Expression of connexins during development and following manipulation of afferent input in the rat locus coeruleus

Synchronous activity of locus coeruleus (LC) neurons during early postnatal development is regulated, in part, by electrotonic coupling. Connexin (Cx) proteins that make up gap junction channels are localized to both neurons and glia in the LC during this period. In adult rats, however, synchrony exists only under certain experimental conditions. The expression of Cx proteins was examined using western blot analysis at several developmental time points. Immunoblot analysis revealed little to no expression of Cx26 while Cx32, Cx43 and Cx36 were present at all time points examined. A progressive increase in Cx43 was identified from the first postnatal week through adulthood. Immunocytochemical detection of Cx36 and Cx43 in adult LC showed that Cx36 was associated with neuronal processes while Cx43 was localized to glia. In adult LC, in vitro intracellular recordings combined with neurobiotin injections confirmed the presence of gap junctional communication albeit to a lesser extent than in early postnatal periods. The degree to which synaptic inputs to LC neurons impact on Cx protein expression was also evaluated. Samples of the LC from rats that received an electrolytic lesion of the amygdala were processed for western blot analysis of Cx36 and Cx43. The predominantly neuronal Cx36 exhibited an increase in expression while the glial Cx43 was unchanged. The present results indicate that, despite subtype-specific changes during development, several Cx proteins are expressed in the adult LC. In addition, manipulating afferent input to the LC, in adult rats, results in increases in neuronal Cx protein levels but not in glial Cx levels suggesting that altering synaptic inputs to the LC may alter synchronous activity in noradrenergic neurons.

Alcohol and drug use among vocational dental practitioners

OBJECTIVE

This study was designed to investigate the prevalence of alcohol and drug use in vocational dental practitioners (VDPs).

DESIGN

Anonymous self-report questionnaire.

SUBJECTS AND METHODS

All UK vocational dental practitioners (n = 719) who started practice in the summer of 1999 were questioned on their use of alcohol, tobacco, cannabis and other illicit drugs whilst a VDP and before graduation.

RESULTS

Eighty-nine per cent of males and 88% of females reported alcohol use. Of these, 35% of males and 36% of females drank above sensible levels (up to 21 units per week for males, 14 units for females), with 48% of males and 52% of females "binge drinking". Thirty-three per cent of respondents reported cannabis use whilst a VDP. Regular drug use (use at least once a month) other than cannabis whilst a VDP was found to be highest among males, with regular ecstasy use reported by 4% and regular cocaine use reported by 2%. Regular tobacco use (ten or more cigarettes per day) was reported by 9% of VDPs. Regular tobacco users were found to be six times more likely to use cannabis on a regular basis, three times more likely to use ecstasy on a regular basis and four times more likely to use cocaine on a regular basis than those VDPs who reported non regular tobacco use.

CONCLUSION

VDPs are drinking above sensible limits, binge drinking, using tobacco and indulging in illicit drug use to a degree that will cause health problems. However, use of all substances had reduced since qualification.

Certification of the European reference soil set (IRMM-443--EUROSOILS). Part I. Adsorption coefficients for atrazine, 2,4-D and lindane

The European Commission has characterised and certified a set of six European soils (the EUROSOILS) under the number IRMM-443. After a successful validation and trial period with a preliminary batch it was decided to produce a new batch of certified reference materials. Part I of this paper describes the certification of adsorption coefficients for atrazine, 2,4-D and lindane in these soils. The adsorption coefficients were determined according to OECD Test Guideline 106. Additionally, the underlying principles for the value assignment process according to the GUM and their practical application to the numerical data obtained during the certification exercise according to ISO Guide 34 and 35 are discussed.

Certification of the European Reference Soil Set (IRMM-443--EUROSOILS). Part II. Soil-pH in suspensions of water and CaCl2

IRMM-443 re-groups a set of six European Reference Soils (EUROSOILS), which had been certified for their adsorption coefficients for atrazine, 2,4-D and lindane (Certification of the European Reference Soil Set (IRMM-443-EUROSOILS)-Part I. Adsorption coefficients for atrazine, 2,4-D and lindane. Sci Total Environ, in press). The certification of these parameters was complemented by an additional certification of pH in suspension as well by the determination of indicative values for total nitrogen, organic and total carbon content. While Part I explained the principles of the value assignment process and discussed their application to the adsorption coefficients, Part II presents the certified values for pH as well as the indicative values for N(tot), C(tot) and C(org). In addition, the assessment of uncertainty components for stability and homogeneity, which have been included in the final uncertainty budget, is discussed.

The value of routine non-invasive tests to predict clinical outcome in stable angina

BACKGROUND

Chronic stable angina is a common condition, but considerable differences exist in the likelihood of acute coronary events such as CHD death, non-fatal myocardial infarction (MI) and unstable angina between individual patients. Effective risk prediction is necessary for optimum management. The aim of this study was to identify clinical features and non-invasive test parameters associated with high risk of these coronary events in stable angina and compose a clinically useful model to predict adverse outcomes in this population.

METHODS

Six hundred and eighty-two patients with stable angina and a positive exercise test (1mm ST depression) from the Total Ischaemic Burden European Trial (TIBET) study, were studied. Resting ECG, exercise tolerance testing and echocardiography were performed at baseline, off anti-anginal therapy. The patients were then randomised to treatment with atenolol, nifedipine or a combination of both. Clinical follow up continued for an average of 2 years (range 1-3 years).

RESULTS AND CONCLUSIONS

Prior MI or prior CABG were the clinical parameters associated with adverse outcome in patients with stable angina and a positive exercise test. On the ECG, left ventricular hypertrophy was predictive, and on echocardiogram, increased left ventricular dimensions were predictive of adverse events. When combined with time to ischaemia on exercise testing in a simple clinically applicable table these factors could be used to predict of 2 year probability of events for an individual patient.

Changes in water quality parameters due to in-sewer processes

Combined sewer systems contain a large number of organic and inorganic pollutants from both domestic and industrial sources. These pollutants are often retained within the combined sewer system for significant lengths of time before entering sewage treatment works, or being spilt to a watercourse via a combined sewer overflow (CSO) during storm conditions. Currently little knowledge exists concerning the effects of in sewer processes on pollutants. Understanding of in-sewer processes is important for the effective and efficient design of treatment works and CSO chambers and for impact assessments on receiving waters. A series of studies covering storm and dry weather flow conditions were undertaken with the aim of investigating the nature of in-sewer processes. These studies consisted of marking a body of water with a fluorescent tracer. The tracer was then monitored at a series of downstream sites, and discrete samples collected from the body of water as it progressed through the sewer. The samples were analysed for water quality parameters and these results investigated in tandem with the detailed hydraulic information gained through the tracer studies. The results highlight the hydraulic differences between storm and dry weather conditions such as increased travel times and mixing under storm conditions. The Advection Dispersion Equation (ADE) and Aggregated Dead Zone (ADZ) model parameters have been quantified for the tracer data. The ADE mixing coefficient is shown to increase by an order of magnitude for storm conditions. The ADZ dispersive fraction parameter is shown to be approximately constant with flow. Chemical reactions and decay within the sewer system were found to be consistent with oxygen limitation.

Anatomical pathways and molecular mechanisms for plasticity in the barrel cortex

The barrel cortex has yielded a wealth of information about cortical plasticity in recent years. Barrel cortex is one of the few cortical areas studied so far where plasticity can be examined from birth through to adulthood. This review looks at plasticity mechanisms in three periods of life: early post-natal development, adolescence and adulthood. Separate consideration is given to depression and potentiation mechanisms. Plasticity can be induced in barrel cortex by whisker deprivation. Single whisker experience leads to expansion of the area of cortex responding to the spared whisker. In early post-natal life, plasticity occurs in thalamocortical pathways, while later in adolescence, intracortical pathways become more important. Ablation of the spared whisker's barrel prevents expression of plasticity in the cortex. A row of lesions between the spared and an adjacent barrel prevents expression of plasticity in the adjacent barrel. This evidence, together with latency of response data and an analysis of pathways capable of inducing long-term potentiation (LTP) within barrel cortex, leads to the view that horizontal and/or diagonal pathways between barrels are responsible for plasticity expression. The mouse has become the most commonly mutated mammalian species and has a well-developed barrel cortex. Therefore, mutations can be used to study the role of particular molecules in experience-dependent plasticity of barrel cortex. Through this work, it has become clear that the major post-synaptic density protein, alpha-CaMKII, and its T286 autophosphorylation site are essential for experience-dependent plasticity. This points to a major role for excitatory transmission in cortical plasticity and raises the possibility that LTP like mechanisms are involved. Furthermore, transgenic mice carrying a reporter gene for CRE have provided evidence that CRE-mediated gene expression is also involved in barrel cortex plasticity. This view is supported by studies on alpha/delta CREB knockouts, and provides a starting point for studying the role of gene expression in experience-dependent cortical plasticity.

Natriuretic peptides in the diagnosis of heart disease--first amongst equals?

The natriuretic peptides and their role in neurohumoral regulation of the cardiovascular system have become the focus of considerable interest from the scientific and clinical community in recent years. BNP in particular has been shown to be an important diagnostic and prognostic marker of use in a wide range of applications. As measurement techniques develop and are refined, routine evaluation of serum levels of these markers is expected to become more widespread. We have reviewed the biochemistry of the natriuretic peptide family, their role in cardiovascular pathophysiology and the evidence supporting their use in the clinical setting.

Stochastic modelling of phosphorus transfers from agricultural land to aquatic ecosystems

This paper describes a simple model of phosphorus (P) transfer from agricultural land to surface waters which incorporates the effects of spatial variability in catchment properties and uncertainty in model parameter values. TOPMODEL concepts are used to estimate water, solute and sediment fluxes to water bodies. The model predicts the spatial distribution of water table depth and saturation-excess overland flow based on topography. Dissolved P (DP) transfer is assumed to occur vertically in the unsaturated zone and laterally in the saturated zone. Readily soluble P is assumed to decrease exponentially with soil depth. Particulate P (PP) transfers are modelled by estimating overland flow discharge and associated sediment transport capacity. Uncertainty in the distribution of soil surface P concentrations and model parameters controlling the mobility of soil P are incorporated using Monte Carlo simulation. Predicted losses of DP are well correlated with discharge and those of PP are episodic. Highest losses of P tended to be predicted near to the stream where the water table is close to the surface. The combination of a deterministic model core with a stochastic generation of model parameters or state variables provides an attractive way of embracing variability and uncertainty in models of this kind.

The effect of autonomous alpha-CaMKII expression on sensory responses and experience-dependent plasticity in mouse barrel cortex

The calcium/calmodulin kinase II (CaMKII) autophosphorylation site is thought to be important for plasticity, learning and memory. If autophosphorylation is prevented by a point mutation (T286A) LTP is blocked in the hippocampus and cortex. Conversely, if the point mutation mimics autophosphorylation (T286D) a range of frequencies that normally produce LTP in wild types cause LTD instead. In order to test whether the alphaCaMKII-T286D mutation increases levels of depression in vivo, we examined the effect of the alphaCaMKII-T286D transgene on plasticity induced in the barrel cortex by whisker deprivation. Surprisingly, the mutation did not affect depression or potentiation. However, in animals reared with the transgene turned on from birth, the surround receptive field responses were greater than normal. This effect may be due to the potentiating action of autophosphorylated CaMKII during early development.

Increased macrophage chemoattractant protein-1 in cerebrospinal fluid precedes and predicts simian immunodeficiency virus encephalitis

Macrophage chemoattractant protein-1 (MCP-1) may be a key trigger for the influx of macrophages into the brain in human immunodeficiency virus (HIV) encephalitis. In this study, simian immunodeficiency virus-infected macaques that developed moderate-to-severe encephalitis had significantly higher MCP-1 levels in cerebrospinal fluid (CSF) than in plasma as early as 28 days after inoculation, which was before the development of brain lesions. In contrast, CSF:plasma MCP-1 ratios remained constant at preinoculation levels in macaques that developed minimal or no encephalitis. Abundant MCP-1 protein and mRNA were detected in both macrophages and astrocytes in the brain. Macaques with increased MCP-1 in CSF had significantly greater expression of markers of macrophage and microglia activation and infiltration (CD68; P= .003) and astrocyte activation (glial fibrillary acidic protein; P= .019 and P= .031 in white and gray matter, respectively). The results suggest that the CSF:plasma MCP-1 ratio may be a valuable prognostic marker for the development of HIV-induced central nervous system disease.

The impact of side effects on family planning use among female clients of the public health services in Jamaica

A one-year longitudinal study was undertaken in Kingston, Jamaica, to examine (i) the experience of side effects among female contraceptive users, (ii) the role of side effects in method continuation, and (iii) counselling regarding side effects. The study consisted of 463 women who utilized public health centres in Kingston and were either new users of contraceptives or who were switching contraceptive methods. They were recruited over a two-month period in 1998 and followed up for one year. All follow-up, interviews were done at the women's homes and complete interviews were obtained for 323 women. Information was collected about socio-economic characteristics, contraceptive history, service factors, experience with method and length of use. Forty-eight per cent of the women experienced side effects with the method accepted on recruitment to the study. Common side effects were irregular bleeding no period, headaches, nausea/dizziness and weight gain/loss. These side effects occurred mainly among pill and injection users. The occurrence of side effects had a negative impact on continuation rates. Forty-seven per cent of the women stated that they had received counselling regarding side effects. The level and impact of side effects among family planning acceptors at public health centres in Jamaica is of significance to the family planning programme. Method options need to be widened and counselling needs to be improved to ensure that women fully understand the issue of side effects and make informed choices about contraception.

Pathogenesis of SIV pneumonia: selective replication of viral genotypes in the lung

Lymphocytic interstitial pneumonia of HIV-infected individuals and SIV pneumonia of macaques are both characterized by diffuse infiltration of the lungs with lymphocytes, plasma cells, and macrophages. This study was undertaken to determine whether there are specific, macrophage-tropic genotypes that selectively replicate in the lung of macaques with SIV pneumonia, as in SIV encephalitis. Using a rapid, reproducible SIV/macaque model of AIDS, 11 pig-tailed macaques were intravenously inoculated with an immunosuppressive viral strain, SIV/DeltaB670, and a macrophage-tropic molecule clone, SIV/17E-Fr, and euthanized at 3 months postinoculation. All 11 macaques had severe (6 macaques) or moderate (5 macaques) pneumonia. To identify the viral genotypes that were replicating in the lung parenchyma, bronchoalveolar lavage (BAL) cells, and peripheral blood mononuclear cells (PBMC) of each macaque, RNA was isolated and the SIV env V1 region was amplified, cloned, and sequenced. Lung homogenates and BAL cells contained a more limited repertoire of viral genotypes than PBMC. SIV/17E-Fr was the major genotype in the lungs of 5 macaques and in BAL cells of 6 macaques. The remainder of the macaques had SIV/17E-Fr and the macrophage-tropic strains of SIV/DeltaB670 clones 2 and 12. In contrast, SIV/17E-Fr was the predominant strain in the PBMC of only 3 of 11 macaques. The viral strain that predominated in PBMC was rarely the strain that predominated in the lungs (only 3 of 11 macaques). The severity of pulmonary lesions did not correlate with the levels of viral RNA in lung homogenates or in plasma. However, when only SIV/17E-Fr was expressed in the lung, the viral load in the lung was significantly higher (P = 0.016) than when SIV/DeltaB670 was present alone or in combination with SIV/17E-Fr. These data suggest that SIV pneumonia is associated with selective replication of specific macrophage-tropic genotypes in the lung and that SIV/17E-Fr has a selective advantage for replication in the lung.

Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 4. The influence of salt speciation, soil type, and sewage sludge on toxicity using the collembolan Folsomia fimetaria and the earthworm Aporrectodea caliginosa as test organisms

Sewage sludge applied to agricultural soils often contains linear alkylbenzene sulfonates (LAS) in the range of 1 to 10 g/kg dry weight, and their toxicity to relevant soil organisms should, therefore, be assessed to ensure safe use of sewage sludge as a fertilizer. Studies of LAS toxicity to soil organisms are few, and to our knowledge, factors that may influence the toxicity in the field have not been studied in detail. In this paper, we report on the influence of speciation of LAS in the test solution added to soil (soluble Na-LAS vs poorly soluble Ca-LAS or Mg-LAS), the influence of soil type, and the modifying effects of sludge amendment on the toxicity of LAS. These issues were investigated using reproduction of Collembola and growth of juvenile earthworms as test parameters. Speciation of the LAS added to test soil did not have any influence on toxicity for any of the test species. Likewise, in three different agricultural soils (sand, loam, and clay), we found almost equal toxicities. The LAS added to test soil in a sludge-water suspension was equally toxic as when it was added in an aqueous solution. However, anaerobic incubation for 7 and 14 d of the LAS-sludge suspension (with no decay of LAS) caused the toxicity to increase almost threefold in both collembolan and earthworm. The relationships between soil constituents, bioavailability, and toxicity are also discussed.

Impact of clinical reverse transcriptase sequences on the replication capacity of HIV-1 drug-resistant mutants

We have shown that the HIV-1 laboratory strain NL4-3 that contains P236L [a reverse transcriptase mutation conferring resistance to the nonnucleoside reverse transcriptase inhibitor (NRTI) delavirdine] replicates more slowly than wild-type NL4-3. Other NNRTI-resistance mutations, such as K103N and Y181C, do not reduce the replication capacity of NL4-3 as much as P236L and develop more frequently in HIV-1 isolates from patients failing delavirdine. However, a minority of patients on delavirdine therapy still have isolates with P236L. We postulated that reverse transcriptase (RT) sequences from these patient isolates contain other mutations that compensate for the adverse effect of P236L. To test this hypothesis, we created 15 chimeric NL4-3 isolates that contained delavirdine-resistant RT sequences derived from eight patient isolates and characterized their replication kinetics. Nine of 10 patient-derived clones containing P236L replicated as slowly as NL4-3 with P236L. In contrast, three of five clones that did not have P236L (but had either K103N or Y181C) replicated significantly better than NL4-3 with P236L. Thus, the majority of patients who acquire P236L during delavirdine therapy do not have RT mutations that compensate for the replication defect conferred by P236L. We hypothesize that HIV-1 isolates with P236L may have a compensatory mutation outside RT. Alternatively, variants of HIV-1 with reduced replication fitness may be selected during antiretroviral therapy, suggesting that stochastic events rather than viral replication fitness may determine which drug-resistant mutants emerge early during antiretroviral failure. In some isolates, it appears that the background RT sequence can contribute significantly to the replication fitness of drug-resistant HIV-1 variants.

The role of cortical activity in experience-dependent potentiation and depression of sensory responses in rat barrel cortex

The role of cortical activity in experience-dependent cortical plasticity was studied in the rat barrel cortex. Plasticity was induced by depriving every other whisker in a chessboard pattern, which is known to cause depression of responses to deprived whisker stimulation and potentiation of responses to spared whisker stimulation. Postsynaptic activity was blocked by muscimol released from elvax slow-release polymer located under the dura and over the barrel field. Spared whisker responses potentiated 2.5-fold in layer II/III and 2.9-fold in layer IV of the near-neighbor barrel in animals implanted with saline-elvax. In contrast, in whisker-deprived animals implanted with muscimol-elvax, responses were indistinguishable from those in undeprived animals. Similarly, in the spared barrel itself, spared whisker responses potentiated 1.3-fold in layer IV in animals implanted with saline-elvax but not at all in muscimol-treated animals. Whiskers that were deprived and then allowed to regrow showed depressed responses in saline-elvax-treated animals, in which 40% of the cells in layer II/III and 26% in layer IV were unresponsive to their principal whisker. These values fell to 17 and 3% for layers II/III and IV, respectively, in muscimol-treated animals, and the response magnitude distributions were indistinguishable from undeprived cases. Cortical activity block had no acute effect on the ventroposteriomedial nucleus responses and had a transient facilitatory effect after 4 d of muscimol treatment, which returned to baseline as the muscimol treatment wore off. We conclude from these studies that cortical activity is required for potentiation and depression of sensory responses in barrel cortex.

GREAT-ER: a new tool for management and risk assessment of chemicals in river basins. Contribution to GREAT-ER #10

The GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) project team has developed and validated an accurate aquatic chemical exposure prediction tool for use within environmental risk assessment schemes. The software system GREAT-ER 1.0 calculates the distribution of predicted environmental concentrations (PECs) of consumer chemicals in surface waters, for individual river stretches as well as for entire catchments. The system uses an ARC/INFO-ArcView (ESRI) based Geographical Information System (GIS) for data storage and visualization, combined with simple mathematical models for prediction of chemical fate. At present, the system contains information for four catchments in Yorkshire, one catchment in Italy, and two in Germany, while other river basins are being added. Great-ER 1.0 has been validated by comparing simulations with the results of an extensive monitoring campaign for two 'down-the-drain' chemicals, i.e. the detergent ingredients boron and Linear Alkylbenzene Sulphonate (LAS). GREAT-ER 1.0 is currently being expanded with models for the terrestrial (diffuse input), air and estaurine compartments.

Monitoring, modelling and environmental exposure assessment of industrial chemicals in the aquatic environment

Monitoring and laboratory data play integral roles alongside fate and exposure models in comprehensive risk assessments. The principle in the European Union Technical Guidance Documents for risk assessment is that measured data may take precedence over model results but only after they are judged to be of adequate reliability and to be representative of the particular environmental compartments to which they are applied. In practice, laboratory and field data are used to provide parameters for the models, while monitoring data are used to validate the models' predictions. Thus, comprehensive risk assessments require the integration of laboratory and monitoring data with the model predictions. However, this interplay is often overlooked. Discrepancies between the results of models and monitoring should be investigated in terms of the representativeness of both. Certainly, in the context of the EU risk assessment of existing chemicals, the specific requirements for monitoring data have not been adequately addressed. The resources required for environmental monitoring, both in terms of manpower and equipment, can be very significant. The design of monitoring programmes to optimise the use of resources and the use of models as a cost-effective alternative are increasing in importance. Generic considerations and criteria for the design of new monitoring programmes to generate representative quality data for the aquatic compartment are outlined and the criteria for the use of existing data are discussed. In particular, there is a need to improve the accessibility to data sets, to standardise the data sets, to promote communication and harmonisation of programmes and to incorporate the flexibility to change monitoring protocols to amend the chemicals under investigation in line with changing needs and priorities.

Imaging high-resolution structure of GFP-expressing neurons in neocortex in vivo

To detect subtle changes in neuronal morphology in response to changes in experience, one must image neurons at high resolution in vivo over time scales of minutes to days. We accomplished this by infecting postmitotic neurons in rat and mouse barrel cortex with a Sindbis virus carrying the gene for enhanced green fluorescent protein. Visualized with 2-photon excitation laser scanning microscopy, infected neurons showed bright fluorescence that was distributed homogeneously throughout the cell, including axonal and dendritic arbors. Single dendritic spines could routinely be resolved and their morphological dynamics visualized. Viral infection and imaging were achieved throughout postnatal development up to early adulthood (P 8-30), although the viral efficiency of infection decreased with age. This relatively noninvasive method for fluorescent labeling and imaging of neurons allows the study of morphological dynamics of neocortical neurons and their circuits in vivo.

Spirituality, religion, and pediatrics: intersecting worlds of healing

Religious practices such as prayer represent the most prevalent complementary and alternative therapies in the United States. However, biomedicine has sometimes viewed faith and related religious worldviews as relevant only when they obstruct implementation of scientifically sound biomedical care. Recent efforts to arrive at a new synthesis raise challenges for pediatricians. This article reviews theories of child faith development, and models of child spirituality from different disciplinary perspectives. It provides sources illustrating how spirituality and religion may inform children's lives; play a part in children's moral formation, socialization, and induction into a sacred worldview; and provide the child with inner resources. It also suggests some of the positive and negative effects of spiritual and religious engagement. Second, this article examines aspects of spirituality and religion that parents may bring to bear in relation to their children's health. Third, this article addresses the spiritual and/or religious identity of the provider. These topics are discussed in the context of cultural competence and the related importance of religious diversity. The authors suggest 1) some approaches for appropriate inclusion of spirituality in clinical practice, 2) challenges for medical education, and 3) areas requiring further research.

A survey of alcohol and drug use among UK based dental undergraduates

OBJECTIVE

This study was designed to investigate the prevalence of alcohol and drug use.

DESIGN

Anonymous self-report questionnaire.

SETTING

A UK dental school in May 1998.

SUBJECTS AND METHODS

1st-5th year dental undergraduates (n = 264) were questioned on their use of alcohol and tobacco, cannabis and other illicit drugs whilst at dental school, and before entry.

RESULTS

Eighty two per cent of male and 90% of female undergraduates reported drinking alcohol. Of those drinking, 63% of males and 42% of females drank in excess of sensible weekly limits (14 units for females, 21 units for males), with 56% of males and 58.5% of females 'binge drinking'. Regular tobacco smoking (10 or more cigarettes a day) was found to have a statistically significant association with year of study, 4th-5th year undergraduates being eight times more likely to regularly smoke than their junior colleagues. Fifty five per cent of undergraduates reported cannabis use at least once or twice since starting dental school, with 8% of males and 6% of females reporting current regular use at least once a week.

CONCLUSION

Dental undergraduates are drinking above sensible weekly limits of alcohol, binge drinking and indulging in illicit drug use. Dental Schools should designate a teacher responsible for education of undergraduates regarding alcohol and substance abuse.

The role of alpha-CaMKII autophosphorylation in neocortical experience-dependent plasticity

Calcium/calmodulin kinase type II (CaMKII) is a major postsynaptic density protein. CaMKII is postulated to act as a 'molecular switch', which, when triggered by a transient rise in calcium influx, becomes active for prolonged periods because of its ability to autophosphorylate. We studied experience-dependent plasticity in the barrel cortex of mice carrying a point mutation of the alpha-CaMKII gene (T286A), which abolishes this enzyme's ability to autophosphorylate. Plasticity was prevented in adult and adolescent mice homozygous for the mutation, but was normal in heterozygotes and wild-type littermates. These results provide evidence that the molecular switch hypothesis is valid for neocortical experience-dependent plasticity.

Analysis of outcomes for high-risk breast cancer based on interval from surgery to postmastectomy radiation therapy

PURPOSE

The success of adjuvant chemotherapy has prolonged the interval between surgery and postmastectomy radiation therapy for high-risk breast cancer patients. The purpose of this study is to determine whether a delay in radiation therapy after mastectomy results in an increased risk of local-regional recurrence of breast cancer.

MATERIALS AND METHODS

A retrospective review was performed of the University of Pennsylvania database of 221 patients with high-risk breast cancer treated with postmastectomy radiation therapy between 1977 and 1992. The surgery to postmastectomy radiation therapy time interval was 2 months or less in 82 patients (37%), 2.1 to 6 months in 50 patients (23%), and greater than 6 months in 89 patients (40%). Adjuvant chemotherapy was utilized in 151 patients (68%). The median follow-up was 4.3 years after postmastectomy radiation therapy.

RESULTS

Because the three groups showed significant differences for a number of prognostic factors, outcomes are reported in terms of local-regional recurrence only and not survival. The actuarial rate of local-regional recurrence at 8 years was 13% for patients with a surgery to radiation therapy interval of 2 months or less, 4% for those with an interval of 2.1 to 6 months, and 12% for those with an interval of greater than 6 months. A similar analysis performed for 4 months or less versus greater than 4 months between surgery and postmastectomy radiation therapy showed no difference in local-regional recurrence (11% versus 10%, respectively).

CONCLUSIONS

A delay in the institution of postmastectomy radiation therapy in favor of the prolongation of chemotherapy for high-risk breast cancer patients does not adversely affect outcome for local-regional recurrence at 8 years.

Plasticity and stability of somatosensory maps in thalamus and cortex

Work on elucidating the mechanisms of plasticity in somatosensory maps continues apace. Recent work has focused on both the nature of the thalamocortical interactions that determine plasticity, and on the differences between plasticity induced by nerve block or damage versus that induced by experience. Recordings from awake behaving animals have thrown light on the thalamocortical circuit mechanisms that underlie map plasticity; meanwhile, intracellular recordings from cortical slices have thrown light on the precise synaptic mechanisms underlying plasticity.

Upregulation of cAMP response element-mediated gene expression during experience-dependent plasticity in adult neocortex

Gene transcription is thought to be essential for memory consolidation and long-lasting changes in synaptic function. In particular, the signal transduction pathways that activate the transcription factor cAMP response element binding protein (CREB) have been implicated in the process of synaptic potentiation. To study the involvement of this pathway in neocortical plasticity within the barrel cortex, we have used a strain of mice carrying a LacZ reporter gene with six cAMP response elements (CREs) upstream of a minimal promoter. Removal of all but one facial whisker results in the expansion of the spared whisker's functional representation within somatosensory cortex. Under the same conditions of whisker deprivation, we observed a strong (eightfold compared with baseline) and highly place-specific upregulation of CRE-mediated gene transcription in layer IV of the spared whisker barrel. Reporter gene upregulation occurred rapidly after deprivation (16 hr) and was only observed under experimental conditions capable of inducing whisker response potentiation. LacZ expression in layer IV was accompanied by an increase in responsiveness of a subpopulation of layers II/III cells to spared whisker stimulation as determined by in vivo single-unit recording. Given that CREB is involved in the expression of plasticity in superficial layers (Glazewski et al., 1999), and yet CRE-mediated gene expression occurs in layer IV, it is likely that the molecular events initiating plasticity occur presynaptically to the cells that exhibit changes in their receptive field properties.

Removal of linear alkylbenzene sulfonate from a small Yorkshire stream: contribution to GREAT-ER project #7

An in-stream removal experiment has been carried out in Red Beck, a small stream which receives effluent from Shibden Head Sewage Treatment Works. This trickling filter works serves a purely domestic population of 9408 but is scheduled to be closed, and the flows diverted to another works, as part of Yorkshire Water's continuing capital investment programme. An anionic detergent, linear alkylbenzene sulfonate (LAS), boron, and standard water quality parameters have been measured at seven sites downstream of the effluent discharge point. Time of travel has been measured by detection of a fluorescent dye added to the effluent sampling chamber, and the increase in flow as the river proceeds through the catchment has been determined from current flow measurements, and from boron dilution data. Assuming a first order removal mechanism, the overall half-life for LAS removal is just over 2 h (2 h 14 min). Faster removal takes place in the upper portion of the stream, and removal over the last five sampling points is somewhat slower, with a half-life of 2 h 40 min. This removal may comprise both primary biodegradation and the deposition of suspended matter to which the surfactant has been adsorbed. There was no significant difference in the removal half-lives of the individual alkyl chain length homologues.

Age-dependent response of the mouse barrel cortex to sensory deprivation: a 2-deoxyglucose study

The effect of age on the plastic response of vibrissal barrel cortex to deprivation was examined in adolescent (1 month at the start of the procedure, 2 months at testing) and mature (10- to 11-month-old) mice. A single vibrissa was plucked out for 3 weeks and allowed to regrow for 10 days; it was previously found that this deprivation paradigm induces strong downregulation of the deprived input. The results of deprivation were assessed with 2-deoxyglucose functional brain-mapping autoradiography. Deprivation was found to reduce the ability of the deprived vibrissa to activate the cortex both in adolescent and mature mice. However, while in young animals the decrease of the extent of cortical labeling, compared with the normal control, was observed in all examined cortical layers (II/III, IV, and V), in older mice the effect was reduced in layers II/III and absent in layer IV. The suppression of response of the infragranular layers was not affected by age. Transition from adolescent to mature adulthood brings about a layer-specific decline in depression of the cortical response to the deprived input.

Take up the caregiver's burden: stories of care for urban African American elders with dementia

This pilot study uses an anthropological gaze to analyze transcripts of extended in-home interviews among a set of ten caregivers of African-American elders with dementia. How are race and ethnicity made to matter in the recognition of, the meaning-making around and the responses to dementing illness among a sample of African-American caregivers? The essay contrasts prevailing cultural representations of African-American caregiver burden with caregiver interview data. What we find is that current constructs which consistently demonstrate "lesser burden" among African-American caregivers compared with Whites may not adequately capture these caregivers' experiences. Interpretations of experiences, meanings of "burden" and the logic of symptoms in the illness narratives generated by these African-American caregivers of elders with dementia require attention to the embodiment of large scale sociopolitical and historical forces like residential, educational and occupational segregation, institutional racism, and economic exploitation over the life course.

Enoxaparin prevents death and cardiac ischemic events in unstable angina/non-Q-wave myocardial infarction. Results of the thrombolysis in myocardial infarction (TIMI) 11B trial

BACKGROUND

Low-molecular-weight heparins are attractive alternatives to unfractionated heparin (UFH) for management of unstable angina/non-Q-wave myocardial infarction (UA/NQMI).

METHODS AND RESULTS

Patients (n=3910) with UA/NQMI were randomized to intravenous UFH for >/=3 days followed by subcutaneous placebo injections or uninterrupted antithrombin therapy with enoxaparin during both the acute phase (initial 30 mg intravenous bolus followed by injections of 1.0 mg/kg every 12 hours) and outpatient phase (injections every 12 hours of 40 mg for patients weighing <65 kg and 60 mg for those weighing >/=65 kg). The primary end point (death, myocardial infarction, or urgent revascularization) occurred by 8 days in 14.5% of patients in the UFH group and 12.4% of patients in the enoxaparin group (OR 0.83; 95% CI 0.69 to 1.00; P=0. 048) and by 43 days in 19.7% of the UFH group and 17.3% of the enoxaparin group (OR 0.85; 95% CI 0.72 to 1.00; P=0.048). During the first 72 hours and also throughout the entire initial hospitalization, there was no difference in the rate of major hemorrhage in the treatment groups. During the outpatient phase, major hemorrhage occurred in 1.5% of the group treated with placebo and 2.9% of the group treated with enoxaparin (P=0.021).

CONCLUSIONS

Enoxaparin is superior to UFH for reducing a composite of death and serious cardiac ischemic events during the acute management of UA/NQMI patients without causing a significant increase in the rate of major hemorrhage. No further relative decrease in events occurred with outpatient enoxaparin treatment, but there was an increase in the rate of major hemorrhage.

Local cortical interactions determine the form of cortical plasticity

Competitive interactions between left and right eye inputs to visual cortex during development are usually explained by the thalamocortical axons competing more or less well for cortical territory during retraction into eye specific domains. Here we review the evidence for competitive and co-operative interactions between cortical columns in barrel cortex which are present several weeks after retraction of thalamocortical axons into barrels. Sensory responses in barrel cortex can be altered by a period of vibrissa deprivation. It was found that responses to previously deprived vibrissae (that had been allowed to regrow) were depressed more if neighboring vibrissae were spared than if all vibrissae were removed simultaneously. Depression of the deprived vibrissa response was greater the closer the cell lay to a spared barrel. It was also found that spared vibrissae responses were potentiated more if several neighboring vibrissae were left intact than if only a single vibrissae was spared. These results suggest a mechanism of cooperative potentiation, perhaps due to intracortical summation of excitation evoked by neighbouring vibrissa stimulation. Thalamic responses to vibrissa stimulation were unaffected by deprivation indicating a cortical origin. One of the consequences of deprivation was that the speed of transmission between barrels was increased for spared and decreased for deprived vibrissa. These results imply that inherent interactions between cortical columns give rise to a property of competition and co-operativity which amplify the effects of sensory deprivation.

The Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry in patients with unstable angina

Clinical approaches to the prevention of the potentially catastrophic consequences of coronary ischemic phenomena such as unstable angina and suspected non-Q-wave myocardial infarction (MI) differ across the world. In addition to prevailing physician beliefs in different societies, the level of access to catheterization laboratories largely determines whether an interventionist or conservative strategy is adopted. The Organization to Assess Strategies for Ischemic Syndromes (OASIS)--a prospective registry of approximately 8,000 patients with acute myocardial ischemia with no ST elevation, treated in 95 hospitals across 6 countries--furnished a unique window into regional differences in clinical management and the frequency and timing of invasive procedures (i.e., angiography, percutaneous transluminal coronary angioplasty [PTCA], and coronary artery bypass graft [CABG] surgery), as well as the outcomes of these trends. At 6 months after symptom onset, patients in the United States and Brazil, where the catheterization laboratory facilities are more accessible, underwent significantly (p <0.001) more angiography (69.4%), PTCA (23.6%), and CABG (25.2%) than in Canada and Australia, where the corresponding rates were 48.4%, 17.0%, and 16.8% (p <0.001), respectively; and in Hungary and Poland, where the respective rates were 23.5%, 5.8%, and 10.9% (p <0.001). This relatively aggressive approach led at 6 months to a more substantial decrease in refractory angina in the United States and Brazil than in Canada and Australia (20.4% vs 13.9%; p <0.001), but no improvement in rates of cardiovascular mortality and MI (10.5% versus 10.5%; p = 0.36). There was a significant (p < or = 0.012) increase in stroke, (1.9% vs 1.3%; p = 0.010) and major bleeding (1.9% vs 1.1%; p = 0.009) events. Furthermore, an inverse correlation emerged between baseline cardiovascular risk status and frequency of angiography and PTCA interventions preferentially for low-risk compared with high-risk patients. In concert with findings from other recent randomized trials, the OASIS Registry data suggest that although there are fewer hospital readmissions for unstable angina, there is a trend toward increased rates of death, MI, and stroke. These data urge a cautious approach to the use of invasive procedures in patients with unstable angina unless future trials demonstrate a clear benefit with an aggressive approach.

Effect of an alpha(2) agonist (mivazerol) on limiting myocardial ischaemia in stable angina

A specific alpha(2) agonist, mivazerol, known to be effective in reducing myocardial ischaemia when given intravenously immediately before an exercise tolerance test, produced a significant increase in exercise duration and time to the onset of angina when given orally over a two week period to 25 patients with stable angina. A non-significant trend to reduction in electrocardiographic signs of ischaemia was also noted. The clinical relevance of this improvement now needs to be tested in larger numbers.

Improving student learning in root canal treatment using self-assessment

AIM

This paper reports the first attempts to implement a new course in endodontology for undergraduate dental students based upon independent, reflective learning and self-assessment.

METHODOLOGY

The responses were analysed of two successive cohorts of third-year students to laboratory courses in (i) the restoration of teeth with crowns and (ii) endodontology and root canal treatment. The major changes introduced to the endodontology course were a substantial reduction in the number of formal lectures, the introduction of a series of structured tutorials, time for private study and the use of self-assessment in practical classes.

RESULTS

The evidence indicates that the new approach increased student confidence in practical skills, although the time available for operative practice was actually reduced; there was a perceived increase in problem-solving ability; and that students felt encouraged to pursue greater understanding. Reports from tutors suggested that students' self-assessments became more accurate as the courses proceeded. Seven experimental learning points were derived from the study. These included the importance of careful planning, well-designed assessment procedures and the creation of a climate of trust and openness.

CONCLUSIONS

The task of developing fully the students' skills of accurate self-assessment remains a challenge.

Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trial

BACKGROUND

Bolus fibrinolytic therapy facilitates early efficient institution of reperfusion therapy. Tenecteplase is a genetically engineered variant of alteplase with slower plasma clearance, better fibrin specificity, and high resistance to plasminogen-activator inhibitor-1. We did a double-blind, randomised, controlled trial to assess the efficacy and safety of tenecteplase compared with alteplase.

METHODS

In 1021 hospitals, we randomly assigned 16,949 patients with acute myocardial infarction of less than 6 h duration rapid infusion of alteplase (< or = 100 mg) or single-bolus injection of tenecteplase (30-50 mg according to bodyweight). All patients received aspirin and heparin (target activated partial thromboplastin time 50-75 s). The primary outcome was equivalence in all-cause mortality at 30 days.

FINDINGS

Covariate-adjusted 30-day mortality rates were almost identical for the two groups--6.18% for tenecteplase and 6.15% for alteplase. The 95% one-sided upper boundaries of the absolute and relative differences in 30-day mortality were 0.61% and 10.00%, respectively, which met the prespecified criteria of equivalence (1% absolute or 14% relative difference in 30-day mortality, whichever difference proved smaller). Rates of intracranial haemorrhage were similar (0.93% for tenecteplase and 0.94% for alteplase), but fewer non-cerebral bleeding complications (26.43 vs 28.95%, p=0.0003) and less need for blood transfusion (4.25 vs 5.49%, p=0.0002) were seen with tenecteplase. The rate of death or non-fatal stroke at 30 days was 7.11% with tenecteplase and 7.04% with alteplase (relative risk 1.01 [95% CI 0.91-1.13]).

INTERPRETATION

Tenecteplase and alteplase were equivalent for 30-day mortality. The ease of administration of tenecteplase may facilitate more rapid treatment in and out of hospital.

The effect of vibrissa deprivation pattern on the form of plasticity induced in rat barrel cortex

Plasticity was induced in the barrel cortex of adolescent rats by depriving every second vibrissa on the contralateral vibrissa pad. This produced a chessboard pattern of barrels in the cortex where each barrel receiving its principal input from a spared vibrissa was surrounded by barrels for which the principal vibrissa had been deprived and conversely, each barrel receiving its principal input from a deprived vibrissa was surrounded by barrels for which the principal vibrissa had been spared. After 7 days' deprivation, responses to the regrown vibrissae were depressed in layers II/III (49% of control levels) and IV (60%). Depression was far greater than that seen with "all vibrissa" deprivation, suggesting that activity in the spared vibrissae accentuated the depression of the deprived vibrissae. Depression was not due to subcortical changes as thalamic Ventral Posterior Medial (VPM) responses to deprived vibrissa were unchanged. The short latency responses in layer IV (5-7 ms) were unaffected by deprivation, but the number of cells responding at intermediate latencies (8-13 ms) was markedly reduced (to 66% of control). Potentiation of the spared vibrissa response was substantial in the near side of the neighbouring barrel (2.2-fold increase in layers II/III, 2.9-fold in layer IV) but had not spread to the far side after 7 days' deprivation. Sparing multiple vibrissae may increase the rate of potentiation since 7 days is insufficient time for potentiation in single vibrissa spared animals. Potentiation was not due to subcortical changes as thalamic VPm responses to the spared vibrissa were normal. However, in the spared barrel the response latency decreased by 1-2 ms. Only the cells responding at short latency exhibited potentiated responses (39% increase) suggesting that some thalamocortical plasticity is still possible at P28-35. These results show that chessboard pattern deprivation is capable of inducing substantial plasticity over a wide area of barrel cortex. All the major forms of plasticity seen with other vibrissa deprivation patterns were present, although no other single deprivation pattern studied so far causes the complete repertoire seen with chessboard deprivation.

Moclobemide in the treatment of major depressive disorder (DSM-3) following traumatic brain injury

Major depression (MDD) following traumatic brain injury (TBI) is a common phenomenon. There are no adequate studies in the literature defining optimum treatments for this condition following TBI. The opportunity arose to analyse a group of patients who were included in a larger study of an antidepressant (moclobemide). As the treatment, but not the delivery, was known, this has the status of an open study. Twenty-six patients with major depression of late onset (mean 4.67 years post-TBI) were identified (18 male, 8 female), with a mean age at injury 28.49 years. The group was moderately depressed with Hamilton Depression score (HAM-D) of 23.385 and moderately anxious with Hamilton Anxiety score (HAM-A) of 21.231. Mean HAM-D reduction was 81% and HAM-A reduction 81%. Of the 26 subjects 23 were defined as responders. Onset of action was rapid, with 17 responding by day 3. Irritability scores showed a mean reduction of 57% and pain scores a reduction of 39%. It is concluded that moclobemide may be an effective treatment for MDD following TBI, but properly controlled studies must be carried out to confirm this.