ground water reflected relatively long residence times and reducing conditions with high levels of alkalinity and conductivity, low dissolved oxygen (DO) and nitrate. At the other locations, connectivity was less evident and, at most times, the hyporheic zone was dominated by downwelling stream water characterized by high DO, low alkalinity and conductivity. Substantial variability in hyporheic chemistry was evident at fine (<10 m) spatial scales and changed rapidly over the course of hydrological events. The nature of the hydrochemical response varied among locations depending on the strength of local ground water influence. It is suggested that greater emphasis on spatial and temporal heterogeneity in ground water–surface water interactions in the hyporheic zone is necessary for a consideration of hydrochemical effects on many aspects of stream ecology. For example, the survival of salmonid eggs in hyporheic gravels varied considerably among the locations studied and was shown to be associated with variation in interstitial chemistry. River restoration schemes and watershed management strategies based only on the surface expression of catchment characteristics risk excluding consideration of potentially critical subsurface processes. Copyright © 2002 John Wiley & Sons, Ltd.
Comparing the hydrology of grassed and cultivated catchments in the semi‐arid Canadian prairies
Authors: van der Kamp G. , Hayashi M. , Gallén D.
Published: January 2003

At the St Denis National Wildlife Area in the prairie region of southern Saskatchewan, Canada, water levels in wetlands have been monitored since 1968. In 1980 and 1983 a total of about one‐third of the 4 km2 area was converted from cultivation to an undisturbed cover of brome grass. A few years after this conversion all the wetlands within the area of grass dried out; they have remained dry since, whereas wetlands in adjacent cultivated lands have held water as before. Field measurements show that introduction of undisturbed grass reduces water input to the wetlands mainly through a combination of efficient snow trapping and enhanced infiltration into frozen soil. In winter, the tall brome grass traps most of the snowfall, whereas in the cultivated fields more wind transport of snow occurs, especially for short stubble and fallow fields. Single‐ring infiltration tests were conducted during snowmelt, while the soil was still frozen, and again in summer. The infiltrability of the frozen soil in the grassland is high enough to absorb most or all of the snowmelt, whereas in the cultivated fields the infiltration into the frozen soil is limited and significant runoff occurs. In summer, the infiltrability increases for the cultivated fields, but the grassland retains a much higher infiltrability than the cultivated land. The development of enhanced infiltrability takes several years after the conversion from cultivation to grass, and is likely due to the gradual development of macropores, such as root holes, desiccation cracks, and animal burrows. Copyright ©2002 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Improving peak flow estimates in artificial neural network river flow models
Authors: Sudheer K. P. , Nayak P. C. , Ramasastri K. S.
Published: January 2003

In this paper, the concern of accuracy in peak estimation by the artificial neural network (ANN) river flow models is discussed and a suitable statistical procedure to get better estimates from these models is presented. The possible cause for underestimation of peak flow values has been attributed to the local variations in the function being mapped due to varying skewness in the data series, and theoretical considerations of the network functioning confirm this. It is envisaged that an appropriate data transformation will reduce the local variations in the function being mapped, and thus any ANN model built on the transformed series should perform better. This heuristic is illustrated and confirmed by many case studies and the results suggest that the model performance is significantly improved by data transformation. The model built on transformed data outperforms the model built on raw data in terms of various statistical performance indices. The peak estimates are improved significantly by data transformation. Copyright © 2003 John Wiley & Sons, Ltd.
Design and use of multi‐affinity surfaces in biomolecular interaction analysis–mass spectrometry (BIA/MS): a step toward the design of SPR/MS arrays
Authors: Nedelkov Dobrin , Nelson Randall W.
Published: January 2003

The feasibility of multi‐affinity ligand surfaces in biomolecular interaction analysis–mass spectrometry (BIA/MS) was explored in this work. Multi‐protein affinity surfaces were constructed by utilizing antibodies to beta‐2‐microglobulin, cystatin C, retinol binding protein, transthyretin, serum amyloid P and C‐reactive protein. In the initial experiments, all six antibodies were immobilized on a single site (flow cell) on the sensor chip surface, followed by verification of the surface activity via separate injections of purified proteins. After an injection of diluted human plasma aliquot over the antibodies‐derivatized surfaces, and subsequent MALDI‐TOF MS analysis, signals representing five out of the six targeted proteins were observed in the mass spectra. Further, to avoid the complexity of the spectra, the six proteins were divided into two groups (according to their molecular weight) and immobilized on two separate surfaces on a single sensor chip, followed by an injection of human plasma aliquot. The resulting mass spectra showed signals from all proteins. Also, the convolution resulting from the multiply charged ion species was eliminated. The ability to create such multi‐affinity surfaces indicates that smaller‐size ligand areas/spots can be employed in the BIA/MS protein interaction screening experiments, and opens up the possibilities for construction of novel multi‐arrayed SPR‐MS platforms and methods for high‐throughput parallel protein interaction investigations. Copyright © 2003 John Wiley & Sons, Ltd.
Human CD30: Structural implications from epitope mapping and modeling studies
Authors: Dong Liying , Hülsmeyer Martin , Dürkop Horst , Hansen Hinrich P. , Schneider‐Mergener Jens , Ziegler Andreas , Uchanska‐Ziegler Barbara
Published: January 2003

The human CD30 molecule is expressed transiently at very low levels on intrafollicular and perifollicular T and B cell blasts in lymphoid tissues, but is specifically upregulated on certain tumor cells, e.g. Hodgkin and Reed–Sternberg (H‐RS) cells. With its specific expression pattern and easy accessibility on the surface of H‐RS cells CD30 is a valuable diagnostic marker and holds considerable promise as a target for in vivo immunotherapy. Knowledge of epitopes on the CD30 molecule is expected to facilitate the design of novel non‐immunogenic anti‐CD30 reagents. Therefore, we have mapped the epitopes of several monoclonal antibodies (mAb) applying a peptide array of overlapping CD30‐derived peptides. For the mAb Ber‐H2, two linear epitopes with identical sequence were found, while the mAb Ki‐2 and the single chain Fv fragment R4‐4 each recognized a single linear antigenic determinant, respectively. On the other hand, the mAb Ki‐1 bound to a discontinuous epitope composed of two regions, one located near the N‐terminus and the other near the membrane‐spanning region of CD30. Using molecular modeling, it was possible to visualize the location of the epitopes on exposed loop regions of the molecule within the N‐terminal domain. Finally, the results obtained with the mAb Ki‐1 imply that the ends of the N‐ and C‐terminal parts of the extracellular portion of CD30 are in close vicinity of each other, suggesting a flower‐like structure for the membrane‐bound homotrimeric CD30 molecule. Copyright © 2003 John Wiley & Sons, Ltd.
Teleconnections between Indian monsoon and Sahel rainfall and the Mediterranean
Authors: Raicich Fabio , Pinardi Nadia , Navarra Antonio
Published: January 2003

The teleconnections with Indian monsoon and Sahel rainfall indices are investigated here on an interannual time scale in terms of meteorological and marine dynamics over the Mediterranean area. Sea‐level pressure from gridded data sets and from individual stations, together with sea‐level data from stations all around the Mediterranean coastlines, are used.

In summer (July–August–September, JAS) the sea‐level pressure field over the eastern Mediterranean anticorrelates with the Indian monsoon index (correlation coefficient C = −0.5 on average). A Mediterranean pressure index (MPI), defined as the standardized difference between sea‐level atmospheric pressure at Mersa Matruh (southeastern Mediterranean) and Marseille (northwestern Mediterranean) stations, anticorrelates with Indian monsoon index even more (C = −0.68). The MPI is proportional to the mean geostrophic surface flow field across an imaginary line joining the two stations and turns out to be significantly correlated with the meridional wind component over the eastern Mediterranean, known as the low‐level Etesian wind regime. This wind regime represents the inflow surface field into the African inter‐tropical convergence zone and, therefore, has an association with the Indian monsoon regime. The ocean response, evident by sea‐level anomalies at coastal stations, shows a maximum anticorrelation with Indian monsoon index in late summer and autumn (September–October–November, SON).

The Sahel index anticorrelates with sea‐level pressure, with the maximum absolute value in June–July–August. This may be interpreted as a tendency of the Mediterranean sea‐level pressure anomalies to precede those of Sahel precipitation, which is characterized by maximum rainfall in July–September. The MPI anticorrelates with Sahel index during and before JAS, indicating that the Etesian wind regime intensity is connected to Sahel rainfall. The sea level again anticorrelates with the Sahel index, with the maximum absolute value in SON, as for the sea‐level–Indian monsoon correlation. Copyright © 2003 Royal Meteorological Society.
Impact of El Niño–southern oscillation on Indian foodgrain production
Authors: Selvaraju R.
Published: January 2003

The impact of El Niño–southern oscillation (ENSO) on Indian foodgrain production was analysed for the period 1950–99. The inverse relationship between sea‐surface temperature (SST) anomalies from June to August (JJA) over the NINO3 sector of the tropical Pacific Ocean and Indian foodgrain production anomalies (r = −0.50) was significant at the 1% level. During the warm ENSO phase, the total foodgrain production frequently decreased (12 out of 13 years) by 1 to 15%. In 10 out of 13 cold ENSO‐phase years, the total foodgrain production increased from normal. The relationship between the SST‐based NINO3 ENSO index and the Kharif season (June–September) foodgrain production anomalies (r = −0.52) was greater than for the Rabi season (October–February) foodgrain production (r = −0.27). The ENSO impact on rice production was greatest among the individual crops. The average drop in rice (Kharif season crop) production during a warm ENSO‐phase year was 3.4 million tonnes (7%). In a cold ENSO‐phase year the average production increase was 1.3 million tones (3%). Wheat (Rabi season crop) production was also influenced by ENSO, as it depends on the carryover soil water storage from the Kharif season. Sorghum and chickpea production are not significantly influenced by ENSO extremes.

Inter‐annual fluctuation of the gross value of Indian foodgrain production was very large, reducing up to US$2183 million in a warm ENSO year and increasing up to US$1251 million in a cold ENSO year. On average, a warm ENSO year costs US$773 million and a cold ENSO year had a financial gain of US$437 million from normal.

The cumulative probability distributions of foodgrain production anomalies during cold and warm ENSO phases are shifted positively or negatively, relative to the neutral distribution. The warm ENSO forcing significantly (1% level) reduced the probability of above‐average production. The cold ENSO forcing moderately increased the above‐average foodgrain production over the neutral ENSO phase (5% level). A simple conditional probability forecast based on annual and JJA NINO3 SST predicted the category of foodgrain production in 11 of the 14 years. The results demonstrated that the relationship between NINO3 ENSO index and foodgrain production could be used for agricultural applications and policy decisions on food security for the rapidly growing population in India. Copyright © 2003 Royal Meteorological Society.
Precipitation trends in the Canary Islands
Authors: García‐Herrera Ricardo , Gallego David , Hernández Emiliano , Gimeno Luis , Ribera Pedro , Calvo Natalia
Published: January 2003

A strong decreasing trend in the Canary Islands' precipitation is detected by studying daily rainfall time series for the second half of the 20th century. An analysis of the extreme events shows that this trend is due mainly to a decrease in the upper percentiles of the precipitation distribution. The results suggest that local factors play a fundamental role on extreme event behaviour. Copyright © 2003 Royal Meteorological Society.
The relationship between land use and soil erosion in the communal lands near Peddie town, Eastern Cape, South Africa
Authors: Kakembo V. , Rowntree K. M.
Published: January 2003

The origins and development of severe forms of erosion are traced in the communal villages located in a part of the dividing ridge between the Great Fish and Keiskamma rivers near Peddie town, Eastern Cape, South Africa. Progressive changes in land use and soil erosion distribution are reconstructed by analysing sequential aerial photographs of the area between 1938 and 1988. The distributions of the two phenomena are mapped and quantified at the different dates using PC ARC/INFO GIS. Observable soil erosion is confined to the communal lands at all the dates. Widespread abandonment of cultivated fields between 1965 and 1988 is noted as the most significant aspect of land use change in the communal lands. Gully initiation and intensification appear predominantly from the mid‐1970s, coinciding with a period of extreme rainfall events. A close spatial correlation between abandoned cultivated land and severe gullies is identified. The research raises questions regarding both the cause for land abandonment and the reasons for its vulnerability to erosion. The observed land degradation is seen as the result of a complex interaction of social, economic and environmental factors which lead to land abandonment and its consequent erosion. Copyright © 2002 John Wiley & Sons, Ltd.
Assessment of certain soil properties related to different land‐use systems in the Kaya watershed of the humid forest zone of Cameroon
Authors: Voundi Nkana J. C. , Tonye J.
Published: January 2003

A field survey was conducted in the Kaya watershed of the humid forest zone of Cameroon to assess changes in particle size distribution and chemical soil properties related to different land‐use systems. The strongly acid soils are mainly composed of sand and clay, and are poor in organic carbon, total nitrogen, mineral nutrients and effective cation exchange capacity (ECEC), with the major portion of nutrients stored in the topsoil, together with organic matter. Land‐use systems significantly affect the sand and the clay fractions and have high proportions of sand in soils of cropped fields, secondary forest and river valleys and high clay percentages under dense forest and fallows. Soil pH and exchangeable Al in the topsoil and the subsoil, organic carbon, available P, base saturation and Al saturation in the topsoil and ECEC in the subsoil significantly differ with the land‐use systems. Soils of food‐crop fields and river valleys presented a higher fertility level than under secondary and dense forests. Permanent vegetation coverage and/or exposure to heavy rains of the soils, disturbance due to land preparation, organic matter supplied by the vegetation, nutrient cycling, nutrient restitution and nutrient uptake could be differentiation factors. For agricultural development, utilization of residue from harvest to cover the soil surface, liming and P fertilization appeared as the first and the most important management options. Nitrogen and K fertilization could be added according to crop requirements. Since farmers cannot afford to buy lime and mineral fertilizers and agroforestery is hardly practised, the utilization of cheap and widely available wood ash as a liming agent and supplier of P and K is a promising option. Field trials at the farmer level are proposed to evaluate this. Copyright © 2002 John Wiley & Sons, Ltd.
Soil erosion, indigenous irrigation and environmental sustainability, Marakwet, Kenya
Authors: Adams W. M. , Watson E. E.
Published: January 2003

Irrigation developed indigenously has long been practised on the Western rift escarpment of the Kerio Valley in Kenya by the Marakwet people. Outsiders have often remarked on the problem of soil erosion, and suggested that the irrigation practices are unsustainable. This article discusses local and outside perceptions of soil erosion under irrigation, and their implications for assessing the sustainability of indigenous irrigation. It argues that erosion is taking place, but that local farmers do not perceive erosion as such as a critical challenge to their farming activities. Copyright © 2002 John Wiley & Sons, Ltd.
Farmers' perceptions of erosion by wind and water in northern Burkina Faso
Authors: Visser S. M. , Leenders J. K. , Leeuwis M.
Published: January 2003

Wind and water erosion are widespread phenomena throughout the Sahel, especially in the early rainy season, when high‐intensity rainstorms are often preceded by severe windstorms. This paper describes the results of a survey on the farmers' perceptions of wind and water erosion processes and control measures. In three villages in northern Burkina Faso, 60 farmers were interviewed using semi‐structured questionnaires. According to most of the farmers, wind‐blown particle transport has an influence on the fertility and the infiltration capacity of the soils. They considered wind‐blown particle transport damaging for their crops. Seedlings are damaged by scouring grains of sand or lost when buried in sand deposits. Only 32 per cent of the farmers observed runoff and 15 per cent observed erosion and deposition during periods of high intense rainfall. According to 22 per cent of the farmers intense rainfall has a negative effect on crop production. Plants die because of the effects of stagnating water and plants are damaged by the forces of flowing water.

All farmers are familiar with techniques to reduce soil erosion and 96 per cent applied one or more of these techniques. The indigenous techniques are application of manure and mulch. The main constraints to apply these techniques are lack of labour, manure and mulch. New techniques introduced by agricultural organizations are zaï (a traditional agricultural practice whereby pits of diameter 10–15 cm are filled with compost for sowing) and half‐lines, stone rows and sand ridges.

Farmers have a good knowledge of wind erosion processes, but do not report the effects of water erosion processes. The farmers are willing to apply new techniques to control soil erosion, but the main constraints to apply these measures are insufficient knowledge and lack of labour. Copyright © 2002 John Wiley & Sons, Ltd.