Effects of temporal association on recognition memory

The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views: in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.

Nitric oxide-enhanced resistance to oral candidiasis

A marine model of oral candidiasis was used to show that nitric oxide (NO) is involved in host resistance to infection with Candida albicans in infection-'resistant' BALB/c and infection-'prone' DBA/2 mice. Following infection, increased NO production was detected in saliva. Postinfection samples of saliva inhibited the growth of yeast in vitro. Treatment with N-G-monomethyl-L-arginine (MMLA), an inhibitor of NO synthesis, led to reduced NO production, which correlated with an increase in C. albicans growth. Reduction in NO production following MMLA treatment correlated with an abrogation of interleukin-4 (IL-4), but not interferon-gamma (IFN-gamma), mRNA gene expression in regional lymph node cells. Down-regulation of IL-4 production was accompanied with an increase in IFN-gamma production in infection-'prone' DBA/2 mice. There was a functional relationship between IL-4 and NO production in that mice treated with anti-IL-4 monoclonal antibody showed a marked inhibition of NO production in saliva and in culture of cervical lymph node cells stimulated with C albicans antigen. The results Support previous conclusions that IL-4 is associated with resistance to oral candidiasis and suggest that NO is involved in controlling colonization of the oral mucosal surface with C albicans.

Skeletal effects of low-intensity pulsed ultrasound on the ovariectomized rodent

Growing evidence supports low-intensity pulsed ultrasound (US) as an osteogenic mechanical stimulus. Its effects on isolated bone cells and on fractured bone are established. However, its effects on osteoporosis are not clear. This study examined US effects on ovariectomy (OVX) induced bone changes within the rodent hindlimb (distal femur and proximal tibia), and on normal bone in animals following sham-OVX. Animals were exposed to daily unilateral active-US and contralateral inactive-US for 12 weeks. Bone status was assessed using dual energy X-ray absorptiometry and histomorphometry. Ovariectomy resulted in significant bone changes. Low-intensity pulsed US did not influence these changes. These results suggest that the US dose introduced may not be a beneficial treatment for osteoporosis, and that intact bone may be less sensitive to US than fractured bone and isolated bone cells. This may relate to the biophysical mechanisms of action of US, US-bone interactions and tissue level processes taking place.

Olfaction in the Queensland fruit fly, Bactrocera tryoni. II: Response spectra and temporal encoding characteristics of the carbon dioxide receptors

Single-unit electrophysiology was used to record the nerve impulses from the carbon dioxide receptors of female Queensland fruit flies, Bactrocera tryoni. The receptors responded to stimulation in a phasic-tonic manner and also had a period of inhibition of the nerve impulses after the end of stimulation, at high stimulus intensities. The cell responding to carbon dioxide was presented with a range of environmental odorants and found to respond to methyl butyrate and 2-butanone. The coding characteristics of the carbon dioxide cell and the ability to detect other odorants are discussed, with particular reference to the known behavior of the fly.

The use of perineal ultrasound to quantify levator activity and teach pelvic floor muscle exercises

Perineal ultrasound was used to detect and quantify levator activity by measuring the displacement of the internal urethral meatus against the inferoposterior margin of the symphysis pubis, Women who had previously been instructed in pelvic floor muscle exercises were more likely to contract the levator muscle when asked to do so than were those without previous instruction (P

The influence of posture on perineal ultrasound imaging parameters

A prospective clinical study was carried out to evaluate the influence of posture on perineal ultrasound imaging parameters. One hundred and thirty-two consecutive women presenting with symptoms of lower urinary tract dysfunction were examined by multichannel videourodynamics and perineal ultrasound, both supine and standing. Ultrasound included color Doppler imaging when available, i.e. in a subgroup of 99 patients. The position of the bladder neck at rest was higher in the supine position (P

The urethral pressure profile and ultrasound imaging of the lower urinary tract

In a prospective study 105 patients with symptoms of stress incontinence underwent video-urodynamic testing, including resting urethral pressure profilometry and translabial ultrasound. The urethral pressure profile (UPP) included maximum urethral closure pressure (MUCP), functional length (FL) and area under the curve (AUC). Ultrasound parameters included urethral thickness, urethral rotation and bladder neck descent, as well as funneling/opening of the internal urethral meatus on Valsalva maneuver. Levator contraction strength was assessed measuring the cranioventral displacement of the internal meatus. Negative correlations between UPP data and age, parity and previous surgery were observed which were consistent with literature data. There was a positive correlation :between the urethral AP diameter on ultrasound and the MUCP, which agrees with reports showing reduced sphincter thickness or volume in stress-incontinent women. Hypermobility on ultrasound did not correlate with UPP data. However, a lower MUCP correlated with extensive opening of the bladder neck. Finally, there was a trend towards poorer pelvic floor function with lower MUCP measurements.

Minimum acceptable standards for digital compression of a fetal ultrasound video-clip

If the Internet could be used as a method of transmitting ultrasound images taken in the field quickly and effectively, it would bring tertiary consultation to even extremely remote centres. The aim of the study was to evaluate the maximum degree of compression of fetal ultrasound video-recordings that would not compromise signal quality. A digital fetal ultrasound videorecording of 90 s was produced, resulting in a file size of 512 MByte. The file was compressed to 2, 5 and 10 MByte. The recordings were viewed by a panel of four experienced observers who were blinded to the compression ratio used. Using a simple seven-point scoring system, the observers rated the quality of the clip on 17 items. The maximum compression ratio that was considered clinically acceptable was found to be 1:50-1:100. This produced final file sizes of 5-10 MByte, corresponding to a screen size of 320 x 240 pixels, running at 15 frames/s. This study expands the possibilities for providing tertiary perinatal services to the wider community.

Realtime fetal ultrasound by telemedicine in Queensland. A successful venture?

We have established a realtime fetal tele-ultrasound consultation service in Queensland, which has been integrated into our routine clinical practice, The service, which uses ISDN transmission at 384 kbit/s, allows patients in Townsville to be examined by subspecialists in Brisbane, 1500 km away. For the 90 tele-ultrasound consultations performed for the first 71 patients, 90% of the babies have been delivered, and outcome data have been received on all the pregnancies. All significant anomalies and diagnoses have been confirmed. The referring clinicians would have physically referred 24 of the 71 patients to Brisbane in the absence of telemedicine. A crude cost-benefit calculation suggests that the tele-ultrasound service resulted in a net saving of A$6340, and at the same time enabled almost four times the number of consultations to be carried out.

Analysis of the microbial community structure and function of a laboratory scale enhanced biological phosphorus removal reactor

A laboratory scale sequencing batch reactor (SBR) operating for enhanced biological phosphorus removal (EBPR) and fed with a mixture of volatile fatty acids (VFAs) showed stable and efficient EBPR capacity over a four-year-period. Phosphorus (P), poly-beta-hydroxyalkanoate (PHA) and glycogen cycling consistent with classical anaerobic/aerobic EBPR were demonstrated with the order of anaerobic VFA uptake being propionate, acetate then butyrate. The SBR was operated without pH control and 63.67+/-13.86 mg P l(-1) was released anaerobically. The P% of the sludge fluctuated between 6% and 10% over the operating period (average of 8.04+/-1.31%). Four main morphological types of floc-forming bacteria were observed in the sludge during one year of in-tensive microscopic observation. Two of them were mainly responsible for anaerobic/aerobic P and PHA transformations. Fluorescence in situ hybridization (FISH) and post-FISH chemical staining for intracellular polyphosphate and PHA were used to determine that 'Candidatus Accumulibacter phosphatis' was the most abundant polyphosphate accumulating organism (PAO), forming large clusters of coccobacilli (1.0-1.5 mum) and comprising 53% of the sludge bacteria. Also by these methods, large coccobacillus-shaped gammaproteobacteria (2.5-3.5 mum) from a recently described novel cluster were glycogen-accumulating organisms (GAOs) comprising 13% of the bacteria. Tetrad-forming organisms (TFOs) consistent with the 'G bacterium' morphotype were alphaproteobacteria , but not Amaricoccus spp., and comprised 25% of all bacteria. According to chemical staining, TFOs were occasionally able to store PHA anaerobically and utilize it aerobically.

Constitutive expression of a phenylalanine ammonia-lyase gene from Stylosanthes humilis in transgenic tobacco leads to enhanced disease resistance but impaired plant growth

Transgenic tobacco plants expressing a phenylalanine ammonia-lyase cDNA (ShPAL), isolated from Stylosanthes humilis, under the control of the 35S promoter of the cauliflower mosaic virus were produced to test the effect of high level PAL expression on disease resistance. The transgenic plants showed up to eightfold PAL activity and were slowed in growth and flowering relative to non-transgenic controls which have segregated out the transgene. The expression of the ShPAL transgene and elevated PAL levels were correlated and stably inherited. In T-1 and T-2 tobacco plants with increased PAL activity, lesion expansion was significantly reduced by up to 55% on stems inoculated with the Oomycete pathogen Phytophthora parasitica pv. nicotianae, Lesion area was significantly reduced by up to 50% on leaves inoculated with the fungal pathogen Cercospora nicotianae. This study provides further evidence that PAL has a role in plant defence. (C) 2002 Elsevier Science Ltd. All rights reserved.

Myocardial abnormalities in hypertensive patients with normal and abnormal left ventricular filling: a study of ultrasound tissue characterization and strain

Abnormal left ventricular (LV) filling is common, but not universal, in hypertensive LV hypertrophy (LVH). We sought to elucidate the relative contributions of myocardial structural changes, loading and hypertrophy to LV dysfunction in 113 patients: 85 with hypertensive LVH and 28 controls without LVH and with normal filling. Patients with normal dobutamine stress echocardiography and no history of coronary artery disease were selected, in order to exclude a contribution from ischaemia or scar. Abnormal LV filling was identified in 65 LVH patients, based on Doppler measurement of transmitral filling and annular velocities. All patients underwent grey-scale and colour tissue Doppler imaging from three apical views, which were stored and analysed off line. Integrated backscatter (113) and strain rate imaging were used to detect changes in structure and function; average cyclic variation of 113, strain rate and peak systolic strain were calculated by averaging each segment. Calibrated 113 intensity, corrected for pericardial 113 intensity, was measured in the septum and posterior wall from the parasternal long-axis view. Patients with LVH differed significantly from controls with respect to all backscatter and strain parameters, irrespective of the presence or absence of abnormal LV filling. LVH patients with and without abnormal LV filling differed with regard to age, LV mass and incidence of diabetes mellitus, but also showed significant differences in cyclic variation (P < 0.01), calibrated 113 in the posterior wall (P < 0.05) and strain rate (P < 0.01), although blood pressure, heart rate and LV systolic function were similar. Multivariate logistic regression analysis demonstrated that age, LV mass index and calibrated IB in the posterior wall were independent determinants of abnormal LV filling in patients with LVH. Thus structural and functional abnormalities can be detected in hypertensive patients with LVH with and without abnormal LV filling. In addition to age and LVH, structural (not functional) abnormalities are likely to contribute to abnormal LV filling, and may be an early sign of LV damage. 113 is useful for the detection of myocardial abnormalities in patients with hypertensive LVH.

EphA receptors and ephrin-A ligands exhibit highly regulated spatial and temporal expression patterns in the developing olfactory system

The spatiotemporal expression patterns of the chemorepulsive EphA receptors, EphA4 and EphA7, and three ephrins-A2, A4 and A5, were examined in the developing rat primary olfactory system. Unlike the visual system that has simple and stable gradients of Ephs and ephrins, the olfactory system demonstrates complex spatiotemporal expression patterns of these molecules. Using immunohistochemistry, we demonstrate that expression of these molecules is dynamic and tightly regulated both within and between different cell types. We reveal restricted targeting of these proteins within subcellular compartments of some neurons. EphA4, ephrin-A2 and ephrin-A5 were expressed by primary olfactory axons during the embryonic formation of the olfactory nerve. There were no gradients in expression along the rostrocaudal or ventrodorsal axes in the nasal cavity and olfactory bulb. However, during the early neonatal period, axons expressing different levels of ephrin-A5 sorted out and terminated in a subpopulation of glomeruli that were mosaically dispersed throughout the bulb. The expression of EphA4 and ephrin-A2 was dramatically down-regulated on all axons during the early neonatal period of glomerular formation. The uniform co-expression of receptors and ligands before glomerular formation suggests they play a generic role in axon-axon interactions in the olfactory nerve and nerve fibre layer. In contrast, loss of EphA4 from axons during glomerular formation may facilitate the interaction of ephrin-A5 with Eph receptors on target cells in the bulb. While EphA4, EphA5 and EphA7 are not mosaically expressed by bulbar neurons, other Eph receptors may have expression patterns complementary to the ephrin-A5-positive subpopulation of glomeruli. (C) 2002 Elsevier Science B.V. All rights reserved.