224 “OLDER PEOPLE WANT TO BE IN THEIR OWN HOMES”: THEMATIC ANALYSIS- PATIENT AND CARER FEEDBACK AFTER PATHFINDER EMERGENCY CALL RESPONSE

Background

Older adults are frequent attendees at the Emergency Department (ED) and experience high rates of adverse outcomes following ED presentation. There is a growing evidence base for alternative care pathway models at the time of a low acuity emergency medical services (EMS) call. Previous research has found a high level of patient satisfaction with the Pathfinder model, in which an Advanced Paramedic and a Physiotherapist or Occupational Therapist respond to EMS calls [1]. However, the reasons underpinning this from a patient perspective have not previously been reported.

Methods

This is a qualitative study employing thematic analysis of open-ended responses recorded in 429 telephone interviews with service users (patients or their next-of-kin), who had been attended by the Pathfinder service following an EMS call.

Results

Five primary themes were identified: (1) the professionalism of the interdisciplinary clinical team; (2) “the right service, in the right place at the right time”; (3) the role of Pathfinder in “getting the ball rolling” through following up and co-ordinating referrals and services; (4) the lasting impact of the experience on the patient and their next-of-kin; (5) the value of skilled communication with the older person, as well as smooth and “tuned-in” communication across the team.

Conclusion

Older people voiced a clear preference for hospital avoidance, and strongly valued the opportunity to be assessed and treated in their homes at the time of an EMS call rather than automatic conveyance to the ED. They recognised the value of a skilled interdisciplinary team, with a follow-up service, that effectively positions itself between the acute hospital and community services.

Reference

1. Bernard P, Corcoran G, Kenna L, et al. Is Pathfinder a safe alternative to the emergency department for older patients? An observational analysis. Age Ageing 2021; 50(5):1854–1858.

215 WHAT IMPACT CAN ‘EMERGENCY DEPARTMENT IN THE HOME’ (EDITH) HAVE ON THE OLDER ADULT POPULATION PRESENTING WITH FALLS?

Background

EDITH is a frailty response service providing medical and occupational therapy input to older adults living within the catchment area of a level 4 acute hospital. EDITH aims to reduce avoidable Emergency Department (ED) attendances and utilise alternative care pathways. Falls are common among older people and are often associated with poorer outcomes. Traditionally, older patients who have had a fall and contact emergency services for assistance are transferred to the ED and this can be associated with elevated risks. Additionally, older patients who have had a fall and are discharged on scene by the emergency services are at greater risk of recurring falls in the absence of immediate onward referral to community falls prevention services (Nowak and Hubbard 2009).

Methods

Paper count method data collection was completed. Inclusion criteria included referrals from the National Ambulance Service within the last 6 months.

Results

75 patients met the inclusion criteria; 34 males, 41 females with an average age of 82. 11 patients were conveyed to hospital, giving a conveyance rate of 14.6%, the average conveyance rate for the EDITH service is 7.2%. 3 patients were conveyed to ED, while 8 patients were conveyed to the Medical Assessment Unit (MAU) in the local level 3 hospital. This resulted in 72% of patients that required hospital conveyance being streamed to the MAU; traditionally 100% of these patients would have presented to ED. Overall, 85.4% of patients seen remained at home.

Conclusion

EDITH are providing targeted medical and occupational therapy assessment(s) for older adults in their homes with successful outcomes. Implementation of alternative care pathways, reduction in avoidable ED attendances and prolonged independence in the home for this patient profile are some of the favourable findings.

Reference

1. Nowak A, Hubbard RE. (2009) Falls and frailty: lessons from complex systems. Journal of the Royal Society of Medicine. 102(3):98–102.

34 PATHFINDER; AN ALTERNATIVE TO THE EMERGENCY DEPARTMENT FOR OLDER PATIENTS WHO DIAL 999/112

Background

Traditionally in Ireland, people who dial 999/112 are transported to the Emergency Department (ED) unless they decline to travel. Many have non-urgent needs that could be treated elsewhere. Older people are particularly vulnerable to adverse events while in hospital. Alternative care pathway models can reduce ED crowding and improve patient outcomes.

Methods

This service is a collaboration between the National Ambulance Service and Occupational Therapy (OT) and Physiotherapy Departments at a Dublin teaching hospital; funded by the Sláintecare Integration fund. It responds to low acuity 999/112 calls for people 65 years and older within the hospital catchment.

The team operates Monday–Friday, a ‘Rapid Response Team’ (Advanced Paramedic and Physiotherapy/OT) (8:00–20:00) and a ‘Follow-Up Team’ (Physiotherapy and OT) (8:00–16:00).

Once activated, the ‘Rapid Response Team’ conduct a comprehensive assessment in the home to establish whether a suitable alternative to the ED is available, commonly through the activation of one or more alternative care pathways (e.g. GP, Integrated Care Team, Primary Care Team, Community Intervention Team, Geriatric Day Hospital).

Results

In the first year, 485 patients were responded to. Average age was 80 years, average Rockwood Clinical Frailty Scale score was 6 (moderately frail). The majority (68%) remained at home following initial review. Less than 1% re-presented within 24 hours, 9% re-presented within 7 days. The three most common reasons for dialling 999/112 were falls, generally unwell and non-traumatic back pain. Patient and care-giver feedback demonstrated a very high level of satisfaction with the service.

Conclusion

This model is a safe alternative to the ED for older people following a low-acuity 999/112 call. Access to a network of alternative care pathways and immediate follow-up are two key enablers. The overwhelmingly positive feedback confirms that older people want this service. It is the first model of this kind to be evaluated in Ireland, and could expand, with local adaptation, nationally.

Long-term outcomes of urethral catheterisation injuries: a prospective multi-institutional study

PURPOSE

There are no prospective data describing the incidence and spectrum of long-term complications associated with traumatic urethral catheterisation (UC). We prospectively monitored the long-term clinical outcomes and complications of patients with traumatic UC injuries.

METHODS

A prospective study at two tertiary university hospitals was performed to record all referrals for iatrogenic urethral injuries caused by UC. Long-term follow-up was prospectively maintained by regular outpatient department visits and by monitoring all urological interventions and their outcomes from urinary catheter-related injuries.

RESULTS

The incidence of traumatic UC was 13.4 per 1000 catheters inserted in male patients and 37 iatrogenic urethral injuries were recorded. The mean age was 74 ± 12 years and the mean length of follow-up was 37 ± 3.7 months. Urethral injuries were caused by inflating the catheter anchoring balloon in the urethra (n = 26) or by creating a false passage with the catheter tip (n = 11). In total, 29 patients (78%) developed urethral stricture disease during their follow-up; of which 11 have required at least one urethral dilation and two have required one urethrotomy. Three patients required long-term indwelling suprapubic catheter placement and seven patients opted for a long-term indwelling urethral catheter. There were eight patient mortalities; one of which was due to severe urosepsis resulting from catheter balloon inflation in the urethra.

CONCLUSION

Catheter-related injuries are associated with significant long-term complications in this vulnerable patient cohort. In future, such injuries may be preventable if the safety profile of the urinary catheter is modified.

Global patterns and drivers of ecosystem functioning in rivers and riparian zones

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth's biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented "next-generation biomonitoring" by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

Internal temperature increase during photothermal tumour ablation in mice using gold nanorods

Laser ablation (LA) is gaining large acceptance in the treatment of tumor. One of the main risks of this treatment is damaging the healthy tissue around the tumor. Among the solutions proposed to improve the selectivity of the LA and to localize heating to tumor tissue, the use of gold nanoparticles is one of the most promising. The aim of this work is threefold: i) to measure the temperature increase within the tumor during plasmonic photothermal therapy using gold nanorods; ii) to investigate the influence of nanorods concentration and laser settings on both the intra-tumoral temperature and the tumor surface temperature; iii) and to establish the nanorods concentrations able to cause tumor resorption at a defined laser settings. Two sets of trials were performed: i) 16 mice were divided in four groups with different treatment time (i.e., 5 min, 2 min, 1 min, and 30s), with constant gold nanorods amount (i.e., 12.5 μg) and laser power (i.e., 3 W·cm(-2)); ii) 16 mice were divided in four groups treated with different amount of gold nanorods (i.e., control, 12.5 μg, 25 μg, 50 μg) for 5 min at 2 W·cm(-2). Results show significant differences between internal and surface temperatures. We also demonstrate that this temperature difference increases with nanoparticle concentrations, decreases with laser power, and is not influenced by treatment time. This information is critical to improve the theoretical models that will guide future study designs in sensitive orthotopic tumor models.

Sensory Constraints on Birdsong Syntax: Neural Responses to Swamp Sparrow Songs with Accelerated Trill Rates

Both sensory and motor mechanisms can constrain behavioral performance. Sensory mechanisms may be especially important for constraining behaviors that depend on experience, such as learned birdsongs. Swamp sparrows learn to sing by imitating the song of a tutor, but sparrows fail to accurately imitate artificial tutor songs with abnormally accelerated trills, instead singing brief and rapid trills interrupted by silent gaps. This "broken syntax" has been proposed to arise from vocal-motor limitations. Here we consider whether sensory limitations exist that could also contribute to broken syntax. We tested this idea by recording auditory-evoked activity of sensorimotor neurons in the swamp sparrow's brain that are known to be important for the learning, performance and perception of song. In freely behaving adult sparrows that sang songs with normal syntax, neurons were detected that exhibited precisely time-locked activity to each repetition of the syllable in a trill when presented at a natural rate. Those cells failed to faithfully follow syllables presented at an accelerated rate, however, and their failure to respond to consecutive syllables increased as a function of trill rate. This "flickering" auditory representation in animals performing normal syntax reveals a central constraint on the sensory processing of rapid trills. Furthermore, because these neurons are implicated in both song learning and perception, and because auditory flickering began to occur at accelerated trill rates previously associated with the emergence of broken song syntax, these sensory constraints may contribute to the emergence of broken syntax.

Avian nucleus retroambigualis: cell types and projections to other respiratory-vocal nuclei in the brain of the zebra finch (Taeniopygia guttata)

In songbirds song production requires the intricate coordination of vocal and respiratory muscles under the executive influence of the telencephalon, as for speech in humans. In songbirds the site of this coordination is suspected to be the nucleus retroambigualis (RAm), because it contains premotor neurons projecting upon both vocal motoneurons and spinal motoneurons innervating expiratory muscles, and because it receives descending inputs from the telencephalic vocal control nucleus robustus archopallialis (RA). Here we used tract-tracing techniques to provide a more comprehensive account of the projections of RAm and to identify the different populations of RAm neurons. We found that RAm comprises diverse projection neuron types, including: 1) bulbospinal neurons that project, primarily contralaterally, upon expiratory motoneurons; 2) a separate group of neurons that project, primarily ipsilaterally, upon vocal motoneurons in the tracheosyringeal part of the hypoglossal nucleus (XIIts); 3) neurons that project throughout the ipsilateral and contralateral RAm; 4) another group that sends reciprocal, ascending projections to all the brainstem sources of afferents to RAm, namely, nucleus parambigualis, the ventrolateral nucleus of the rostral medulla, nucleus infra-olivarus superior, ventrolateral parabrachial nucleus, and dorsomedial nucleus of the intercollicular complex; and 5) a group of relatively large neurons that project their axons into the vagus nerve. Three morphological classes of RAm cells were identified by intracellular labeling, the dendritic arbors of which were confined to RAm, as defined by the terminal field of RA axons. Together the ascending and descending projections of RAm confirm its pivotal role in the mediation of respiratory-vocal control.

Precise auditory-vocal mirroring in neurons for learned vocal communication

Brain mechanisms for communication must establish a correspondence between sensory and motor codes used to represent the signal. One idea is that this correspondence is established at the level of single neurons that are active when the individual performs a particular gesture or observes a similar gesture performed by another individual. Although neurons that display a precise auditory-vocal correspondence could facilitate vocal communication, they have yet to be identified. Here we report that a certain class of neurons in the swamp sparrow forebrain displays a precise auditory-vocal correspondence. We show that these neurons respond in a temporally precise fashion to auditory presentation of certain note sequences in this songbird's repertoire and to similar note sequences in other birds' songs. These neurons display nearly identical patterns of activity when the bird sings the same sequence, and disrupting auditory feedback does not alter this singing-related activity, indicating it is motor in nature. Furthermore, these neurons innervate striatal structures important for song learning, raising the possibility that singing-related activity in these cells is compared to auditory feedback to guide vocal learning.

Physiology of neuronal subtypes in the respiratory-vocal integration nucleus retroamigualis of the male zebra finch

Learned vocalizations, such as bird song, require intricate coordination of vocal and respiratory muscles. Although the neural basis for this coordination remains poorly understood, it likely includes direct synaptic interactions between respiratory premotor neurons and vocal motor neurons. In birds, as in mammals, the medullary nucleus retroambigualis (RAm) receives synaptic input from higher level respiratory and vocal control centers and projects to a variety of targets. In birds, these include vocal motor neurons in the tracheosyringeal part of the hypoglossal motor nucleus (XIIts), other respiratory premotor neurons, and expiratory motor neurons in the spinal cord. Although various cell types in RAm are distinct in their anatomical projections, their electrophysiological properties remain unknown. Furthermore, although prior studies have shown that RAm provides both excitatory and inhibitory input onto XIIts motor neurons, the identity of the cells in RAm providing either of these inputs remains to be established. To characterize the different RAm neuron types electrophysiologically, we used intracellular recordings in a zebra finch brain stem slice preparation. Based on numerous differences in intrinsic electrophysiological properties and a principal components analysis, we identified two distinct RAm neuron types (types I and II). Antidromic stimulation methods and intracellular staining revealed that type II neurons, but not type I neurons, provide bilateral synaptic input to XIIts. Paired intracellular recordings in RAm and XIIts further indicated that type II neurons with a hyperpolarization-dependent bursting phenotype are a potential source of inhibitory input to XIIts motor neurons. These results indicate that electrically distinct cell types exist in RAm, affording physiological heterogeneity that may play an important role in respiratory-vocal signaling.

Synaptic transformations underlying highly selective auditory representations of learned birdsong

Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird's own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium (NIf) could eliminate all auditory-evoked subthreshold activity in both HVC PN types, consistent with NIf serving as the major auditory afferent of HVC. Simultaneous multiunit extracellular recordings in NIf and intracellular recordings in HVC revealed that NIf population activity and HVC subthreshold responses were similar in their selectivity for BOS and that NIf spikes preceded depolarizations in all HVC cell types. These results indicate that information about the BOS as well as other auditory stimuli is transmitted synaptically from NIf to HVC. Unlike HVC PNs, however, HVC-projecting NIf neurons fire throughout playback of BOS as well as non-BOS stimuli. Therefore, temporally sparse BOS-evoked firing and enhanced BOS selectivity, manifested as an absence of suprathreshold responsiveness to non-BOS stimuli, emerge in HVC. The transformation to a sparse auditory representation parallels differences in NIf and HVC activity patterns seen during singing, which may point to a common mechanism for encoding sensory and motor representations of song.

Monoamine oxidase inhibitors l-deprenyl and clorgyline protect nonmalignant human cells from ionising radiation and chemotherapy toxicity

l-Deprenyl (R-(−)-deprenyl, selegiline) is an inhibitor of monoamine oxidase-B (MAO-B) that is known to protect nerve cells from a variety of chemical and physical insults. As apoptosis is a common mechanism of radiation-induced cell death, the effect of l-deprenyl on the survival of cultured cells and tissue explants was studied following exposure to gamma radiation. The results obtained were compared with the effects of the less-selective MAO-B inhibitor pargyline and the MAO-A inhibitor clorgyline. l-Deprenyl at a concentration of 10⁻⁹ M protected the nontumorigenic cell line (HaCaT) and normal human urothelial explants from the effects of cobalt-60 gamma radiation, but did not protect tumorigenic human cell lines HaCaT-ras, HPV-transfected human keratinocytes (HPV-G cells), or PC3. Human bladder carcinoma explants were not protected. Clorgyline showed a smaller protective effect of normal cells, whereas pargyline had no effect. Radiation-induced delayed effects (genomic instability measured as delayed cell death) were prevented in normal cells by l-deprenyl but, interestingly, deprenyl appeared to increase the amount of delayed death in the tumorigenic cell lines. Studies using l-deprenyl prior to the exposure of nonmalignant cells to cisplatin showed that cell death due to this agent was also reduced. Treatment of cultures of nontumorigenic cells with l-deprenyl or clorgyline significantly increased the levels of the protein Bcl-2 following irradiation, but there was no such effect on the already-elevated levels of this protein in the tumour samples. Since the Bcl-2 has been shown to be an inhibitor of apoptosis or programmed cell death, this would imply that the protective effects of l-deprenyl and clorgyline involve activation of antiapoptotic pathways within the normal cell. This hypothesis is supported by data showing reduced levels of apoptosis in HaCAT cells and in normal bladder explant cultures following treatment with l-deprenyl.

A bird's eye view: top down intracellular analyses of auditory selectivity for learned vocalizations

The "song system" refers to a group of interconnected brain nuclei necessary for the utterance of learned song and for the generation of vocal plasticity important to both song learning and adult song maintenance. Although song learning and, in some species, song maintenance depend on auditory feedback, how audition influences vocalization remains unknown. One attractive idea is that auditory signals propagate directly to those telencephalic nuclei implicated in song patterning, providing a convenient substrate for sensorimotor integration. Consistent with this idea, auditory neurons highly selective for the bird's own song have been detected in telencephalic song nuclei, and lesions of these structures can impair song perception as well as song production. This review discusses evidence for an auditory-perceptual role of the song system, the anatomical pathways by which auditory information enters the song system, the synaptic events underlying highly selective action potential responses to learned song, and the possible roles such activity could play in song learning and maintenance.

Auditory representation of the vocal repertoire in a songbird with multiple song types

Neural mechanisms for representing complex communication sounds must solve the problem of encoding multiple and potentially overlapping signals. Birdsong provides an excellent model for such processing, in that many songbird species produce multiple song types. Although auditory song representations in single song type species have been studied, how song is represented in the brains of species that sing multiple song types remains unknown. Here we examine song type representations in swamp sparrows (Melospiza georgiana), a multiple song type species, by making in vivo intracellular recordings from the telencephalic nucleus HVc, the major auditory-vocal interface in the songbird brain. These recordings show that single HVc relay neurons often generate action potentials to playback of only a single song type, even though synaptic inputs on these cells can be activated by playback of other song types in the bird's repertoire and songs of other birds. These subthreshold response patterns suggest that the song evoked action potential discharge of a single relay neuron is more selective than its presynaptic network. One component of this presynaptic network is likely to be in HVc, because multiple recordings from single birds show that different relay neurons can respond best to different song types, whereas single interneurons can generate action potentials to all song types in the bird's repertoire. These results show that single HVc neurons can generate song type-specific action potential responses, a feature that may facilitate the selective auditory encoding of multiple learned vocalizations in a single brain area.

Androgens and isolation from adult tutors differentially affect the development of songbird neurons critical to vocal plasticity

Song learning in oscine birds occurs during a juvenile sensitive period. One idea is that this sensitive period is regulated by changes in the electrophysiological properties of neurons in the telencephalic song nucleus lateral magnocellular nucleus of the anterior neostriatum (LMAN), a structure critical for song development but not adult singing. A corollary of this idea is that manipulations affecting the pace and quality of song learning will concomitantly affect the development of LMAN's electrophysiological properties. Manipulations known to affect song development include treating juvenile male zebra finches with exogenous androgens, which results in abnormally truncated adult songs, and isolation of the juvenile from adult tutors and their songs, which extends the sensitive period for song learning. Previously, we showed that synaptic transmission in LMAN changes over normal song development and that these changes are accelerated or retarded, respectively, by androgen treatment and isolation from an adult tutor. The intrinsic properties of LMAN neurons afford another potential target for regulation by steroid hormones and experience of adult tutors. Indeed previous studies showed that the capacity for LMAN neurons to fire action potentials in bursts, due to a low-threshold calcium spike, and the width of single action potentials in LMAN, wane over development. Here we analyzed these and other intrinsic electrophysiological features of LMAN neurons over normal development, then tested whether either early androgen treatment or isolating juveniles from adult tutors affected the timing of these changes. The present study shows that androgen but not isolation treatment alters the developmental time at which LMAN neurons progress from the bursting to nonbursting phenotype. In addition, other intrinsic properties, including the half-height spike width and the magnitude of the spike afterhyperpolarization (AHP), were found to change markedly over development but only changes to the AHP were androgen sensitive. Interestingly of all of the synaptic and intrinsic electrophysiological properties in LMAN studied to date, only the half-height spike width continues to change in the late juvenile stages of song learning. Furthermore raising juveniles in isolation from an adult tutor transiently delays the maturation of this property. The present results underscore that beyond their effects on LMAN's synaptic properties, both androgens and adult tutor experience are potent and selective regulators of the intrinsic properties of LMAN neurons.

Bird communication: two voices are better than one

How do emperor penguins find their mates on a featureless ice flow, packed at densities of ten animals per square meter? A recent study has revealed how use of their 'two-voice' calls enables emperor penguins to locate their mates and chicks under some of nature's most extreme conditions.

Intrinsic and extrinsic contributions to auditory selectivity in a song nucleus critical for vocal plasticity

The development, maintenance, and perception of learned vocalizations in songbirds are likely to require auditory neurons that respond selectively to song. Neurons with song-selective responses have been described in several brain nuclei critical to singing, but the mechanisms by which such response properties arise, are modified, and propagate are poorly understood. The lateral magnocellular nucleus of the anterior neostriatum (LMAN) is the output of an anterior forebrain pathway (AFP) essential for learning and maintenance of song, processes dependent on auditory feedback. Although neurons throughout this pathway respond selectively to auditory presentation of the bird's own song, LMAN is the last stage at which responses to this auditory information could be transformed before being transmitted to vocal motor areas, where such responses may influence vocal production. Indeed, previous extracellular studies have indicated that LMAN's auditory selectivity is greater than that at earlier stages of the AFP. To determine whether LMAN local circuitry transforms or simply relays song-related auditory information to vocal control neurons, it is essential to distinguish local from extrinsic contributions to LMAN's auditory selectivity. In vivo intracellular recordings from LMAN projection neurons, coupled with local circuit inactivation, reveal that much of LMAN's song selectivity is supplied by its extrinsic inputs, but selective blockade of GABA receptors indicates that local inhibition is required for the expression of song selectivity. Therefore, LMAN neurons receive highly song-selective information, but LMAN's local circuitry can mask these selective inputs, providing a mechanism for context-dependent auditory feedback.

Different subthreshold mechanisms underlie song selectivity in identified HVc neurons of the zebra finch

Songbirds learn and maintain their songs via auditory experience. Neurons in many telencephalic nuclei important to song production and development are song selective, firing more to forward auditory playback of the bird's own song (BOS) than to reverse BOS or conspecific songs. Elucidating circuits that generate these responses can localize where auditory experience influences vocalization, bridging cellular and systems analyses of song learning. Song-selective responses in many song nuclei, including the vocal premotor nucleus robustus archistriatalis (RA) and the basal ganglia homolog area X, are thought to originate in nucleus HVc (used as a proper name), which contains interneurons and relay cells that innervate either RA or area X. Previous studies indicated that only X-projecting neurons have auditory responses, leaving open the source of RA's auditory input and the degree to which song selectivity may be refined in HVc. Here, in vivo intracellular recordings from morphologically and electrophysiologically identified HVc neurons revealed that both relay cell types fire song-selectively. However, their firing arises via markedly different subthreshold processes, and only X-projecting neurons appear to be sites for auditory refinement. RA-projecting neurons exhibited purely depolarizing subthreshold responses that were highly song selective and that were excitatory. In contrast, subthreshold responses of X-projecting neurons included less-selective depolarizing and highly selective hyperpolarizing components. Within individual birds, these BOS-evoked hyperpolarizations closely matched interneuronal firing, suggesting that HVc interneurons make restricted inputs onto X-projecting neurons. Because of the two relay cell types' subthreshold differences, factors affecting their resting membrane potentials could enable them to transmit distinct song representations to their targets.

Involvement of energy metabolism in the production of 'bystander effects' by radiation

These experiments were done to determine if interference with energy metabolism and REDOX biochemistry during low LET radiation exposure would alter the ability of medium harvested from the irradiated cells to induce a bystander effect in unirradiated cells. Human keratinocyte cells and CHO-K1 mutant cell lines were irradiated using cobalt 60. Clonogenic assays were used to determine the reproductive death of the cells exposed to direct irradiation or medium from irradiated cells. The persistence in progeny was also examined. Use of apoptosis inhibitors or medium from the LDH or G6PD null cell lines, reduced or prevented the bystander effect. Transfection with G6PD recovered the effect. Treatment with anti-oxidant substances, L-lactate and L-deprenyl prevented bystander factor associated cell kill. The lactate analogue, oxamate, was less effective. Data from experiments where media harvested from the different cell lines was exchanged suggest that signal production and cellular response may involve different mechanisms. The effects on exposed cells were transmitted to progeny which also showed excessive levels of cell death for several generations. The results suggest that energy/REDOX metabolism may be involved in the expression of a radiation induced bystander response. Given the aberrant energy metabolism in tumour cells, this may have implications for dose escalation in radiotherapy.

Slow NMDA-EPSCs at synapses critical for song development are not required for song learning in zebra finches

Birdsong, like human speech, is learned via auditory experience during a developmentally restricted sensitive period. Within projection neurons of two avian forebrain nuclei, NMDA receptor-mediated EPSCs (NMDA-EPSCs) become fast during song development, a transition posited to limit learning. To discover whether slow NMDA-EPSCs at these synapses are required for learning, we delayed song learning beyond its normal endpoint, post-hatch day (PHD) 65, by raising zebra finches in isolation from song tutors. At PHD45, before learning, isolation delayed NMDA-EPSC maturation, but only transiently. By PHD65, NMDA-EPSCs in isolates were fast and adult-like, yet isolates presented with tutors readily learned song. Thus song learning did not require slow NMDA-EPSCs at synapses critical for song development.

Lesions of an avian forebrain nucleus that disrupt song development alter synaptic connectivity and transmission in the vocal premotor pathway

The avian forebrain nucleus, the lateral magnocellular nucleus of the anterior neostriatum (LMAN), is necessary for normal song development because LMAN lesions made in juvenile birds disrupt song production but do not disrupt song when made in adults. Although these age-limited behavioral effects implicate LMAN in song learning, a potential confound is that LMAN lesions could disrupt normal vocal motor function independent of any learning role by altering LMAN's premotor target, the song nucleus, the robust nucleus of the archistriatum (RA). To date, however, no studies have examined directly the effects of LMAN lesions on the circuitry of the RA. We report here that juvenile LMAN lesions rapidly and profoundly affect RA, altering synaptic connectivity within this nucleus, including descending inputs from the song nucleus HVc. Specifically, morphological assays of the dendritic spines of RA projection neurons and axon terminal boutons arising from HVc show a numerical decline in the density of connections in RA in LMAN-lesioned juveniles compared with controls. Concurrently, LMAN lesions alter excitatory transmission within the juvenile RA: after LMAN lesions, the stimulus-response relationship between HVc fibers and RA neurons steepens, and the amplitude of spontaneous monophasic EPSCs increases. Rather than arresting RA in a juvenile state, LMAN lesions transform the structure and function of RA and its connections, such that it is distinct from that of the normal juvenile. In many ways, RA circuitry in LMAN-lesioned juveniles resembles that of normal adults, suggesting that LMAN lesions induce a premature maturation of the vocal motor pathway, which may lead to a loss of behavioral plasticity and abnormal song development.

Androgens modulate NMDA receptor-mediated EPSCs in the zebra finch song system

Androgens potently regulate the development of learned vocalizations of songbirds. We sought to determine whether one action of androgens is to functionally modulate the development of synaptic transmission in two brain nuclei, the lateral part of the magnocellular nucleus of the anterior neostriatum (LMAN) and the robust nucleus of the archistriatum (RA), that are critical for song learning and production. We focused on N-methyl-D-aspartate-excitatory postsynaptic currents (NMDA-EPSCs), because NMDA receptor activity in LMAN is crucial to song learning, and because the LMAN synapses onto RA neurons are almost entirely mediated by NMDA receptors. Whole cell recordings from in vitro brain slice preparations revealed that the time course of NMDA-EPSCs was developmentally regulated in RA, as had been shown previously for LMAN. Specifically, in both nuclei, NMDA-EPSCs become faster over development. We found that this developmental transition can be modulated by androgens, because testosterone treatment of young animals caused NMDA-EPSCs in LMAN and RA to become prematurely fast. These androgen-induced effects were limited to fledgling and juvenile periods and were spatially restricted, in that androgens did not accelerate developmental changes in NMDA-EPSCs recorded in a nonsong area, the Wulst. To determine whether androgens had additional effects on LMAN or RA neurons, we examined several other physiological and morphological parameters. In LMAN, testosterone affected alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprianate-EPSC (AMPA-EPSC) decay times and the ratio of peak synaptic glutamate to AMPA currents, as well as dendritic length and spine density but did not alter soma size or dendritic complexity. In contrast, testosterone did not affect any of these parameters in RA, which demonstrates that exogenous androgens can have selective actions on different song system neurons. These data are the first evidence for any effect of sex steroids on synaptic transmission within the song system. Our results support the idea that endogenous androgens limit sensitive periods for song learning by functionally altering synaptic transmission in song nuclei.

Can an old bird change his tune?

The stereotyped courtship songs of 'age-limited' songbirds, which learn their songs during a specific early period of their lives, were once thought immutable, but recent studies suggest that their maintenance may actually rely on subtle cues provided by auditory feedback.

Hypoketotic hypoglycemic coma in a 21-month-old child

We present the case of a 21-month-old child with hypoketotic hypoglycemic coma. The differential diagnosis initially included metabolic causes versus a toxicologic emergency (unripe ackee fruit poisoning). Using information obtained from the emergency department, the diagnosis was confirmed as the late-onset form of glutaric acidemia type II. This case illustrates the importance of emergency physicians in the diagnosis and management of children with inborn errors of metabolism.

Stimulation of transposition of the Mycobacterium tuberculosis insertion sequence IS6110 by exposure to a microaerobic environment

The Mycobacterium tuberculosis-specific insertion sequence IS6110/986 has been widely used as a probe because of the multiple polymorphism observed among different strains. To investigate transposition of IS6110, a series of artificially constructed composite transposons containing IS6110 and a kanamycin resistance marker were constructed. The composite transposons were inserted into a conditionally replicating, thermosensitive, Escherichia coli-mycobacterial shuttle vector and introduced into M. smegmatis mc2155. Lawns of transformants were grown at the permissive temperature on kanamycin-supplemented agar and subsequently prevented from further growth by shifting to the non-permissive temperature. Under normal atmospheric conditions, kanamycin-resistant papillae appeared after only about 5-6 weeks of incubation. However, these events were not associated with transposon mobilization. In contrast, lawns that were exposed to a 48 h microaerobic shock generated kanamycin-resistant papillae after only 6-14 days. These events were generated by conservative transposition of the IS6110 composite transposon into the M. smegmatis chromosome, with loss of the shuttle vector. In common with other IS3 family elements, transposition of IS6110 is thought to be controlled by translational frameshifting. However, we were unable to detect any significant frameshifting within the putative frameshifting site of IS6110, and the level of frameshifting was not affected by microaerobic incubation. The finding that transposition of IS6110 is stimulated by incubation at reduced oxygen tensions may be relevant to transposition of IS6110 in M. tuberculosis harboured within TB lesions.

Long-range inhibition within the zebra finch song nucleus RA can coordinate the firing of multiple projection neurons

The zebra finch forebrain song control nucleus RA (robust nucleus of the archistriatum) generates a phasic and temporally precise neural signal that drives vocal and respiratory motoneurons during singing. RA's output during singing predicts individual notes, even though afferent drive to RA from the song nucleus HVc is more tonic, and predicts song syllables, independent of the particular notes that comprise the syllable. Therefore RA's intrinsic circuitry transforms neural activity from HVc into a highly precise premotor output. To understand how RA's intrinsic circuitry effects this transformation, we characterized RA interneurons and projection neurons using intracellular recordings in brain slices. RA interneurons fired fast action potentials with steep current-frequency relationships and had small somata with thin aspinous processes that extended throughout large portions of the nucleus; the similarity of their fine processes to those labeled with a glutamic acid decarboxylase (GAD) antibody strongly suggests that these interneurons are GABAergic. Electrical stimulation revealed that RA interneurons receive excitatory inputs from RA's afferents, the lateral magnocellular nucleus of the anterior neostriatum (LMAN) and HVc, and from local axon collaterals of RA projection neurons. To map the functional connections that RA interneurons make onto RA projection neurons, we focally uncaged glutamate, revealing long-range inhibitory connections in RA. Thus these interneurons provide fast feed-forward and feedback inhibition to RA projection neurons and could help create the phasic pattern of bursts and pauses that characterizes RA output during singing. Furthermore, selectively activating the inhibitory network phase locks the firing of otherwise unconnected pairs of projection neurons, suggesting that local inhibition could coordinate RA output during singing.

Sensitive periods and circuits for learned birdsong

Experience influences the development of certain behaviors and their associated neural circuits during a discrete period after birth. Songbirds, with their highly quantifiable vocal output and well-delineated vocal control circuitry, provide an excellent context in which to examine the neural mechanisms regulating sensitive periods for learning. Recent discoveries indicate that auditory input to the vocal control circuitry in songbirds is dynamically modulated and show that neural circuitry previously thought to be used only in plastic juvenile song may also actively maintain stable adult song. These findings provide important clues to how sensitive periods for auditory feedback and vocal plasticity are regulated during song development.

Expression of delayed toxicity and lethal mutations in the progeny of human cells surviving exposure to radiation and other environmental mutagens

PURPOSE

Delayed expression of lethal mutations in the progeny of cells which survived a toxic insult was first shown for ionizing radiation and is one of the signs of induced genomic instability. The effect appears to be related to DNA strand breakage or repair but not to the physical break itself. To investigate this and the relationship of lethal mutations or delayed death to other instability endpoints, cultures of immortal but non-transformed human keratinocytes were exposed to a range of environmental mutagens or cytotoxic compounds with different DNA damaging properties.

METHODS

Delayed expression of damage was assessed by scoring a number of endpoints in the progeny of cells which survived exposure and underwent at least 15 population doublings. Endpoints included delayed apoptosis, cloning efficiency of cells in 'healthy' colonies and expression of the apoptosis regulatory proteins bcl-2 and BAX.

RESULTS

The results clearly linked expression of delayed lethal mutations with substances that induced DNA strand breaks. All these substances are known also to induce oxidative stress. The occurrence of delayed damage required a threshold level of toxicity in the initially exposed population, which was remarkably similar for all the effective substances except cadmium. Alkylating agents or microtubule poisons that do not permit repair of DNA damage did not cause any delayed death.

CONCLUSION

It is concluded that delayed cell death may be caused by widespread radical damage to DNA which is either signalled, thereby inducing an apoptotic response, or (mis-)repaired yielding a weak or unstable genome. It is likely that the process may be an important factor in determining the long-term response of populations to 'sublethal' levels of environmental mutagens whose mechanism of action includes DNA strand breakage and repair.

Dose reduction in a paediatric X-ray department following optimization of radiographic technique

A survey of radiation doses to children from diagnostic radiography has been carried out in a dedicated paediatric X-ray room. Entrance surface dose (ESD) and dose-area product (DAP) per radiograph were simultaneously measured with thermoluminescent dosemeters (TLDs) and a DAP meter to provide mean dose values for separate age ranges. Results of ESD and DAP were lower than the mean values from other UK studies for all ages and radiographs, except for the infant pelvis AP radiograph. Comparison of ESD and radiographic technique with CEC quality criteria highlighted a need for reduction of dose to infants and implied an increase in tube filtration might overcome the limitations of the room's three-phase, 12-pulse generator, allowing higher tube potentials to be used on infants. Additional tube filtration of 3 mmA1 was installed following assessment of dose reduction and image quality with test objects and phantoms, and confirmation from the paediatric radiologist that clinical image quality was not-significantly altered. The tube potential was increased from 50 to 56 kVp for the infant pelvis AP radiograph. The resulting ESD and effective dose fell by 51% and 38%, respectively. The CEC quality criteria have proved useful as a benchmark against which technique in X-ray departments can be compared, and as such are a useful tool for optimizing radiographic technique and reducing patient dose.

The effects of cadmium exposure on the cytology and function of primary cultures from rainbow trout

Cultured epidermal cells from explants of skin of rainbow trout were used to study the cytological and functional changes following sublethal exposure to cadmium stress. The aim was to develop diagnostic markers for ecotoxicology. Cultures were exposed to the pollutant for 48 h. Cell structural and cytological changes were established by light and electron microscopy. Metabolic alterations were detected by immunohistochemistry. The relation between the initiation of cellular alterations and cadmium concentrations was compared in cultures exposed in commercially-available serum-free and serum-containing medium. The expression of stress proteins (metallothionein and heat shock protein) was also studied. Rainbow trout epithelial cells exposed to cadmium showed typical morphological changes indicative of cell death by apoptosis. Sublethal exposure also resulted in cellular metabolic disturbances with increased deposits of glycogen. Increased melanization was also observed. These changes appeared at lower concentrations of cadmium when cells were exposed in serum-free media than in serum-containing media. Cadmium induced the expression of heat shock proteins but not of metallothioneins. The results broadly confirm in vivo findings for cadmium toxicity and suggest that this in vitro technique may have applications in aquatic toxicology.

Development of intrinsic and synaptic properties in a forebrain nucleus essential to avian song learning

In male zebra finches, the lateral magnocellular nucleus of the anterior neostriatum (LMAN) is necessary for the development of learned song but is not required for the production of acoustically stereotyped (crystallized) adult song. One hypothesis is that the physiological properties of LMAN neurons change over development and thus limit the ability of LMAN to affect song. To test this idea, we used in vitro intracellular recordings to characterize the intrinsic and synaptic properties of LMAN neurons in fledgling [posthatch days (PHD) 22-32] and juvenile zebra finches (PHD 40-51) when LMAN lesions disrupt normal song development, and in adults (>PHD 90) when LMAN lesions are without effect. In fledglings, depolarizing currents caused LMAN projection neurons to fire bursts of action potentials because of a putative low-threshold calcium spike (LTS). In contrast, juvenile and adult LMAN projection neurons fired accommodating trains of action potentials when depolarized but did not exhibit the burst mode of firing. Electrical stimulation of thalamic afferents elicited both monosynaptic EPSPs mediated by AMPA and NMDA receptors and polysynaptic IPSPs mediated by GABAA receptors from LMAN neurons at all ages studied here. In whole-cell voltage-clamp recordings, the EPSCs (NMDA-EPSCs) consisted of fast and slow components. Unlike juvenile and adult NMDA-EPSCs, those in fledglings were dominated by the slower component. Thus, both the intrinsic and synaptic properties of LMAN neurons change markedly during early song development (PHD 22-40) and achieve several adult-like properties during early sensorimotor learning and well before the time when LMAN lesions no longer disrupt song development.

Tethering of the large subunits of Escherichia coli RNA polymerase

The rpoB and rpoC genes of eubacteria and archaea, coding, respectively, for the beta and beta'-like subunits of DNA-dependent RNA polymerase, are organized in an operon with rpoB always preceding rpoC. Here, we show that in Escherichia coli the two genes can be fused and that the resulting 2751-amino acid beta::beta' fusion polypeptide assembles into functional RNA polymerase in vivo and in vitro. The results establish that the C terminus of the beta subunit and the N terminus of the beta' subunit are in close proximity to each other on the surface of the assembled RNA polymerase during all phases of the transcription cycle and also suggest that RNA polymerase assembly in vivo may occur co-translationally.

Bird song: of tone and tempo in the telencephalon

Songbirds learn a new song by matching the sound they produce to a memorized model. A distributed central pattern-generating circuit has now been identified that governs song production; the new results have important implications for the way songs are learned.

Thalamic relay of spontaneous retinal activity prior to vision

Before vision, retinal ganglion cells produce spontaneous waves of action potentials. A crucial question is whether this spontaneous activity is transmitted to lateral geniculate nucleus (LGN) neurons. Using a novel in vitro preparation, we report that LGN neurons receive periodic barrages of postsynaptic currents from the retina that drive them to fire bursts of action potentials. Groups of LGN neurons are highly correlated in their firing. Experiments in wild-type and NMDAR1 knockout mice show that NMDA receptor activation is not necessary for firing. The transmission of the highly correlated retinal activity to the LGN supports the hypothesis that retinal waves drive retinogeniculate synaptic remodeling. Because LGN neurons are driven to fire action potentials, this spontaneous activity could also act more centrally to influence synaptic modification within the developing visual cortex.

Behavioral learning. The illuminated songbird

Recent studies of the neural mechanisms of avian song learning suggest that pathways for adult song production are distinct from those essential to juvenile song development.

Waiting periods versus early innervation: the development of axonal connections in the zebra finch song system

This study examines the development of two neural pathways within the zebra finch forebrain that function respectively in the juvenile acquisition and the adult production of learned song. In the adult male zebra finch forebrain, the song nuclei L-MAN and HVc both innervate nucleus RA; L-MAN plays a crucial role in juvenile song acquisition but, unlike HVc and RA, is not essential for adult song production. Previous studies have shown that HVc axons arrive at the dorsal border of RA as early as posthatch day 15 (day 15), and only enter the male RA after days 25-30, but never enter the female RA. The present study examines the development of axonal projections from L-MAN to RA and finds that, in contrast to HVc axons, L-MAN terminals are present within the male and female RA by day 15, and persist there throughout adult life. Unlike RA-projecting HVc neurons, HVc neurons projecting to area X innervate this target by day 20. Like L-MAN, area X plays a transient role in song acquisition. These results suggest that in the zebra finch forebrain, neural pathways essential to juvenile song learning develop before those needed for adult song production.

Graded pelvic muscle exercise. Effect on stress urinary incontinence

The purpose of this research was to determine the effect of pelvic muscle exercise (PME) on stress urinary incontinence in middle-aged and elderly women. The protocol required 16 weeks of exercise three times per week, for a total of 48 sessions. Measures were taken at baseline, after a 4-week control period and after 4, 8, 12 and 16 weeks of PME, corresponding to PME levels 1, 2, 3 and 4, respectively. Urine loss was evaluated using a urinary diary and 24-hour pad test at baseline, after the control period and after PME levels 2 and 4. Pelvic muscle function was evaluated every four weeks. Sixty-five parous women 35-75 years of age (mean, 51.3) with mild to moderate stress urinary incontinence were studied. No significant changes in the outcome variables were found after the control period. The results showed significant reductions in urine loss on the 24-hour pad test (t = -4.7, P < or = .0001), and episodes of urine loss decreased from 2.6 to 1.0 between the control period and PME level 4. In addition, a significant improvement occurred in pressures developed by the pelvic muscles in response to PME (t = 6.8, P < or = .0001). Significant correlations between changes in pelvic muscle pressure and in urine loss variables were not found. Women who completed the study experienced a significant reduction in the amount of urine loss as well as a significant increase in pelvic muscle characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of transmission at the developing retinogeniculate synapse

Axon terminals from retinal ganglion cells in the left and right eyes initially overlap with each other in the lateral geniculate nucleus of the neonatal ferret, then segregate into eye-specific layers via an activity-dependent process. Brain slices were used to show that, during this period of reorganization, retinal terminals within the lateral geniculate nucleus evoke excitatory postsynaptic currents composed of both NMDA and non-NMDA receptor-mediated currents. The amplitude of these currents could be enhanced for several tens of minutes to more than an hour by several bursts of high frequency synaptic stimulation, and the induction of enhancement appears to depend on NMDA receptor activation. Synaptic enhancement such as this could provide one of the physiological mechanisms by which retinal terminals segregate into eye-specific layers during development.

Effects of age, parity, and adherence on pelvic muscle response to exercise

OBJECTIVE

To examine factors that affect pelvic muscle response to 12 weeks of pelvic muscle exercise.

DESIGN

Repeated measures design in which intravaginal pressures during pelvic muscle contractions were recorded at baseline and after four exercise levels.

SETTING

College of Nursing research site in Gainesville, Florida.

PARTICIPANTS

Eighty-five parous, community-dwelling women, aged 35-78 years and without incontinence as a primary concern.

INTERVENTIONS

A 12-week graded program of regular (three times per week, every other day) pelvic muscle exercise at home.

MAIN OUTCOME MEASURES

The hypotheses were that younger age, lower parity, higher baseline intravaginal pressures, and adherence to the pelvic muscle exercise program each would result in significant improvement in maximum intravaginal pressures.

RESULTS

The only factor showing significance in predicting a successful outcome was age (t = -2.29, df = 41, one-tail probability = .0136).

CONCLUSIONS

Regular, graded exercise over several weeks is needed to build pelvic muscles, and some women who exercise do not improve. Although the reasons for not improving are unclear, age is a significant factor.

Synaptic basis for developmental plasticity in a birdsong nucleus

The development and adult production of birdsong are subserved by specialized brain nuclei, including the robust nucleus of the archistriatum (RA), and its afferents originating in the caudal nucleus of the ventral hyperstriatum (HVc) and the lateral portion of the magnocellular nucleus of the anterior neostriatum (L-MAN). An in vitro brain slice preparation was used to characterize the electrophysiological properties of L-MAN and HVc axonal synapses within RA and to examine how these synaptic connections change during the course of song development. Electrical stimulation of L-MAN and not HVc fibers evoked excitatory synaptic potentials from virtually all RA neurons in brain slices prepared from male and female zebra finches less than 25 d of age. These "L-MAN" EPSPs were blocked substantially by the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid (D-APV; 50-100 microM) and by hyperpolarization of the postsynaptic membrane. In contrast, when slices were prepared from male finches greater than 35 d of age, electrical stimulation of the L-MAN and the HVc fiber tracts evoked synaptic responses from over 70% of RA neurons. Although the L-MAN EPSPs resembled those seen in RA before day 25, the "HVc" EPSPs were relatively insensitive to D-APV, but almost completely abolished by 6-cyano-7-nitroquinoxaline-2,3-dione, a non-NMDA glutamate receptor antagonist. These experiments indicate that L-MAN and HVc axons make pharmacologically distinct synapses on the same RA neurons, and that these synapses first form at different stages during development.

Strength and function in the normal and rheumatoid hand

We have reevaluated the Martin vigorimeter to measure grip strength in healthy subjects, and patients with rheumatoid arthritis (RA), and investigated the correlation of grip strength and hand function using the Jebsen hand function tests and Purdue pegboard test before and after treatment. The vigorimeter showed good test-retest reliability (r greater than 0.911) and interrater reliability (r greater than 0.915). Test-retest reliability was greater than 0.97 for the Jebsen test, and greater than 0.94 for the Purdue test in healthy individuals. Seventeen patients with RA were studied at intervals of 1 to 16 weeks. Active joint count and grip strength both improved significantly. Improvement in grip strength correlated with improvement in active joint count. Hand function tests were significantly impaired in the patients with RA.

Two distinct inputs to an avian song nucleus activate different glutamate receptor subtypes on individual neurons

Although neural circuits mediating various simple behaviors have been delineated, those generating more complex behaviors are less well described. The discrete structure of avian song control nuclei promises that circuits controlling complex behaviors, such as birdsong, can also be understood. To this end, we developed an in vitro brain slice preparation containing the robust nucleus of the archistriatum (RA), a forebrain song control nucleus, and its inputs from two other song nuclei, the caudal nucleus of the ventral hyperstriatum (HVc) and the lateral part of the magnocellular nucleus of the anterior neostriatum (L-MAN). Using intracellular recordings, we examined the pharmacological properties of the synapses made on RA neurons by L-MAN and HVc axons. Electrical stimulation of the L-MAN and the HVc fiber tracts evoked excitatory postsynaptic potentials (EPSPs) from >70% of RA neurons when slices were prepared from male birds of 40-90 days of age, suggesting that many individual RA neurons receive excitatory input from L-MAN and HVc axons. The "L-MAN" EPSPs were blocked by the N-methyl-D-aspartate (NMDA) receptor antagonist D-(-)-2-amino-5-phosphonovaleric acid (D-APV) as well as the broad-spectrum glutamate receptor antagonist kynurenic acid but were relatively unaffected by the non-NMDA receptor blocker 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). In contrast, "HVc" EP-SPs were relatively insensitive to D-APV but almost completely abolished by CNQX. These experiments suggest that L-MAN and HVc axons provide pharmacologically distinct types of excitatory input to many of the same RA neurons.

The effect of circumvaginal muscle (CVM) exercise

Circumvaginal muscle (CVM) home training based on principles of exercise physiology were tested on 48 healthy reproductive-age women. The effect of CVM exercise with a resistance device in place, CVM exercise without a device, and no exercise with device in place was studied. After random assignment to home training, CVM assessment was carried out prior to and after 6 weeks of CVM training at home. Each subject served as her own control and change scores of the three groups, on CVM variables were subjected to analysis of variance. Peak maximum pressure (PMP) was significantly different for the three groups. F = 4.56, df = 2.45, p = .016. PMP of exercise without a device was significantly different from the no exercise group (Dunett's test). Analysis of measurement error between- and within-subjects showed that the inherent variability between women was approximately four times larger than the measurement error. The results support the prescription of CVM exercise to hypertrophy the CVM, and indicate that further investigation of the large variance found in the pressure data is needed.