Antibacterial effects of nanopillar surfaces are mediated by cell impedance, penetration and induction of oxidative stress

Some insects, such as dragonflies, have evolved nanoprotrusions on their wings that rupture bacteria on contact. This has inspired the design of antibacterial implant surfaces with insect-wing mimetic nanopillars made of synthetic materials. Here, we characterise the physiological and morphological effects of mimetic titanium nanopillars on bacteria. The nanopillars induce deformation and penetration of the Gram-positive and Gram-negative bacterial cell envelope, but do not rupture or lyse bacteria. They can also inhibit bacterial cell division, and trigger production of reactive oxygen species and increased abundance of oxidative stress proteins. Our results indicate that nanopillars' antibacterial activities may be mediated by oxidative stress, and do not necessarily require bacterial lysis.

Clinical Presentation and Positive Outcome of Two Siblings with Holocarboxylase Synthetase Deficiency Caused by a Homozygous L216R Mutation

Purpose The L216R mutation, seen in individuals of Polynesian descent, is considered one of the most severe mutations associated with holocarboxylase synthetase (HLCS) deficiency and is regarded as being unresponsive to biotin. This report describes the presentation and outcome in two surviving siblings, homozygous for this highly lethal mutation. Methods and results Both cases had perinatal head imaging findings of brain hemorrhage and subependymal cysts. Both had metabolic decompensation within 24 h after birth consisting of metabolic acidosis, lactic acidosis, and thrombocytopenia. Biochemical profiles were consistent with HLCS deficiency, and genetic analysis confirmed homozygosity for the L216R mutation. After resolution of neonatal metabolic crisis, dosing of biotin was titrated on an outpatient basis to primarily control dermatitis. The eldest is currently on 1.2 g of oral biotin daily, well above any dose previously reported to treat HLCS deficiency. To date, neither patient has required hospital readmission for acute metabolic decompensation. At the age of 7, the eldest child is, to our knowledge, the oldest patient ever described in the literature who is homozygous for the L216R mutation. She has mild intellectual disability. Conclusion This report contrasts previous reports of poor outcomes and neonatal deaths in homozygous L216R patients. We also provide data on the potential upper tolerable limit of biotin. These cases suggest that the outcome of HCLS deficiency due to a homozygous L216R mutation, when diagnosed and treated early with high-level neonatal care and biotin, may not be as severe as previously reported.

Role of riverine colloids in macronutrient and metal partitioning and transport, along an upland-lowland land-use continuum, under low-flow conditions

An assessment is made of the role of riverine colloids in macronutrient (nitrogen, phosphorus and carbon), metal and trace element partitioning and transport, for five rivers in the Ribble and Wyre catchments in north-western England, under baseflow/near-baseflow conditions. Cross-flow ultrafiltration was used to separate colloidal (<0.45 µm >1 kDa) and truly dissolved (<1 kDa) fractions from river water. Clear patterns were observed, along the upland-lowland land use continuum, in the partitioning and transport of macronutrients and metals between the colloidal, truly dissolved and acid-available particulate (>0.45 μm, suspended) fractions. Of these operationally-defined fractions measured, colloids were generally more important for both macronutrient and metal transport in the upland than in the lowland rivers. The results suggest that organic moieties in truly dissolved form from sewage effluent may have a greater capacity to chelate metals. Organic-rich colloids in the upland moorlands and metal oxide colloidal precipitates in the industrial rivers had a higher capacity for binding metals than the colloidal fractions in the urban and agricultural lowland rivers. Aggregation of these colloids may provide an important mechanism for formation of larger suspended particulates, accounting for a higher degree of metal enrichment in the acid-available particulate fractions of the upland moorland and lowland industrial rivers, than in the lowland agricultural and urban rivers. This mechanism of transfer of contaminants to larger aggregates via colloidal intermediates, known as 'colloidal pumping' may also provide a mechanism for particulate P formation and the high proportion of P being transported in the particulate fraction in the uplands. The cross-flow ultrafiltration data also allowed refinement of partition coefficients, by accounting for colloids within the solids phase and replacing the filtered (<0.45 μm) fraction with the truly dissolved (<1 kDa) concentrations. These provided a clearer description of the controls on metal and P partitioning along the upland-lowland continuum.

Manganese in the upper Severn mid-Wales

The concentrations of manganese (Mn) in the Upper River Severn (the Plynlimon catchments) are examined in relation to rainfall, cloud water, throughfall, stemflow and stream water concentrations where there is over 20 years of monitoring data available. Manganese concentrations are particularly low in rainfall and cloud water, with maximum concentrations occurring under low volumes of catch due to atmospheric "washout" of contaminants and dry deposition. There is strong Mn enrichment in throughfall and stemflow and this is probably linked to cycling through the vegetation. Manganese in the streams and groundwaters are primarily supplied from within-catchment sources. The highest concentrations occur within the tree canopy probably due to element cycling and in groundwaters due to mobilisation from the rock. Manganese concentrations in streams are at their lowest during spring and summer following long dry spells, with rapid increases following subsequent rain. There is no clear long-term trend in Mn concentration in the streams although there are increases in Mn concentrations for years when there is extensive felling of spruce plantation forest and in 1995 following a more extensive dry period. New high resolution monitoring picks up the effects of the rising limb of the hydrograph when concentrations rapidly increase, diurnal patterns during summer low-flow periods and contrasting dynamics between moorland and forested catchments.

Changes in water quality of the River Frome (UK) from 1965 to 2009: is phosphorus mitigation finally working?

The water quality of the River Frome, Dorset, southern England, was monitored at weekly intervals from 1965 until 2009. Determinands included phosphorus, nitrogen, silicon, potassium, calcium, sodium, magnesium, pH, alkalinity and temperature. Nitrate-N concentrations increased from an annual average of 2.4 mg l⁻¹ in the mid to late 1960s to 6.0 mg l⁻¹ in 2008-2009, but the rate of increase was beginning to slow. Annual soluble reactive phosphorus (SRP) concentrations increased from 101 μg l⁻¹ in the mid 1960s to a maximum of 190 μg l⁻¹ in 1989. In 2002, there was a step reduction in SRP concentration (average=88 μg l⁻¹ in 2002-2005), with further improvement in 2007-2009 (average=49 μg l⁻¹), due to the introduction of phosphorus stripping at sewage treatment works. Phosphorus and nitrate concentrations showed clear annual cycles, related to the timing of inputs from the catchment, and within-stream bioaccumulation and release. Annual depressions in silicon concentration each spring (due to diatom proliferation) reached a maximum between 1980 and 1991, (the period of maximum SRP concentration) indicating that algal biomass had increased within the river. The timing of these silicon depressions was closely related to temperature. Excess carbon dioxide partial pressures (EpCO₂) of 60 times atmospheric CO₂ were also observed through the winter periods from 1980 to 1992, when phosphorus concentration was greatest, indicating very high respiration rates due to microbial decomposition of this enhanced biomass. Declining phosphorus concentrations since 2002 reduced productivity and algal biomass in the summer, and EpCO₂ through the winter, indicating that sewage treatment improvements had improved riverine ecology. Algal blooms were limited by phosphorus, rather than silicon concentration. The value of long-term water quality data sets is discussed. The data from this monitoring programme are made freely available to the wider science community through the CEH data portal (http://gateway.ceh.ac.uk/).

The biogeochemistry of arsenic in a remote UK upland site: trends in rainfall and runoff, and comparisons with urban rivers

Ten years of monitoring of rainfall and streams in the remote acidic and acid sensitive moorland and afforested moorland of upland mid-Wales reveals concentrations of arsenic (As) typically <1 µg L(-1). On average, the lowest concentrations occur within rainfall and they have declined over time probably in response to reductions in global emissions. There is a corresponding reduction within the streams except for forested systems where concentrations up to doubled following clear-fell. Within the streams there are both annual cycling and diurnal cycling of As. The annual cycling gives maxima during the summer months and this probably reflects the importance of groundwater inputs and mineralisation/desorption from the surface soil layers. Correspondingly, the diurnal cycling occurs during the summer months at low flow periods with As concentrations highest in the afternoon/evening. For the urban/industrial basins of northern England with historically a much higher As deposition, land contamination and effluent discharges, comparative data indicate As concentrations around three fold higher: strong seasonal patterns are observed for the same reasons as with the uplands. Across the sites, the As concentrations are over an order of magnitude lower than that of environmental concern. Nonetheless, the results clearly show the effects of declining emissions on rainfall deposition and some indication of areas of historic contamination. Arsenic is mainly present in the <0.45 fraction, but cross-flow filtration indicates that approx. 43% is in the colloidal phase at the clean water sites, and 16% in the colloidal phase at the contaminated sites. Part of this colloidal component may well be associated with organic carbon.

Challenges in the design and conduct of controlled clinical effectiveness trials in schizophrenia

BACKGROUND

The introduction of antipsychotic medication has been a major advance in the treatment of schizophrenia and allows millions of people to live outside of institutions. It is generally believed that long-acting intramuscular antipsychotic medication is the most effective approach to increasing medication adherence and thereby reduce relapse in high-risk patients with schizophrenia, but the data are scant.

PURPOSE

To report the design of a study to assess the effect of long-acting injectable risperidone in unstable patients and under more realistic conditions than previously studied and to evaluate the effect of this medication on psychiatric inpatient hospitalization, schizophrenia symptoms, quality of life, medication adherence, side effects, and health care costs.

METHODS

The trial was an open randomized clinical comparative effectiveness trial in patients with schizophrenia or schizo-affective disorders in which parenteral risperidone was compared to an oral antipsychotic regimen selected by each control patient's psychiatrist. Participants had unstable psychiatric disease defined by recent hospitalization or exhibition of unusual need for psychiatric services. The primary endpoint was hospitalization for psychiatric indications; the secondary endpoint was psychiatric symptoms.

RESULTS

Overall, 382 patients were randomized. Determination of a persons' competency to understand the elements of informed consent was addressed. The use of a closed-circuit TV interview for psychosocial measures provided an economical, high quality, reliable means of collecting data. A unique method for insuring that usual care was optimal was incorporated in the follow-up of all subjects.

LIMITATIONS

Patients with schizophrenia or schizo-affective disorders and with the common co-morbid illnesses seen in the VA are a challenging group of subjects to study in long-term trials. Some techniques unique in the VA and found useful may not be generalizable or applicable in other research or treatment settings.

CONCLUSIONS

The trial tested a new antipsychotic medication early in its adoption in the Veterans Health Administration. The VA has a unique electronic medical record and database which can be used to identify the endpoint, that is, first hospitalization due to a psychiatric problem, with complete ascertainment. Several methodologic solutions addressed competency to understand elements of consent, the costs and reliability of collecting interview data gathering, and insuring usual care.

A spatial and seasonal assessment of river water chemistry across North West England

This paper presents information on the spatial and seasonal patterns of river water chemistry at approximately 800 sites in North West England based on data from the Environment Agency regional monitoring programme. Within a GIS framework, the linkages between average water chemistry (pH, sulphate, base cations, nutrients and metals) catchment characteristics (topography, land cover, soil hydrology, base flow index and geology), rainfall, deposition chemistry and geo-spatial information on discharge consents (point sources) are examined. Water quality maps reveal that there is a clear distinction between the uplands and lowlands. Upland waters are acidic and have low concentrations of base cations, explained by background geological sources and land cover. Localised high concentrations of metals occur in areas of the Cumbrian Fells which are subjected to mining effluent inputs. Nutrient concentrations are low in the uplands with the exception sites receiving effluent inputs from rural point sources. In the lowlands, both past and present human activities have a major impact on river water chemistry, especially in the urban and industrial heartlands of Greater Manchester, south Lancashire and Merseyside. Over 40% of the sites have average orthophosphate concentrations >0.1mg-Pl(-1). Results suggest that the dominant control on orthophosphate concentrations is point source contributions from sewage effluent inputs. Diffuse agricultural sources are also important, although this influence is masked by the impact of point sources. Average nitrate concentrations are linked to the coverage of arable land, although sewage effluent inputs have a significant effect on nitrate concentrations. Metal concentrations in the lowlands are linked to diffuse and point sources. The study demonstrates that point sources, as well as diffuse sources, need to be considered when targeting measures for the effective reduction in river nutrient concentrations. This issue is clearly important with regards to the European Union Water Framework Directive, eutrophication and river water quality.

The validation of a bioanalytical method for the determination of clopidogrel in human plasma

A fast, sensitive and specific LC-MS/MS bioanalytical method for the determination of unchanged clopidogrel in human plasma has been developed and validated over the range of 10-12,000 pg mL(-1) (r2 0.9993) by the Contract Research group at HFL. Samples (0.3 mL) were buffered (pH 6.8), extracted using diethyl ether and 10 microL of the sample extract was injected onto the LC-MS/MS system. Analysis was performed using a C8 column (temperature controlled to 50 degrees C) by gradient elution at a flow rate of 0.9 mL min(-1) over a 3 min run time. Retention times of 1.61 and 1.59 min were observed for clopidogrel and 2H3-clopidogrel (I.S.), respectively. Detection was achieved using a Sciex API 4000, triple quadrupole mass spectrometer, in positive TurboIonspray (electrospray) ionisation mode. Ion transitions were monitored using MRM (multiple reaction monitoring) for clopidogrel (m/z 322-212) and for 2H3-clopidogrel (m/z 327-217). This validated method was used to support a pharmacokinetic study in healthy volunteers.

Mitochondrial-related gene expression changes are sensitive to agonal-pH state: implications for brain disorders

Mitochondrial defects in gene expression have been implicated in the pathophysiology of bipolar disorder and schizophrenia. We have now contrasted control brains with low pH versus high pH and showed that 28% of genes in mitochondrial-related pathways meet criteria for differential expression. A majority of genes in the mitochondrial, chaperone and proteasome pathways of nuclear DNA-encoded gene expression were decreased with decreased brain pH, whereas a majority of genes in the apoptotic and reactive oxygen stress pathways showed an increased gene expression with a decreased brain pH. There was a significant increase in mitochondrial DNA copy number and mitochondrial DNA gene expression with increased agonal duration. To minimize effects of agonal-pH state on mood disorder comparisons, two classic approaches were used, removing all subjects with low pH and agonal factors from analysis, or grouping low and high pH as a separate variable. Three groups of potential candidate genes emerged that may be mood disorder related: (a) genes that showed no sensitivity to pH but were differentially expressed in bipolar disorder or major depressive disorder; (b) genes that were altered by agonal-pH in one direction but altered in mood disorder in the opposite direction to agonal-pH and (c) genes with agonal-pH sensitivity that displayed the same direction of changes in mood disorder. Genes from these categories such as NR4A1 and HSPA2 were confirmed with Q-PCR. The interpretation of postmortem brain studies involving broad mitochondrial gene expression and related pathway alterations must be monitored against the strong effect of agonal-pH state. Genes with the least sensitivity to agonal-pH could present a starting point for candidate gene search in neuropsychiatric disorders.

Use of a nitrogen arm-stabilized endoscopic microdriver in neuroendoscopic surgery

Stabilization and manipulation of instruments in endoscopic neurosurgery has traditionally been a manual task. Conventional self-retaining retractors have failed to provide reliable fixation for endoscopic procedures. Most surgeons rely on a team approach to endoscopy with one individual controlling the endoscope while the other manipulates instruments within the field of view. This two-surgeon approach is manpower intensive and not an option at many facilities. Recently developed technology provides the independent practitioner with another option. Several nitrogen-powered stabilizing arms have been introduced which decrease or eliminate problems with post-positioning drift. To facilitate fine maneuvering of the endoscope, a new positioning arm is available with an incorporated microdriver capable of sub-millimeter adjustments. We present an illustrative case of the utility of this device in selected endoscopic procedures.

Chemical behaviour of the Wheal Jane bioremediation system

The effectiveness of remediation of the highly acidic and transition metal polluted mine water discharge from the Wheal Jane Mine by the Wheal Jane Passive Treatment Plant is described. The success of the remediation required that all the system components work as predicted. The study shows considerable success in the removal of key toxic metals and clearly demonstrates the potential for natural attenuation of acid mine drainage, particularly iron oxidation, by microbial populations. The Wheal Jane Passive Treatment Plant provides the only experimental facility of its kind.

Henoch-Schönlein purpura following hepatitis B vaccination

The use of recombinant hepatitis B vaccines has led to the effective prevention of hepatitis B infection and its chronic sequelae in immunocompetent individuals. Whilst rare, a variety of serious adverse effects have been reported following vaccination including cutaneous vasculitis in eight previous cases. We describe a case of Henoch-Schönlein purpura developing after hepatitis B vaccination.

A summary of boron surface water quality data throughout the European Union

The distribution of boron in rivers across European Union countries is described. The data have been collected from national and international monitoring programmes. The data show a wide range of concentrations but only in a few instances do concentrations exceed environmental quality standards. Although there is a good body of data for the analysis presented here, it is clear that there is not a full coverage of environments and for some studies there is a clear bias towards sampling of the main rivers or specific rivers where there are environmental concerns. The variations in concentration link directly to pollutant sources although assessment of the details of the spatial variations is clouded by factors such as the location of monitoring points in relation to pollutant discharges, the variation in dilution potential of the various rivers and contrasting hydrological and geological environments. The data are presented to complement more detailed studies on particular river basins as a basis for the further development of regional environmental impact water quality modelling frameworks and within the newly developing field of typological settings.

Seasonality and water quality trends in a maturing recreated reed bed

The socio-economic and ecological value of wetland ecosystems is widely acknowledged. As a result, considerable efforts are now being made to rehabilitate and in some cases recreate wetlands throughout Europe. An option for the restoration of worked-out peat pits is to establish reed beds. Ham Wall, located in Somerset in the UK, comprises reed bed and a mosaic of other wetland habitats that has been constructed as a wildlife area. Since 1996, water chemistry has been monitored for a 16.5 ha wetland compartment planted with reeds in July 1995. Water is pumped into the reed bed from Ham Wall Rhyne, a drainage ditch supplied with nutrient-rich runoff from the surrounding agricultural land. The principal objectives of the research described in this paper were to investigate differences in the chemistry of water from different locations in the vicinity of the wetland and to evaluate seasonal changes and trends in water quality as the reeds matured. The results obtained provide insight into the biogeochemical functioning of the wetland system.

Measuring in-stream productivity: the potential of continuous chlorophyll and dissolved oxygen monitoring for assessing the ecological status of surface waters

Continuous (hourly) measurements of dissolved oxygen and chlorophyll (determined by fluorimetry) were made for an inter-linked lowland river and canal system. The dissolved oxygen data were used to estimate daily rates of re-aeration, photosynthesis and respiration, using a process-based analytical technique (the Delta method). In-situ fluorimeter measurements of chlorophyll were ground-truthed on a fortnightly basis using laboratory methanol extraction of chlorophyll and spectrophotometric analysis. Water samples were also analysed for algal species on a fortnightly basis. The river and canal exhibited very similar rates of photosynthesis and respiration during the summer of 2001, despite much higher chlorophyll concentrations and total algal counts, indicating that benthic algae and/or aquatic macrophytes may be making an important contribution to photosynthesis rates in the river. Suspended algal populations in the canal are dominated by planktonic species, whereas the river has a higher proportion of species which are predominantly benthic in habitat. The river exhibited higher rates of respiration, reflecting a higher organic loading from external (e.g. sewage effluent) sources.

Phosphorus uptake into algal biofilms in a lowland chalk river

This paper examines the growth and uptake of phosphorus into algal biofilms in the River Kennet, a lowland chalk (Cretaceous-age) stream in southern England. Algal biofilms were grown on artificial plastic substrates (templates) placed (i) on the riverbed and (ii) within the mid-water column. Experiments were set up to examine differences in growth rates of newly colonising biofilms compared with biofilms left to accumulate for periods of up to 6 months. Rates of algal biofilm production were measured by the chlorophyll a concentration that had accumulated per cm2 over the number of days that the biofilm template had been immersed in the river water. An algal biofilm bloom occurred in early spring, prior to peak suspended chlorophyll a concentrations within the water column. Biofilm samples collected in February and March had the highest chlorophyll a and total phosphorus concentrations. The biofilm bloom corresponded with increased solar radiation and declining river flow conditions. Periodic increases in soluble reactive phosphorus concentrations in the overlying river water did not correspond with any significant increase in biofilm production. These results suggest that light, rather than phosphorus is a key factor for biofilm growth in the River Kennet. Higher rates of chlorophyll a development in mid-water column biofilms may be linked to greater light exposure; however, maximum total-P concentrations were similar for both bed and water column biofilms. Newly colonising biofilms exhibited higher chlorophyll a and total-P concentrations than biofilms left to accumulate over longer terms, suggesting that fresh substrate availability promotes high rates of biofilm growth. Both 'condensed and organic' P (stored in biomass) and 'inorganic' (mineral) P fractions within the biofilms were present in varying proportions, although the early spring biofilm bloom resulted in maximum proportions and absolute concentrations of 'condensed and organic' P. Calcite was the only crystalline mineral detected within the biofilms. Ratios of Ca:inorganic P are largely consistent with the presence of CaCO3-P co-precipitates, although one very low value suggested that there may also be additional sources of inorganic P, possibly P adsorbed to clays or organics within the biofilm. However, poor linkages between CaCO3 and inorganic P concentrations suggest that, although the inorganic P fraction within the biofilm may be derived largely from CaCO3-P co-precipitation, the subsequent processes controlling overall CaCO3 and inorganic P concentrations in the biofilm are complex.

Calcite saturation in the River Dee, NE Scotland

The spatial and temporal variations in calcite (calcium carbonate) solubility within the Dee basin of NE Scotland were assessed using water chemistry data gathered from a network of 59 sites monitored for water quality from June 1996 to May 1997. Calcite solubility, expressed in terms of a saturation index (SIcalcite), was determined from measured streamwater pH, Gran alkalinity and calcium concentrations and water temperature. In general, the waters of the Dee system are undersaturated with respect to calcite, though the saturation index is higher during the summer months indicating a dependency on flow conditions and biological activity. Under low-flow conditions, the streamwaters are dominated by water derived from the lower soil horizons and deeper groundwater stores and therefore, ions such as Gran alkalinity and calcium are at their highest concentrations as they are derived mainly from bedrock weathering. The influence of biological activity on the carbonate system is also evident as the observed pH and estimated EpCO2 values indicate strong seasonal patterns, with the highest pH and lowest EpCO2 values occurring during the summer low-flow periods. Only at three sites in the lowland region of the catchment, during the summer low-flow period, are the waters oversaturated. As such, the Dee system represents an extreme 'end-member' case when compared to many UK rivers that span both under- and oversaturated conditions during the year. Regression analysis highlights a systematic change in the SIcalcite-pH relationship in a broad east-west direction across the Dee system. At sites draining the relatively impermeable upland areas, the regression of SIcalcite against pH gives a straight line with a gradient in the range 1.6-2.4. Correspondingly, under the most extreme alkaline conditions found at sites draining lowland agricultural areas, a straight-line relationship exists but with a gradient of unity. It is concluded that these changes in the SIcalcite-pH relationship are due to variations in the bicarbonate system induced by the flow conditions and biological activity. Given the waters are undersaturated, then calcite precipitation and hence phosphorus co-precipitation cannot occur within the water column.

Quasi-periodic substructure in the microvessel endothelial glycocalyx: a possible explanation for molecular filtering?

The luminal surface of endothelial cells is lined with the glycocalyx, a network structure of glycoproteins probably 50 to 100 nm thick. It has been suggested that a relatively regular fibre-matrix structure may be responsible for the ultrafiltration properties of microvascular walls, both when the endothelium is continuous and when it is fenestrated. Positive structural evidence demonstrating an underlying periodicity in the glycocalyx has been hard to obtain. Here we present structural analysis of glycocalyx samples prepared in a variety of ways for electron microscopy. Using computed autocorrelation functions and Fourier transforms of representative areas of the electron micrograph images, we show that there is an underlying three-dimensional fibrous meshwork within the glycocalyx with characteristic spacings of about 20 nm. Together with a fibre diameter consistent with our observations of about 10-12 nm, the 20-nm spacing provides just the size regime to account satisfactorily for the observed molecular filtering; the observations are consistent with the fibre matrix model. We also show that the fibrous elements may occur in clusters with a common intercluster spacing of about 100 nm and speculate that this may reveal organisation of the glycocalyx by a quasi-regular submembranous cytoskeletal scaffold.

Widespread collaboration of Isw2 and Sin3-Rpd3 chromatin remodeling complexes in transcriptional repression

The yeast Isw2 chromatin remodeling complex functions in parallel with the Sin3-Rpd3 histone deacetylase complex to repress early meiotic genes upon recruitment by Ume6p. For many of these genes, the effect of an isw2 mutation is partially masked by a functional Sin3-Rpd3 complex. To identify the full range of genes repressed or activated by these factors and uncover hidden targets of Isw2-dependent regulation, we performed full genome expression analyses using cDNA microarrays. We find that the Isw2 complex functions mainly in repression of transcription in a parallel pathway with the Sin3-Rpd3 complex. In addition to Ume6 target genes, we find that many Ume6-independent genes are derepressed in mutants lacking functional Isw2 and Sin3-Rpd3 complexes. Conversely, we find that ume6 mutants, but not isw2 sin3 or isw2 rpd3 double mutants, have reduced fidelity of mitotic chromosome segregation, suggesting that one or more functions of Ume6p are independent of Sin3-Rpd3 and Isw2 complexes. Chromatin structure analyses of two nonmeiotic genes reveals increased DNase I sensitivity within their regulatory regions in an isw2 mutant, as seen previously for one meiotic locus. These data suggest that the Isw2 complex functions at Ume6-dependent and -independent loci to create DNase I-inaccessible chromatin structure by regulating the positioning or placement of nucleosomes.

An RGD sequence in the P2Y(2) receptor interacts with alpha(V)beta(3) integrins and is required for G(o)-mediated signal transduction

The P2Y(2) nucleotide receptor (P2Y(2)R) contains the integrin-binding domain arginine-glycine-aspartic acid (RGD) in its first extracellular loop, raising the possibility that this G protein-coupled receptor interacts directly with an integrin. Binding of a peptide corresponding to the first extracellular loop of the P2Y(2)R to K562 erythroleukemia cells was inhibited by antibodies against alpha(V)beta(3)/beta(5) integrins and the integrin-associated thrombospondin receptor, CD47. Immunofluorescence of cells transfected with epitope-tagged P2Y(2)Rs indicated that alpha(V) integrins colocalized 10-fold better with the wild-type P2Y(2)R than with a mutant P2Y(2)R in which the RGD sequence was replaced with RGE. Compared with the wild-type P2Y(2)R, the RGE mutant required 1,000-fold higher agonist concentrations to phosphorylate focal adhesion kinase, activate extracellular signal-regulated kinases, and initiate the PLC-dependent mobilization of intracellular Ca(2+). Furthermore, an anti-alpha(V) integrin antibody partially inhibited these signaling events mediated by the wild-type P2Y(2)R. Pertussis toxin, an inhibitor of G(i/o) proteins, partially inhibited Ca(2+) mobilization mediated by the wild-type P2Y(2)R, but not by the RGE mutant, suggesting that the RGD sequence is required for P2Y(2)R-mediated activation of G(o), but not G(q). Since CD47 has been shown to associate directly with G(i/o) family proteins, these results suggest that interactions between P2Y(2)Rs, integrins, and CD47 may be important for coupling the P2Y(2)R to G(o).

The environmental impact of heavy metals from sewage sludge in ferralsols (São Paulo, Brazil)

The spreading of sewage sludge on acidic ferralsol soil was simulated in a column experiment in order to estimate the potential impact on water and soil quality. Drainage and runoff water were sampled daily over a 2-month experiment and analysed for Fe, Ni, Cu, Pb and DOC. Results show a clear influence of the sludge on the water quality, especially at the start of the experiment, increasing the export of Cu, Ni, Pb and in DOC from the soil, mainly in dissolved form. Nickel was usually the most mobile element in the sludge and in the soil. In the soil, Pb mobility was complex and increased drastically with time compared to the other elements. No significant increase in soil heavy metal content due to the sludge spreading was recorded on this time scale.

Alkalinity measurements within natural waters: towards a standardised approach

A discussion on the measurement of alkalinity in bicarbonate bearing and acidic waters is presented as a move towards developing a standardised approach within the aquatic sciences. The discussion is based on theoretical and practical considerations. Practical illustrations are provided from measurements of calcium bicarbonate bearing waters (River Thames) and acidic to near neutral waters from acidic soil systems with calcium bearing groundwater sources (the mid-Wales region and the Scottish Dee basin). A comparison of single endpoint and Gran procedures is made and the various error terms assessed. It is concluded that single endpoint and Gran methodologies are applicable in the standard pH titration used in aquatic research (pH 4.5-4.0). However, analytical errors increase, particularly for the single endpoint titration, the lower the endpoint/endpoint-range in pH. For the Thames, the value of a single endpoint over a Gran procedure is illustrated. The Thames results show that some buffering components may still be titrated out within the Gran titration range used: this leads to an underestimate in the alkalinity. Indeed, by making a comparison between single endpoint and Gran alkalinity measurements, the Thames results indicated the presence of unexpected buffering components: the interrogative nature of this type of analysis is highlighted. A standardised approach is outlined.

Use of continuous water quality records for hydrograph separation and to assess short-term variability and extremes in acidity and dissolved carbon dioxide for the River Dee, Scotland

A combination of continuous (15-min) pH, conductivity and temperature measurements and fortnightly spot-sampled water quality data were used to examine temporal variability and extremes in river water quality in an upland Scottish river: the River Dee at Mar Lodge. An empirical relationship was established for Gran-alkalinity by multiple regression against flow and conductivity for the fortnightly data. Applying this relationship to the continuous data, an estimate of continuous Gran-alkalinity was calculated. The continuous Gran-alkalinity record was used as (1) a conservative tracer in a simple two-component mixing model to determine the relative proportions of near-surface runoff and deeper groundwater contributing to stream flow; (2) to deconvolute the contribution of weathering and sea-salt contributions to stream conductivity; and (3) to calculate the excess partial pressure of carbon dioxide in stream water. The episodic variations in pH, weathering and sea-salt conductivity and excess partial pressures of carbon dioxide (EpCO2) associated with high flow events in the River Dee suggest that hydrological pathways play an important role in determining stream chemistry. The results of the hydrograph separation indicate that groundwater provides an important contribution to stream flow, and that there are large and hydrologically active stores of groundwater within the upper River Dee catchment. Sea-salts have an important influence on stream conductivity, particularly with the onset of storm runoff following summer drought periods. This suggests that sea-salts are concentrated in the upper soil horizons by dry deposition and/or evapotranspiration. EpCO2 behaves non-conservatively and shows marked diurnal variability under low-flow conditions during summer, inducing diurnal pH variations, and indicating the importance of within-river biological processes. This study emphasises the very intermittent nature of water quality extremes with stream spates and the diurnal nature of biologically-induced responses. Fortnightly sampling programmes do not capture the range of high flow extremes, and with sampling undertaken during the working day, biological extremes occurring at night are also missed, introducing bias. This study shows the value of continuous measurements for infilling aspects of these intermittent extremes. However, it is also noted that the relatively simple patterns of response observed from the continuous measurements may well belie a much more varied response at the sub-catchment and hillslope scales, as local chemical and hydrological heterogeneities do occur. Thus, the two-component mixing model used is, in practice, based on catchment integrated values for a range of soil water and groundwater endmembers.

Environmental change, land use and water quality in Scotland: current issues and future prospects

An outline of both the scientific and management needs facing the future water quality issues of Scotland is discussed. The scientific needs are considered in terms of monitoring to increase the understanding of hydrochemical processes, issues of scaling, and the need for improved modelling under changing environmental processes. In terms of the management needs, the requirements highlighted relate to improving the ecological quality of Scottish rivers and the implementation of integrated river basin management plans.

Association of the cyclin-dependent kinases and 14-3-3 sigma negatively regulates cell cycle progression

14-3-3 sigma, implicated in cell cycle arrest by p53, was cloned by expression cloning through cyclin-dependent kinase 2 (CDK2) association. 14-3-3 sigma shares cyclin-CDK2 binding motifs with different cell cycle regulators, including p107, p130, p21(CIP1), p27(KIP1), and p57(KIP2), and is associated with cyclin.CDK complexes in vitro and in vivo. Overexpression of 14-3-3 sigma obstructs cell cycle entry by inhibiting cyclin-CDK activity in many breast cancer cell lines. Overexpression of 14-3-3 sigma can also inhibit cell proliferation and prevent anchorage-independent growth of these cell lines. These findings define 14-3-3 sigma as a negative regulator of the cell cycle progression and suggest that it has an important function in preventing breast tumor cell growth.

Loaded hydroxylapatite-coated implants and uncoated titanium-threaded implants in distracted dog alveolar ridges

AIMS

The aim of this study was to determine the response of alveolar bone after it was augmented vertically with distraction osteogenesis, implanted with hydroxylapatite (HA)-coated implants and noncoated titanium-threaded implants, and subsequently loaded for 1 year.

METHODS

Eight dogs each had 4 implants placed horizontally into an edentulous mandibular quadrant. After integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the distraction devices were stabilized with light cured resin. After bone fill of the distraction gap was radiographically confirmed in all dogs at 10 weeks, 2 implants were placed into the ridges. Four dogs had threaded titanium implants placed, and 4 dogs had threaded HA-coated implants placed, with 1 implant in the distracted bone and 1 implant in adjacent nondistracted bone, for both groups. After 4 months for implant integration, bridges were fabricated and secured to the implants with screws. Crestal bone levels were evaluated by radiographs through 1 year of function. Animals were killed after 1 year of loading for histologic evaluation.

RESULTS

The vertical ridge augmentation averaged 8.8 +/- 1.0 mm after 10 weeks of healing after distraction. Analysis of variance indicated a significantly greater change from baseline for HA-coated implants and for distracted bone sites. Histologic examination showed that bone had formed between the distracted segments creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone or the lingual and labial nondistracted cortical bone. The presence of a dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation.

CONCLUSION

Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis were functional for the length of this study.

The water quality of the River Kennet: initial observations on a lowland chalk stream impacted by sewage inputs and phosphorus remediation

The water quality of seven sites on the upper reaches of the River Kennet round the market town of Marlborough is described and related to the introduction of phosphorus treatment of effluent from Marlborough sewage treatment works (STW). The River Kennet is mainly groundwater-fed from a Cretaceous chalk aquifer and hence the river water is calcium- and bicarbonate-bearing and has a relatively constant composition of many major water quality determinants. In-stream biological activity gives rise to marked diurnal fluctuations in pH (of approx. 0.8 units). Dissolved carbon dioxide and dissolved oxygen also show marked diurnal fluctuations. Dissolved carbon dioxide varies from approximately 10 to 70 times atmospheric pressure, indicating net release of carbon dioxide and the dominance of heterotrophic (respiratory) processes over autotrophic processes (photosynthesis). Much of the excess carbon dioxide is probably associated with carbon dioxide laden groundwater inputs and the relatively short within-stream residence times ensures only limited degassing to the atmosphere. Diurnal fluctuations in dissolved oxygen vary from approximately 20% to 200% saturation. For both dissolved carbon dioxide and dissolved oxygen, the amplitude of fluctuations is much lower during the winter period, when biological activity is at its lowest. The concentrations of soluble reactive phosphorus (SRP), total phosphorus (TP) and boron increase markedly just downstream of the sewage works as a result of this point source input. These concentrations slowly decline further downstream as additional groundwater inputs dilute the effluent further. The introduction of chemical treatment of sewage effluent for phosphorus reduction at Marlborough STW resulted in a marked decrease in within-river SRP and TP concentrations to levels approximately the same as those upstream of the STW. A comparison of SRP and boron concentrations reveals a reduction in in-stream SRP concentrations by approximately 75% following effluent treatment. In terms of within-river processes controlling in-stream phosphorus concentrations, previous studies have indicated that one potentially important mechanism within calcium bicarbonate bearing rivers may be related to co-precipitation of phosphorus with calcium carbonate (calcite). The present study shows that the waters are oversaturated with respect to calcium carbonate, that no equilibrium conditions exist and that phosphorus removal has led to undetectable changes in calcium carbonate oversaturation. Hence, it is concluded that the primary changes in phosphorus levels within the river is directly associated with changing point source contributions from the STW and physical dilution within the river. However (1) the results relate to only the first year of study and subsequent differences may become apparent and (2) reactions between the water column and plant and bottom sediment interfaces may be important in regulating phosphorus fluxes within the river. The results presented in this paper mark a pilot phase of a longer-term initiative and this paper provides a background setting. The paper discusses the longer-term objectives and important gaps in knowledge of the system that requires further address.

Conclusions to the special issue of Science of the Total Environment concerning 'The water quality of UK rivers entering the North Sea'

This paper presents an overview of the water quality functioning of eastern UK rivers draining into the North Sea. It summarises the results of three special issues of Science of the Total Environment and related work and complements a companion bibliography (Neal and Turner, 2000, this volume). The rivers are described in straightforward broad terms, and the reader is guided via the bibliography to the special volumes for the detailed findings. The water quality is shown to be highly variable over space and time. The changes over the past 300 years reflect first the transition from a rural society to the major impact of the industrial revolution and subsequently to one of the worlds' most successful environmental cleanups. The present water quality reflects the relative impacts of diffuse agricultural sources, urban and industrial point source discharges together with background inputs associated with geology: all these can be modified by within-river processes associated with physical mixing, biology and inorganic reactions. The work is set within the context of water quality, modelling and flux outputs to the North Sea and contemporary and future environmental research and management needs. A range of environmental impact studies is included. The detailed information is now available on a major and easily accessible database.

The water quality of the River Thames at a rural site downstream of Oxford

Water quality information is presented for the River Thames 34 km downstream of the market town of Oxford in Oxfordshire to provide an overview of the hydrochemical functioning of a major agriculturally impacted river entering the North Sea. The data, which cover the period from the spring of 1997 to the spring of 1999, relate to three types of data. These types are: (1) weekly spot sampling for determination of major, minor and trace elements, pH, alkalinity and herbicides; (2) tri-weekly spot sampling for pH, alkalinity and dissolved silicon; and (3) continuous measurements of pH and dissolved oxygen. Calcium and bicarbonate provide, respectively, the dominant cation and anion in solution and their compositions remain relatively constant through time, irrespective of flow levels. In contrast, many determinands show seasonally related fluctuations. Concentrations for most of the major anions, sodium, potassium as well as soluble reactive phosphorus and several soluble trace elements such as boron, antimony, arsenic and molybdenum decrease as flow increases. A reverse pattern is observed for nitrate, some herbicides and trace elements associated with particulate phases: concentrations increase with increasing flow. These patterns reflect the influence of: (1) a calcium carbonate rich groundwater system which provides the main stream flow component; (2) dilution of point source pollutant inputs associated with sewage and possibly light industry at high flows for several major, nutrient and trace elements; (3) enhanced nitrate and herbicide runoff from agricultural land at high flows; (4) enhanced microparticulate trace metal levels associated with increased suspended sediment loads at high flows; and (5) biological processes which affect pH, dissolved silicon, dissolved carbon dioxide and dissolved oxygen levels. An examination of soluble reactive phosphorus (SRP) and boron relationships reveals a reduction in concentrations for SRP associated possibly with phosphorus removal from a major sewage treatment works on an upstream tributary of the Thames, the Thame.

Temporal and small-scale spatial variations of dissolved oxygen in the Rivers Thames, Pang and Kennet, UK

Small-scale spatial dissolved oxygen concentrations were measured on three rivers by taking a number of transects along a river reach. Temporal (diurnal) variations were measured by use of continuous (15-min) monitors located at the mid-transect of the spatial observations. Spatial variation of dissolved oxygen concentrations were found to be relatively small (approx. +/- 10% dissolved oxygen) and biologically insignificant compared to diurnal changes under conditions of high productivity (approx. +/- 60% dissolved oxygen). The diurnal curves were analysed in order to estimate values of reaeration, photosynthesis and respiration on a daily basis for almost 3 months using process-based analytical techniques (the Delta and Hornberger and Kelly methods). The River Kennet was shown to be the most productive river followed by the River Pang and then the River Thames. The patterns of reaeration, photosynthesis and respiration and the behaviour of the three rivers are discussed.

A summary of river water quality data collected within the Land-Ocean Interaction Study: core data for eastern UK rivers draining to the North Sea

A numerical summary of the water quality of rivers draining into the North Sea from the eastern UK is presented using core information collected within the Land-Ocean Interaction Study (LOIS) and a companion study by the Institute of Hydrology. The analysis is based on weekly monitoring for periods from 1993 to 1999 for major, minor, nutrient, trace and other water quality determinand chemistry. The data cover rivers ranging from the rural Tweed in southeastern Scotland, to the urban and industrially impacted Wear and Humber rivers in the north and central England and two agriculturally impacted rivers in the south of England (Great Ouse and Thames). Within the analysis, monthly averaged concentrations are plotted to show the seasonality. The summary provides specific information on the water quality of UK rivers which is of use in developing European and global initiatives for assessing pollutant inputs to estuarine, coastal and open-sea environments.

A bibliography for the conclusions to the special issue of Science of the Total Environment concerning 'The water quality of UK rivers entering the North Sea'. Sci. Tot. Environ., this volume

In this document, a bibliography for the conclusions to the special issue of Science of the Total Environment concerning 'The water quality of UK rivers entering the North Sea'. Sci. Tot. Environ., this volume, is presented. It comprises a list of the papers presented in five special issues in learned journals, three in Science of the Total Environment (this volume and volumes 194/195, 1997 and 210/211, 1998) as well as Hydrological Processes (1999, vol 13: Special Issue, River Basin Sediment Dynamics, eds. Anderson, M.G., Peters, N.E. and Walling, D.E.) and Marine Pollution Bulletin [1999, vol 37(3-7) Special Issue: Flux of Materials between Rivers and Coastal Waters, eds. Stebbing, A.R.D., Huntley, D. and Leeks, G.J.L.]. The bibliography comprises six main sections with subsections for specific water quality issues. These are as follows: Section 1 deals with the introduction to LOIS and contained in this section is background material over the nature of the programme, the study area, remit, water quality issues and international context. Section 2 provides the main meat to the bibliography and it splits into Section 2.1 historical and Section 2.2 current water quality issues. Within Section 2.2 there are subsections dealing with specific current aspects of water quality (Section 2.2.1, major ions; Section 2.2.2, pH, dissolved carbon dioxide and dissolved oxygen; Section 2.2.3 nutrients; Section 2.2.4, trace elements; Section 2.2.5 micro-organics; Section 2.2.6 sediments; Section 2.2.7 biology). Section 3 deals with hydrology and climate variability, Section 4, modelling, Section 5 load estimation and Section 6 conclusions. A full listing of the LOIS programme is available from the LOIS programme office, CCMS, Plymouth Laboratory, Prospect Place, West Hoe, Plymouth, PL1 3DH, UK (e-mail lois@ccms.ac.uk).

The water quality of the Great Ouse

The results of a 1-year detailed water quality study of the Great Ouse are presented. Being recharged to an important degree from groundwater sources within the carbonate bearing bedrock, the waters are enriched in base cations and they are of relatively high alkalinity (approx. 4000 microEq./l) and pH (approximately 8). Many chemical constituents such as sodium, chloride, boron, nitrate and soluble reactive phosphorus vary over time in response to changing flow conditions. For most determinands, concentrations decrease with increasing flow in response to dilution of point and groundwater sources by rainfall. However, for barium and nitrate, concentrations increase with flow and this is indicative of increased runoff from the agriculturally impacted soils. While this feature is certainly expected for nitrate due to fertiliser application, the pattern for barium is at face value unexpected as it would normally be expected to behave like other divalent base cations such as calcium, coming from aquifer leaching. However, it seems that agricultural disturbance of the land can also lead to enhanced runoff: a feature now becoming apparent in several UK studies. The concentrations of micro-organic herbicides vary over time in response to the different times of application and only isoproturon shows a clear response to varying flow conditions. With regards to biological processes, this is manifest by changes in pH, dissolved carbon dioxide and silica. At most times of the year the waters are oversaturated with respect to atmospheric CO2 (EpCO2) by a factor of approximately 6 and at these times pH is approximately 7.7 and silica concentrations are approximately 4 mg-Si/l. However, in the early spring period pH increases to values over 8, EpCO2 declines to about the atmospheric levels and silica declines to approximately 1 mg-Si/l. This change probably reflects the dynamic diatom blooms and decays common in this river.

The water quality of a tributary of the Thames, the Pang, southern England

The water quality of a tributary of the Thames, the Pang, draining a rural part of the Thames basin is described and related to the influences of inputs from farming activity and groundwater from the underlying chalk aquifer as modified by biological within-stream processes. The groundwater inputs ensures that the waters are calcium and bicarbonate bearing and have relatively uniform concentrations. Agricultural inputs result in enhanced levels of nutrients, nitrate and soluble reactive phosphorus (SRP) in particular. For nitrate, the concentrations are higher during the winter months due to increased surface runoff. In contrast, SRP shows a more erratic behaviour with higher concentrations occurring during the early storm hydrograph rise following summer baseflow recession. Within the stream, biological activity results in: (a) marked diurnal fluctuations in the dissolved levels of carbon dioxide and oxygen; (b) a strong seasonal pattern in chlorophyll a levels; and (c) dissolved silica concentration reductions during the early spring period. Carbon dioxide levels are particularly high in the groundwater (typically approximately 60 times the atmospheric value) as observed at a spring discharge. However, within the stream, considerable degassing occurs although values remain an order of magnitude above atmospheric pressure. The findings are discussed in the context of the water quality functioning of agriculturally and sewage impacted southern eastern UK rivers. For example, the work shows that unlike for riverine systems with point sewage discharges or limited groundwater storage, there is a very poor link between chemical concentrations and flow even for components such as SRP and boron which are often connected to sewage discharges.

Riverine inputs of major ions and trace elements to the tidal reaches of the River Tweed, UK

This paper examines spatial and temporal variability in freshwater inputs of trace elements and major ions to the tidal reaches of the River Tweed. The relationships between concentrations of major ions and trace elements (in dissolved and acid-available particulate forms) and flow are examined, and a simple two-component endmember mixing analysis performed to link river water chemistry to catchment sources, and to identify whether within-river processes modify concentrations to produce non-conservative behaviour. The results indicate that most dissolved major ions and trace elements behave conservatively in the lower reaches of the River Tweed, the variability in concentrations being dominated by hydrology and the existence of different high-flow and low-flow endmember runoff chemistries. This suggests that the variability in concentration of most dissolved trace elements and major ions in the lower Tweed can be modelled using simple mixing relationships. However, the relationships between pH, Ca, Mg and Gran alkalinity show pronounced non-conservative behaviour, indicating the importance of understanding within-river process for modelling these determinants. The non-conservative behaviour identified is related to biological controls and the resultant diurnal variations in pH which promote daytime removal of Ca from solution by precipitation of calcium carbonate (and corresponding removal of Mg by co-precipitation) during extreme low-flow conditions and algal blooms during the summer.

Phosphate measurement in natural waters: two examples of analytical problems associated with silica interference using phosphomolybdic acid methodologies

Assessment of phosphate species for bicarbonate-bearing lowland rivers of the Thames valley, England and acidic Welsh upland streams (the Plynlimon area, mid-Wales) reveal problems of silica interference when employing standard automated 'phosphomolybdic acid' colorimetric methodologies. The interference occurs under a combination of two conditions: (1) when the reagents and samples are heated to speed up the rate of formation of phosphomolybdic acid; and (2) when the strength of a sulfuric acid reagent is too low. While this paper alerts researchers to potential analytical problems with silica interference within phosphomolybdic acid methodologies to determine soluble reactive phosphorus (SRP) concentrations, it cannot detail whether or not there is a general problem. This lack of specificity occurs because there are a variety of phosphomolybdic acid methodologies available which vary in their reagent recipes and it is not clear which methods will or will not suffer from silica interference. Changing the sulfuric acid reagent strength by a factor of two overcame the problem, in this case, with regards to the determination of soluble reactive phosphorus. However, even here, the method may not be applicable to very high alkalinity waters owing to their potential for reducing the acidity of the analyte. With regard to total dissolved phosphorus (TDP) and total phosphorus (TP) measurements, the importance of undertaking the analysis under ambient conditions is clearly shown. There are many small variants on standard phosphomolybdate methods for determining SRP, TDP and TP in use and it is not always clear which methods will or will not show silica interference for particular water types. It is therefore recommended that individual laboratories check their methodologies for silica interference using phosphate-free solutions with similar silica and alkalinity ranges for the waters being assayed.

River water quality in the Humber catchment: an introduction using GIS-based mapping and analysis

The regional water quality of the Humber catchment was mapped for key inorganic chemical determinands using a GIS system and an extensive Environment Agency and LOIS monitoring database. The resultant maps revealed the major factors affecting the general characteristics of regional water quality. Sewage inputs from industrial and domestic sources account for the high concentration of many determinands in urban areas. The concentrations of particulate components increase in tidal zones because of sediment trapping and tidal re-suspension effects. Some determinands also exhibit localized high concentrations related to coal mine drainage, soil pollution caused by past ore mining, bedrock geology, the agricultural use of fertilizers and the ingression of seawater into the estuary.

Frequency of BRCA1/BRCA2 mutations in a population-based sample of young breast carcinoma cases

BACKGROUND

There is a clear and growing need for data regarding BRCA1 and BRCA2 mutation frequencies among breast carcinoma cases not specifically ascertained on the basis of extreme family history profiles. Toward this end, the authors previously reported results with regard to BRCA1 in breast carcinoma patients drawn from a population-based study. In the current study the authors present new findings concerning BRCA2 mutation frequency in this same population, as well as summary data regarding the combined contribution of these two genes.

METHODS

Subjects were drawn from two population-based, case-control studies of breast carcinoma in young women conducted in western Washington State and focused on 1) women diagnosed with breast carcinoma before age 35 years (n = 203); and 2) women with a first-degree family history of breast carcinoma who were diagnosed before age 45 years (n = 225). Similarities and differences between BRCA2 carriers and BRCA1 carriers were analyzed in terms of age at diagnosis, family history status, and disease features.

RESULTS

Of cases diagnosed before age 35 years, all of whom were unselected for family history, 9.4% carried germline mutations (3.4% for BRCA2 and 5.9% for BRCA1). Of cases diagnosed before age 45 years who had a first-degree family history of breast carcinoma, 12.0% carried germline mutations (4.9% for BRCA2 and 7.1% for BRCA1). Increased frequencies of mutations were observed in cases with a personal or family history of early age at diagnosis and in those with four or more family members affected with breast carcinoma. BRCA2 mutations were less common than BRCA1 mutations in families with any history of ovarian carcinoma.

CONCLUSIONS

Overall, given current constraints on health care resources, these data suggest that screening for germline mutations in these breast carcinoma susceptibility genes may have the greatest impact on overall health care if it is prioritized toward high and moderate risk populations.

Flumazenil in drug overdose: randomized, placebo-controlled study to assess cost effectiveness

OBJECTIVE

To investigate cost effectiveness of administration of flumazenil to patients presenting with suspected acute drug overdose.

DESIGN

Double-blind, prospective, placebo-controlled randomized study.

SETTING

University teaching hospital.

PATIENTS

Forty-three adults presenting with suspected drug overdose and having a Glasgow Coma Scale (GCS) score of <13. Patients with known benzodiazepine/tricyclic ingestion were excluded.

INTERVENTIONS

Intravenous administration of flumazenil (up to 2 mg) or placebo.

MEASUREMENTS AND MAIN RESULTS

Individual patient costs were assessed and data aggregated for each treatment group. Major diagnostic and therapeutic interventions were recorded and between group comparisons performed. Clinical response to study drug administration was assessed by obtaining pre- and post-drug GCS scores and observation of the patient for at least 180 mins for signs of resedation. Aggregate cost or number of major diagnostic and therapeutic interventions were not different between groups. Patients randomized to the flumazenil group showed a marked increase in GCS score (7.4 to 11.8) compared with those in the placebo group (8.2 to 8.6).

CONCLUSION

Use of flumazenil in intentional drug overdose of unknown etiology is not cost effective.