Bronchopulmonary dysplasia and neurobehavioural outcomes at birth and 2 years in infants born before 30 weeks

OBJECTIVE

To identify neurobehavioural risks in preterm infants with bronchopulmonary dysplasia (BPD) prior to hospital discharge.

DESIGN AND PATIENTS

Longitudinal study of 676 newborns born before 30 weeks of gestation.

SETTING

Nine university NICUs affiliated with six universities. All were Vermont Oxford Network (VON) participants.

PATIENTS AND INTERVENTIONS

Infants were enrolled in the Neonatal Neurobehavior and Outcomes in Very Preterm Infants Study from April 2014 to June 2016. Prospective medical record reviews, VON definitions and criteria, and maternal interviews were used to collect maternal and neonatal medical variables and socioenvironmental data.

MAIN OUTCOME MEASURES

NICU Network Neurobehavioral Scale (NNNS) at the time of hospital discharge; Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) and Gross Motor Function Classification System at 2 years' corrected age.

RESULTS

Infants with moderate/severe BPD were less attentive (Wald χ2 9.68, p=0.008), more lethargic (Wald χ2 9.91, p=0.007), with increased non-optimal reflexes (Wald χ2 7.37, p=0.025). Infants with moderate/severe BPD were more likely to have Bayley-III language and motor scores <85 (adjusted OR (aOR) 1.74, 95% CI 1.06 to 2.85, and aOR 2.06, 95% CI 1.10 to 3.85). Infants with both moderate/severe and mild BPD were more likely to have a cerebral palsy diagnosis (aOR 2.96, 95% CI 1.34 to 6.54, and aOR 2.81, 95% CI 1.32 to 5.99).

CONCLUSIONS

BPD severity presents risks for poor neurodevelopment at NICU discharge and at age 2 years. Early identification of poorly regulated behaviour can provide critical information for early preventive and targeted interventions with potential to improve long-term outcomes.

Hawai'i IDeA Center for Pediatric and Adolescent Clinical Trials

As one of 17 clinical sites of the Environmental influences on Child Health Outcomes (ECHO) IDeA States Pediatric Clinical Trials Network (ISPCTN), the Hawai'i IDeA Center for Pediatric and Adolescent Clinical Trials (HIPACT) was established in 2016 to participate in community-valued and scientifically-valid multi-center pediatric clinical trials to improve health and well-being of diverse multi-ethnic populations of Hawai'i. Hawai'i is home to large populations of diverse rural and underserved populations, including indigenous Hawaiian communities and immigrant populations of Pacific Islanders and Asians. Many of these communities experience significant health disparities, made worse by their geographic isolation and many socio-economic factors. In addition to providing opportunities for children and their families to participate in clinical trials, HIPACT's goal is to provide opportunities for junior faculty of the John A. Burns School of Medicine (JABSOM), University of Hawai'i at Manoa, to acquire knowledge about and to develop skills in clinical trials. HIPACT's partners include the Hawai'i Pacific Health with Kapi'olani Medical Center for Women and Children, and Waianae Coast Comprehensive Health Center. HIPACT builds on the experiences gained through partnerships with the Mountain West IDeA Clinical and Translational Research-Infrastructure Network, and Research Centers in Minority Institutions Translational Research Network. Apart from participating in ECHO ISPCTN-sponsored studies, HIPACT junior faculty serve as committee members, Working Group leaders, Protocol Study Principal Investigators (PI) and site study PIs with ECHO ISPCTN. Through participation in ECHO ISPCTN, HIPACT has successfully increased the number of pediatric and maternal-fetal medicine faculty involved in the conduct of clinical trials.

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.

School-Aged Outcomes following Prenatal Methamphetamine Exposure: 7.5-Year Follow-Up from the Infant Development, Environment, and Lifestyle Study

OBJECTIVE

To assess the relationship between prenatal methamphetamine exposure (PME) and behavior problems at age 7.5 years and the extent to which early adversity mediated this relationship.

STUDY DESIGN

The multicenter, longitudinal Infant Development, Environment, and Lifestyle study enrolled 412 mother-infant pairs at 4 sites. Methamphetamine-exposed participants (n = 204) were identified by self-report and/or gas chromatography/mass spectrometry confirmation of amphetamine and metabolites in infant meconium. Matched participants (n = 208) denied methamphetamine use and had a negative meconium screen. At the 7.5-year follow-up, 290 children with complete Child Behavior Checklist data and an early adversity index score were available for analysis (n = 146 exposed).

RESULTS

PME was significantly associated with an increased early adversity index score (P < .001) and with increased externalizing, rule-breaking behavior, and aggressive behavior (P < .05). Early adversity was also associated with higher externalizing behavior scores. Early adversity significantly mediated the relationship between PME and behavioral problems. After adjusting the mediation model for sex, prenatal tobacco, alcohol, and marijuana exposures, and study site, the association of PME with early adversity remained significant.

CONCLUSIONS

Though PME is associated with behavioral problems, early adversity may be a strong determinant of behavioral outcome for children exposed to methamphetamine in utero. Early adversity significantly mediated the relationship between PME and behavioral problems.

Developmental and behavioral consequences of prenatal methamphetamine exposure: A review of the Infant Development, Environment, and Lifestyle (IDEAL) study

This study reviews the findings from the Infant Development, Environment, and Lifestyle (IDEAL) study, a multisite, longitudinal, prospective study designed to determine maternal outcome and child growth and developmental findings following prenatal methamphetamine exposure from birth up to age 7.5 years. These findings are presented in the context of the home environment and caregiver characteristics to determine how the drug and the environment interact to affect the outcome of these children. No neonatal abstinence syndrome requiring pharmacologic intervention was observed but heavy drug exposure was associated with increased stress responses in the neonatal period. Poorer inhibitory control was also observed in heavy methamphetamine exposed children placing them at high risk for impaired executive function. Independent of methamphetamine exposure, children with more responsive home environments to developmental and emotional needs demonstrated lower risks for internalizing and externalizing behavior.

Prenatal methamphetamine exposure and neonatal and infant neurobehavioral outcome: results from the IDEAL study

BACKGROUND

Methamphetamine (MA) use among pregnant women is an increasing problem in the United States. How MA use during pregnancy affects neonatal and infant neurobehavior is unknown.

METHODS

The Infant Development, Environment, and Lifestyle (IDEAL) study screened 34,833 subjects at 4 clinical centers. Of the subjects, 17,961 were eligible and 3705 were consented, among which 412 were enrolled for longitudinal follow-up. Exposed subjects were identified by self-report and/or gas chromatography/mass spectroscopy (GC/MS) confirmation of amphetamine and metabolites in meconium. Comparison subjects were matched (race, birth weight, maternal education, insurance), denied amphetamine use, and had a negative meconium screen. Both groups included prenatal alcohol, tobacco, and marijuana use, but excluded use of opiates, lysergic acid diethylamide, or phencyclidine. The Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scale (NNNS) was administered within the first 5 days of life and again at 1 month to 380 enrollees (185 exposed, 195 comparison). Analysis of variance (ANOVA) tested exposure effects on NNNS summary scores at birth and 1 month. General linear model (GLM) repeated-measures analysis assessed the effect of MA exposure over time on the NNNS scores with and without covariates.

RESULTS

By 1 month of age, both groups demonstrated higher quality of movement (P = .029), less lethargy (P = .001), and fewer asymmetric reflexes (P = .012), with no significant differences in NNNS scores between the exposed and comparison groups. Over the first month of life, arousal increased in exposed infants but decreased in comparison infants (P = .031) and total stress was decreased in exposed infants, with no change in comparison infants (P = .026).

CONCLUSIONS

Improvement in total stress and arousal were observed in MA-exposed newborns by 1 month of age relative to the newborn period.

Effects of prenatal methamphetamine exposure on behavioral and cognitive findings at 7.5 years of age

OBJECTIVE

To examine child behavioral and cognitive outcomes after prenatal exposure to methamphetamine.

STUDY DESIGN

We enrolled 412 mother-infant pairs (204 methamphetamine-exposed and 208 unexposed matched comparisons) in the Infant Development, Environment, and Lifestyle study. The 151 children exposed to methamphetamine and 147 comparisons who attended the 7.5-year visit were included. Exposure was determined by maternal self-report and/or positive meconium toxicology. Maternal interviews assessed behavioral and cognitive outcomes using the Conners' Parent Rating Scale-Revised: Short Form.

RESULTS

After adjusting for covariates, children exposed to methamphetamine had significantly higher cognitive problems subscale scores than comparisons and were 2.8 times more likely to have cognitive problems scores that were above average on the Conners' Parent Rating Scale-Revised: Short Form. No association between prenatal methamphetamine exposure and behavioral problems, measured by the oppositional, hyperactivity, and attention-deficit/hyperactivity disorder index subscales, were found.

CONCLUSIONS

Prenatal methamphetamine exposure was associated with increased cognitive problems, which may affect academic achievement and lead to increased negative behavioral outcomes.

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.

A bridge between academic and community radiation oncology treatment planning

PURPOSE

To evaluate Telesynergy (TS) as a method of interactive treatment planning between academic and community radiation oncology departments.

METHODS

Through a grant from the National Cancer Institute to improve cancer outcomes for underserved populations, community radiation oncologists at New Hanover Regional Medical Center (NHRMC) in Wilmington, North Carolina, partnered with those at the University of North Carolina (UNC) in Chapel Hill, North Carolina. TS suites were installed at both sites to facilitate teleconferencing and review of treatment planning for intensity-modulated radiation therapy (IMRT). Patients with locally advanced head and neck cancer at NHRMC who were enrolled on a clinical trial of chemoirradiation underwent IMRT planning utilizing commercial software. NHRMC physicians contoured tumor targets and adjacent healthy organs. Physics staff at NHRMC generated an initial IMRT plan for each patient. Radiation oncologists at UNC then reviewed individual IMRT plans via TS conferences.

RESULTS AND CONCLUSION

Between August 2004 and August 2005, seven IMRT plans were reviewed in eight TS conferences. Physician contours of tumor targets and healthy organs, dose volume histograms, IMRT beams, and isodose distributions were shared during each TS conference successfully. Median time for each session was 35 minutes (range, 30 to 75). Physician satisfaction with the interactive planning process was high at both NHRMC and UNC. A cycle would likely evolve of initial intensive use of TS conferences, to gradual use for ongoing quality control, then greater use as the treatment planning technology undergoes its next change. Complex IMRT treatment planning review was feasible between an academic and community hospital via TS with a high level of physician participant satisfaction.

Prenatal methamphetamine exposure, home environment, and primary caregiver risk factors predict child behavioral problems at 5 years

This study investigated the prospective association between prenatal methamphetamine (MA) exposure and child behavioral problems at 5 years while also examining the home environment at 30 months and several primary caregiver (PC) risk factors. Participants were 97 MA-exposed and 117 comparison children and their PCs enrolled in the Infant Development, Environment and Lifestyle Study. Hypotheses were that child behaviors would be adversely impacted by (a) prenatal MA exposure, (b) home environments that provided less developmental stimulation and emotional responsiveness to the child, and (c) the presence of PC psychological symptoms and other risk factors. Prenatal MA exposure was associated with child externalizing behavioral problems at 5 years. Home environments that were more conducive to meeting children's developmental and emotional needs were associated with fewer internalizing and externalizing behavioral problems. Independent of prenatal MA exposure, PC parenting stress and psychological symptoms were associated with increased child behavioral problems. Findings suggest prenatal MA exposure may contribute to externalizing behavioral problems in early childhood and the importance of considering possible vulnerabilities related to prenatal MA exposure in the context of the child's caregiving environment.

Examining the relationships between prenatal methamphetamine exposure, early adversity, and child neurobehavioral disinhibition

Methamphetamine use is a growing problem among pregnant women in the United States. Many negative consequences of methamphetamine use have been documented for the users, but little research has examined the long-term association between prenatal methamphetamine exposure (PME) and childhood outcomes. The current study examined the extent to which PME was predictive of childhood neurobehavioral disinhibition (ND), as well as the extent to which early adversity mediated this relationship. A sample of 320 mother-infant dyads (162 PME) was followed from birth through 6.5 years of age. ND was conceptualized as a two factor model consisting of deficits in (a) behavioral and emotional control, and (b) executive function. PME was associated with behavioral and emotional control at 5 years, which was associated with executive function deficits at 6.5 years. Early adversity (birth through year 3) significantly mediated the relationship between PME and ND. Associations with previous research and implications for prevention are discussed.

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.

Maternal depression and prenatal exposure to methamphetamine: neurodevelopmental findings from the infant development, environment, and lifestyle (ideal) study

BACKGROUND

Maternal depression is associated with a higher incidence of behavioral problems in infants, but the effects of maternal depression as early as 1 month are not well characterized. The objective of this study is to determine the neurobehavioral effects of maternal depression on infants exposed and not exposed to methamphetamine (MA) using the NICU Network Neurobehavioral Scale (NNNS).

METHODS

Four hundred twelve mother-infant pairs were enrolled (MA = 204) and only biological mothers with custody of their child were included in the current analysis. At the 1-month visit (n = 126 MA-exposed; n = 193 MA-unexposed), the Beck Depression Inventory-II (BDI-II) was administered, and the NNNS was administered to the infant. Exposure was identified by self-report and/or gas chromatography/mass spectroscopy confirmation of amphetamine and metabolites in newborn meconium. Unexposed subjects were matched, denied amphetamine use, and had negative meconium screens. General Linear Models tested the effects of maternal depression and prenatal MA exposure on NNNS, with significance accepted at P < .05.

RESULTS

The MA group had an increased incidence of depression-positive diagnosis and increased depression scores on the BDI-II. After adjusting for covariates, MA exposure was associated with increased arousal and handling scores, and a decreased ability to self-regulate. Maternal depression was associated with higher autonomic stress and poorer quality of movement. No additional differences were observed in infants whose mothers were both depressed and used MA during pregnancy.

CONCLUSIONS

Maternal depression is associated with neurodevelopmental patterns of increased stress and decreased quality of movement, suggesting maternal depression influences neurodevelopment in infants as young as 1 month.

Prenatal methamphetamine exposure and short-term maternal and infant medical outcomes

OBJECTIVE

Examine maternal and infant medical outcomes of prenatal exposure to methamphetamine (MA).

STUDY DESIGN

Four hundred and twelve mother-infant pairs (204 MA-exposed and 208 unexposed matched comparisons) were enrolled in the Infant Development, Environment and Lifestyle (IDEAL) study. Exposure was determined by maternal self-report during this pregnancy and/or positive meconium toxicology. Maternal interviews assessed prenatal drug use, pregnancy course, and sociodemographic information. Medical chart reviews provided medical history, obstetric complications, infant outcomes, and discharge placement.

RESULTS

MA-using mothers were more likely to be poor, to have a psychiatric disorder/emotional illness and less prenatal care, and to be less likely to breast-feed their infant than comparison mothers. After adjusting for covariates, MA-exposed infants were more likely to exhibit poor suck, to have smaller head circumferences and length, to require neonatal intensive care unit (NICU) admission, and to be referred to child protective services (CPS). Several outcomes previously reported from studies that lacked adequate control groups or adjustment for covariates were not significantly different in this study.

CONCLUSION

Prenatal MA exposure is associated with maternal psychiatric disorder/emotional illness, poor suck, NICU admission, and CPS involvement, and MA-exposed infants were less likely to be breast-fed; however, the absence of many serious complications, such as fetal distress, chronic hypertension, preeclampsia, placenta previa, abruptio placentae, and cardiac defects, suggests confounding variables influenced prior studies.

Prenatal methamphetamine exposure and childhood behavior problems at 3 and 5 years of age

OBJECTIVE

We evaluated behavior problems in children who were prenatally exposed to methamphetamine (MA) at ages 3 and 5 years.

METHODS

The Infant Development, Environment, and Lifestyle study, a prospective, longitudinal study of prenatal MA exposure and child outcome, enrolled subjects postpartum in Los Angeles, California; Honolulu, Hawaii; Des Moines, Iowa; and Tulsa, Oklahoma. Prenatal exposure was determined by maternal self-report and/or meconium results. Exposed and comparison groups were matched on race, birth weight, public health insurance, and education. Mothers in the comparison group denied use and had a negative meconium screen for amphetamines. Prenatal exposures to tobacco, alcohol, or marijuana occurred in both groups. At ages 3 and 5 years, 330 children (166 exposed and 164 comparison) were assessed for behavior problems by using the caregiver report on the Child Behavior Checklist. General linear mixed models were used to determine the effects of prenatal MA exposure, including heavy exposure (≥3 days per week), age, and the interaction of exposure and age on behavior problems with adjustment for other drugs of abuse and environmental risk factors.

RESULTS

MA exposure was associated with increased emotional reactivity and anxious/depressed problems at both ages and externalizing and attention-deficit/hyperactivity disorder problems by age 5 years. Heavy exposure was related to attention problems and withdrawn behavior at both ages. There were no effects of MA on the internalizing or total behavior problems scales.

CONCLUSIONS

This first report of behavior problems in patients as young as 3 years associated with MA exposure identifies an important public health problem. Continued follow-up can inform the development of preventive intervention programs.

The effects of prenatal methamphetamine exposure on childhood growth patterns from birth to 3 years of age

We examined the effects of prenatal methamphetamine (MA) exposure on growth parameters from birth to age 3 years. The 412 subjects included (n = 204 exposed) were enrolled at birth in the Infant Development, Environment and Lifestyle study, a longitudinal study assessing the effects of prenatal MA exposure on childhood outcomes. Individual models were used to examine the effects of prenatal MA exposure on weight, head circumference, height, and weight-for-length growth trajectories. After adjusting for covariates, height trajectory was lower in the exposed versus the comparison children (p = 0.021) over the first 3 years of life. Both groups increased height on average by 2.27 cm per month by age 3 years. In term subjects, MA exposure was also associated with a lower height trajectory (p = 0.034), with both the exposed and comparison groups gaining 2.25 cm per month by age 3 years. There was no difference in weight, head circumference, or weight-for-length growth trajectories between the comparison and the exposed groups. Children exposed prenatally to MA have a modest decrease in height growth trajectory during the first 3 years of life with no observed difference in weight, head circumference, or weight-for-length trajectories.

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.

Phase II trial of hyperfractionated intensity-modulated radiation therapy and concurrent weekly cisplatin for Stage III and IVa head-and-neck cancer

PURPOSE

To investigate a novel chemoradiation regimen designed to maximize locoregional control (LRC) and minimize toxicity for patients with advanced head-and-neck squamous cell carcinoma (HNSCC).

METHODS AND MATERIALS

Patients received hyperfractionated intensity modulated radiation therapy (HIMRT) in 1.25-Gy fractions b.i.d. to 70 Gy to high-risk planning target volume (PTV). Intermediate and low-risk PTVs received 60 Gy and 50 Gy, at 1.07, and 0.89 Gy per fraction, respectively. Concurrent cisplatin 33 mg/m(2)/week was started Week 1. Patients completed the Quality of Life Radiation Therapy Instrument pretreatment (PRE), at end of treatment (EOT), and at 1, 3, 6, 9, and 12 months. Overall survival (OS), progression-free (PFS), LRC, and toxicities were assessed.

RESULTS

Of 39 patients, 30 (77%) were alive without disease at median follow-up of 37.5 months. Actuarial 3-year OS, PFS, and LRC were 80%, 82%, and 87%, respectively. No failures occurred in the electively irradiated neck and there were no isolated neck failures. Head and neck QOL was significantly worse in 18 of 35 patients (51%): mean 7.8 PRE vs. 3.9 EOT. By month 1, H&N QOL returned near baseline (mean 6.2, SD = 1.7). The most common acute Grade 3+ toxicities were mucositis (38%), fatigue (28%), dysphagia (28%), and leukopenia (26%).

CONCLUSIONS

Hyperfractionated IMRT with low-dose weekly cisplatin resulted in good LRC with acceptable toxicity and QOL. Lack of elective nodal failures despite very low dose per fraction has led to an attempt to further minimize toxicity by reducing elective nodal doses in our subsequent protocol.

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.

Antenatal maternal stress and long-term effects on child neurodevelopment: how and why?

We review a significant body of evidence from independent prospective studies that if a mother is stressed while pregnant, her child is substantially more likely to have emotional or cognitive problems, including an increased risk of attentional deficit/hyperactivity, anxiety, and language delay. These findings are independent of effects due to maternal postnatal depression and anxiety. We still do not know what forms of anxiety or stress are most detrimental, but research suggests that the relationship with the partner can be important in this respect. The magnitude of these effects is clinically significant, as the attributable load of emotional/behavioral problems due to antenatal stress and/or anxiety is approximately 15%. Animal models suggest that activity of the stress-responsive hypothalamic-pituitary-adrenal (HPA) axis and its hormonal end-product cortisol are involved in these effects in both mother and offspring. The fetal environment can be altered if stress in the mother changes her hormonal profile, and in humans, there is a strong correlation between maternal and fetal cortisol levels. However, many problems remain in understanding the mechanisms involved in this interaction. For example, maternal cortisol responses to stress decline over the course of pregnancy, and earlier in pregnancy, the link between maternal and fetal cortisol is less robust. It is possible that the effects of maternal anxiety and stress on the developing fetus and child are moderated by other factors such as a maternal diet (e.g., protein load). It is suggested that extra vigilance or anxiety, readily distracted attention, or a hyper-responsive HPA axis may have been adaptive in a stressful environment during evolution, but exists today at the cost of vulnerability to neurodevelopmental disorders.

Selective breeding for divergence in novelty-seeking traits: heritability and enrichment in spontaneous anxiety-related behaviors

Outbred Sprague-Dawley rats can be classified as high responders (HR) or low responders (LR) based on their levels of exploratory locomotion in a novel environment. While this novelty-seeking dimension was originally related to differential vulnerability to substance abuse, behavioral, neuroendocrine and gene expression studies suggest a fundamental difference in emotional reactivity between these animals. Here, we report the first study to selectively breed rats based on this novelty-seeking dimension. Response to novelty was clearly heritable, with a > 2-fold difference in behavior seen after eight generations of selection. Three tests of anxiety-like behavior consistently showed significantly greater anxiety in LR-bred rats compared to HR-bred animals, and this difference was diminished in the open field test by administration of the anxiolytic benzodiazepine drug, chlordiazepoxide. Cross-fostering revealed that responses to novelty were largely unaffected by maternal interactions, though there was an effect on anxiety-like behavior. These selected lines will enable future research on the interplay of genetic, environmental and developmental variables in controlling drug seeking behavior, stress and emotional reactivity.

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.

Transcriptional profiling of the developing rat brain reveals that the most dramatic regional differentiation in gene expression occurs postpartum

Neural development involves the expression of ensembles of regulatory genes that control the coordinate and region-specific expression of a host of other genes, resulting in the unique structure, connectivity, and function of each brain region. Although the role of some specific genes in neural development has been studied in detail, we have no global view of the orchestration of spatial and temporal aspects of gene expression across multiple regions of the developing brain. To this end, we used transcriptional profiling to examine expression levels of 9955 genes in the hypothalamus, hippocampus, and frontal cortex across seven stages of postnatal development and up to four stages of prenatal development in individual male rats (six per group). The results reveal dramatic changes across development in >97% of the neurally expressed genes. They also uncover a surprising degree of regional differentiation occurring after birth and through the first 2 weeks of life. Cluster analysis identifies 20 clusters of transcripts enriched in genes related to particular functions, such as DNA metabolism, nuclear function, synaptic vesicle transport, myelination, and neuropeptide hormone activity. Thus, groups of genes with related functions change in the brain at specific times, possibly marking critical periods for each function. These findings can broadly serve as a backdrop for studying the role of individual genes in neural development. They also underscore the importance of early postnatal life in the rat, which corresponds to late gestation in the human, as a critical late phase of neural organization and differentiation, even in subcortical regions.

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.

99m Tc anti-CD 15 monoclonal antibody (LeuTech) imaging improves diagnostic accuracy and clinical management in patients with equivocal presentation of appendicitis

BACKGROUND

Appendicitis frequently presents in an atypical fashion leading to misdiagnosis or a delay in diagnosis. This is particularly true in early cases where the patient may be erroneously discharged from an emergency department and will invariably return with perforated appendicitis. The standard of care is hospital admission for observation or early operation. Adjunctive imaging tests have been used with mixed results in this equivocal patient population. The authors studied a promising new monoclonal antibody, 99mTc-labeled anti-CD 15 (LeuTech; Palatin Technologies, Inc., Princeton, NJ), which specifically targets neutrophils and may be used for imaging appendicitis. This prospective, multicenter, open-label study evaluated the diagnostic efficacy and clinical impact of LeuTech scintigraphy for detecting appendicitis in patients with an equivocal presentation.

METHODS

A total of 200 patients (121 females, 79 males; age range 5-86 years; mean age 30.5 +/- 16.5 years) completed the study. Management plan was formulated before and reassessed following LeuTech imaging to determine impact on management. Following intravenous injection of LeuTech, the abdomen was imaged with a standard gamma camera for 30 to 90 minutes.

RESULTS

Fifty-nine patients had a histopathologic diagnosis of acute appendicitis. LeuTech identified 53 of 59 patients with appendicitis (90% sensitivity) and was negative in 122 of 141 patients without appendicitis (87% specificity). Accuracy, positive predictive value, and negative predictive value were 88%, 74%, and 95%, respectively. Diagnostic efficacy was unchanged in a subgroup of 48 pediatric patients (5-17 years). Diagnostic images for appendicitis were achieved within 8 minutes postinjection in 50% of patients and within 47 minutes in 90% of patients. Significant shifts in patient management decisions were evident following LeuTech results. LeuTech was well tolerated with no serious adverse events reported.

CONCLUSION

LeuTech is a convenient, safe, rapid, and sensitive imaging test for diagnosis of appendicitis and favorably impacts patient management in adult and pediatric patients with equivocal signs and symptoms.

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.