Behavior of major and trace elements in a transient surface water/groundwater system following removal of a long-term wastewater treatment facility source.

In many aquatic environments, municipal wastewater treatment facility (WWTF) effluent discharges influence local hydrologic and chemical connectivity between the surface-water and adjacent alluvial shallow-groundwater systems. Fourmile Creek located in Polk County, Iowa received effluent from the Ankeny WWTF for nearly forty years before it was shut down in November 2013. The decommissioning of the municipal WWTF provided a unique opportunity to characterize the recovery from impacts of treated wastewater discharge on water quality at the surface-water/groundwater interface in a shallow, unconfined alluvial aquifer. Dissolved major element and trace element concentrations in Fourmile Creek surface water, hyporheic-zone water, and shallow, unconfined groundwater were monitored upstream and downstream from the WWTF discharge before and after the shutdown. Multivariate statistical techniques including principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were used to differentiate source-water contributions, characterize elemental components, and describe surface-water/groundwater interaction dynamics. During the post-closure assessment, there was subsurface attenuation of wastewater constituents including Al, B, Cu, Gd, K, Mo, Na, P, Pb, Sb, and Zn. During the same time, groundwater concentrations increased for As, Ba, Ca, Fe, Mg, Mn, SiO2, Sr, and U and represented a profile characteristic of the shallow alluvial aquifer. Hydrologic conditions transitioned from predominantly wastewater infiltration and hyporheic exchange before the WWTF shutdown, to predominantly discharge of native groundwater. Precipitation-driven streamflow events created fluctuations in the groundwater water-table elevations, resulting in variable contact between the saturated and unsaturated zones within the unconfined, alluvial aquifer and intermittent exposure to constituents stored in the sediments. The inorganic fingerprint of municipal wastewater was flushed relatively quickly (≤19 weeks) from the hyporheic zone indicating that processes like diffusion or sorption/desorption that might extend recovery may not be important for many trace elements in this system.

Care delivery and self-management strategies for adults with epilepsy.

BACKGROUND: Epilepsy care has been criticised for its lack of impact. Various service models and strategies have been developed in response to perceived inadequacies in care provision. OBJECTIVES: To compare the effectiveness of any specialised or dedicated intervention for the care of adults with epilepsy to the effectiveness of usual care. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2006), MEDLINE (1966 to May 2006), EMBASE (1988 to May 2006), PsychINFO (1806 to May 2006) and CINAHL (1982 to May 2006). SELECTION CRITERIA: Randomised controlled trials, controlled or matched trials, cohort studies or other prospective studies with a control group, or time series studies. DATA COLLECTION AND ANALYSIS: Each review author independently selected studies, extracted data and assessed the quality of included studies. MAIN RESULTS: There are 13 trials and 16 reports included in this review. Seven distinct groups of interventions were identified: seven papers reported on five trials of specialist epilepsy nurses. Of the 13 trials, at least three (four reports) have methodological weaknesses, and some of the results from other analyses within studies need to be interpreted with caution because of limiting factors in the studies. Consequently, there is currently limited evidence for the effectiveness of interventions to improve the health and life quality of people with epilepsy. It was not possible to combine study results in a meta-analysis because of the heterogeneity of outcomes, study populations, interventions, and time scales across the studies. AUTHORS' CONCLUSIONS: Two intervention types, the specialist epilepsy nurse and self-management education, have some evidence of benefit. However, we did not find clear evidence that other service models substantially improve outcomes for adults with epilepsy. It is also possible that benefits are situation specific and may not generalise to other settings. These studies included only a small number of service providers whose individual competence or expertise may have had a significant impact on outcomes. At present it is not possible to advocate any single model of service provision.

The effects of age and visual experience on potentiation of responses in slices from the chick forebrain.

A single coronal slice, containing the intermediate part of the medial hyperstriatum ventrale (IMHV) was cut from the left forebrain of a series of domestic chicks and maintained in vitro. Records were made of field responses evoked in the IMHV by local electrical stimuli. Two 1-min periods of 5 Hz stimulation, separated by 10 min, were used in attempts to induce persistent potentiation of the responses (PPR) to test stimulation at 0.1 Hz. In dark-hatched chicks the probability of producing PPR is much higher in slices from chicks aged 2-5 days post-hatch than in those from either younger or older birds. As an independent measure of plasticity in dark-hatched chicks, the probability of eliciting unit responses to repeated stimulation of remote sites in the slice at 3.3 Hz was analysed. This probability was greater in slices from chicks aged 2-5 days than in those from either younger or older birds. In light-hatched chicks the probability of inducing PPR is significantly higher during the first day post-hatch, than in dark-hatched chicks of this age. The probability of producing PPR in slices from light-hatched chicks aged 2-3 days is less than that in slices from either younger or older birds. It is clear that both the age and past experience of the domestic chick affect the neurophysiological properties of slices of brain, tested in vitro.

Potentiation of synaptic responses in slices from the chick forebrain.

Coronal slices, containing part of the medial hyperstriatum ventrale (MHV), were cut from the left forebrains of domestic chicks and maintained in vitro. Records were made of the field responses evoked in the MHV by local electrical stimuli provided at 0.1 Hz. Two 1 min periods of stimulation at 5 Hz, separated by 10 min, were used in attempts to induce a persistent increase in the size of the postsynaptic response to test stimulation at 0.1 Hz. This procedure produced a potentiation which usually lasted longer than 2 h. The probability of inducing this persistent potentiation of the response (PPR) is not distributed evenly over the whole anteroposterior length of the MHV but is higher in slices that also contain the septo-mesencephalic tract ventrally. These are the slices that contain the intermediate part of the medial hyperstriatum ventrale (IMHV); an area that is essential for early behavioural learning. At this level PPR is not confined to the IMHV. It can also be produced in the lateral neostriatum in response to similar local stimulation at 5 Hz. No PPR was observed in either the caudal ectostriatum, or the paleostriatum.

Morphological correlates of protein kinase C induced potentiation in the chick brain slice.

Continuous perfusion of a chick brain slice with 10 microM 4 beta phorbol 12,13 diacetate (PDAc) produces a significant increase in the amplitude of the response to electrical stimulation at 0.1 Hz recorded within the intermediate and medial part of the hyperstriatum ventrale (IMHV). This PDAc-induced potentiation and that induced by tetanising stimulation appear to share similar mechanisms. Quantitative electron microscopy of synapses within the IMHV from slices in which a PDAc induced potentiation had been produced 30 minutes earlier showed that compared with control slices there was a significant increase in the size of the postsynaptic density of spine synapses. The change was greater in magnitude than that observed in spine synapses following tetanically induced potentiation. No other synaptic parameters were affected.

Protein kinase activity and synaptic plasticity in a chick brain slice.

In an in vitro slice preparation of the chick brain it is possible to record responses to single electrical stimuli from within the intermediate and medial part of the hyperstriatum ventrale (IMHV), a region known to be involved in learning. The amplitude of such responses is significantly increased by superfusion of the slice with 10 microM 4 beta-phorbol 12,13 diacetate (PDAc), a phorbol ester which stimulates protein kinase activity. The ability of PDAc to induce potentiation is greatest in chicks less than 6 days old. Administration of the kinase antagonist H7 prevents the induction of persistent potentiation and in fact produces a long lasting depression of response amplitude. H7 also produces a short term increase in excitability within the IMHV and results in increased expression of N-methyl-D-aspartate receptor activity.

Morphological correlates of persistent potentiation in the chick brain slice.

In an in-vitro slice preparation of the chick brain it is possible to induce persistent potentiation of responses to single electrical stimuli by giving two bursts of 300 stimuli at 5 Hz separated by ten minutes of control stimulation at 0.1 Hz. We investigated the morphological correlates of this potentiation in a group of 2 day old chicks using quantitative electron microscopical techniques. It was found that in slices which showed a clearly potentiated response there was a significant increase in the size of the postsynaptic densities of synapses on spines in the left hyperstriatum ventrale (IMHV). No such increases were seen in a control group nor in slices which failed to potentiate. These results provide further evidence for the lability of synapses in the IMHV.

Noradrenaline and potentiation in the chick brain slice.

The role of the noradrenergic system as a modulator of neurotransmission in the chick forebrain was investigated in brain slices containing the medial hyperstriatum ventrale, an area known to be involved in learning and memory. The alpha 2-agonist clonidine (20 microM) decreased the post-synaptic response to local stimulation at 0.1 Hz, while activation of beta 2 receptors increased this response. Induction of persistent potentiation following stimulation at 5 Hz was blocked by drugs (20 microM ICI 118,551; 20 microM propranolol) which showed preferential antagonistic activity at the beta 2 receptor but not by the beta 1-preferential antagonist timolol. This effect may be due to an interaction with the NMDA receptor system.

NMDA-receptors and potentiation in an area of avian brain essential for learning.

The intermediate medial part of the hyperstriatum ventrale (IMHV), part of the avian forebrain, is essential for early learning in the domestic chick. Persistent potentiation (PP) can sometimes be induced in the IMHV in vitro. One can predict success from events which occur during the stimulation (1 min at 5 Hz) which is used for induction: the original response must be transiently replaced by a later, slower response (the LPSR). The LPSR has a comparatively high threshold of activation, its rate of development is inversely related to magnesium concentration and it can be eliminated by NMDA antagonists, as can the induction of PP. PP in the IMHV is therefore dependent upon NMDA receptors and the LPSR represents the activation of these receptors.

Post-synaptic GABA(B) receptors--possible controllers of coincidence detection?

Post-synaptic GABA(B) responses (slow, late hyperpolarisations which can be eliminated by perfusion with phaclofen) can be recorded in vitro from many, but not all, neurones in the intermediate medial hyperstriatum ventrale (IMHV). The IMHV is an area of the chick forebrain which is remarkable for its plasticity, and for its essential role in two specific types of early learning-imprinting, and a form of one-trial passive-avoidance learning. Post-synaptic GABA(B) responses are strongly statistically associated with other properties (such as high membrane resistance) which are, themselves, dependent on a bird's past history. There is also evidence that their incidence changes with prior training in vivo and with age. GABA(B) hyperpolarisations are always offset to a varying extent by excitatory NMDA components. These two components follow a very similar time-course, so that the duration and (to a lesser extent), the magnitude of a response is controlled by the balance between the two systems. The evidence suggests that this balance fluctuates, and that its fluctuations determine the extent to which any neurone can function as a coincidence detector.

State-dependent recall can be induced by protein synthesis inhibition: behavioural and morphological observations.

The possibility that the amnesia induced by protein synthesis inhibition is state dependent was investigated. Chicks injected with the protein synthesis inhibitor anisomycin and then trained in a single-trial passive avoidance learning task showed no recall for the task when tested 6 h later in the absence of the drug. If, however, the same chicks were subsequently retested 30 min after a second administration of the drug they demonstrated clear recall for the task. Control groups showed that this effect was not the result of the administration of anisomycin per se but was due to state-dependent recall. Quantitative morphological characterisation of synapses in a region of the chick forebrain (the intermediate part of the medial hyperstriatum ventrale (IMHV) previously shown to be involved in passive avoidance learning was performed. The characteristic increase in the length of the postsynaptic density in the left IMHV was only evident in chicks killed after the behavioural test in which they had demonstrated recall. No synaptic changes were observed in chicks in which state-dependent recall had been demonstrated in a previous test but which were killed after a test in which they appeared amnestic. These results suggest that a memory trace may be established even in the absence of protein synthesis but that this trace may not normally be accessible. It is also suggested that the synaptic changes observed following learning may be dependent on some aspect of the recall phenomenon.

The application of network analysis to the study of branching patterns of large dendritic fields.

Network analysis of dendritic fields not only defines the topology and connectivity of segments of an arborescence, but offers a means of discovering how networks grow. An important theory has recently been formulated29 suggesting that dendritic branching patterns may be established by synaptogenic interaction of dendritic growth cones with growing axons. This thesis may be verified through network analysis since the theory predicts that growth at pendant vertices will predominate in dendritic networks, that dendritic growth will be directed into areas of maximal synaptogenic activity and that arc lengths will be inversely related, and the order of branching at vertices directly related, to the magnitude of the synaptogenic activity operating about growing dendritic terminals. The possibility of a preponderance of terminal growth may be detected by comparing the topologies in an observed dendritic network with those of a series of hypothetical growth models. This paper provides the frequency table for models grown by monochotomous, dichotomous and trichotomous branching on random pendant vertices and random arcs for large networks in which 'set theory' contingencies are included. The paper also describes a method of calculating branching probabilities from the measurement of segment lengths, which is a means of testing the last mentioned prediction of the synaptogenic theory of denddritic growth. The method of network analysis is then discussed in relation to probable dendritic growth patterns, the constancy of segment lengths and the interaction of extrinsic and intrinsic factors in determining branching probabilities.

The effects of protein synthesis inhibition on structural changes associated with learning in the chick.

The effect of the protein synthesis inhibitor anisomycin on the structural changes associated with passive avoidance learning in the chick was investigated. Chicks were trained when they were 24 h old by allowing them to peck at a shiny bead coated with either water or the aversive-tasting substance methylanthranilate (MeA). Chicks which peck the MeA-coated bead will on subsequent testing avoid pecking a similar, but water-coated bead. Behavioural testing was carried out 12 h after training and immediately afterwards the chicks were killed and their brains prepared for electron microscopy. A specific region of the forebrain, the intermediate and medial part of the hyperstriatum ventrale (IMHV) was investigated. When the IMHV of the MeA trained chicks was compared with that of water-trained controls structural changes of the synapse were detected. These changes involved a significant increase in the mean length of the postsynaptic density (LPSD) of symmetrical synapses in the left IMHV. Chicks injected with 0.8 mg of anisomycin 30 min before training with a MeA-coated bead showed aversion for the shiny bead when tested 12 h later. Electron microscopic analysis of the IMHV from these amnestic chicks showed no evidence for the change in LPSD demonstrated in the water-injected controls. These results are discussed in relation to the nature of the memory trace induced by training on a passive avoidance task.

Low-threshold N-methyl-D-aspartate receptor function correlates negatively with learning.

The intermediate, medial hyperstriatum ventrale (IMHV) is an area of the forebrain of the domestic chick which exhibits great plasticity. Moreover, there is a strong link between plasticity in the IMHV and specific changes in behaviour. The IMHV in vitro is still plastic, and many of its physiological properties are age-dependent, peaking in slices taken from 3- or 4-day-old birds. This 'window' coincides with an important transitional period in a chick's normal behavioural development. It has also been claimed that reversal training is at its most effective in 3- and 4-day-old birds - a proposition which was confirmed by the experiments reported here. A combination of in vivo training followed by in vitro electrophysiology also revealed that the function of low-threshold N-methyl-D-aspartate receptors (one of the age-related variables) is negatively related to the effectiveness of reversal training, when age is held constant.

Age and the effects of 2-D,L-amino-5-phosphonovalerate in an area of the chick forebrain which is essential for early learning.

The intermediate, medial part of the hyperstriatum ventrale (IMHV) is a region of the avian forebrain which is known to be essential for early learning in the domestic chick. The IMHV in an in vitro slice preparation displays two forms of synaptic plasticity. The incidence of both varies with age and is maximal between 3 and 5 days post-hatch. Since NMDA receptors are critical for at least one of these plasticities, we have investigated the relationship between age and the contribution of NMDA receptors to the field response evoked by local, low-frequency stimulation and have found that the magnitude of the NMDA-dependent component of the response varies with age peaking between 3 and 5 days post-hatch. Spontaneous neural activity, recorded intracellularly, can be completely and reversibly silenced by NMDA receptor blockade and the incidence of spontaneous activity also varies with age, peaking between 3 and 5 days. These results suggest that the IMHV contains NMDA receptors which can be activated near resting membrane potential. Either the efficiency or the numbers of these receptors is maximal at a specific point in development and their peak activity coincides with a peak in synaptic plasticity. These characteristics are similar to those reported for young mammals.

Electrophysiological correlates of prior training: an in vitro study of an area of the avian brain which is essential for early learning.

Day-old domestic chicks will peck at any small, distinct object, such as a metal bead. One-trial passive avoidance learning can be established by coating the metal bead with methyl anthranilate (MeA) and allowing the birds to peck it once, after which they conspicuously avoid it. We have used birds successfully trained not to peck metal beads, and a control set of chicks where the training beads were innocuously dipped in water. Brain slices were prepared from both groups, containing the left, intermediate, medial part of the hyperstriatum ventrale (IMHV)--a region essential for this form of early learning. The electrophysiological properties of neurones in the IMHV were examined in vitro. Neurones recorded intracellularly in slices taken from MeA-trained birds had higher membrane resistances than did cells from water-trained controls. MeA training was also associated with an increased incidence of spontaneous, large EPSPs. Field responses to local electrical stimulation appeared to be somewhat greater in MeA-trained birds than in water-trained controls. In contrast, field potentials proved harder to potentiate with a burst of relatively high frequency stimulation in MeA-trained birds: the change in amplitude was less in MeA-trained birds, and there was less variability than in slices from water-trained controls.

Morphological and electrophysiological properties of neurons in an area of the chick brain involved in learning.

The intermediate, medial part of the hyperstriatum ventrale (IMHV) is an area of the avian forebrain which is essential for two forms of early learning in the domestic chick. We have developed an in vitro slice preparation which contains part of the IMHV and have found that the electrophysiological properties of the area show a considerable degree of plasticity. In particular, age and prior learning appear to modify the properties of single neurons recorded intracellularly. We have used the in vitro slice preparation to make intracellular recordings from 38 single neurons in the IMHV and have then dye-injected each cell to find out whether there is any relationship between electrophysiological and morphological characteristics. The basic membrane properties of each neuron were measured. Responses to standard electrical stimuli, delivered extracellularly, were also recorded, and each neuron was classified on this basis. Finally, the presence or absence of spontaneously occurring bursts of EPSPs was noted. At the end of recording biocytin was injected into the cell. After the tissue had been processed, each cell was drawn. The area of the cell body was measured, the number of dendrites was counted, and dendritic extent and branching were estimated. Each cell was also classified as 'spiny' or 'non-spiny'. We found that neurons displaying one particular type of response to external stimulation possessed a well defined set of morphological and electrical properties. In addition, three parameters--electrical resistance, somatic area, and the presence or absence of dendritic spines--were related to specific subsets of anatomical and physiological characteristics. The possible relevance of these findings to the plasticity of the IMHV is discussed.

Effect of anti-tuberculosis treatment on the tuberculin interferon-gamma response in tuberculin skin test (TST) positive health care workers and patients with tuberculosis.

SETTING: Public hospital, Victoria, Australia. OBJECTIVE: To evaluate the effect of multidrug treatment and isoniazid (INH) chemoprophylaxis on the tuberculin interferon-y assay (QIFN) in 19 patients with culture-confirmed Mycobacterium tuberculosis and 119 health care workers (HCWs) with tuberculin skin tests (TST) > or =15 mm. DESIGN: Patients with M. tuberculosis were treated with standard medication and tested with QIFN at diagnosis and at regular intervals over a 12-month period. All HCWs, 59 (50%) of whom were prescribed INH chemoprophylaxis, were tested with QIFN at baseline, 2, 4, 6 and 12 months. RESULTS: QIFN results in patients with tuberculosis were consistent and reproducible. At the initial time point QIFN assays were positive for M. tuberculosis in 67%, and once positive, the QIFN assay remained so over the 12-month period. In the HCWS, initial QIFN assays were positive in 73 (61%). During the 12-month study, 91 HCWs had a QIFN assay on at least two occasions. The overall reproducibility between tests was fair (kappa statistic = 0.45), and was little affected by administration of INH. CONCLUSION: These data suggest that although the QIFN assay is generally positive in patients with proven tuberculosis, it does not provide clinically useful information during the first 12 months of treatment with multidrug chemotherapy or INH chemoprophylaxis.

The effect of dark-rearing on dendritic development in two regions of the forebrain of the domestic chick.

The effects of dark-rearing on dendritic development were studied in domestic chicks aged 72 h. Two areas of the forebrain were investigated, the hyperstriatum accessorium (HA) and the intermediate part of the medial hyperstriatum ventrale (IMHV). Dark-rearing significantly reduced spine density on the dendrites of large multipolar neurones in both left and right HA. In the IMHV there was a significant decrease in spine density in the left hemisphere in chicks reared in the light. No other parameters of dendritic development were affected. These results reinforce the conclusion that in the young domestic chick the left IMHV is a particularly labile region.

Effects of light hatching on synapse number and size in the intermediate and medial part of the hyperstriatum ventrale of the domestic chick.

The effects of pre-hatch light exposure on synaptic development in the intermediate and medial part of the hyperstriatum ventrale (IMHV) of the chick brain were investigated. Quantitative electron microscopical techniques were used to determine the size and numerical density of synapses and it was seen that in light hatched chicks there was a significant increase in the density of synapses in the left IMHV but that the size of synapses in these birds was decreased. These results provide a link between synaptic development and plasticity.