bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the association between diabetic nephropathy and polymorphisms in the aldose reductase gene in Type 1 and Type 2 diabetes mellitus
Authors: Neamat‐Allah M. , Feeney S. A. , Savage D. A. , Maxwell A. P. , Hanson R. L. , Knowler W. C. , El Nahas A. M. , Plater M. E. , Shaw J. , Boulton A. J. M. , Duff G. W. , Cox A.
Published: March 2003

Aims  To investigate the association between polymorphisms of the aldose reductase gene and diabetic nephropathy in both Type 1 and Type 2 diabetes mellitus, and to carry out a meta‐analysis of published results.

Methods  We have investigated the role of two aldose reductase polymorphisms in four independent cohorts of cases and controls (two each with Type 1 and Type 2 diabetes) drawn from two ethnic populations, including 471 patients with nephropathy and 494 control diabetic patients without nephropathy. A C/T transition at position −106, and a (CA)n microsatellite marker 2.1 kb from the start site of the aldose reductase gene were genotyped in nephropathic patients and non‐nephropathic controls from each cohort.

Results  Carriage of the −106 T allele was significantly associated with diabetic nephropathy in three of the four study groups. The Mantel‐Haenszel combined odds ratio was 2.22 (95% CI 1.69, 2.94), P = 1.05 × 10−8. We found no evidence for association of the microsatellite marker with nephropathy, despite moderate levels of disequilibrium between the two markers. Meta‐analysis of published data yielded no evidence for association of the microsatellite marker with diabetic nephropathy in Type 2 diabetes, but varying degrees of association with diabetic nephropathy in Type 1 diabetes.

Conclusions  Meta‐analyses provide more convincing evidence of a role for the ALR2–106 marker than for the microsatellite marker in diabetic nephro pathy (DN). More studies are now required to confirm these results and to establish whether the ALR2–106 polymorphism has a functional role in DN.

Diabet. Med. 18, 906–914 (2001)
Effect of selected literature on dentists' decisions to remove asymptomatic, impacted lower third molars
Authors: Van Der Sanden Wil J. M. , Mettes Dirk G. , Plasschaert Alphons J. M. , Grol Richard P. G. M. , Van'T Hof Martin A. , Knutsson Kerstin , Verdonschot Emiel H.
Published: March 2003

The aim of this study was to assess the effect of studying selected literature on dentists' decisions to remove asymptomatic, impacted lower third molars. A pre‐test–post‐test control group design was used. Given 36 patient cases, two groups of 16 general dental practitioners each were asked to assess the need for removal of asymptomatic impacted lower third molars. The cases were classified by three parameters: ‘position of the third molar’, ‘impaction type’, and ‘patient age’. After studying selected literature on this subject by the intervention group, both groups were asked to assess the same cases again. Frequencies of decisions to remove the third molars were calculated. For each participant, tables were composed by crosstabulating the indication to remove a third molar with each of the three parameters. T‐tests were used to test the significance of the difference between pre‐test and post‐test decisions. The overall number of indications to remove asymptomatic, impacted lower third molars decreased by 37% in the intervention group. In the control group, the difference between pre‐ and post‐test was not statistically significant. It was concluded that the provision of selected literature significantly influences treatment decision making by dentists in a third molar decision task.
The effect of dental restorative materials on dental biofilm
Authors: Auschill Thorsten Mathias , Arweiler Nicole Birgit , Brecx Michel , Reich Elmar , Sculean Anton , Netuschil Lutz
Published: March 2003

To investigate the arrangement of biofilms formed in vivo, volunteers wore splints with slabs of six different dental materials inserted to collect smooth surface plaque. After 5 d of undisturbed plaque accumulation, the specimens were vital stained and analyzed by the confocal laser scanning microscopy (CLSM) to evaluate the percentage of vital biofilm microflora (VF percentage). Further parameters were the area of the specimens covered by plaque (surface coating; SC, %) and the height of the biofilms (BH, µm). The metals amalgam and gold, the compomer, as well as the glass‐ionomer cement harboured an almost entirely dead biofilm (VF <8%). Resin composite led to vitality values between 4 and 21%, while a very thin biofilm on ceramic revealed the highest vitality values (34–86%). SC varied from 6% on glass‐ionomer cement to 100% on amalgam. BH reached its highest value on amalgam and gold of 17 and 11 µm, respectively, while heights of between 1 and 6 µm were found on the ceramic, resin composite, compomer and the glass‐ionomer cement. Within their limits, the present findings indicate that amalgam, gold, compomer and glass‐ionomer cement exert an influence against the adhering biofilm. No general relationship could be established between the different parameters VF percentage, SC percentage and BH (µm).
Tectonic controls on the deposits of a foreland basin: an example from the Eocene Corbières–Minervois basin, France
Authors: Martı´n‐Martı´n M. , Rey J. , Alcala‐Garcia F. J. , Tosquella J. , Deramond J. , Lara‐Corona E. , Duranthon F. , Antoine P.‐O.
Published: March 2003

ABSTRACT During the Eocene in the Corbières–Minervois foreland basin, southern France, there was a transition from marine carbonate to fluvial–lacustrine sedimentation. This evolution took place in six depositional sequences, the first controlled by a eustatic rise or flexural downwarping, then following under compressive tectonic conditions. The second to the fourth sequences show marine to marshy, mainly carbonate sediments with a transgressive–regressive evolution, while the last two comprise terrigenous and carbonate continental sediments. The tectonic evolution is marked by blind fault‐propagation folds which deformed the basin during the Ilerdian–Cuisian. A paroxysmal compressive tectonic phase occurred at the Bartonian when the ancient blind thrusts started to emerge. A model for the evolution of the basin is presented, involving the northward propagation of structural culminations, which focused shallow water or emergent conditions, and structural lows in which deeper water sedimentation took place. The diachronous migration of these structural zones can be constrained from the high biostratigraphic resolution of the foreland basin fill.
The KCl cotransporter, KCC2, is highly expressed in the vicinity of excitatory synapses in the rat hippocampus
Authors: Gulyás A. I. , Sík A. , Payne J. A. , Kaila K. , Freund T. F.
Published: March 2003

Immunocytochemical visualization of the neuron‐specific K+/Cl– cotransporter, KCC2, at the cellular and subcellular level revealed an area‐ and layer‐specific diffuse labelling, and a discrete staining outlining the somata and dendrites of some interneurons in all areas of the rat hippocampus. KCC2 was highly expressed in parvalbumin‐containing interneurons, as well as in subsets of calbindin, calretinin and metabotropic glutamate receptor 1a‐immunoreactive interneurons. During the first 2 postnatal weeks, an increase of KCC2 staining was observed in the molecular layer of the dentate gyrus, correlating temporally with the arrival of entorhinal cortical inputs. Subcellular localization demonstrated KCC2 in the plasma membranes. Immunoreactivity in principal cells was responsible for the diffuse staining found in the neuropil. In these cells, KCC2 was detected primarily in dendritic spine heads, at the origin of spines and, at a much lower level on the somata and dendritic shafts. KCC2 expression was considerably higher in the somata and dendrites of interneurons, most notably of parvalbumin‐containing cells, as well as in the thorny excrescences of CA3 pyramidal cells and in the spines of spiny hilar and stratum lucidum interneurons. The data indicate that KCC2 is highly expressed in the vicinity of excitatory inputs in the hippocampus, perhaps in close association with extrasynaptic GABAA receptors. A high level of excitation is known to lead to a simultaneous net influx of Na+ and Cl–, as evidenced by dendritic swelling. KCC2 located in the same microenvironment may provide a Cl– extrusion mechanism to deal with both ion and water homeostasis in addition to its role in setting the driving force of Cl– currents involved in fast postsynaptic inhibition.
Oxidant stress induces gamma‐glutamylcysteine synthetase and glutathione synthesis in human bronchial epithelial NCI‐H292 cells
Authors: Ray S. , Watkins D. N. , Misso N. L. A. , Thompson P. J.
Published: March 2003

Background The bronchial epithelium is exposed to reactive oxygen species (ROS) derived from cigarette smoke, air pollutants and activated leucocytes. Glutathione (GSH) prevents ROS‐mediated loss of cell function, tissue injury and inflammation, and its synthesis is regulated by γ‐glutamylcysteine synthetase (γ‐GCS). However, the capacity of bronchial epithelial cells to adapt to oxidative stress and the mechanisms involved are not known.

Objective To investigate the effects of oxidative stress on the regulation of GSH synthesis in human bronchial epithelial (NCI‐H292) cells.

Methods NCI‐H292 cells were exposed to menadione and intracellular GSH concentrations were measured by spectrophotometry. γ‐GCS activity was measured by HPLC assay and changes in γ‐GCS mRNA by Northern blotting.

Results Exposure to menadione (MQ, 10–200 µm, 30–120 min) decreased total cellular GSH content, measured immediately after exposure to MQ. However, GSH content measured 6–12 h after withdrawal of the oxidant stress (MQ, 50 µm, 30 min), increased c. two fold over baseline levels (P < 0.001). γ‐GCS activity measured 6 h (21.7 ± 3.4 nmol/min/mg, SD, n = 5, P < 0.01) or 12 h (23.2 ± 4.6, P < 0.001) after MQ treatment was also significantly increased compared with untreated cells (12.8 ± 1.0). Similarly, γ‐GCS mRNA expression increased 1.3–1.6‐fold relative to GAPDH mRNA, 3–6 h after MQ treatment. The MQ‐induced increase in γ‐GCS mRNA expression was completely inhibited by actinomycin D.

Conclusions Bronchial epithelial (NCI‐H292) cells respond rapidly and sensitively to oxidant stress, and this adaptive response is mediated by increased γ‐GCS mRNA transcription and enzyme activity.
Rhinovirus‐induced alterations on peripheral blood mononuclear cell phenotype and costimulatory molecule expression in normal and atopic asthmatic subjects
Authors: Papadopoulos N. G. , Stanciu L. A. , Papi A. , Holgate S. T. , Johnston S. L.
Published: March 2003

Background Rhinovirus (RV) infection is the commonest trigger of acute asthma exacerbations; however, the immune response to these viruses and any potential implications in the mechanisms leading to asthma exacerbations are not well understood.

Objective To assess the effects of in vitro RV infection on the phenotype and expression of costimulatory molecules on peripheral blood mononuclear cells (PBMC) from normal and atopic asthmatic subjects, as a model for RV antigen presentation.

Methods PBMC from seven normal and seven asthmatic subjects were exposed to one infectious unit/cell of RV16 for 48 h. Surface expression of CD25, CD28, CD40, CD54, CD80, CD86 and CTLA‐4 was evaluated on CD3, CD4, CD8, CD14 and CD19 PBMC subpopulations by three‐colour flow cytometry.

Results No changes in the percentage of CD3, CD4, CD8 or CD19 were observed. CD14 was significantly reduced by the infection and this was more pronounced in normal subjects. On Th cells CTLA‐4 was increased after RV infection only in the asthmatic group. Levels of CD80 and CD86 in the control cultures were lower in the asthmatic group. RV infection induced a significant increase of CD80 on monocytes and of CD86 on B cells, which occurred in both groups but were less marked in atopic asthmatic subjects.

Conclusion Exposure of PBMC to RV is able to activate the antigen presentation machinery. Differences between normal and atopic asthmatic individuals are compatible with the hypothesis that an aberrant immune response to RV may be involved in the development of acute exacerbations in atopic asthmatic subjects.
Identification of a polymorphic microsatellite marker in the mouse Fas ligand gene
Authors: Lévi‐Strauss M. , Beauvais C. , Karray S.
Published: March 2003

We describe the characterization of a polymorphic microsatellite marker, located 1.8 kb downstream of exon 4 in the mouse Fas ligand gene. This (GT) repeat sequence allows the identification of four alleles which can very easily be distinguished by simple agarose electrophoresis.
Evidence and techniques in endometrial ablation: consensus
Authors: Garry Ray
Published: March 2003

This consensus is drawn principally from the published data, complemented by the experience of the participants who attended a workshop in Middlesbrough, UK, 7–9 December 2000. The delegates at this meeting included most of those who had introduced and developed the various techniques to be investigated. We believe that ‘the relative value of the various intra‐uterine procedures designed to treat dysfunctional uterine bleeding will only be resolved with unbiased, properly designed randomised studies’.1
Influence of ethnicity on emergency department pain management
Authors: Todd Knox H
Published: March 2003

See Commentary, page 271.
Practical approach to the febrile child in the emergency department
Authors: Browne Gary J , Currow Kathy , Rainbow Jo
Published: March 2003

See Commentary, page 405.
Agreement between troponin T levels from plain and heparinized tubes
Authors: Jones Peter G , McClelland Andy , McNeil Alan , Gamble Greg
Published: March 2003

Objective:

To determine whether there was a clinically significant effect on troponin T measurement when the sample was collected in a heparinized (plasma) blood collection tube compared with a serum tube.

Methods:

Prospective cohort study using a convenience sample of 198 patients with undifferentiated illness presenting to an Emergency Department who required troponin T measurement. Samples were collected in both plain (serum) tubes and plasma tubes for comparison. All samples were measured using an Elecsys 2010 Immunoassay system (Roche‐Boehringer Mannheim, Germany).

Results:

There were 35 troponin T measurements ≥ 0.03 µg/L (the limit of reproducibility of the test). The negative predictive value for troponin T performed in heparinized tubes compared with plain tubes was 100% (95% confidence interval 96.4–100) at the ≥ 0.03 µg/L level and 100% (95% confidence interval 97–100%) at the ≥ 0.1 µg/L level. At a cut‐off point for risk stratification in acute coronary syndromes (≥ 0.1 µg/L), there was 100% concordance between the two measurements for each sample.

Conclusion:

The use of plasma (heparinized) tubes for the collection of troponin T samples is unlikely to produce clinically significant false‐negative results compared with collection of troponin T samples in serum (plain) tubes.
STRETCHING DISTRICT NURSING SERVICES TO MEET RURAL NEEDS
Authors: Alford Katrina , O'Meara Angela
Published: March 2003

This article evaluates the adequacy of District Nursing Service (DNS) provision in the Goulburn Murray region in Victoria. It draws on a survey of the region’s DNS and communication with several community health agencies in response to problems identified by service providers. The results suggest that these rural health services face problems not experienced in urban areas. District nurses in rural areas have to travel far and wide to accommodate their clients and they put in extra unpaid hours if necessary. Their travel time, management and communication skills are not sufficiently recognised in the current funding formula. Although this includes some weighting for rurality, it is insufficient for District Nursing Services catering for smaller, more dispersed populations. Current and future demand pressures on home and community‐based nursing services highlight the importance of redressing this deficiency. Several issues raised in this article may reflect problems that are common in rural regions, including funding inadequacies, unpaid additional work, access and equity difficulties and boundary issues. As a result, recommendations to improve service delivery may have broader applicability.
QUALITY ASSURANCE AND CONTINUING EDUCATION NEEDS OF RURAL AND REMOTE GENERAL PRACTITIONERS: HOW ARE THEY CHANGING?
Authors: Booth Barbara , Lawrance Richard
Published: March 2003

The Royal Australian College of General Practitioners’ (RACGP) 1998 Rural Quality Assurance and Continuing Education (QA & CE) Needs Assessment Project was designed to generate sufficient data to inform strategic planning for rural and remote GPs participating in the College’s QA & CE Program. Results indicated that the demand for QA & CE activities has changed over the past 12 years. Three distinct streams of continuing education emerged, where once only one was researched. This reflected a move towards continuing professional development (CPD) rather than purely continuing medical education (CME). However, differences between the CME needs identified suggested that national data could not be reduced to the local level. Data on CME in which rural and remote GPs felt underserviced, proved more useful in relation to other workforce variables such as age, length of service and gender. A broad ‘rural set’ of CPD topics was established, and the survey yielded information on learning format preferences that will be of use to providers of QA & CE activities for rural GPs across Australia.
WORK EXPERIENCE PROGRAM AT A METROPOLITAN PAEDIATRIC HOSPITAL: ASSISTING RURAL AND METROPOLITAN ALLIED HEALTH PROFESSIONALS EXCHANGE CLINICAL SKILLS
Authors: Parkin Ann E. , McMahon Sandra , Upfield Nancy , Copley Jodie , Hollands Karen
Published: March 2003

The needs of rural allied health professionals (AHPs) have been widely documented. In particular, problems of professional isolation, lack of professional development opportunities and limited support systems have been highlighted as problems associated with working in rural and remote areas. This research aimed to provide rural and remote AHPs with an opportunity to gain experience in paediatric clinical areas of their choice, to provide rural/remote and metropolitan AHPs with an opportunity to share clinical knowledge and expertise, and to develop networks between rural/remote and metropolitan AHPs. A clinical experience program was developed to meet these aims. Twenty‐nine AHPs from rural and remote areas of Queensland participated in the program. Participants completed questionnaires at the end of clinical experience program and 4–8 weeks after the visit. A focus group was also conducted. Analyses found the program met the majority of participants goals and expectations. Enhanced clinical skills in specialist paediatric areas, increased networking and access to resources were reported by rural/remote AHPs as benefits of the program. The role of a clinical consultant was found to be critical to the success of the program.
Effect of Helicobacter pylori‐Induced Cyclooxygenase‐2 on Gastric Epithelial Cell Kinetics: Implication for Gastric Carcinogenesis
Authors: Wambura Casmir , Aoyama Nobuo , Shirasaka Daisuke , Sakai Toshiyuki , Ikemura Takahiro , Sakashita Masanori , Maekawa Shuji , Kuroda Kohei , Inoue Takashi , Ebara Shigeyuki , Miyamoto Masaki , Kasuga Masato
Published: March 2003

Background. Cyclooxygenase (COX)‐2 induced by Helicobacter pylori is thought to enhance gastric carcinogenesis by affecting the maintenance of epithelial homeostasis.

Materials and Methods. Gastric biopsies from 160 subjects, 97 with nonulcer dyspepsia (47 H. pylori negative, 50 H. pylori positive) and 63 with gastric cancer were examined immunohistochemically for COX‐2 expression, cell proliferation and apoptotic indices.

Results. COX‐2 expression in corpus was significantly higher in H. pylori positive than in negative non‐ulcer dyspepsia (NUD) (p < .05). Regardless of site, gastric cancer subjects had higher COX‐2 expression in both antrum and corpus compared with H. pylori negative and positive NUD (p < .005). Proliferation was higher in cancer and H. pylori positive than in negative NUD (p < .0001). Moreover, cancer had enhanced proliferation than H. pylori positive NUD in corpus greater (p = .0454) and antrum lesser (p = .0215) curvatures. Apoptosis was higher in H. pylori positive than in negative NUD (p < .05). However, both had a higher index than the cancer subjects (p < .0001). Apoptosis : proliferation ratio was higher in corpus of H. pylori negative than in positive NUD in greater (p = .0122) and lesser (p = .0009) curvatures. However, both had a higher A:P ratio than cancer cases (p = .0001). A negative correlation between COX‐2 expression and A:P ratio was found in corpus greater (r = –.176, p= .0437) and lesser (r = –.188, p= .0312) curvatures.

Conclusion. The expression of COX‐2 is associated with disruption in gastric epithelial kinetics and hence may play a role in gastric carcinogenesis.
Involvement of chromatin structure in the regulation of mouse zygotic gene activation
Authors: CHO Tasuku , SAKAI Senkiti , NAGATA Masao , AOKI Fugaku
Published: March 2003

We investigated the contribution of the global changes in chromatin structure to the mechanism regulating zygotic gene activation in mouse embryos by in vitro transcription assay and in situ DNase I sensitivity assay. Changes in the DNase I sensitivity and transcriptional activity were similar from the late 1‐cell to the late 2‐cell stage, but were not in the early 1‐cell stage. The DNase I sensitivity decreased at the late 1‐cell stage when compared with the sensitivity at the early 1‐cell stage. It increased at the early 2‐cell stage and then decreased at the late 2‐cell stage. Similarly, the transcriptional activity increased at the early 2‐cell stage when compared with the activity at the late 1‐cell stage, and then decreased at the late 2‐cell stage. The DNase I sensitivity was not decreased in embryos which were treated with aphidicolin, where the first round of DNA replication was inhibited. A similar result was observed in embryos when the second DNA replication was inhibited. These results suggested that the chromatin structure is one of the important factors regulating gene expression from the late 1‐cell stage and that DNA replication is an event responsible for the establishment of the repressive state in the chromatin structure. The inhibition of protein synthesis did not affect the DNase I sensitivity in the 1‐cell embryos, while it is known that protein synthesis is indispensable for gene activation. This result suggests that the protein synthesized after fertilization, but not the chromatin structure, is responsible for the initiation of the gene activation.
Effect of mate selection on fuzzy selective mating criteria in closed dairy multiple ovulation and embryo transfer nucleus programs
Authors: NAKAMURA Atsushi , TOGASHI Kenji , YAMAMOTO Naoyuki , NISHIURA Akiko
Published: March 2003

In order to control rates of response and inbreeding, mate selection using fuzzy selective mating criteria (FMC) was investigated in adult multiple ovulation and embryo transfer nucleus schemes for dairy cattle. Stochastic simulation was used to model the closed nucleus scheme. This mate selection was examined in four alternative mating and male selection schemes: (i) a hierarchical scheme; (ii) a hierarchical sibship scheme (two males per sibship); (iii) a factorial scheme (two sires per dam); and (iv) a factorial sibship scheme (two males per sibship and two sires per dam). Genetic response and inbreeding rate tended to be reduced by increasing the trade‐off parameter of FMC between the expected breeding value and inbreeding of progeny. Inbreeding rates in all schemes were reduced by reducing the variance of family size through selection and the average coancestry of mating pairs through mate allocation.
Immunohistochemical detection of cellular prion protein (PrPc) in the rat central nervous system
Authors: NAKAMURA Fumio , SEKI Iwao , KOBAYASHI Ken , TANAKA Masakazu , FUKUNAGA Shigeharu
Published: March 2003

A simple conventional method of immunohistochemistry (i.e. fixing the frozen sections in cold methanol) was used to determine the immunolocalization of cellular prion protein (PrPc), with good results. In the rat cerebrum, the cytoplasm of neural cells in the cortex and corpus stratum, pia mater, membrane limitans gliae superficialis, choroid plexus and blood vessel wall were immunostained. The formation of network structures of immunostained neural and/or glial fibers in the cerebral cortex was also observed. These immunostained network structures of neural and/or glial fibers were also observed in cultured neural cells. The results suggest that fixation of frozen sections and cultured cells with cold methanol is a useful method for detecting the immunolocalization of PrPc and that PrPc exists in the various components of the central nervous system of the rat.
Responses of gas exchange and growth in Merkus pine seedlings to expected climatic changes in Thailand
Authors: Koskela Jarkko
Published: March 2003

Responses of gas exchange and growth in Merkus pine (Pinus merkusii Jungh. et de Vriese) seedlings to changing climate were analysed for high‐ and low‐altitude sites in Thailand. A gas exchange model, based on the optimality approach, derived the effect of drought from the probability of rains. A carbon‐and nitrogen‐balance growth model applied structural regularities of a tree and a modification of functional balance between foliage and fine roots as growth‐ guiding rules. Adaptation to local climates was incorporated in the models.

   The simulations yielded physiologically reasonable behaviour for annual photosynthesis (A) and transpiration (E) in relation to the distributions of precipitation over the course of a year. An annual temperature increase of 2 °C and a prolonged dry season (scenario 2) reduced A by 5–11% and E by 5–8% as compared to present climate (scenario 1). Doubled CO2 concentration and the increased temperature (scenario 3) enhanced A by 56–59% and E by 14%. Simultaneously these changes (scenario 4) increased A by 41–53% and E by 1–5%. Simulated growth in scenario 1 fitted reasonably well to field data. By the age of five years, simulated total biomass (TB) and height (h) were reduced by 31–67% and 12–42%, respectively, in scenario 2 compared to scenario 1. In scenario 3, TB and h increased by 279–330% and 94–191%, and in scenario 4, by 83–241% and 55–69%, respectively. Large increases in TB and h are explained by the exponential growth phase of the young seedlings. These results suggest that climatic changes enhance growth and thus shorten the duration of the grass stage in these seedlings. However, the effects of climatic changes on growth depend strongly on how rainfall seasonality is altered in SE Asia because prolonged drought episodes may retard the fertilizing effects of the increasing CO2 concentration.
Modelling the interannual variability of net ecosystem CO2 exchange at a subarctic sedge fen
Authors: Griffis Timothy J. , Rouse Wayne R.
Published: March 2003

This paper presents an empirical model of net ecosystem CO2 exchange (NEE) developed for a subarctic fen near Churchill, Manitoba. The model with observed data helps explain the interannual variability in growing season NEE. Five years of tower‐flux data are used to test and examine the seasonal behaviour of the model simulations. Processes controlling the observed interannual variability of CO2 exchange at the fen are examined by exploring the sensitivity of the model to changes in air temperature, precipitation and leaf area index. Results indicate that the sensitivity of NEE to changing environmental controls is complex and varies interannually depending on the initial conditions of the wetland. Changes in air temperature and the timing of precipitation events have a strong influence on NEE, which is largely manifest in gross ecosystem photosynthesis (GEP). Climate change scenarios indicate that warmer air temperatures will increase carbon acquisition during wet years but may act to reduce wetland carbon storage in years that experience a large water deficit early in the growing season. Model simulations for this subarctic sedge fen indicate that carbon acquisition is greatest during wet and warm conditions. This suggests therefore that carbon accumulation was greatest at this subarctic fen during its early developmental stages when hydroclimatic conditions were relatively wet and warm at approximately 2500 years before present.
Polyanionic stretch‐deleted histone chaperone cia1/Asf1p is functional both in vivo and in vitro
Authors: Umehara Takashi , Chimura Takahiko , Ichikawa Natsuko , Horikoshi Masami
Published: March 2003

Background: CIA, an interactor of the CCG1 histone acetyltransferase subunit of TFIID, was identified as a human histone chaperone. The Saccharomyces cerevisiae orthologue ASF1, when it was over‐expressed, was reported to cause de‐repression of silent loci; however, the involvement of Asf1p in the alteration of nucleosomal structures remained unknown. Curiously, there is a polyanionic stretch, a structural motif characteristic of histone chaperones, in S. cerevisiae Asf1p, but not in human CIA. We investigated how CIA/Asf1p utilizes its domain(s) for the alteration of nucleosomal structure.

Results: To characterize the relationships between the domain structures and nuclear functions of CIA, we isolated the gene for the CIA counterpart in Schizosaccharomyces pombe, designated cia1+, whose putative product contains a polyanionic stretch. Gene disruption of cia1+ was lethal, which is the distinct phenotype of viable S. cerevisiae asf1. The cia1− lethality was rescued by the introduction of S. cerevisiae ASF1, but not by the introduction of human CIA cDNA. To our surprise, the construct that produces Asf1p, lacking the polyanionic stretch, is capable of rescuing the lethality caused by the cia1+ deletion, while the highly conserved N‐terminal region of Asf1p is essential for the complementation of cia1− growth defects. The polyanionic stretch‐deleted Asf1p is sufficient both for interaction with histones H3/H4 and for nucleosome assembly in vitro, as well as for telomeric de‐repression in vivo.

Conclusion: These findings suggest that the areas responsible for both the conserved and species‐specific functions of CIA/cia1/Asf1p are within their highly conserved regions and that the yeast‐specific polyanionic stretch of cia1/Asf1p is not necessary for viability, histone binding, nucleosome assembly, or anti‐silencing.
Serotonin and neuroendocrine peptides influence DNA synthesis in rat and human small intestinal cells	in vitro
Authors: ZACHRISSON  , URIBE
Published: March 2003

Animal studies suggest a mediator role for neuroendocrine peptides and amines in regulating cell proliferation in the gastrointestinal epithelium. Our aim was to examine the effect of serotonin and selected gastrointestinal peptides on DNA synthesis in a rat and human small intestinal cell line in vitro. IEC‐6 and FHs‐74 cells were incubated with epidermal growth factor (EGF), insulin‐like growth factor II, glucagon, substance P, neurokinin A, calcitonin gene‐related peptide (GRP, CCGRP), neurotensin and serotonin. The cells were labelled with [methyl‐3H] thymidine and processed for autoradiography. DNA synthesis was evaluated by the labelling index. Epidermal growth factor, insulin‐like growth factor II, glucagon, and substance P increased the labelling index in a dose‐related manner (P < 0.003). In contrast, a significant dose‐dependent reduction of the labelling index was observed after administration of serotonin and neurokinin A (P < 0.0001). Neurotensin and CGRP did not affect the labelling index. EGF, insulin‐like growth factor II, glucagon, substance P, serotonin and neurokinin A may be important physiological regulators of proliferation, of gastrointestinal cells.
Effects of age and gender on shortening velocity and myosin isoforms in single rat muscle fibres
Authors: Degens H. , Yu F. , Li X. , Larsson L.
Published: March 2003

The maximum velocity of unloaded shortening (V0) and the myosin heavy chain (MyHC) and light chain (MyLC) isoform composition were determined in single fibres from soleus and extensor digitorum longus (EDL) muscles of male and female rats 3–6 and 22–24 months old. In the soleus muscle, the β/slow (type I MyHC) isoform predominated in both young and old animals, irrespective of gender. In the EDL, fibres expressing type IIX MyHC or a combination of IIX and IIB (IIXB) MyHC isoforms were predominant in old rats, while type IIB MyHC fibres predominated in young individuals of both genders. The V0 of soleus fibres expressing the type I MyHC isoform decreased (P < 0.001) by 40% with age in spite of an unchanged MyLC composition. In the EDL, the V0 of fibres expressing IIX, IIXB and IIB MyHC isoforms did not change with age or differ between males and females. In conclusion, similar age‐related changes in V0 and MyHC composition were observed in single muscle cells from both male and female rats. The present results demonstrate that the relationship between V0 and MyHC isoform composition at the single fibre level is similar in male and female rats, and that similar qualitative changes take place during ageing in both genders.
A2 adenosine receptors in Mongolian gerbil middle ear epithelium and their regulation of Cl− secretion
Authors: Furukawa M. , Ikeda K. , Oshima T. , Suzuki H. , Yamaya M. , Sasaki H. , Takasaka T.
Published: March 2003

The present study investigates the effects of adenosine and its analogues on Cl− secretion in primary cultures of gerbil middle ear epithelium. Short‐circuit current (Isc), an index of transepithelial active transport, was measured on the same cells cultured on porous filters. Baseline Isc and transepithelial resistance were 27.0 ± 0.7 μA cm−2 and 275 ± 7 Ω cm2, respectively (n = 178). Extracellular adenosine and its analogues elicited a sustained increase in Isc when added to apical or basolateral surfaces. Both the A2A selective agonist 2‐p‐(2‐carboxyethyl)phenethylamino‐5′‐N‐ethylcarboxamido adenosine and the A2A/A2B nonselective agonist 5'‐(N‐ethyl‐carboxamido)adenosine (NECA) increased Isc, but NECA was more effective than CGS21680. A1 selective antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine did not reduce NECA‐induced Isc. These results suggest the presence of both A2A and A2B receptors. NECA did not stimulate a rise in the intracellular Ca2+ concentration ([Ca2+]i) in single middle ear epithelial cells cultured on glass coverslips. Dibutyryl cAMP (dbcAMP) induced an initial transient increase in Isc followed by the sustained plateau. Addition of dbcAMP also caused a transient increase in [Ca2+]i. The protein kinase A inhibitor, N‐[2‐(p‐bromocinnamylamino)ethyl]‐5‐isoquinolinesulfonamide, greatly reduced the increase in the Isc responses to NECA. 1,2‐Bis‐(2‐aminophenoxy)ethane N,N,N',N'‐tetraacetic acid‐acetoxymethyl ester influenced neither the NECA‐induced increase in Isc nor the dbcAMP‐induced sustained phase of Isc, but greatly inhibited the dbcAMP‐induced transient increase in Isc. Glibenclamide, a cystic fibrosis transmembrane conductance regulator (CFTR) channel inhibitor, reduced the NECA‐induced Isc. These results indicate that extracellular adenosine and its analogues activate the cAMP‐protein kinase A system, but not intracellular Ca2+‐dependent mechanisms, leading to Cl− secretion, possibly through the CFTR Cl− channels in the cultured gerbil middle ear epithelium.
Effect of chronic electrical stimulation and β‐GPA diet on GLUT4 protein concentration in rat skeletal muscle
Authors: YASPELKIS III B.B. , CASTLE A.L. , FARRAR R.P. , IVY J.L.
Published: March 2003

The present study investigated whether alterations in the muscle high energy phosphate state initiates the contraction‐induced increase in skeletal muscle GLUT4 protein concentration. Sprague‐Dawley rats were provided either a normal or a 2% β‐guanidinoproprionic acid (β‐GPA) diet for 8 weeks and then the gastrocnemius of one hind limb was subjected to 0, 14 or 28 days of chronic (24 h day−1) low‐frequency electrical stimulation (10 Hz). The β‐GPA diet, in the absence of electrical stimulation, significantly reduced ATP, creatine phosphate, creatine and inorganic phosphate and elevated GLUT4 protein concentration by 60% without altering adenylate cyclase activity or cAMP concentration. Following 14 days of electrical stimulation, GLUT4 protein concentration was elevated above non‐stimulated muscle in both groups but was significantly more elevated in the β‐GPA group. Concurrent with this greater rise in GLUT4 protein concentration was a greater decline in the high energy phosphates and a greater rise in cAMP. After 28 days of electrical stimulation, GLUT4 protein concentration and cAMP stabilized and was not different between diet treatments. However, the high energy phosphates were significantly higher in the normal diet rats as opposed to the β‐GPA rats. These findings therefore suggest that a reduction in cellular energy supply initiates the contraction‐induced increase in muscle GLUT4 protein concentration, but that a rise in cAMP may potentiate this effect.
Effects of endothelin receptor type A antagonism and nitric oxide synthase inhibition on cerebral blood flow in hypertensive rats
Authors: GRANSTAM  , GRANSTAM  , FELLSTRÖM  , LIND
Published: March 2003

Effects of the endothelin receptor type A antagonist BQ 123 and the NO synthase inhibitor L‐NMMA on cerebral blood flow were studied in vivo in anaesthetized hypertensive (SHR) and normotensive (WKY) rats. The effects of acetylcholine following pre‐treatment with these drugs were also studied with the microsphere method for blood flow determination in the cortex, thalamus, caudatus, pons, medulla, cerebellum and hypophysis. BQ 123 (1 mg kg−1) induced only minor effects on cerebral blood flow in both strains (n = 8), whereas
L‐NMMA (N = 8; 20 mg kg−1) reduced regional cerebral blood flow significantly in most regions (21–54%) in the hypertensive, but not in the normotensive rat. In normotensive rats pre‐treated with BQ 123 intravenous administration of acetylcholine (2 μg kg−1 min−1) induced a widespread significant increase (20–50%) in cerebral blood flow despite a reduction of the mean arterial blood pressure, while no significant effects were seen in hypertensive animals. Intravenous infusion of acetylcholine in animals pre‐treated with
L‐NMMA did not affect cerebral blood flow in most regions in either of the two rat strains. In conclusion, a vasodilatory response to acetylcholine was found following endothelin receptor A antagonism in the WKY rat only, suggesting a role for endothelin in the control of cerebral blood flow in this strain. Furthermore, a higher basal vasodilating nitric oxide‐tone seems to be present in the hypertensive rat compared with the normotensive rat.
K+ channel modulation in arterial smooth muscle
Authors: STANDEN  , QUAYLE
Published: March 2003

Potassium channels play an essential role in the membrane potential of arterial smooth muscle, and also in regulating contractile tone. Four types of K+ channel have been described in vascular smooth muscle: Voltage‐activated K+ channels (KV) are encoded by the Kv gene family, Ca2+‐activated K+ channels (BKCa) are encoded by the slogene, inward rectifiers (KIR) by Kir2.0, and ATP‐sensitive K+ channels (KATP) by Kir6.0 and sulphonylurea receptor genes. In smooth muscle, the channel subunit genes reported to be expressed are: Kv1.0, Kv1.2, Kv1.4–1.6, Kv2.1, Kv9.3, Kvβ1–β4, slo α and β, Kir2.1, Kir6.2, and SUR1 and SUR2. Arterial K+ channels are modulated by physiological vasodilators, which increase K+ channel activity, and vasoconstrictors, which decrease it. Several vasodilators acting at receptors linked to cAMP‐dependent protein kinase activate KATP channels. These include adenosine, calcitonin gene‐related peptide, and β‐adrenoceptor agonists. β‐adrenoceptors can also activate BKCa and KV channels. Several vasoconstrictors that activate protein kinase C inhibit KATP channels, and inhibition of BKCa and KV channels through PKC has also been described. Activators of cGMP‐dependent protein kinase, in particular NO, activate BKCa channels, and possibly KATP channels. Hypoxia leads to activation of KATP channels, and activation of BKCa channels has also been reported. Hypoxic pulmonary vasoconstriction involves inhibition of KV channels. Vasodilation to increased external K+ involves KIR channels. Endothelium‐derived hyperpolarizing factor activates K+ channels that are not yet clearly defined. Such K+ channel modulations, through their effects on membrane potential and contractile tone, make important contributions to the regulation of blood flow.
Confocal imaging of calcium release events in single smooth muscle cells
Authors: BOLTON  , GORDIENKO
Published: March 2003

Localized [Ca2+]i transients (‘sparks’) first directly detected in cardiac myocytes were considered to represent ‘elementary’ Ca2+‐release events playing a key role during excitation–contraction coupling (
Cheng et al. 1993
). In this study we employed confocal [Ca2+]i imaging to characterize subcellular calcium signalling in fluo‐3 loaded visceral and vascular smooth muscle cells. In some experiments membrane potential of the myocyte was controlled using whole‐cell patch clamp technique and changes in membrane current were recorded simultaneously with [Ca2+]i imaging. Some local [Ca2+]i transients were very similar to ‘Ca2+ sparks’ observed in heart, i.e. lasting ≈200 ms with a peak fluorescence ratio of 1.75 ± 0.23 (mean ± SD, n = 33). Ca2+ sparks were found to occur in certain preferred locations in the cell, termed frequent discharge sites. Other events were faster and smaller, lasting only ≈40 ms with a peak normalized fluorescence of 1.36 ± 0.09 (mean ± SD, n = 28). A high correlation between spontaneous transient outward currents and spark occurrence was observed. Proliferating waves of elevated [Ca2+]i initiated during membrane depolarization seem to arise from spatio‐temporal recruitment of local Ca2+‐release events. The spatial non‐uniformity of sarcoplasmic reticulum and ryanodine receptor distribution within the cell may account for the existence of ‘frequent discharge sites’ and the wide variation in the Ca2+ wave propagation velocities observed.
Tension/stiffness ratio of skinned rat skeletal muscle fibre types at various temperatures
Authors: GALLER  , HILBER
Published: March 2003

It is well known that shortening velocity and maximal tension of muscle preparations are strongly dependent on experimental temperature. Conversely, studies about temperature effects on muscle fibre stiffness are scarce. In the present study, we measured tension and stiffness of maximally Ca2+‐activated skinned rat skeletal muscle fibres of different types over a wide temperature range. All fibre types exhibited a similar tension/stiffness ratio at each experimental temperature. This ratio increased almost linearly from 6 to 18 nm when the temperature was raised from 6 to 34 °C. Our results are discussed in the light of the drastic discrepancies reported for the amount of compliance inside and outside the attached myosin cross‐bridges of activated muscle fibres (Ford et al. 1981, Huxley et al. 1994, Kojima et al. 1994, Wakabayashi et al. 1994, Higuchi et al. 1995). The relation between these compliances had been deduced from various experimental approaches executed at different temperatures. The large temperature sensitivity of the tension/stiffness ratio found in this study provides evidence for the assumption that the compliance outside the cross‐bridges increases with rising temperature. This view would reconcile the contrasting results reported for the relation of compliances inside and outside the attached cross‐bridges.
The role of antidiuretic hormone in cold‐induced diuresis in the anaesthetized rat
Authors: BROMAN  , KÄLLSKOG  , NYGREN  , WOLGAST
Published: March 2003

The aim of this study was to investigate whether the increased diuresis in consequence of hypothermia is due to a depression of the hypothalamic release of antidiuretic hormone (ADH). The plasma concentration of antidiuretic hormone and the effect of intravenous (i.v.) administration of 65 ng kg−1 desmopressin (selective V2‐receptor agonist) were determined in the anaesthetized rat. In spite of a 50% (P < 0.001) decrease in glomerular filtration rate, urine flow increased sixfold (P < 0.01) and urine sodium excretion increased sevenfold (P < 0.05), whereas urine osmolality decreased (P < 0.001). At the same time plasma antidiuretic hormone decreased from 7.5 ± 1.1 to 3.8 ± 0.4 pg mL−1 (P = 0.01). After injection of desmopressin urine flow was completely restored, whereas urine osmolality and sodium excretion were only partially normalized. Since tubular conservation of water and fractional water reabsorption decreased during hypothermia, the diuresis must have resulted from an augmented loss of water. This is further supported by the fact that osmolal excretion was not influenced either by hypothermia or by desmopressin. It is concluded that the diuresis in consequence to hypothermia is due both to a decrease in the release of ADH and to a reduction of renal medullary hypertonicity.
Neural regulation of myosin gene expression in regenerating skeletal muscle
Authors: SCHIAFFINO  , SERRANO  , JERKOVIC  , LISI  , MURGIA
Published: March 2003

Excitation–transcription coupling, namely the process whereby plasma membrane depolarization leads to gene activation or inactivation, is still a black box for most muscle genes. Muscle regeneration is a useful model system to ask basic questions concerning the triggering signals and the transduction pathways involved in activity‐dependent gene regulation. We report ongoing research in our laboratory concerning (1) myosin heavy chain changes in regenerating muscle in the presence and absence of the nerve, as well as changes induced by electrical stimulation, (2) identification of activity response elements in the promoter of a slow myosin light chain gene, and (3) potential approaches to define the transduction pathways induced by neural or electrical activity and implicated in muscle gene regulation.
Haemodynamic influence and endothelin‐1 plasma concentrations by selective or non‐selective endothelin receptor antagonists in the pig in vivo
Authors: HOLM  , FRANCO‐CERECEDA
Published: March 2003

In the present study the haemodynamical effects of endothelin (ET)‐receptor antagonism was evaluated using selective and non‐selective ETA‐ and ETB‐receptor blockade in normoxic pigs in vivo. In addition, the influence of the ET‐antagonists on circulating plasma ET‐1 levels was determined. BMS‐182874 (10 and 30 mg kg−1 i.v.), a selective ETA‐receptor antagonist decreased the pulmonary and systemic vascular resistances. bosentan (10 and 30 mg −1 i.v.), a non‐selective ETA‐ and ETB‐ receptor antagonist caused principally similar effects as ETA‐antagonism alone. No effects were observed by selective ETB‐blockade using BQ‐788 (30 μg kg−1 i.v.). Of the three antagonists used only bosentan increased the circulating plasma ET‐1 levels. It may therefore be concluded that ET contributes to basal systemic and pulmonary vascular tone through ETA‐receptor activation. ETB‐receptors are likely to cause the elevated plasma levels of ET‐1 observed after bosentan administration. Furthermore, circulating plasma levels of ET‐1 do not reflect the physiological effects of ET‐1.