Age of acquisition effects in recognition without identification tasks.

The Age of Acquisition (AoA) effect results in early-acquired words being processed more quickly and accurately than later-acquired words. This effect is argued to result from a gradual development of semantic representations and a changing neural network throughout development (Chang, Y.-N., Monaghan, P., & Welbourne, S., 2019). Some forms of the Recognition Without Identification (RWI) effects have been observed at a perceptual level. The present study used the RWI paradigm to examine whether the AoA effect is located at the perceptual loci. A total of 174 participants were presented a list of pictures (Experiment 1) or words (Experiment 2) followed by a list of mixed early- and late-acquired picture or word fragments that participants had to identify; half of which corresponded to studied words and half of which to unstudied words. Irrespective of whether the item was identified, participants then rated the likelihood that the item appeared in the study phase. In both experiments, results showed that studied items were recognised more accurately than unstudied items, even when they could not be identified and late-acquired items were recognised more than early-acquired items, even when they were not identified. Finally, RWI interacted with the AoA effect only in pictorial stimuli, suggesting that the RWI and AoA effects are located at the perceptual level.

Effects of age of acquisition and priming on picture naming.

Four experiments examined the interaction of age of acquisition (AoA) and priming on picture naming. Experiment 1 found that initial-letter priming and AoA significantly affected picture-naming latencies, but there was no interaction between them. Experiment 2 found that initial-phoneme priming and AoA significantly affected picture-naming latencies, but again there was no interaction. Experiment 3 repeated Barry, Hirsh, Johnston, and Williams's (2001) priming study using a very short interval between prime and target. Experiment 3 replicated previous findings of a significant interaction between priming and AoA. Experiment 4 repeated this investigation with a procedure that did not require participants to articulate the prime. Once again, there were significant effects of priming, AoA, and the interaction between them. The implications of these findings in relation to accounts of AoA and its locus of effect are discussed.

Age of acquisition effects on an object-name verification task.

Naming latencies for words, objects and faces have been shown to be affected by the age at which an item is acquired (AoA). Originally, this effect was explained in terms of differential access to name representations. However, a number of recent studies have found AoA effects in tasks which do not require access to names (e.g. Brysbaert, Van Wijnendaele, & De Deynes, 2000; Lewis, 1999; Moore, Smith Spark, & Valentine, 2004; Moore & Valentine, 1999). Ellis and Lambon Ralph (2000) propose an alternative account of AoA, predicting that the effect should arise in any task where previously stored information is retrieved. The current study explored the effect of AoA on an object-name verification task. Experiments 1 and 2 demonstrated that early acquired objects were verified significantly faster than later acquired objects. A third experiment collected naming latencies for the same picture stimuli in order to allow a comparison of the magnitude of the AoA effect for object verification and naming. The implications of these findings for accounts of AoA and its locus of effect are discussed.

Delayed hydrocephalus as an unusual complication of a stab injury to the spine.

STUDY DESIGN: Case report. OBJECTIVE: To report a rare complication following a stab injury to the upper cervical spine and cord. SETTING: National spinal injury unit in a Scottish university teaching hospital. CASE REPORT: A 19-year-old male sustained a stab injury to his upper cervical spine, with a partial cord transection. After 5 months of rehabilitation, his condition deteriorated. CT scans showed hydrocephalus, which was treated by shunting. After shunting, the patient's condition improved but he remained tetraplegic requiring ventilatory support at night. CONCLUSION: Hydrocephalus as a late complication of a cervical spine injury is rare but should be considered if the condition of the patient with an upper cervical spine injury deteriorates. The likely mechanism of the hydrocephalus development is also discussed.

Differential effects of ozone on airway and tissue mechanics in obese mice.

Obesity is an important risk factor for asthma. We recently reported increased ozone (O(3))-induced hyperresponsiveness to methacholine in obese mice (Shore SA, Rivera-Sanchez YM, Schwartzman IN, and Johnston RA. J Appl Physiol 95: 938-945, 2003). The purpose of this study was to determine whether this increased hyperresponsiveness is the result of changes in the airways, the lung tissue, or both. To that end, we examined the effect of O(3) (2 parts/million for 3 h) on methacholine-induced changes in lung mechanics with the use of a forced oscillation technique in wild-type C57BL/6J mice and mice obese because of a genetic deficiency in leptin (ob/ob mice). In ob/ob mice, O(3) increased baseline values for all parameters measured in the study: airway resistance (Raw), lung tissue resistance (Rtis), lung tissue damping (G) and elastance (H), and lung hysteresivity (eta). In contrast, no effect of O(3) on baseline mechanics was observed in wild-type mice. O(3) exposure significantly increased Raw, Rtis, lung resistance (Rl), G, H, and eta responses to methacholine in both groups of mice. For G, Rtis, and Rl there was a significant effect of obesity on the response to O(3). Our results demonstrate that both airways and lung tissue contribute to the hyperresponsiveness that occurs after O(3) exposure in wild-type mice. Our results also demonstrate that changes in the lung tissue rather than the airways account for the amplification of O(3)-induced hyperresponsiveness observed in obese mice.

Responses to ozone are increased in obese mice.

Epidemiological data indicate an increased incidence of asthma in overweight adults and children. Ozone (O3) is a common trigger for asthma. Accordingly, the purpose of this study was to compare O3-induced airway hyperresponsiveness and airway inflammation in lean, wild-type (C57BL/6J) mice and mice that are obese as a consequence of a genetic defect in the gene encoding the satiety hormone leptin (ob/ob mice). The ob/ob mice eat excessively and weighed more than twice as much as age- and gender-matched wild-type mice. Airway responsiveness to intravenous methacholine was measured by forced oscillation. In air-exposed controls, baseline pulmonary resistance was greater, and the dose of methacholine required to double pulmonary resistance was lower in ob/ob than wild-type mice. Exposure to O3 (2 parts/million for 3 h) caused AHR and airway inflammation in both groups of mice, but responses to O3 were enhanced in ob/ob compared with wild-type mice. Administration of exogenous leptin did not reverse the enhanced inflammatory response observed in ob/ob mice, but augmented airway inflammation in wild-type mice. The inhaled dose of O3 per gram of lung tissue was greater in ob/ob than wild-type mice. Our results indicate that O3-induced airway responses are enhanced in ob/ob mice and suggest that inhaled O3 dose may be one factor contributing to this difference, but other aspects of the obese phenotype may also contribute. Our results also indicate that the hormone leptin, which is increased in the obese, has the capacity to increase airway inflammation.

Ozone-induced airway hyperresponsiveness is reduced in immature mice.

During ozone (O(3)) exposure, adult mice decrease their minute ventilation (VE). To determine whether there are age-related differences in the ventilatory response to O(3), A/J mice, aged 2, 4, 8, or 12 wk, were exposed to O(3) (0.3-3.0 parts/million for 3 h) in nose-only exposure plethysmographs. Baseline VE normalized for body weight (VE/g) decreased with increasing age, consistent with the higher metabolic rates of younger animals. O(3) caused a concentration-related decrease in VE in mice of all ages, but the response was significantly less in 2-wk-old than in older mice. The increased baseline VE/g and smaller decrements in VE induced by O(3) in immature mice resulted in an inhaled dose of O(3) normalized for body weight that was three to four times higher than in adult mice. O(3) exposure caused a dose-related increase in airway responsiveness in 8- and 12-wk-old mice but did not cause airway hyperresponsiveness at any dose in either 2- or 4-wk-old mice, although higher inhaled doses of O(3) normalized for body weight were delivered to these younger animals. Interleukin-6 and macrophage inflammatory protein-2 levels in bronchoalveolar lavage fluid were also increased in 8-wk-old compared with 2-wk-old mice exposed to O(3). The results suggest that immature mice are less sensitive than adult mice to O(3), at least in terms of the ability of O(3) to induce airway hyperresponsiveness and promote release of certain cytokines.

Factors predictive of subsequent deterioration in rheumatoid cervical myelopathy.

OBJECTIVE: To identify the features of rheumatoid cervical spine disease associated with deterioration resulting in the need for surgical intervention or death. PATIENTS AND METHODS: Patients with rheumatoid cervical myelopathy who underwent cervical spine magnetic resonance imaging (MRI) between 1991 and 1996 were identified. Patients requiring immediate surgical intervention were excluded. The remainder were divided into two groups. Deterioration group: patients requiring surgical intervention during the follow-up period and deaths resulting from cervical myelopathy. Conservative group: all other patients. Relevant clinical features and radiology reports were extracted retrospectively from the casesheet. RESULTS: The deterioration group comprised 11 patients (12%), median time to deterioration 15 months (range 4-84 months). The conservative group included 82 patients. Initial clinical features did not differ significantly between the two groups. Sixty per cent of those patients with compression or impingement at the atlanto-axial level on first MRI deteriorated over a median of 12 months (range 4-36 months). CONCLUSION: Deterioration is likely if there is evidence of cord compromise at the atlanto-axial level on MRI regardless of initial clinical and plain X-ray features.

Best face forward: similarity effects in repetition priming of face recognition.

Two experiments examined the graded similarity effect in the repetition priming of familiar face recognition. From the model of repetition priming proposed by Burton, Bruce, and Johnston (1990) it was predicted that similarity effects may be a confound of stimulus preparation. Experiment 1 was used to discount this hypothesis, but failed to replicate a pattern of graded priming related to the similarity of prime and target faces. Experiment 2 attempted a more extensive investigation using two different measures of prime-target similarity. The results replicated Ellis, Young, Flude, and Hay's (1987) finding that similar primes confer more priming than dissimilar ones, but found no correlation between amount of priming and the degree of prime-target resemblance for either similarity metric used. In view of these findings the mechanism of repetition priming in familiar face recognition is discussed.

Thoracic radiculopathy caused by a myodil cyst.

We report the case of a myodil cyst causing a thoracic radiculopathy in a patient who had undergone a myelogram 30 years previously. Although myodil is no longer used, sequelae can continue to be seen for many years.

Use of antibiotics in penetrating craniocerebral injuries. "Infection in Neurosurgery" Working Party of British Society for Antimicrobial Chemotherapy.

The Working Party was instituted to investigate the rationale of prophylactic and therapeutic antibiotic use in penetrating craniocerebral injuries (PCCI), and to make recommendations for current practice. A systematic review of papers on civilian and military PCCI over the past 25 and 50 years, respectively, was done via electronic databases and secondary sources, and data were evaluated. Guidelines on the removal of indriven bone or metal fragments only if further neural damage can be avoided were supported. However, no publications were identified where the data on infection or its treatment and prevention were complete or satisfactorily derived, and no controlled trials have been published. All studies were retrospective or anecdotal. Working Party recommendations are based on the data available and the professional experience and knowledge of the members. Broad-spectrum antibiotic prophylaxis is recommended for both military and civilian PCCI, Including those due to sports or recreational injuries.

Improved medical and surgical management of cervical spine disease in patients with rheumatoid arthritis over 10 years.

OBJECTIVES: (1) To compare clinical outcome and symptomatology of rheumatoid cervical myelopathy between patients managed conservatively and surgically. (2) To determine if surgical outcome has improved since the series published from this unit in 1987. (3) To examine the role of magnetic resonance imaging (MRI) in the diagnosis of cervical myelopathy. METHODS: Patients undergoing MRI of the cervical spine between 1991 and 1996 were identified. Case records were reviewed retrospectively. RESULTS: 111 patients with RA underwent 124 MRI scans. The median age at onset of cervical spine symptoms was 58 years (range 16-87) with median disease duration of 16 years (range 1-59). 18 (16%) required surgery immediately after MRI. 93 (84%) were managed conservatively, 9 of whom (10%) later required surgery. 2/7 deaths in the conservative group were directly related to cervical myelopathy. Patients requiring surgery were more likely to report paraesthesia, weakness, unsteadiness and to exhibit extensor plantar reflexes, gait disturbance, and reduced power. MRI findings did not correlate with clinical features. When compared with the 1974-82 cohort, fewer patients had severe myelopathy (Ranawat grade IIIB) before surgery (34% versus 7%). Early postoperative mortality improved from 9% to 0% and surgical complication rate fell from 50% to 22%. 89% of patients in the 1991-96 cohort reported subjective improvement in overall function. CONCLUSION: In this series surgical outcome has improved. The major factor in this more favourable outcome is probably that patients presenting with rheumatoid cervical myelopathy are now referred for surgery at an earlier stage of disease. Clinical findings correlate poorly with MRI findings, therefore clinical history should remain the key to determining the need for MRI.

Effect of ozone treatment on airway reactivity and epithelium-derived relaxing factor in guinea pigs.

Ozone (O(3)) is toxic to respiratory epithelium and causes airway inflammation and hyperreactivity. To evaluate the role of the epithelium in the development of hyperreactivity, we examined in guinea pigs the effects of inhaled O(3) (3 ppm for 1 h; 0-24 h after exposure) on 1) reactivity to inhaled methacholine (MCh), 2) reactivity of the isolated, perfused trachea (IPT) to MCh, 3) epithelium-derived relaxing factor (EpDRF)-mediated relaxations of IPT induced by mucosal hyperosmolar solutions, 4) neurogenic contraction and relaxation responses, 5) transepithelial potential difference, and 6) microscopic analysis of nitrotyrosine immunofluorescence, substance P fiber density, and tracheal morphology. At 0 h, O(3) caused hyperreactivity to inhaled MCh and mucosally but not serosally applied MCh in IPT (only in the presence of the epithelium) and a decrease in transepithelial potential difference. Inhibition of EpDRF-induced relaxation responses occurred at 2 h. All of these changes returned to control by 12 to 18 h. O(3) had no effect on neurogenic responses. Nitrotyrosine immunofluorescence appeared in the trachea at 0 h in detached epithelial cell ghosts and in intrapulmonary airways by 6 h. Substance P fiber density was elevated in smooth muscle at 0 and 18 h but not in epithelium or lamina propria of intrapulmonary and extrapulmonary bronchi. Loss of cilia and mucosubstances in the mucosa occurred at 0 h; the epithelium became markedly attenuated over 12 to 24 h. A reversible increase in epithelial permeability and a decrease in EpDRF production may contribute to O(3)-induced hyperreactivity to MCh.

Modeling scintillation from an aperiodic Kolmogorov phase screen.

We propose a technique for the accurate modeling and simulation of scintillation patterns that are due to Kolmogorov statistics without assuming periodic boundary conditions. We show how the more physically justifiable assumption of smoothness results in a propagation kernel of finite extent. This allows the phase screen dimensions for an accurate simulation to be determined, and truncation can then be used to eliminate the unwanted spectral leakage and diffraction effects usually inherent in the use of finite apertures. A detailed outline of the proposed technique and comparison of simulations with analytic results are presented.

Fast simulation of a kolmogorov phase screen.

A previously presented method for modeling Kolmogorov phase fluctuations over a finite aperture is both formalized and improved on. The method relies on forming an initial low-resolution Kolmogorov phase screen from direct factorization of a covariance. The resolution of the screen is then increased by a randomized interpolation to produce a Kolmogorov phase screen of the desired size. The computational requirement is asymptotically proportional to the number of points in the phase screen.

Understanding caricatures of faces.

Lateral caricatures are transformed faces like caricatures but the transformation is orthogonal (in the face-space, Valentine, 1991) to the direction of caricaturization. It has been reported that lateral caricatures are more difficult to recognize than anti-caricatures (Rhodes & Tremewan, 1994). To investigate this effect, oblique caricatures (transformed obliquely to caricaturing) were generated by morphing between a veridical face and a reference face. Two experiments used a forced-choice similarity task to find which images are perceived to have the least change from the veridical. An advantage for caricatures over anti-caricatures was found, but none was found between oblique and anti-caricatures. Performance of theoretical lateral caricatures was extrapolated from the oblique caricature data. These lateral caricatures would be perceived as more similar to veridical faces than were the anti-caricatures.

Structure of the complex of Maclura pomifera agglutinin and the T-antigen disaccharide, Galbeta1,3GalNAc.

Maclura pomifera agglutinin is a tetrameric plant seed lectin with high affinity for the tumor-associated T-antigen disaccharide, Galbeta1,3GalNAcalpha, and hence for many O-linked glycopeptide structures. Unlike members of most lectin families, it lacks both metal ions and Cys residues. The structure of its complex with Galbeta1,3GalNAc was determined to 2.2 by first using multiwavelength anomalous diffraction with a lead derivative of the native protein, and then using molecular replacement with the unrefined structure as a model to solve the structure of the complex. The subunits share the beta-prism architecture and three-fold pseudo-symmetry of the related lectin jacalin, with the 21-residue beta-chains in the center of the tetramer. Interactions with the GalNAc predominate in the binding of the disaccharide. It forms a network of H-bonds with only one side chain, from an Asp residue, the amino group of the N-terminal Gly of the alpha-chain, and peptide backbone atoms of two aromatic residues. The Gal moiety does not H-bond directly with residues in the same monomer, i.e. there is no true subsite for it, but there are interactions through two water molecules. In the crystal, it interacts with residues in the binding site of an adjacent tetramer. The minimum energy conformation expected for the disaccharide is retained, despite its mediating the tetramer-tetramer interactions in the crystal packing. The resulting lattice is comparable to those seen for complexes of other lectins with branched glycopeptides.

Transoral evacuation of a clivus extradural haematoma with good recovery: a case report.

We report a case of traumatic atlanto-axial dislocation with a clivus and upper cervical extradural haematoma causing tetraplegia and respiratory paralysis. Surgical evacuation via the transoral route with posterior atlanto-axial fixation resulted in survival with a good outcome.