Chronic exposure to insecticides impairs honeybee optomotor behaviour

Honeybees use wide-field visual motion information to calculate the distance they have flown from the hive, and this information is communicated to conspecifics during the waggle dance. Seed treatment insecticides, including neonicotinoids and novel insecticides like sulfoxaflor, display detrimental effects on wild and managed bees, even when present at sublethal quantities. These effects include deficits in flight navigation and homing ability, and decreased survival of exposed worker bees. Neonicotinoid insecticides disrupt visual motion detection in the locust, resulting in impaired escape behaviors, but it had not previously been shown whether seed treatment insecticides disrupt wide-field motion detection in the honeybee. Here, we show that sublethal exposure to two commonly used insecticides, imidacloprid (a neonicotinoid) and sulfoxaflor, results in impaired optomotor behavior in the honeybee. This behavioral effect correlates with altered stress and detoxification gene expression in the brain. Exposure to sulfoxaflor led to sparse increases in neuronal apoptosis, localized primarily in the optic lobes, however there was no effect of imidacloprid. We propose that exposure to cholinergic insecticides disrupts the honeybee's ability to accurately encode wide-field visual motion, resulting in impaired optomotor behaviors. These findings provide a novel explanation for previously described effects of neonicotinoid insecticides on navigation and link these effects to sulfoxaflor for which there is a gap in scientific knowledge.

A model of feedforward, global, and lateral inhibition in the locust visual system predicts responses to looming stimuli

Detection of looming obstacles is a vital task for both natural and artificial systems. Locusts possess a visual nervous system with an extensively studied obstacle detection pathway, culminating in the lobula giant movement detector (LGMD) neuron. While numerous models of this system exist, none to date have incorporated recent data on the anatomy and function of feedforward and global inhibitory systems in the input network of the LGMD. Moreover, the possibility that global and lateral inhibition shape the feedforward inhibitory signals to the LGMD has not been investigated. To address these points, a novel model of feedforward inhibitory neurons in the locust optic lobe was developed based on the recent literature. This model also incorporated global and lateral inhibition into the afferent network of these neurons, based on their observed behaviour in existing data and the posited role of these mechanisms in the inputs to the LGMD. Tests with the model showed that it accurately replicates the behaviour of feedforward inhibitory neurons in locusts; the model accurately coded for stimulus angular size in an overall linear fashion, with decreasing response saturation and increasing linearity as stimulus size increased or approach velocity decreased. The model also exhibited only phasic responses to the appearance of a grating, along with sustained movement by it at constant speed. By observing the effects of altering inhibition schemes on these responses, it was determined that global inhibition serves primarily to normalize growing excitation as collision approaches, and keeps coding for subtense angle linear. Lateral inhibition was determined to suppress tonic responses to wide-field stimuli translating at constant speed. Based on these features being shared with characterizations of the LGMD input network, it was hypothesized that the feedforward inhibitory neurons and the LGMD share the same excitatory afferents; this necessitates further investigation.

Neural conduction, visual motion detection, and insect flight behaviour are disrupted by low doses of imidacloprid and its metabolites

While neonicotinoid insecticides impair visually guided behaviours, the effects of their metabolites are unknown and measurements of environmental concentrations of neonicotinoids, typically lower than those required to elicit toxic effects, tend to exclude metabolites. Here we examined the contributions of imidacloprid and two of its metabolites, imidacloprid-olefin and 5-hydroxy-imidacloprid, on neural conduction velocity, visual motion detection and flight in the locust (Locusta migratoria) using a combination of electrophysiological and behavioural assays. We show reduced visual motion detection and impaired flight behaviour following treatment of metabolite concentrations equal to sublethal doses of the parent compound. Additionally, we show for the first time that imidacloprid and its metabolites result in a decrease in conduction velocity along an unmyelinated axon. We suggest that secondary effects of the insecticide on the biophysical properties of the axon may result in decreased neural conduction. As these metabolites display neurotoxicity similar to the parent compound they should be considered when quantifying environmental concentrations.

Three-dimensional shape and velocity changes affect responses of a locust visual interneuron to approaching objects

Adaptive collision avoidance behaviours require accurate detection of complex spatiotemporal properties of an object approaching in an animal's natural, three-dimensional environment. Within the locust, the lobula giant movement detector and its postsynaptic partner, the descending contralateral movement detector (DCMD), respond robustly to images that emulate an approaching two-dimensional object and exhibit firing rate modulation correlated with changes in object trajectory. It is not known how this pathway responds to visual expansion of a three-dimensional object or an approaching object that changes velocity, both of which represent natural stimuli. We compared DCMD responses with images that emulate the approach of a sphere with those elicited by a two-dimensional disc. A sphere evoked later peak firing and decreased sensitivity to the ratio of the half size of the object to the approach velocity, resulting in an increased threshold subtense angle required to generate peak firing. We also presented locusts with an approaching sphere that decreased or increased in velocity. A velocity decrease resulted in transition-associated peak firing followed by a firing rate increase that resembled the response to a constant, slower velocity. A velocity increase resulted in an earlier increase in the firing rate that was more pronounced with an earlier transition. These results further demonstrate that this pathway can provide motor circuits for behaviour with salient information about complex stimulus dynamics.

Three-dimensional shape and velocity changes affect responses of a locust visual interneuron to approaching objects

Adaptive collision avoidance behaviours require accurate detection of complex spatiotemporal properties of an object approaching in an animal's natural, three-dimensional environment. Within the locust, the lobula giant movement detector and its postsynaptic partner, the descending contralateral movement detector (DCMD), respond robustly to images that emulate an approaching two-dimensional object and exhibit firing rate modulation correlated with changes in object trajectory. It is not known how this pathway responds to visual expansion of a three-dimensional object or an approaching object that changes velocity, both of which represent natural stimuli. We compared DCMD responses with images that emulate the approach of a sphere with those elicited by a two-dimensional disc. A sphere evoked later peak firing and decreased sensitivity to the ratio of the half size of the object to the approach velocity, resulting in an increased threshold subtense angle required to generate peak firing. We also presented locusts with an approaching sphere that decreased or increased in velocity. A velocity decrease resulted in transition-associated peak firing followed by a firing rate increase that resembled the response to a constant, slower velocity. A velocity increase resulted in an earlier increase in the firing rate that was more pronounced with an earlier transition. These results further demonstrate that this pathway can provide motor circuits for behaviour with salient information about complex stimulus dynamics.

Complex object motion represented by context-dependent correlated activity of visual interneurones

Accurate and adaptive encoding of complex, dynamic visual information is critical for the survival of many animals. Studies across a range of taxa have investigated behavioral and neuronal responses to objects that represent a threat, such as a looming object approaching along a direct collision course. By investigating neural mechanisms of avoidance behaviors through recording multineuronal activity, it is possible to better understand how complex visual information is represented in circuits that ultimately drive behaviors. We used multichannel electrodes to record from the well-studied locust nervous system to explore how object motion is reflected in activity of correlated neural activity. We presented locusts (Locusta migratoria) with objects that moved along one of 11 unique trajectories and recorded from descending interneurons within the ventral nerve cord. Spike sorting resulted in 405 discriminated units across 20 locusts and we found that 75% of the units responded to some form of object motion. Dimensionality reduction through principal component (PCA) and dynamic factor (DFA) analyses revealed population vector responses within individuals and common firing trends across the pool of discriminated units, respectively. Population vector composition (PCA) varied with the stimulus and common trends (DFA) showed unique tuning related to changes in the visual size and trajectory of the object through time. These findings demonstrate that this well-described collision detection system is more complex than previously envisioned and will drive future experiments to explore fundamental principles of how visual information is processed through context-dependent dynamic ensembles of neurons to initiate and control complex behavior.

Background visual motion affects responses of an insect motion-sensitive neuron to objects deviating from a collision course

Stimulus complexity affects the response of looming sensitive neurons in a variety of animal taxa. The Lobula Giant Movement Detector/Descending Contralateral Movement Detector (LGMD/DCMD) pathway is well-characterized in the locust visual system. It responds to simple objects approaching on a direct collision course (i.e., looming) as well as complex motion defined by changes in stimulus velocity, trajectory, and transitions, all of which are affected by the presence or absence of background visual motion. In this study, we focused on DCMD responses to objects transitioning away from a collision course, which emulates a successful locust avoidance behavior. We presented each of 20 locusts with a sequence of complex three-dimensional visual stimuli in simple, scattered, and progressive flow field backgrounds while simultaneously recording DCMD activity extracellularly. DCMD responses to looming stimuli were generally characteristic irrespective of stimulus background. However, changing background complexity affected, peak firing rates, peak time, and caused changes in peak rise and fall phases. The DCMD response to complex object motion also varied with the azimuthal approach angle and the dynamics of object edge expansion. These data fit with an existing correlational model that relates expansion properties to firing rate modulation during trajectory changes.

Burst Firing in a Motion-Sensitive Neural Pathway Correlates with Expansion Properties of Looming Objects that Evoke Avoidance Behaviors

The locust visual system contains a well-defined motion-sensitive pathway that transfers visual input to motor centers involved in predator evasion and collision avoidance. One interneuron in this pathway, the descending contralateral movement detector (DCMD), is typically described as using rate coding; edge expansion of approaching objects causes an increased rate of neuronal firing that peaks after a certain retinal threshold angle is exceeded. However, evidence of intrinsic DCMD bursting properties combined with observable oscillations in mean firing rates and tight clustering of spikes in raw traces, suggest that bursting may be important for motion detection. Sensory neuron bursting provides important timing information about dynamic stimuli in many model systems, yet no studies have rigorously investigated if bursting occurs in the locust DCMD during object approach. We presented repetitions of 30 looming stimuli known to generate behavioral responses to each of 20 locusts in order to identify and quantify putative bursting activity in the DCMD. Overall, we found a bimodal distribution of inter-spike intervals (ISI) with peaks of more frequent and shorter ISIs occurring from 1–8 ms and longer less frequent ISIs occurring from 40–50 ms. Subsequent analysis identified bursts and isolated single spikes from the responses. Bursting frequency increased in the latter phase of an approach and peaked at the time of collision, while isolated spiking was predominant during the beginning of stimulus approach. We also found that the majority of inter-burst intervals (IBIs) occurred at 40–50 ms (or 20–25 bursts/s). Bursting also occurred across varied stimulus parameters and suggests that burst timing may be a key component of looming detection. Our findings suggest that the DCMD uses two modes of coding to transmit information about looming stimuli and that these modes change dynamically with a changing stimulus at a behaviorally-relevant time.

Background complexity affects response of a looming-sensitive neuron to object motion

An increasing number of studies show how stimulus complexity affects the responses of looming-sensitive neurons across multiple animal taxa. Locusts contain a well-described, descending motion-sensitive pathway that is preferentially looming sensitive. However, the lobula giant movement detector/descending contralateral movement detector (LGMD/DCMD) pathway responds to more than simple objects approaching at constant, predictable trajectories. In this study, we presented Locusta migratoria with a series of complex three-dimensional visual stimuli presented while simultaneously recording DCMD activity extracellularly. In addition to a frontal looming stimulus, we used a combination of compound trajectories (nonlooming transitioning to looming) presented at different velocities and onto a simple, scattered, or progressive flow field background. Regardless of stimulus background, DCMD responses to looming were characteristic and related to previously described effects of azimuthal approach angle and velocity of object expansion. However, increasing background complexity caused reduced firing rates, delayed peaks, shorter rise phases, and longer fall phases. DCMD responded to transitions to looming with a characteristic drop in a firing rate that was relatively invariant across most stimulus combinations and occurred regardless of stimulus background. Spike numbers were higher in the presence of the scattered background and reduced in the flow field background. We show that DCMD response time to a transition depends on unique expansion parameters of the moving stimulus irrespective of background complexity. Our results show how background complexity shapes DCMD responses to looming stimuli, which is explained within a behavioral context.

Responses of a pair of flying locusts to lateral looming visual stimuli

We presented a pair of locusts flying loosely tethered with laterally looming discs. Two experiments tested whether looming-evoked flight behaviour was affected by the presence (1) or relative position (2) of a conspecific. We recorded: the type of behavioural response, motion within 6 degrees of freedom, behavioural onset time and duration, distance between individuals and relative direction of motion. Response distributions of the locust furthest from the stimulus (L1) were not affected by the presence or relative position of a conspecific, whereas distributions of the closer locust (L2) were affected by its position relative to the stimulus. Motion tracks of L1 were affected by the presence of L2, which generated relatively robust responses directed forward and away from the stimulus. Translational and rotational motion of L1 differed across treatments in both experiments, whereas L2 motion was less sensitive to the presence or position of a conspecific. The start and duration of the behaviour were invariant to the presence or position of a conspecific and locust pairs maintained a fixed distance during responses to looming. Results suggest that looming-evoked behaviour is influenced by visual cues from a conspecific in the vicinity.

Spatiotemporal stimulus properties modulate responses to trajectory changes in a locust looming-sensitive pathway

The lobula giant movement detector (LGMD) and descending contralateral movement detector (DCMD) constitute one motion-sensitive pathway in the locust visual system that is implicated in collision-avoidance behaviors. While this pathway is thought to respond preferentially to objects approaching on a direct collision course, emerging studies suggest the firing rate is able to monitor more complicated movements that would occur under natural conditions. While previous studies have compared the response of the DCMD to objects on collision courses that travel at different speeds, velocity has not been manipulated for other simple or compound trajectories. Here we test the possibility that the LGMD/DCMD pathway is capable of responding uniquely to complex aspects of object motion, including translation and trajectory changes at different velocities. We found that the response of the DCMD to translational motion initiated in the caudal visual field was a low-amplitude peak in firing rate that occurred before the object crossed 90° azimuth that was invariant to different object velocities. Direct looms at different velocities resulted in peak firing rates that occurred later in time and with greater amplitude for higher velocities. In response to transitions from translational motion to a collision course, the firing rate change depended on both the location within the visual field and the velocity. These results suggest that this pathway is capable of conveying information about multiple properties of a moving object's trajectory.

Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects

We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours.

Accounting for Lean Implementation in Government Enterprise

This research explores the effects of implementing a lean production system in a government facility. The organization’s formal accounting practices delay recognition of production savings, but informally the facility promotes its lean efforts through attention-getting, off-the-books, “innovative” accounting. The authors state three propositions relating to customer effects of the lean improvements and the financial approaches. They then state four hypotheses relating to the measures’ unintended effects within the defense logistics enterprise as workload varies, and test the hypotheses employing a system dynamics simulation. Through review of qualitative data and a system dynamics simulation, the authors identify minor effects upon customer behavior and labor rates oscillation, thereby filling gaps in the literature relating to government productivity improvements, and expanding knowledge on lean-induced labor savings, work demand, and workplace effects of lean change in a government environment. They identify the greater effects of supplemental funding provided to such facilities, and begin the discussion of alternatives to current enterprise-wide government finance practices that may promote greater transformational behavior.

A looming-sensitive pathway responds to changes in the trajectory of object motion

Two identified locust neurons, the lobula giant movement detector (LGMD) and its postsynaptic partner, the descending contralateral movement detector (DCMD), constitute one motion-sensitive pathway in the visual system that responds preferentially to objects that approach on a direct collision course and are implicated in collision-avoidance behavior. Previously described responses to the approach of paired objects and approaches at different time intervals (Guest BB, Gray JR. J Neurophysiol 95: 1428–1441, 2006) suggest that this pathway may also be affected by more complicated movements in the locust's visual environment. To test this possibility we presented stationary locusts with disks traveling along combinations of colliding (looming), noncolliding (translatory), and near-miss trajectories. Distinctly different responses to different trajectories and trajectory changes demonstrate that DCMD responds to complex aspects of local visual motion. DCMD peak firing rates associated with the time of collision remained relatively invariant after a trajectory change from translation to looming. Translatory motion initiated in the frontal visual field generated a larger peak firing rate relative to object motion initiated in the posterior visual field, and the peak varied with simulated distance from the eye. Transition from translation to looming produced a transient decrease in the firing rate, whereas transition away from looming produced a transient increase. The change in firing rate at the time of transition was strongly correlated with unique expansion parameters described by the instantaneous angular acceleration of the leading edge and subtense angle of the disk. However, response time remained invariant. While these results may reflect low spatial resolution of the compound eye, they also suggest that this motion-sensitive pathway may be capable of monitoring dynamic expansion properties of objects that change the trajectory of motion.

Visual stimuli induced by self-motion and object-motion modify odour-guided flight of male moths (Manduca sexta L.)

Animals rely on multimodal sensory integration for proper orientation within their environment. For example, odour-guided behaviours often require appropriate integration of concurrent visual cues. To gain a further understanding of mechanisms underlying sensory integration in odour-guided behaviour, our study examined the effects of visual stimuli induced by self-motion and object-motion on odour-guided flight in male M. sexta. By placing stationary objects (pillars) on either side of a female pheromone plume, moths produced self-induced visual motion during odour-guided flight. These flights showed a reduction in both ground and flight speeds and inter-turn interval when compared with flight tracks without stationary objects. Presentation of an approaching 20 cm disc, to simulate object-motion,resulted in interrupted odour-guided flight and changes in flight direction away from the pheromone source. Modifications of odour-guided flight behaviour in the presence of stationary objects suggest that visual information, in conjunction with olfactory cues, can be used to control the rate of counter-turning. We suggest that the behavioural responses to visual stimuli induced by object-motion indicate the presence of a neural circuit that relays visual information to initiate escape responses. These behavioural responses also suggest the presence of a sensory conflict requiring a trade-off between olfactory and visually driven behaviours. The mechanisms underlying olfactory and visual integration are discussed in the context of these behavioural responses.

Treatment of ulcerative colitis from the patient's perspective: a survey of preferences and satisfaction with therapy

BACKGROUND

Data available regarding patient perspectives on ulcerative colitis (UC) and their preferences and satisfaction with therapy are limited.

AIMS

To examine the preferences of UC patients to understand better what they look for in a therapy when managing their disease, as this may influence overall medication adherence.

METHODS

The study surveyed 100 Canadian UC patients on topics including educational resources used to learn about the disease, medication attributes that are most valued and preferred by the patient and satisfaction with current therapy.

RESULTS

Overall, efficacy- and safety-related medication attributes were rated by patients to be more important than those related to dosing regimen (e.g. dosing frequency, number of pills), cost and formulary coverage. In pair-wise comparisons of specific medication attributes, UC patients rated speed of symptom relief and few side effects as the most important factors when considering a UC medication (preferred on average 84% and 74% of the time respectively).

CONCLUSION

This study provides insight into UC patient preferences and satisfaction with therapy that may be important when counselling on treatment options, and generates relevant discussions on adherence. Larger studies may be warranted to examine further how these findings can be extrapolated to broader UC populations.

Increased health costs from mandated Therapeutic Substitution of proton pump inhibitors in British Columbia

BACKGROUND

In 2003, British Columbia's PharmaCare programme implemented a drug reimbursement policy called Therapeutic Substitution, which required patients with acid-related diseases, primarily gastro-oesophageal reflux disease (GERD), to make a medically unnecessary switch from their prescribed proton pump inhibitor (PPI) to the cheapest available brand name PPI (Pariet, rabeprazole sodium), comprising a different (nongeneric) chemical.

AIM

To evaluate the independent effects of PPI Therapeutic Substitution on individual healthcare utilization among those complying with the policy.

METHODS

We used the BC Ministry of Health Services' individual-level linked data, allowing isolation of healthcare utilization for the entire population of PPI consumers from 2002 to 2005.

RESULTS

After controlling for individual case variation in age, gender and a proxy for pre-existing health status, regression analysis revealed statistically significant greater overall use of PPIs, physician services and hospital services independently associated with patients who complied with Therapeutic Substitution. Over the 3-year period 2003-2005, this represented net healthcare expenditures totalling approximately C$43.51 million (C$9.11 million in total PPI drug expenditures, C$24.65 million for physician services and C$9.75 million for hospital services).

CONCLUSION

Medically unnecessary drug switching caused by compliance with Therapeutic Substitution policy appears to be independently associated with higher overall healthcare utilization.

EMG spike time difference based feedback control

Flight control in insects has been studied extensively; however the underlying neural mechanisms are not fully understood. Output from the central nervous system (CNS) must drive wing phase shifts and flight muscle depressor asymmetries associated with adaptive flight maneuvers. These maneuvers will, in turn, influence the insect's sensory environment, thus closing the feedback loop. We present a novel method that utilizes asymmetrical timing of bilateral depressor muscles, the forewing first basalars (m97), of the locust to close a visual feedback loop in a computer-generated flight simulator. The method converts the time difference between left and right m97s to analog voltage values. These voltage values can be obtained using open-loop experiments (visual motion controlled by the experimenter), or can be used to control closed-loop experiments (muscle activity controls the visual stimuli) experiments. Electromyographic (EMG) signals were obtained from right and left m97 muscles; spike time difference between them was calculated and converted to voltage values. Testing this circuit with real animals, we were able to detect the spike time difference and convert that to voltage that controlled the presentation of a stimulus in a closed-loop environment. This method may be used in conjunction with the flight simulator to understand the manner in which sensory information is integrated with the activity of the flight circuitry to study the neural control of this complex behaviour.

Effects of different levels of torso coactivation on trunk muscular and kinematic responses to posteriorly applied sudden loads

BACKGROUND

Studies examining rapid spine loading have documented the influence of steady-state trunk preloads, and the resulting levels of trunk muscle preactivation, on the control of spine stability. However, the effects of different levels of muscle coactivation, and resulting spine loads, on the response to a perturbation of the externally unloaded trunk are unclear.

METHODS

Fourteen male subjects coactivated the abdominal muscles at four different levels (approximately 0%, 10%, 20% and 30% of the maximal voluntary contraction) monitored by an electromyography biofeedback system while semi-seated in a neutral lumbar spine position. They were loaded posteriorly in two directions (0 degrees and 30 degrees from the sagittal plane) and with two different loads (6.80 and 9.07 kg). Force perturbation, spine displacement and electromyography activity were measured, and torso compression and stability were modeled.

FINDINGS

Abdominal coactivation significantly increased spine stability and reduced the movement of the lumbar spine after perturbation, but at the cost of increasing spinal compression. Preactivation also reduced the frequency and magnitude, and delayed the onset of muscle reactions, mainly for the back muscles and the internal oblique. The higher magnitude load and the load applied in an oblique direction both showed more potentially hazardous effects on the trunk.

INTERPRETATION

Torso coactivation increases spinal stiffness and stability and reduces the necessity for sophisticated muscle responses to perturbation. Although further investigation is needed, it appears there is an asymptotic function between coactivation and both stiffness and stability. There also appears to be more hazard when buttressing twisting components of a sudden load compared to sagittal components. Patients with trunk instability and intolerance to spine compression may benefit from low to moderate levels of coactivation.

Responses of a Looming-Sensitive Neuron to Compound and Paired Object Approaches

The lobula giant movement detector (LGMD) and its target neuron, the descending contralateral movement detector (DCMD), constitute a motion-sensitive pathway in the locust visual system that responds preferentially to objects approaching on a collision course. LGMD receptive field properties, anisotropic distribution of local retinotopic inputs across the visual field, and localized habituation to repeated stimuli suggest that this pathway should be sensitive to approaches of individual objects within a complex visual scene. We presented locusts with compound looming objects while recording from the DCMD to test the effects of nonuniform edge expansion on looming responses. We also presented paired objects approaching from different regions of the visual field at nonoverlapping, closely timed and simultaneous approach intervals to study DCMD responses to multiple looming stimuli. We found that looming compound objects evoked characteristic responses in the DCMD and that the time of peak firing was consistent with predicted values based on a weighted ratio of the half size of each distinct object edge and the absolute approach velocity. We also found that the azimuthal position and interval of paired approaches affected DCMD firing properties and that DCMDs responded to individual objects approaching within 106 ms of each other. Moreover, comparisons between individual and paired approaches revealed that overlapping approaches are processed in a strongly sublinear manner. These findings are consistent with biophysical mechanisms that produce nonlinear integration of excitatory and feed-forward inhibitory inputs onto the LGMD that have been shown to underlie responses to looming stimuli.

Screening for familial ovarian cancer-management and outcome of women with moderate to high risk of developing ovarian cancer

Five percent to ten percent of ovarian cancers are hereditary. Individual genetic risk of developing ovarian malignancy is discussed in women. Currently, prophylactic surgery is advised to women with a moderate to high risk of developing ovarian cancer. Workload and outcome of the multidisciplinary familial ovarian screening clinic in South Wales were assessed. This was an observational study of 145 women registered with the Familial Ovarian Screening Clinic between January 1998 and December 2003. The data were retrieved from the medical notes. Yearly follow-ups were investigated with a transvaginal scan and CA125 level. Post-surgery women were followed up with yearly CA125 estimations: 46.9% fell into moderate-risk and 50.3% into high-risk category. The median age was 42 (SD 10.4), 71.7% were pre menopausal, and 10.3% had a personal history of breast cancer and 1.4% colon cancer. Whereas 36.5% opted for surgery, the remaining women (but two) opted for annual follow-up. Histology of the women who had surgery showed three cases of malignancies (fallopian tube carcinoma, atypical ovarian epithelial cells, and metastatic breast cancer). Seven women developed breast cancer during the observation period. The follow-up period is too short to come to a final conclusion as to the benefits of yearly screening in this group of women. In our series, a significant number of patients developed malignancies, despite prophylactic surgery.

Habituated visual neurons in locusts remain sensitive to novel looming objects

Many animals must contend with visual cues that provide information about the spatiotemporal dynamics of multiple objects in their environment. Much research has been devoted to understanding how an identified pair of interneurons in the locust, the Descending Contralateral Movement Detectors(DCMDs), respond to objects on an impending collision course. However, little is known about how these neurons respond when challenged with multiple,looming objects of different complex shapes. I presented locusts with objects resembling either another locust or a bird approaching on a direct collision course at 3 m s-1 while recording from the DCMD axon within the mesothoracic ganglion. Stimulus presentations were designed to test: (i)whether DCMD habituation was related to the frequency of approach, (ii) if habituated DCMDs were able to respond to a novel stimulus and (iii) if non-looming motion within complex objects (internal object motion) during approach affects habituation. DCMD responses to simulated locusts or birds habituated more when the time interval between consecutive approaches within similar sequences decreased from 34 s to 4 s. Strongly habituated DCMDs were,however, able to respond to the same object approaching along a new trajectory or to a larger object approaching along the same trajectory. Habituation was not affected by internal object motion. These data are consistent with earlier findings that DCMD habituation occurs at localized synapses, which permits maintained sensitivity to multiple objects in the animal's environment.

Improving the referral process for familial breast cancer genetic counselling: findings of three randomised controlled trials of two interventions

OBJECTIVES

To evaluate the effectiveness and cost-effectiveness of two complementary interventions, using familial breast cancer as a model condition. The primary care intervention consisted of providing computerised referral guidelines and related education to GPs. The nurse counsellor intervention evaluated genetic nurses as substitutes for specialist geneticists in the initial assessment and management of referred patients.

DESIGN

The computerised referral guidelines study was a pragmatic, cluster randomised controlled trial (RCT) with general practices randomised to intervention or control groups. The nurse counsellor intervention was tested in two concurrent RCTs conducted in separate UK health service locations, using predetermined definitions of equivalence.

SETTING

The computerised referral guidelines trial took place in general practices in Scotland from November 2000 to June 2001. The nurse counsellor intervention took place in a regional genetics clinic in Scotland, and in two health authorities in Wales served by a single genetics service during 2001.

PARTICIPANTS

The computerised referral guidelines study involved GPs and referred patients. Both nurse counsellor intervention trials included women referred for the first time, aged 18 years or over and whose main concern was family history of breast cancer.

INTERVENTIONS

The software system was developed with GPs, presenting cancer genetic referral guidelines in a checklist approach. Intervention GPs were invited to postgraduate update education sessions, and both intervention and control practices received paper-based guidelines. The intervention period was November 2000 to June 2001. For the nurse counsellor trial, trial 1 ran outpatient sessions with the same appointment length as the standard service offered by geneticists, but the nurse counsellor saw new patients at the first appointment and referred back to the GP or on to a clinical geneticist according to locally developed protocol, under the supervision of a consultant geneticist. The control intervention was the current service, which comprised an initial and a follow-up appointment with a clinical geneticist. In trial 2, a nurse counsellor ran outpatient sessions with the same appointment length as the new consultant-based cancer genetics service and new patients were seen at the first appointment and referred as in trial 1. The control intervention was a new service, and comprised collection of family history by telephone followed by a consultation with a clinical assistant or a specialist registrar, supervised by a consultant. The intervention was implemented between 1998 and 2001.

MAIN OUTCOME MEASURES

In the software system trial, the primary outcome was GPs' confidence in their management of patients with concerns about family history of breast cancer. For the nurse counsellor trial, the primary outcome was patient anxiety, measured using standard scales.

RESULTS

In the software system trial, 57 practices (230 GPs) were randomised to the intervention group and 29 (116 GPs) to the control group. No statistically significant differences were detected in GPs' confidence or any other outcomes. Fewer than half of the intervention GPs were aware of the software, and only 22 reported using it in practice. The estimated total cost was GBP3.12 per CD-ROM distributed (2001 prices). For the two arms of the nurse counsellor trial, 289 patients (193 intervention, 96 control) and 297 patients (197 intervention and 100 control) consented, were randomised, returned a baseline questionnaire and attended the clinic for trials 1 and 2 respectively. The analysis in both cases suggested equivalence in all anxiety scores, and no statistically significant differences were detected in other outcomes in either trial. A cost-minimisation analysis suggested that the cost per counselling episode was GBP10.23 lower in intervention arm than in the control arm and GBP10.89 higher in the intervention arm than in the control arm (2001 prices) for trials 1 and 2, respectively. Taking the trials together, the costs were sensitive to the grades of doctors and the time spent in consultant supervision of the nurse counsellor, but they were only slightly affected by the grade of nurse counsellor, the selected discount rate and the lifespan of equipment.

CONCLUSIONS

Computer-based systems in the primary care intervention cannot be recommended for widespread use without further evaluation and testing in real practice settings. Genetic nurse counsellors may be a cost-effective alternative to assessment by doctors. This trial does not provide definitive evidence that the general policy of employing genetics nurse counsellors is sound, as it was based on only three individuals. Future evaluations of computer-based decision support systems for primary care must first address their efficacy under ideal conditions, identify barriers to the use of such systems in practice, and provide evidence of the impact of the policy of such systems in routine practice. The nurse counsellor trial should be replicated in other settings to provide reassurance of the generalisability of the intervention and other models of nurse-based assessment, such as in outreach clinics, should be developed and evaluated. The design of future evaluations of professional substitution should also address issues such as the effect of different levels of training and experience of nurse counsellors, and learning effects.

Steroid-induced dendritic regression reduces anatomical contacts between neurons during synaptic weakening and the developmental loss of a behavior

Steroid hormones alter dendritic architecture in many animals, but the exact relationship between dendritic anatomy, synaptic strength, and behavioral expression is typically unknown. In larvae of the moth Manduca sexta, the tip of each abdominal proleg (locomotory appendage) bears an array of mechanosensory hairs, each innervated by a planta hair sensory neuron (PH-SN). In the CNS, PH-SN axons make monosynaptic, excitatory nicotinic cholinergic connections with accessory planta retractor (APR) motoneurons. These synapses mediate a proleg withdrawal reflex behavior that is lost at pupation. The prepupal peak of ecdysteroids (molting hormones) triggers the regression of APR dendrites and a >80% reduction in the amplitude of EPSPs produced in APRs by PH-SNs that innervate posterior planta hairs. The present study tested the hypothesis that a decrease in the number of synaptic contacts from PH-SNs to APRs contributes to this synaptic weakening. Pairs of PH-SNs and APRs were fluorescently labeled in larvae and pupae, and the number of indistinguishably close anatomical contacts (putative synapses) was counted by confocal laser scanning microscopy. During APR dendritic regression, the mean number of contacts from posterior PH-SNs decreased by approximately 80%, whereas the size of individual contacts did not change detectably and the axonal arbors of PH-SNs did not regress. These results suggest that the steroid-induced regression of motoneuron dendrites physically disconnects the motoneurons from the synaptic terminals of sensory neurons, producing synaptic weakening and the developmental loss of the proleg withdrawal reflex behavior at pupation.

A method for recording behavior and multineuronal CNS activity from tethered insects flying in virtual space

We describe a low cost, novel virtual reality-based insect flight simulator that combines visual, olfactory and mechanosensory stimuli with multichannel neurophysiological recording techniques. Three-dimensional visual environments were created using customized modifications of a first person flight simulator computer game. Experiments could be performed in open-loop, where the flying insect's movement through the environment is 'driven' by the human operator, or in closed-loop where the movement of the environment is controlled by optically sensed movements of the insect's abdomen. During flight, we recorded multineuronal activity from the ventral nerve cord between the brain and thoracic ganglia. Results show that in open-loop conditions, induced turns of the environment evoked characteristic compensatory optomotor responses. Coordination of wing and body kinematics was similar to that observed in free flight. In closed-loop conditions, the insect was able to navigate through the simulated environment and produce flight tracks in response to presentation of pheromone that resemble those observed in free flight. We discuss the effectiveness of this preparation and its utility for addressing specific questions of insect flight as well as general questions in neuroethology.

Emotional modulation of cognitive control: approach-withdrawal states double-dissociate spatial from verbal two-back task performance

Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach-withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion-cognition interactions.

Paclitaxel and carboplatin adjuvant therapy alone or with radiotherapy for resected nonsmall cell lung carcinoma: a feasibility study of the Minnie Pearl Cancer Research Network

BACKGROUND

The objective of this study was to determine the feasibility and toxicity of paclitaxel and carboplatin given in the adjuvant setting alone for patients with resected Stage IB disease and combined with radiotherapy for patients with resected Stages II and IIIA disease and selected patients with Stage IIIB and IV disease (Revised International System for Staging of Lung Cancer).

METHODS

One hundred two patients with resected nonsmall cell lung carcinoma were treated in the postoperative period with 3 courses of paclitaxel 200 mg/m(2) intravenously (i.v.) over 1 hour and carboplatin area under the curve of 6 i.v. every 3 weeks for 3 courses. Patients with Stage IB received no further therapy, and those with higher stages also subsequently received radiotherapy plus concurrent weekly paclitaxel and carboplatin over 6 weeks. The median age was 61 years, with 56 men and 46 women, and the predominant histologic type was adenocarcinoma. Twenty pneumonectomies, 80 lobectomies, and 2 other procedures were performed. Ninety percent of the patients (92 of 102) received all 3 courses of adjuvant paclitaxel and carboplatin (84% received full doses). Seventy-three percent received full doses of radiotherapy and concurrent weekly chemotherapy (49 of 67 patients), and 14 others received greater than 75% of the radiotherapy and concurrent chemotherapy.

RESULTS

Toxicity of the chemotherapy was mild with only three hospitalizations for neutropenia and fever and no treatment-related deaths. Severe hypersensitivity occurred in six patients (6%). Concurrent radiation therapy and weekly chemotherapy also was well tolerated with the exception of Grade 3-4 esophagitis observed in 27% (17 of 67 patients). Follow-up was short with a median of 10 months, and 65% of all patients remained progression free.

CONCLUSIONS

Three courses of paclitaxel and carboplatin is tolerable, feasible, and can be delivered in most patients in the adjuvant setting. Subsequently, in higher stage patients, concurrent postoperative radiation therapy and weekly paclitaxel and carboplatin is well tolerated and delivered in most patients. Definitive prospective randomized Phase III adjuvant trials are warranted.

Emotional modulation of cognitive control: approach-withdrawal states double-dissociate spatial from verbal two-back task performance

Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach-withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion-cognition interactions.

Anterior cingulate cortex and response conflict: effects of frequency, inhibition and errors

Anterior cingulate cortex (ACC) may play a key role in cognitive control by monitoring for the occurrence of response conflict (i.e. simultaneous activation of incompatible response tendencies). Low-frequency responding might provide a minimal condition for eliciting such conflict, as a result of the need to overcome a prepotent response tendency. We predicted that ACC would be selectively engaged during low-frequency responding, irrespective of the specific task situation. To test this hypothesis, we examined ACC activity during the performance of simple choice-discrimination tasks, using rapid event-related functional magnetic resonance imaging. Subjects were scanned while performing three tasks thought to tap different cognitive processes: 'Go/No-go' (response inhibition), 'oddball' (target detection), and two-alternative forced- choice (response selection). Separate conditions manipulated the frequency of relevant task events. Consistent with our hypothesis, the same ACC region was equally responsive to low-frequency events across all three tasks, but did not show differential responding when events occurred with equal frequency. Subregions of the ACC were also identified that showed heightened activity during the response inhibition condition, and on trials in which errors were committed. Task-sensitive activity was also found in right prefrontal and parietal cortex (response inhibition), left superior temporal and tempoparietal cortex (target detection), and supplementary motor area (response selection). Taken together, the results are consistent with the hypothesis that the ACC serves as a generic detector of processing conflict arising when low-frequency responses must be executed, but also leave open the possibility that further functional specialization may occur within ACC subregions.

Activity of descending contralateral movement detector neurons and collision avoidance behaviour in response to head-on visual stimuli in locusts

We recorded the activity of the right and left descending contralateral movement detectors responding to 10-cm (small) or 20-cm (large) computer-generated spheres approaching along different trajectories in the locust's frontal field of view. In separate experiments we examined the steering responses of tethered flying locusts to identical stimuli. The descending contralateral movement detectors were more sensitive to variations in target trajectory in the horizontal plane than in the vertical plane. Descending contralateral movement detector activity was related to target trajectory and to target size and was most sensitive to small objects converging on a direct collision course from above and to one side. Small objects failed to induce collision avoidance manoeuvres whereas large objects produced reliable collision avoidance responses. Large targets approaching along a converging trajectory produced steering responses that were either away from or toward the side of approach of the object, whereas targets approaching along trajectories that were offset from the locust's mid-longitudinal body axis primarily evoked responses away from the target. We detected no differences in the discharge properties of the descending contralateral movement detector pair that could account for the different collision avoidance behaviours evoked by varying the target size and trajectories. We suggest that descending contralateral movement detector properties are better suited to predator evasion than collision avoidance.

Carcinoma of unknown primary site

BACKGROUND

The long term survival and toxicity associated with the chemotherapy combination of paclitaxel, carboplatin, and extended-schedule etoposide used for the treatment of patients with metastatic carcinoma of unknown primary site were evaluated.

METHODS

Seventy-one patients were treated between March 1995 and November 1996 with paclitaxel, carboplatin, and oral etoposide every 21 days. Stable or responding patients received four to eight courses of therapy. The following histologies were represented: well differentiated adenocarcinoma (34 patients); poorly differentiated adenocarcinoma or poorly differentiated carcinoma (30 patients); poorly differentiated neuroendocrine carcinoma (6 patients); and squamous cell carcinoma (1 patient).

RESULTS

Forty-eight percent of assessable patients had major responses to therapy (95% confidence interval, 39%-55%), and 10 patients (15%) had complete responses. There were no response differences among the major histologic types. The median survival for all 71 patients was 11 months, and the 1-year, 2-year, and 3-year survival rates were 48%, 20%, and 14%, respectively. The minimum follow-up period was 34 months (range, 34-50 mos). The regimen was tolerated well with no treatment-related deaths and only 12 hospitalizations for neutropenia and fever. There was no serious long term toxicity.

CONCLUSIONS

In this large Phase II trial, the combination of paclitaxel, carboplatin, and oral etoposide produced major responses or stable disease status in nearly 80% of patients who had carcinoma of unknown primary site. The median survival and 1-year, 2-year, and 3-year survival rates were noteworthy. The current study obtained similar or superior results to those seen with chemotherapy for many other groups of patients, such as those who had well defined advanced malignancies, those who were considered to have responsive tumors, and those who had obtained substantial benefits from cytotoxic therapy. Although the regimen reported in the current study can become an attractive option for many patients with carcinoma of unknown primary site, there remains a need for further clinical trials.

In vivo enhancement of chemotherapy with static electric or magnetic fields

We evaluated the ability of both static electric and static magnetic fields to enhance the in vivo action of a chemotherapeutic agent, adriamycin, against transplanted mammary tumors in mice. Female B6C3F1 mice with transplanted mammary adenocarcinoma were divided into four randomized groups and injected with 10 mg/kg adriamycin on day 7 of the study. Three of the groups were then exposed to nonuniform static electric or static magnetic fields. The resulting tumor regression in each group was measured four times during the remaining 13 days of the 20 day study. Two-sided statistical tests revealed all of the static field exposed groups achieved significantly greater (P </=.05) tumor regression than the group treated with adriamycin only, with P-values in a range as low as. 0001. There is an almost universal need in disease treatment to increase the efficacy and delivery of bioactive agents against target cells. The technology demonstrated here may result in improved use of therapeutic materials ranging from drugs to genetic agents. In addition, our findings point to possible hazards from the in vivo enhancing action of static fields on administered or environmentally encountered chemicals.

Preoperative combined modality therapy with paclitaxel, carboplatin, prolonged infusion 5-fluorouracil, and radiation therapy in localized esophageal cancer: preliminary results of a Minnie Pearl Cancer Research Network phase II trial

PURPOSE

To evaluate the feasibility, toxicity, and therapeutic efficacy of 1-hour paclitaxel, carboplatin, continuous low-dose infusional 5-fluorouracil, and concurrent radiation therapy administered preoperatively in patients with localized esophageal cancer.

PATIENT AND METHODS

Forty-nine patients with localized esophageal cancer, of either squamous cell carcinoma or adenocarcinoma histology, were enrolled into this phase II trial. All patients were candidates for surgical resection and received the following neoadjuvant therapy: paclitaxel, 200 mg/m2, 1 hour IV on days 1 and 22; carboplatin, AUC 6.0, IV on days 1 and 22; 5-fluorouracil, 225 mg/m2/day, continuous IV infusion on days 1 to 42; and radiation therapy, 45 Gy, administered by 1.8-Gy daily fractions beginning on day 1 of chemotherapy. Upon completion of this neoadjuvant regimen, patients were reevaluated, and all responding patients were resected within 6 weeks of completing neoadjuvant treatment.

RESULTS

Administration of this combined modality regimen was associated with moderate toxicity and was tolerated by most patients. Leukopenia (65%) and esophagitis (31%) were the most common toxicities. Most patients did not require nutritional support. There were no treatment-related deaths during neoadjuvant therapy; however, three patients (9%) experienced postoperative death. Preliminary assessment of treatment efficacy is encouraging, with 17 of 37 evaluable patients (46%) achieving pathologic complete remission and an additional 11 patients (30%) having only microscopic residual disease.

CONCLUSIONS

This novel, combined-modality neoadjuvant approach for the treatment of localized esophageal carcinoma is feasible and can be administered with toxicity that compares favorably to previously reported neoadjuvant regimens containing high-dose cisplatin. Preliminary assessment of efficacy is also encouraging, with 46% of patients having pathologic complete response. Further follow-up and larger numbers of patients are required to assess efficacy more definitively.

Effect of RenaGel, a non-absorbed, calcium- and aluminium-free phosphate binder, on serum phosphorus, calcium, and intact parathyroid hormone in end-stage renal disease patients

BACKGROUND

Control of dietary phosphate absorption in end-stage renal disease patients is essential to prevent the deleterious sequelae of phosphorus retention. Efficacy of currently available calcium- and aluminium-containing phosphate binders is constrained by the side-effects associated with the absorption of calcium and aluminium. The current study examined the efficacy of RenaGel, a calcium- and aluminium-free, polymeric phosphate binder, in end-stage renal disease patients.

METHODS

Administration of calcium- or aluminium-containing phosphate binders ceased during a 2-week washout period. RenaGel, at starting doses of one, two, or three 500-mg capsules three times per day with meals, was administered for 8 weeks. RenaGel dose was titrated up 1 capsule per meal at the end of each 2-week period if necessary to achieve phosphorus control. A second 2-week washout period followed the end of RenaGel treatment.

RESULTS

Mean serum phosphorus rose from a pre-washout level of 6.9 mg/dl (2.23 mmol/l) to 8.1 mg/dl (2.62 mmol/l) at the end of the initial 2-week washout. With RenaGel treatment, serum phosphorus declined and returned to pre-washout levels after 4 weeks. Serum phosphorus reached a nadir of 6.5 mg/dl (2.10 mmol/l) after 7 weeks of RenaGel treatment. Serum phosphorus rose to 8.2 mg/dl (2.65 mmol/l) 2 weeks after cessation of RenaGel treatment. As anticipated, calcium declined during the initial washout period when calcium-based phosphate binders were stopped for the majority of patients. The rise in serum phosphorus and decline in serum calcium during washout resulted in an increase in median intact parathyroid hormone (iPTH) levels from 292 pg/ml to 395 pg/ml. iPTH fell to 283 pg/ml after 6 weeks of RenaGel treatment despite a persistently lower serum calcium. RenaGel treatment also reduced serum total and LDL cholesterol by 25 mg/dl (0.65 mmol/l) and 23 mg/dl (0.59 mmol/l) respectively.

CONCLUSIONS

RenaGel appears to be an effective phosphate binder free of calcium and aluminium. Phosphorus control with two to four RenaGel capsules per meal appears to result in comparable phosphorus lowering seen with calcium- or aluminium-based phosphate binders. RenaGel may offer an alternative for the control of phosphorus retention in end-stage renal disease patients.

Life expectancy in British Marfan syndrome populations

A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970-1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3+/-16.5 years. 50% median cumulative survival in the total cohort (n=206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome.

Paclitaxel, carboplatin, and extended-schedule etoposide in the treatment of small-cell lung cancer: comparison of sequential phase II trials using different dose-intensities

PURPOSE

In two sequential phase II studies, we evaluate the feasibility and efficacy of adding paclitaxel to a standard platinum/etoposide regimen in the first-line treatment of small-cell lung cancer.

PATIENTS AND METHODS

One hundred seventeen patients with small-cell lung cancer were treated between June 1993 and July 1996. The first 38 patients received a lower-dose regimen: paclitaxel 135 mg/m2 by 1-hour infusion, carboplatin at an area under the concentration-time curve (AUC) of 5.0, and etoposide 50 mg alternating with 100 mg orally on days 1 to 10. When only mild myelosuppression was observed, doses of paclitaxel and carboplatin were increased in the subsequent 79 patients (paclitaxel 200 mg/m2 by 1-hour infusion and carboplatin at an AUC of 6.0). All patients received four courses of treatment, administered at 21-day intervals. Patients with limited-stage small-cell lung cancer also received thoracic radiation therapy (1.8 Gy/d; total dose, 45 Gy) administered concurrently with courses 3 and 4 of chemotherapy.

RESULTS

Seventy-two of 79 patients (91%) who receive the higher-dose regimen had major responses. Thirty-two of 38 (84%) with extensive-stage disease responded (21% complete response rate); median survival was 10 months for this group. With limited-stage disease, the overall response rate was 98%, with 71% complete responses; the median survival time has not been reached at 16 months. Median survival in extensive-stage patients was longer in patients who received the higher-dose regimen (10 months) than in the previous group treated with lower doses (7 months; P = .008). The higher-dose regimen was well tolerated, with myelosuppression being the major toxicity. Compared with the lower-dose regimen, grade 3/4 neutropenia increased from 8% to 38% of courses, but the incidence of hospitalization for neutropenia and fever did not increase. Other nonhematologic toxicities were uncommon, and did not increase substantially with the higher-dose regimen.

CONCLUSION

Paclitaxel can be added at full dose (200 mg/m2) to a carboplatin/etoposide combination while maintaining a tolerable toxicity profile. Median survival times in both extensive- and limited-stage patients compare favorably with other reported regimens. This regimen merits further investigation, and a randomized trial to compare this regimen with a standard carboplatin/etoposide combination is underway.

Comparison of preoperative characteristics of men and women undergoing coronary artery bypass grafting (the Post Coronary Artery Bypass Graft [CABG] Biobehavioral Study)

A cohort of 759 coronary artery bypass grafting (CABG) patients (269 women and 490 men) was enrolled in the prospective POST CABG Biobehavioral Study at 5 clinical centers in the United States and Canada. Sociodemographic and medical data were obtained by interview and from medical charts. Health-related quality of life and psychosocial data were ascertained preoperatively by interview and questionnaire for those patients whose condition allowed preoperative assessment and was compared among patients from hospitals enrolling both male and female patients (143 women and 267 men). Women enrolled in the Biobehavioral Study were older than men (65.4 +/- 9.0 vs 61.8 +/- 9.7 years, p < 0.001) and more likely to have a preoperative medical condition which precluded biobehavioral evaluation (47% vs 34%, p < 0.001). Women were less likely to be high school graduates (59% vs 74%, p < 0.001), were less likely to be earning > or = $25,000 per year (39% vs 69%, p < 0.001), and were married less often at the time of surgery (59% vs 85%, p < 0.001). Fewer women than men were able to perform basic self-care activities (p < 0.001) and social activities (p < 0.001). Women were also less able to perform the more demanding activities required for independent living, recreation, and maintaining a household (p < 0.001). Women were also more anxious (p = 0.01) and reported more depressive symptoms (p < 0.001) than men. These data suggest that plans for perioperative and convalescent care for women undergoing CABG should take into account their less favorable medical and psychosocial status relative to men.

The tumor conference: an integral component of the oncology program

This periodic meeting of individuals with oncologic expertise represents the best that modern medicine can be: a true multidisciplinary approach to patient care. Nowhere else in healthcare will you find a better example of combining different expertise for the express purpose of improving the delivery of care for an individual patient.

A clinical severity grading scale for Marfan syndrome

There is considerable interest in assessing patients with Marfan syndrome at the clinical, protein, and genetic levels. Clinical assessments are inconsistent between centres and between clinicians. There are no satisfactory clinical grading scales against which to analyse the molecular information, limiting the scope of clinical/ molecular correlations. We present grading scales for the major clinical systems involved in Marfan syndrome and suggest that their widespread use will facilitate collaborative approaches to clinical/ molecular correlations and international assessments of therapy.

Paclitaxel in combination chemotherapy with radiotherapy in patients with unresectable stage III non-small-cell lung cancer

PURPOSE

The addition of combination chemotherapy to standard radiation therapy has improved treatment for locally unresectable non-small-cell lung cancer. In this phase II study, we evaluated the toxicity and efficacy of a novel chemotherapy regimen that included paclitaxel, cisplatin, and etoposide plus concurrent radiation therapy in this group of patients.

PATIENTS AND METHODS

Thirty-three patients with previously untreated, unresectable stage III non-small-cell lung cancer (stage IIIA, 11 patients; stage IIIB, 22 patients) initially received two courses of chemotherapy, which included paclitaxel 135 mg/m2 by 1-hour infusion on day 1, cisplatin 60 mg/m/ intravenously (i.v.) on day 2, and etoposide 100 mg/m2 i.v. on days 1, 2 and 3. On week 6, radiation therapy (60 Gy in 30 fractions) was initiated in conjunction with two additional courses of chemotherapy: paclitaxel 135 mg/m2 i.v. by 1-hour infusion on day 1, cisplatin 5 mg/m2 i.v. on days 2- to 10, and etoposide 25 mg/m2 on days 1 to 10.

RESULTS

This combined modality program was feasible and well tolerated by most patients. During the two courses of induction chemotherapy, grade 3 or 4 myelosuppression occurred in only six patients (18%). Esophagitis was common during combined modality therapy (grade 3, 10 patients; grade 4 five patients). Forty-two percent of patients had partial response after two courses of induction therapy, and 82% of patients had an objective response at completion of therapy. Twelve patients (36%) had a complete response. Nineteen patients remain progression-free at a median of 8 months; the median survival time has not been reached.

CONCLUSION

This paclitaxel-containing combined modality therapy is feasible and highly active in patients with inoperable stage III lung cancer. Esophagitis is the most common severe toxicity with this program. Further studies with paclitaxel-containing combination regimens in patients with stage III non-small-cell lung cancer are indicated.

Marfan syndrome

Images

Structure of the forewing stretch receptor axon in immature and mature adult locusts

During the first 2 weeks following imaginal ecdysis, the wingbeat frequency of Locusta migratoria doubles, and the activity of the forewing stretch receptor (fSR), in response to wing elevation, increases. We examined the three-dimensional structure of the centrally projecting axon of the fSR during adult maturation to determine if there are changes in the branching geometry. We found that changes occur in the mesothoracic projection (IISR Meso). Here, there was a significant increase in the volume of the projection from 2.3 x 10(4) +/- 0.2 x 10(4) microns 3 in immature locusts to 6.0 x 10(4) +/- 1.2 x 10(4) microns 3 in mature locusts. There were also significant increases in the total length, the number of branch points, the number of axonal swellings, and the diameters of first- and second-order branches of the projection. No significant changes were observed in the prothoracic projection (IISR Pro), and the only significant change observed in IISR Meta was negative allometric growth relative to IISR Meso. These results demonstrate that during adult maturation, growth of the fSR axon is heteromorphic between different ganglionic projections and that there is a potential increase in the connectivity of IISR Meso to other flight neurons in the mesothoracic ganglion. We suggest that this may be a mechanism for maintaining the efficacy of afferent input to flight interneurons that are also growing during maturation.