Opportunities, approaches and challenges to the engagement of citizens in filling small water body data gaps.

Monitoring the condition (water quality, biodiversity, hydromorphology) of small water bodies presents a challenge for the relevant authorities in terms of time and resources (labour and financial) due to the extensive length of the stream network or the sheer number of small standing water bodies. Citizen science can help address information gaps, but the effort required should not be underestimated if such projects are to generate reliable and sustained data collection. The overall aim of this paper is to propose a framework for operationalisation of citizen science targeting collection of data from small water bodies. We first consider the data gaps and the elements (water chemistry, ecology, hydromorphology) to be addressed, in order to define where citizen science could best make an impact. We review examples of tools and methods that are appropriate for small water bodies, based on experience from a selection of freshwater citizen science projects, and the support that is needed for effective and sustained small water body projects across Europe.

Validation of scale-age determination in European grayling Thymallus thymallus using tag-recapture analysis.

To validate age determination from scales in European grayling Thymallus thymallus, the scale-read age of fish was compared with the true age obtained by tag-recapture analysis. A total of 3997 individuals were tagged with visible implant tags and passive integrated transponder (PIT) tags in the River Wylye, south-west England during 1999-2007. Annual repeat surveys were undertaken and collected scales read without prior knowledge of tag-recapture age. Accuracy of fish ageing by scales was highest in 1 and 2 year-old fish but decreased in older fish. In later life stages (>4 years old), underestimation of age occurred and the error in reading scales rose to 51.9% in 5 year-old fish. Age assigned from scales underestimated the tag-recapture assigned age by as much as 3 years. This study suggests that use of scales is an appropriate method to age a short-lived population of T. thymallus inhabiting productive lotic systems. The underestimation of age in older fish, however, needs to be considered in the management of fish stocks because it may lead to undesirable exploitation of population.

Extracellular matrix contains insulin-like growth factor binding protein-5: potentiation of the effects of IGF-I.

Insulin-like growth factor binding proteins (IGFBPs) have been shown to serve as carrier proteins for the insulin-like growth factors (IGFs) and to modulate their biologic effects. Since extracellular matrix (ECM) has been shown to be a reservoir for IGF-I and IGF-II, we examined the ECM of cultured human fetal fibroblasts and found that IGFBP-5 was incorporated intact into ECM, while mostly inert proteolytic fragments were found in the medium. In contrast, two other forms of IGFBP that are secreted by these cells were either present in ECM in minimal amounts (IGFBP-3) or not detected (IGFBP-4). Likewise, when purified IGFBPs were incubated with ECM, IGFBP-5 bound preferentially. IGFBP-5 was found to bind to types III and IV collagen, laminin, and fibronectin. Increasing salt concentrations inhibited the binding of IGFBP-5 to ECM and accelerated the release of IGFBP-5 from ECM, suggesting an ionic basis for this interaction. ECM-associated IGFBP-5 had a sevenfold decrease in affinity for IGF-I compared to IGFBP-5 in solution. Furthermore, when IGFBP-5 was present in cell culture substrata, it potentiated the growth stimulatory effects of IGF-I on fibroblasts. When IGFBP-5 was present only in the medium, it was degraded to a 22-kD fragment and had no effect on IGF-I-stimulated growth. We conclude that IGFBP-5 is present in fibroblast ECM, where it is protected from degradation and can potentiate the biologic actions of IGF-I. These findings provide a molecular explanation for the association of the IGF's with the extracellular matrix, and suggest that the binding of the IGF's to matrix, via IGFBP-5, may be important in mediating the cellular growth response to these growth factors.

Factors influencing movement behaviour and home range size in ide Leuciscus idus.

Seventeen individuals of ide Leuciscus idus were radio-tracked weekly from September 2003 to September 2004 in the River Elbe, Czech Republic, to examine migration patterns and the influence of environmental factors on their diurnal behaviour. Of the 10 environmental factors measured, L. idus were significantly influenced by turbidity, which increased diurnal movement and the home range size of the species. The peak of longitudinal movement occurred in the spring, indicating pre-spawning migration. Migrating fish moved downstream and later returned upstream to the vicinity of their original locations, displaying a homing behaviour.

Determining the sources of nutrient flux to water in headwater catchments: Examining the speciation balance to inform the targeting of mitigation measures.

Diffuse water pollution from agriculture (DWPA) is a major environmental concern, with significant adverse impacts on both human and ecosystem health. However, without an appropriate understanding of the multiple factors impacting on water, mitigation measures cannot be targeted. Therefore, this paper addresses this gap in understanding, reporting the hydrochemical monitoring evidence collected from the UK Government's Demonstration Test Catchments (DTC) programme including contrasting chalk and clay/mudstone catchments. We use data collected at daily and sub-daily frequency over multiple sites to address: (1) How does the behaviour of the full range of nitrogen (N) species and phosphorus (P) fractions vary? (2) How do N species and P fractions vary inter- and intra-annually? (3) What do these data indicate about the primary pollution sources? And (4) which diffuse pollution mitigation measures are appropriate in our study landscapes? Key differences in the rates of flux of nutrients were identified, dependent on catchment characteristics. Full N speciation and P fractionation, together with dissolved organic carbon (DOC) enabled identification of the most likely contributing sources in each catchment. Nitrate (NO3-N) was the dominant N fraction in the chalk whereas organic and particulate N comprised the majority of the load in the clay/mudstone catchments. Despite current legislation, orthophosphate (PO4-P) was not found to be the dominant form of P in any of the catchments monitored. The chalk sub-catchments had the largest proportion of inorganic/dissolved organic P (DOP), accompanied by episodic delivery of particulate P (PP). Contrastingly, the clay/mudstone sub-catchments loads were dominated by PP and DOP. Thus, our results show that by monitoring both the inorganic and organic fractions a more complete picture of catchment nutrient fluxes can be determined, and sources of pollution pin-pointed. Ultimately, policy and management to bring nutrient impacts under control will only be successful if a multi-stressor approach is adopted.

Does fine sediment source as well as quantity affect salmonid embryo mortality and development?

Fine sediments are known to be an important cause of increased mortality in benthic spawning fish. To date, most of the research has focussed on the relationship between embryo mortality and the quantity of fine sediment accumulated in the egg pocket. However, recent evidence suggests a) that the source of fine sediment might also be important, and b) that fitness of surviving embryos post-hatch might also be impacted by the accumulation of fine sediments. In this paper, we report an experiment designed to simulate the incubation environment of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). During the experiment, the incubating embryos were exposed to different quantities of fine (<63 µm) sediment derived from four different sources; agricultural topsoils, damaged road verges, eroding river channel banks and tertiary level treated sewage. Results showed that mass and source are independently important for determining the mortality and fitness of alevin. Differences between species were observed, such that brown trout are less sensitive to mass and source of accumulated sediment. We demonstrate for the first time that sediment source is an additional control on the impact of fine sediment, and that this is primarily controlled by the organic matter content and oxygen consumption of the catchment source material.

Tackling agricultural diffuse pollution: What might uptake of farmer-preferred measures deliver for emissions to water and air?

Mitigation of agricultural diffuse pollution poses a significant policy challenge across Europe and particularly in the UK. Existing combined regulatory and voluntary approaches applied in the UK continue to fail to deliver the necessary environmental outcomes for a variety of reasons including failure to achieve high adoption rates. It is therefore logical to identify specific on-farm mitigation measures towards which farmers express positive attitudes for higher future uptake rates. Accordingly, a farmer attitudinal survey was undertaken during phase one of the Demonstration Test Catchment programme in England to understand those measures towards which surveyed farmers are most receptive to increasing implementation in the future. A total of 29 on-farm measures were shortlisted by this baseline farm survey. This shortlist comprised many low cost or cost-neutral measures suggesting that costs continue to represent a principal selection criterion for many farmers. The 29 measures were mapped onto relevant major farm types and input, assuming 95% uptake, to a national scale multi-pollutant modelling framework to predict the technically feasible impact on annual agricultural emissions to water and air, relative to business as usual. Simulated median emission reductions, relative to current practise, for water management catchments across England and Wales, were estimated to be in the order sediment (20%)>ammonia (16%)>total phosphorus (15%) ≫ nitrate/methane (11%)>nitrous oxide (7%). The corresponding median annual total cost of the modelled scenario to farmers was £3 ha(-1)yr(-1), with a corresponding range of -£84 ha(-1)yr(-1) (i.e. a net saving) to £33 ha(-1)yr(-1). The results suggest that those mitigation measures which surveyed farmers are most inclined to implement in the future would improve the environmental performance of agriculture in England and Wales at minimum to low cost per hectare.

Understanding the controls on deposited fine sediment in the streams of agricultural catchments.

Excessive sediment pressure on aquatic habitats is of global concern. A unique dataset, comprising instantaneous measurements of deposited fine sediment in 230 agricultural streams across England and Wales, was analysed in relation to 20 potential explanatory catchment and channel variables. The most effective explanatory variable for the amount of deposited sediment was found to be stream power, calculated for bankfull flow and used to index the capacity of the stream to transport sediment. Both stream power and velocity category were highly significant (p ≪ 0.001), explaining some 57% variation in total fine sediment mass. Modelled sediment pressure, predominantly from agriculture, was marginally significant (p<0.05) and explained a further 1% variation. The relationship was slightly stronger for erosional zones, providing 62% explanation overall. In the case of the deposited surface drape, stream power was again found to be the most effective explanatory variable (p<0.001) but velocity category, baseflow index and modelled sediment pressure were all significant (p<0.01); each provided an additional 2% explanation to an overall 50%. It is suggested that, in general, the study sites were transport-limited and the majority of stream beds were saturated by fine sediment. For sites below saturation, the upper envelope of measured fine sediment mass increased with modelled sediment pressure. The practical implications of these findings are that (i) targets for fine sediment loads need to take into account the ability of streams to transport/retain fine sediment, and (ii) where agricultural mitigation measures are implemented to reduce delivery of sediment, river management to mobilise/remove fines may also be needed in order to effect an improvement in ecological status in cases where streams are already saturated with fines and unlikely to self-cleanse.

Binding of [125I]iodipine to parathyroid cell membranes: evidence of a dihydropyridine-sensitive calcium channel.

The parathyroid cell is unusual, in that an increase in extracellular calcium concentrations inhibits PTH release. Calcium channels are glycoproteins that span cell membranes and allow entry of extracellular calcium into cells. We have demonstrated that the calcium channel agonist (+)202-791, which opens calcium channels, inhibits PTH release and that the antagonist (-)202-791, which closes calcium channels, stimulates PTH release. To identify the calcium channels responsible for these effects, we used a radioligand that specifically binds to calcium channels. Bovine parathyroid cell membranes were prepared and incubated under reduced lighting with [125I] iodipine (SA, 2000 Ci/mmol), which recognizes 1,4-dihydropyridine-sensitive calcium channels. Bound ligand was separated from free ligand by rapid filtration through Whatman GF/B filters. Nonspecific binding was measured by the inclusion of nifedipine at 10 microM. Specific binding represented approximately 40% of the total binding. The optimal temperature for [125I] iodipine binding was 4 C, and binding reached equilibrium by 30 min. The equilibrium dissociation constant (Kd) was approximately 550 pM, and the maximum number of binding sites was 780 fmol/mg protein. Both the calcium channel agonist (+)202-791 and antagonist (-)202-791 competitively inhibited [125I] iodipine binding, with 50% inhibition concentrations of 20 and 300 nM, respectively. These data indicate the presence of dihydropyridine-sensitive calcium channels on parathyroid cell membranes.

Insulin-like growth factor (IGF)-binding proteins inhibit the smooth muscle cell migration responses to IGF-I and IGF-II.

Smooth muscle cells have been shown to migrate in response to insulin-like growth factor I (IGF-I). However, the role of IGF-binding proteins (IGFBPs) in this process has not been determined. As IGFBPs are synthesized and secreted by smooth muscle cells and bind to IGFs with high affinity, this study was undertaken to determine the ability of IGFBP-1 and -2 to modulate cellular migration in response to IGF-I and -II. Confluent monolayers of porcine vascular smooth muscle cells were wounded with a razor blade. After wounding, IGF-I and -II induced increases of 159 +/- 49% (mean +/- SD) and 108 +/- 33%, respectively, above control values in the number of cells migrating over a fixed distance in 4 days. The addition of IGFBP-1 caused a 19-21% inhibition of IGF-I- or IGF-II-stimulated migration, whereas the addition of IGFBP-2 inhibited the effect of both by greater than 60%. The addition of IGFBP-2 alone had no effect, whereas IGFBP-1 addition was associated with a 42 +/- 12% increase. In contrast, [Trp221]IGFBP-1 in which the RGD sequence was changed to WGD, thus eliminating its capacity to bind to the alpha 5 beta 1 integrin, inhibited IGF-I-stimulated migration by 67 +/- 17%. An IGF analog that has a reduced affinity for IGFBP-2-stimulated migration equally well as IGF-I alone even in the presence of IGFBP-2. Likewise, the addition of insulin, which cannot bind to IGFBPs, at supraphysiological concentrations that are adequate to activate the IGF-I receptor resulted in a similar increase in migration. In summary, IGF-I and -II stimulate smooth muscle cell migration after wounding. This migratory response is modulated by IGFBPs. Both IGFBP-1 and IGFBP-2 appear to neutralize the effects of the IGFs by inhibiting their interaction with IGF receptors, but IGFBP-1 also has a direct stimulatory effect that requires an intact RGD integrin recognition sequence.

Physiology and organ-related pathology of the elderly: stomach ulcers.

Peptic ulcer disease, particularly as a result of its complications, is a burden that is focused on the elderly through their higher Helicobacter pylori prevalence and use of non-steroidal anti-inflammatory drugs (NSAIDs). In these patients, senescence may further increase ulcer susceptibility, particularly in the stomach, by the loss of mucosal protection and repair mechanisms. Age is mainly a marker for the increased prevalence of other complicated ulcer risk factors such as previous ulcer history and use of anti-coagulants, steroids and aspirin. The development of selective cyclo-oxygenase inhibitors (coxibs) has reduced the specific risk of NSAID ulceration, but the residual incidence in high risk patients remains substantially higher than that in young patients without other risk factors. The argument for early surgery versus endoscopic therapy in high risk patients with bleeding ulcers has not been resolved, both having a high mortality. There is still potential for the development of new strategies to prevent primary and secondary ulcers, either by new drug development or by expanding existing co-prescription strategies.

The Spacehaler for delivery of salbutamol: a comparison with the standard metered-dose inhaler plus Volumatic spacer device.

The Spacehaler is a new, compact, pressurized aerosol device that uses the same canister as a conventional metered-dose inhaler (MDI). Its design, however, reduces the velocity of the aerosol cloud that emerges from the inhaler, thereby reducing the amount of the non-respirable fraction of the drug delivered to the patient. Large volume spacers achieve a similar effect, but they are bulky and therefore inconvenient to use and carry around. This study compared the bronchodilator effect of 200 micrograms salbutamol delivered by the Spacehaler to that of an MDI used with a Volumatic spacer (MDI plus spacer) in patients with reversible obstructive airways disease. Twenty-five patients with asthma, having a forced expiratory volume in 1 s (FEV1) between 50 and 90% predicted and a reversibility of > or = 15% to 200 micrograms salbutamol given by the conventional (standard) MDI entered the study. On two separate study days, they inhaled 200 micrograms salbutamol either via the Spacehaler or the MDI plus spacer. To maintain blinding, they received placebo on both study days via the alternate device. Their FEV1, forced vital capacity (FVC) and peak expiratory flow (PEF) were measured before and at regular intervals for 6 h after inhalation. Assessment of equivalence between the two devices was based on whether the 90% confidence interval for the difference between the weighted mean FEV1 was within +/- 0.25 1. Patient preference was assessed by a questionnaire at the end of the second study day. Twenty-four patients completed the study. Both devices produced a significant improvement in FEV1 (P < 0.02). The upper and lower 90% confidence limits for the difference in weighted mean FEV1 between the devices was +/- 0.041, and the 99% confidence limits were +0.061 and -0.071. The weighted means for FVC and PEF, and the duration of effect and peak responses for FEV1, FVC and PEF also showed no difference between the two devices. Patients found no difficulty in using the Spacehaler, and 20 out of 24 patients (83.3%) preferred it to the MDI plus spacer. The bronchodilator effect of 200 micrograms salbutamol administered by a Spacehaler was equivalent to that produced by an MDI plus spacer in this group of patients with reversible airways obstruction. The majority of patients preferred it to a large volume spacer.

Improved targeting of beclomethasone diproprionate (250 micrograms metered dose inhaler) to the lungs of asthmatics with the Spacehaler.

The Spacehaler (Evans Medical Ltd, Leatherhead, U.K.) is a new, compact, inhaler device containing the same aerosol canister as a conventional metered dose inhaler (MDI). However, the design of the Spacehaler has been shown to reduce the velocity of the aerosol, thus reducing the proportion of non-respirable particles delivered to the patient. This study compared radioaerosol deposition patterns following inhalation of 250 micrograms of beclomethasone dipropionate from the Spacehaler and a conventional MDI (Beclazone, Norton Health Care, Harlow, U.K.). After rigorous in vitro validation of the radiolabelling technique, 12 asthmatic subjects (seven men aged 20-69 years, mean baseline FEV1 2.59 1 (SD 0.55 1) received one dose of 99mTc-labelled beclomethasone dipropionate 250 micrograms via either a Spacehaler or MDI on each of two study days in a randomized cross-over manner. All subjects had been taught the required inhalation technique before the dose was administered. Inhalation details were recorded using a spirometer connected in series with the device. Lung and oropharyngeal depositions were measured by gamma scintigraphy. The mean percentage of the metered dose deposited in the lungs was 23.0% (SD 8.3%) for the Spacehaler and 12.8% (SD 6.8%) for the MDI (P < 0.01). However, there was no significant difference in the distribution patterns within the lungs between the two devices. Oropharyngeal deposition was significantly lower (P < 0.01) for the Spacehaler than for the MDI [mean (SD) 27.9% (16.4%) and 73.6% (8.7%), respectively] whilst the percentage of the metered dose remaining on the Spacehaler actuator was significantly greater than that on the MDI actuator [mean (SD) 48.0% (11.8%) and 12.4% (8.5%) respectively, P < 0.01]. There was evidence from the inhalation recordings that some patients experienced the 'cold Freon effect' whilst using the metered dose inhaler which may have contributed to the lower lung deposition seen with this device. This study demonstrates that the proportion of a 250 micrograms dose of beclomethasone dipropionate that is delivered to the lungs is significantly greater with the Spacehaler than the MDI. The Spacehaler also reduces the proportion of the does that is deposited in the oropharynx to less than half that observed with the MDI, and reduces the total dose of drug received by the patient.

Do submerged aquatic plants influence their periphyton to enhance the growth and reproduction of invertebrate mutualists?

It has been suggested that submerged aquatic plants can influence the nutritional quality of the periphyton which grows on their surfaces, making it more nutritious for grazing invertebrates, particularly snails. In return, these grazers might preferentially feed on the periphyton and clear the plants of a potential competitor, with the plants and grazers both gaining from this mutualistic relationship. A highly replicated experiment was conducted, in which the nature of the plant (isoetid and elodeid types compared with similar-shaped inert substrata), the nutrient loading, and the influence of periphyton grazers (the bladder snail, Physa fontinalis) of similar size and history were controlled. Plant growth and survival significantly increased in the presence of the periphyton grazer. Whilst the presence of the grazers had the largest influence on periphyton abundance, nutrient availability and plant type also had effects. Plant type had little influence on the nutritional quality of the periphyton measured as carbohydrate, protein and C:N. Effects of treatment on snail growth, and the timing and extent of snail reproduction disappeared when they were compared with the quantity of periphyton available. There was no evidence of enhanced grazer success in the presence of the live plants compared with inert substrata. Although submerged plants affect the growth and reproduction of the grazers which feed on their surfaces, through differences in the amount of periphyton which grows there, we found no evidence that they manipulate the periphyton to encourage such grazers.

Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England.

The ingress of particulate material into freshwater spawning substrates is thought to be contributing to the declining success of salmonids reported over recent years for many rivers. Accordingly, the need for reliable information on the key sources of the sediment problem has progressed up the management agenda. Whilst previous work has focussed on apportioning the sources of minerogenic fine sediment degrading spawning habitats, there remains a need to develop procedures for generating corresponding information for the potentially harmful sediment-bound organic matter that represents an overlooked component of interstitial sediment. A source tracing procedure based on composite signatures combining bulk stable (13)C and (15)N isotope values with organic molecular structures detected using near infrared (NIR) reflectance spectroscopy was therefore used to assess the primary sources of sediment-bound organic matter sampled from artificial spawning redds. Composite signatures were selected using a combination of the Kruskal-Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were collected using time-integrating basket traps which were inserted at the start of the salmonid spawning season and extracted in conjunction with critical phases of fish development (eyeing, hatch, emergence, late spawning). Over the duration of these four basket extractions, the overall relative frequency-weighted average median (±95% confidence limits) source contributions to the interstitial sediment-bound organic matter were estimated to be in the order: instream decaying vegetation (39±<1%; full range 0-77%); damaged road verges (28±<1%; full range 0-77%); septic tanks (22±<1%; full range 0-50%), and; farm yard manures/slurries (11±<1%; full range 0-61%). The reported procedure provides a promising basis for understanding the key sources of interstitial sediment-bound organic matter and can be applied alongside apportionment for the minerogenic component of fine-grained sediment ingressing the benthos. The findings suggest that human septic waste contributes to the interstitial fines ingressing salmonid spawning habitat in the study area.

Gastrointestinal safety of COX-2 specific inhibitors.

Coxibs are a major advance in the therapy of patients with painful and inflammatory conditions. At present, the theoretical harm that derives from inhibiting vascular COX-2 has not emerged as a significant risk, although more research is needed. What has emerged is that some NSAIDs, particularly naproxen, may have an aspirin-like effect in reducing the risk of vascular disease, although more research is needed. Whether this finding is sufficient to recommend naproxen for the management of patients with arthritis who also require vascular protection is intriguing and worth further evaluation. It is widely believed and maintained that coxibs have the greatest potential value in patients with other risk factors for ulcer disease, and this seems likely to be the case for patients taking corticosteroids or anticoagulants and probably those who are elderly. Dosing should be [figure: see text] cautious in old patients, however, because of the ability of NSAIDs and coxibs to cause fluid retention, heart failure, and hypertension. It is less clear that coxibs reduce risk sufficiently in patients with previous ulceration (particularly recent) to make them a better strategy than acid co-therapy. This possibility requires further evaluation, as does the competing value of the 2 strategies for patients infected with H. pylori. If coxibs are used in patients with H. pylori-associated risks, there are grounds to recommend eradication. For patients taking aspirin or drugs [figure: see text] with an aspirin-like effect, the intrinsic risk of these drugs may mandate use of acid suppression and obviate the use of coxibs (Fig. 8). Available data suggest that the risk reduction in patients with no risk factors who use coxibs may be almost as great as in patients with risk factors, with the added advantage that patients may be taken to a state that is virtually free of any risk of ulcer complications that otherwise might require additional therapy. Contrary to current popular truisms, the greatest value of coxibs may be in patients without risk factors because it is in this unconfounded group that the ability of coxibs to free patients of ulcer risk appears to be delivered in full.

The roles of integrins and extracellular matrix proteins in the insulin-like growth factor I-stimulated chemotaxis of human breast cancer cells.

The effects of insulin-like growth factor I (IGF-I) on the migration of two human breast cancer cell lines, MCF-7 and MDA-231, were examined using a modified Boyden chamber. 10 ng/ml was the optimal IGF-I concentration for stimulation of migration. The majority of IGF-I-stimulated migration in both cell types was due to chemotaxis. MCF-7 cells failed to migrate on membranes coated with gelatin or fibronectin and migrated only in small numbers on laminin. In contrast, when vitronectin- or type IV collagen-coated membranes were used, the MCF-7 cells migrated in large numbers specifically in response to IGF-I but not to 10% fetal calf serum, epidermal growth factor, fibroblast growth factor, or platelet derived growth factor-BB. An IGF-I receptor-blocking antibody inhibited IGF-I-stimulated migration in both cell types. In addition, a blocking antibody to the alpha v beta 5 integrin (a vitronectin receptor) inhibited migration of MCF-7 cells in response to IGF-I through vitronectin but not through type IV collagen. Similarly, blocking antibodies specific for alpha 2 and beta 1 integrins significantly inhibited migration of both cell types through type IV collagen-coated membranes but not through vitronectin-coated membranes. We conclude that: 1) IGF-I stimulates migration of these two cell types through the IGF-I receptor; 2) interaction of vitronectin with the alpha v beta 5 integrin or collagen with the alpha 2 beta 1 integrin is necessary for the complete IGF-I response in MCF-7 cells, and 3) because migration represents an in vitro model for metastatic spread, integrins, extracellular matrix proteins, and IGF-I may play coordinated roles in the metastasis of breast cancer in vivo.

Characterization of insulin-like growth factor binding protein-1 kinases from human hepatoma cells.

The phosphorylation of insulin-like growth factor binding protein-I (IGFBP-1) alters its binding affinity for insulin-like growth factor I (IGF-I) and thus regulates the bioavailability of IGF-I for binding to the IGF-I receptor. The kinase(s) responsible for the phosphorylation of IGFBP-1 has not been identified. This study was designed to characterize the IGFBP-1 kinase activity in HepG2 human hepatoma cells, a cell line that secretes IGFBP-1 primarily as phosphorylated isoforms. IGFBP-1 kinase activity was partially purified from detergent extracts of the cells by phosphocellulose chromatography and gel filtration. Two kinases of approximate M(r) 150,000 (peak I kinase) and M(r) 50,000 (peak II kinase) were identified. Each kinase phosphorylated IGFBP-1 at serine residues that were phosphorylated by intact HepG2 cells. The kinases were distinct based on their differential sensitivity to inhibition by heparin (IC50 = 2.5 and 16.5 micrograms/ml, peak I and II kinase, respectively) and inhibition by the isoquinoline sulfonamide CKI-7 (IC50 = 50 microM and 100 microM, peak I and II kinase, respectively). In addition, a tenfold molar excess of nonradioactive GTP relative to [gamma-32P]ATP lowered the incorporation of 32P into IGFBP-1 by 80% when the reaction was catalyzed by the peak I kinase, whereas GTP had no effect on the reaction catalyzed by the peak II kinase. In the presence of polylysine, IGFBP-1 was radiolabeled by the partially purified kinase activity when [gamma-32P]GTP served as the phosphate donor indicating the presence of casein kinase II activity. Furthermore, IGFBP-1 was phosphorylated by purified casein kinase I and casein kinase II at sites phosphorylated by the peak I and II kinases. Our data suggest that at least two kinases could be responsible for the phosphorylation of IGFBP-1 in intact HepG2 cells and that the kinases are related to the casein kinase family of protein kinases.