An audit of the accuracy of fine needle aspiration using a liquid-based cytology system in the setting of a rapid access breast clinic.

We have assessed the effectiveness and accuracy of reporting fine needle aspirates of the breast (FNAB) using a liquid-based cytology (LBC) system (the Cytospin) method) in the pressure situation of a rapid access clinic (RAC). We have reviewed every case from the RAC from June 1997 to February 2001 inclusive. There were 1322 cases, which accounted for 26% of the total FNAB received in our department over the period. There were 323 cancers and 999 benign cases in the group. The inadequate/nondiagnostic rate (C1) was 18%. The absolute sensitivity, including C1 cases, was 73% with the complete sensitivity being 90%. The groups of 'atypical, probably benign' (C3) and 'suspicious, probably malignant' (C4) accounted for a total of 6.2%. There were 28 false negative cases and 1 false positive case (a borderline phyllodes tumour). Comparing our results with the standards recommended by the NHSBSP has shown that the diagnosis of FNAB using this LBC method is feasible, accurate and reliable even in the pressure situation of a RAC.

Counting probability distributions: differential geometry and model selection.

A central problem in science is deciding among competing explanations of data containing random errors. We argue that assessing the "complexity" of explanations is essential to a theoretically well-founded model selection procedure. We formulate model complexity in terms of the geometry of the space of probability distributions. Geometric complexity provides a clear intuitive understanding of several extant notions of model complexity. This approach allows us to reconceptualize the model selection problem as one of counting explanations that lie close to the "truth." We demonstrate the usefulness of the approach by applying it to the recovery of models in psychophysics.

Toward an explanation of the power law artifact: insights from response surface analysis.

The power law (y = ax-b) has been shown to provide a good description of data collected in a wide range of fields in psychology. R. B. Anderson and Tweney (1997) suggested that the model's data-fitting success may in part be artifactual, caused by a number of factors, one of which is the use of improper data averaging methods. The present paper follows up on their work and explains causes of the power law artifact. A method for studying the geometric relations among responses generated by mathematical models is introduced that shows the artifact is a result of the combined contributions of three factors: arithmetic averaging of data that are generated from a nonlinear model in the presence of individual differences.

Syllabic effects in word processing: evidence from the structural induction paradigm.

Spoken words have a rich structural organization in memory, consisting of syllabic and subsyllabic representations. A phoneme monitoring paradigm, in which the target phoneme occurs more frequently in one syllabic position than another (e.g., onset of the 2nd syllable vs. the coda of the 1st syllable: neu-tral vs. nut-meg; C. Pallier, N. Sebastian-Galles, T. Felguera, A. Christophe, & J. Mehler, 1993) was used to explore the formation of syllabic structure during word processing. Experiment 2 investigated how a recognition system that uses syllabic structure processes words with unclear syllable boundaries (e.g., pa-lace or pal-ace?). Two methodological issues were explored: The importance of a baseline condition for measuring effects of induction (Experiment 1) and the form of the representation used in the induction paradigm (Experiment 3). Findings suggest that syllabic structure begins to form early in word processing, and they demonstrate the adequacy of the induction procedure for measuring such processes.

Phonological processes and the perception of phonotactically illegal consonant clusters.

The perception of consonant clusters that are phonotactically illegal word initially in English (e.g., /tl/,/sr/) was investigated to determine whether listeners' phonological knowledge of the language influences speech processing. Experiment 1 examined whether the phonotactic context effect (Massaro & Cohen, 1983), a bias toward hearing illegal sequences (e.g.,/tl/) as legal (e.g., /tr/), is more likely due to knowledge of the legal phoneme combinations in English or to a frequency effect. In Experiment 2, Experiment 1 was repeated with the clusters occurring word medially to assess whether phonotactic rules of syllabification modulate the phonotactic effect. Experiment 3 examined whether vowel epenthesis, another phonological process, might also affect listeners' perception of illegal sequences as legal by biasing them to hear a vowel between the consonants of the cluster (e.g., /talae/). Results suggest that knowledge of the phonotactically permissible sequences in English can affect phoneme processing in multiple ways.

Interference effects in short-term memory for timbre.

Four experiments investigated memory for timbre using the interpolated-tone paradigm [Deutsch, Science 168, 1604-1605 (1970)], in which participants discriminate pairs of tones (standard and comparison) separated by intervening (interpolated) tones. Interpolated tones varied from the standard tone in spectral similarity (within-dimensional variation), fundamental frequency (cross-dimensional variation), and repetition frequency. While the latter two variables had negligible effects on timbre memory, interference with timbre memory increased with the spectral similarity of the interpolated tones to the standard tone. The findings closely parallel those found for pitch memory, and suggest that memory interference depends on perceptual similarity in both cases.

Reflux oesophagitis and Helicobacter pylori infection in elderly patients.

Helicobacter pylori is associated with gastritis, peptic ulcers and gastric malignancies. Little attention has been paid to the possibility that it may also have a role in the pathogenesis of reflux oesophagitis. This is especially true in elderly patients who have life-long infection and provide an ideal group to study the mucosal changes associated with the organism. The aim of this study was to determine if H pylori is associated with reflux oesophagitis in elderly patients. Consecutive gastroscopy patients were recruited. Multiple biopsies were taken from oesophagus, stomach, antrum and duodenum for histology and rapid urease tests. Patients also had IgG ELISA antibodies and 13C-urea breath tests performed. Patients with macroscopic or microscopic evidence of reflux oesophagitis were compared to patients with macroscopically normal upper gastrointestinal tracts and no microscopic evidence of reflux. A total of 114 patients were recruited, average age 78.9 years (+/- 5.4). There were 37 refluxers and 33 non-refluxers. We found no evidence for an association between the presence of H pylori and reflux oesophagitis in elderly patients. The high prevalence of H pylori in patients with reflux oesophagitis can be explained by the presence of incidental gastritis.

Lack of association between helicobacter pylori and gastric atrophy or intestinal metaplasia in elderly patients.

Helicobacter pylori (Hp) is associated with gastritis and peptic ulcers. It may also induce gastric atrophy (GA) and intestinal metaplasia (IM), and these changes may be the precursors of gastric carcinoma. The aim of this study was to determine if GA or IM is associated with Hp infection in elderly patients. Consecutive patients admitted for gastroscopy were recruited. Multiple biopsies were taken for histology and rapid urease (CLO) tests along with IgG enzyme-linked immunosorbent assay antibodies and (13)C-urea breath tests. Statistical analysis was by chi(2) tests. 114 patients were recruited, the average age was 78.9 + or - 5.4 years. Histology was available on 105 patients, 80 (76.2%) had gastritis, and 61/80 (76.25%) had evidence of definite current Hp infection. Seven patients had reflux gastritis, and these were excluded from the analysis described below. 20 patients had GA and 24 IM. The relationship between Hp and GA or IM was investigated by dividing patients into four groups: Group 1 patients (n = 57) were taken to be definitely currently infected (GA 7 patients, IM 11, both 1). Group 2 patients (n = 18) had old infection (GA 2, IM 4, both 3). Group 3 patients (n = 16) have never been infected previously (GA 1, IM 1, both 3). Group 4 patients (n = 4) had a poor immunological response to Hp (GA 1, IM 1, both 0). There were no significant differences in the numbers of patients with GA or IM in any group as compared with any other, with the exception of less patients with histological evidence of combined GA and IM among patients with definite current infection as compared with those with either previous infection (p = 0.04) or 'never' infection (p = 0.03). We conclude that the mucosal changes of GA or IM are not consistently associated with Hp infection in the elderly.

Pseudoangiosarcomatous carcinoma of the genitourinary tract.

Two cases of pseudoangiosarcomatous carcinoma of the genitourinary tract, arising in the vulva in one and the bladder in the other, are presented. In case 1, an 84 year old woman, the vulvectomy specimen contained an irregular ulcerated tumour, infiltrating the left labia and extending into the clitoris. In case 2, a 59 year old woman, the excised bladder showed diffuse thickening of its wall by infiltrating haemorrhagic tumour. Both tumours showed focal keratinisation. This, in association with the presence of atypical squamous epithelium, immunohistochemistry and ultrastructural analysis, led to a diagnosis of pseudosarcomatous carcinoma in both cases. Pseudoangiosarcomatous carcinoma should be considered in the differential diagnosis of malignant angiomatoid tumours, particularly those that arise at sites, like the genitourinary tract, where angiosarcoma is rare.

Spindle cell and pleomorphic lipoma: an ultrastructural study.

Spindle cell and pleomorphic lipoma are rare benign tumors of adipose tissue. Their histogenesis is poorly understood and pleomorphic lipoma has not previously been studied ultrastructurally. This study describes the morphology and ultrastructure of 6 cases of spindle cell and pleomorphic lipoma. Both spindle cell and pleomorphic lipomas showed similar ultrastructural features with an interrupted basal lamina, occasional non-membrane-bound lipid vacuoles and abundant rER. In all the cases mast cells were conspicuous and were intimately related to both spindle and pleomorphic cells. It is proposed that both the spindle and pleomorphic multinucleated cells that characterize these tumors are prelipoblastic mesenchymal cells. The possible significance of an interaction between these cells and mast cells is discussed.

Lexical and sublexical feedback in auditory word recognition.

Currently, there are two qualitatively different model classes in the field of spoken language understanding. Autonomous models allow only bottom-up information flow, whereas interactive models allow higher level representations (e.g., lexical) to affect processing at lower levels (e.g., phonemic). Part 1 of the present study included a test of a prediction that differentiates the two model classes: Is phoneme monitoring faster for targets in real words than in pseudowords, even before the word could in principle be recognized? The results indicate that this lexical advantage does occur, in accord with the predictions of interactive models. In Part 2, speech compression and expansion were used to assess the sufficiency or necessity of bottom-up evidence and of processing time in accomplishing lexical access. The results of Parts 1 and 2 suggested that in addition to the lexical effects posited by current models, sublexical activation may also play an important role. Data are presented in Part 3 that support this interpretation. Collectively, the results in the current study support interactive models of lexical processing, but require additional sublexical processes as well.

The locus of the lexical shift in phoneme identification.

The lexical identification shift is used as a measure of speech processing in the phoneme identification task (W. F. Ganong, 1980). Interactive (bottom-up and top-down) models of word recognition account for the shift by claiming that lexical knowledge feeds back to a prelexical level and aids speech processing. Autonomous models (bottom-up only) maintain that the shift arises by other means and at later stages of processing. The locus of the lexical shift was investigated by using detection theory analysis procedures to measure perceptual changes in phoneme processing. Lexical status (word-nonword) of the utterance was varied in Experiments 1 and 3 and was found to influence phoneme processing. In Experiment 2 the effects of a postperceptual manipulation, monetary payoff, did not show up in the detection theory analysis. Implications of the results for both classes of models are discussed.

Data fitting and detection theory: reply to Massaro and Oden (1995).

D. W. Massaro and G. C. Oden (1995) claimed that M. A. Pitt's (1995) data provide strong evidence in favor of independence, not interactivity, as argued by Pitt. Massaro and Oden's arguments rested on an evaluation of the fit of the fuzzy logical model of perception (FLMP) to the identification data and on criticisms of the detection theory analyses. In this reply, Pitt shows that the latter criticisms were unfounded and that the data-fitting demonstrations raised questions about FLMP's ability to capture the phenomenon of interest (i.e., lexical context effects).

Serosal reaction in chronic gastric ulcers: an immunohistochemical and ultrastructural study.

AIM: To study the serosal reaction in gastrectomy specimens with benign chronic peptic ulcers. METHODS: Gastrectomy specimens were fixed in neutral buffered formalin and paraffin wax, and examined using immunohistochemical and ultrastructural techniques. RESULTS: Nine of the 22 (41%) cases examined showed reactive hyperplasia of the serosal cells. The cells were predominantly spindle-shaped and were positive on staining with Cam 5.2, AE1/3 and for vimentin. Eight of nine were also positive for smooth muscle actin and five for desmin. Ultrastructural analysis of these cells suggests that they may be myofibroblastic in nature. CONCLUSIONS: These results support the concept of "multipotential" subserosal cells which may differentiate into surface serosa or, in the reactive state, modulate the thin cytoskeletal filaments and become more myofibroblastic. Particular care should be taken not to confuse these reactive serosal cells with carcinoma or smooth muscle tumours in endoscopic biopsy specimens.

Evidence for a central representation of instrument timbre.

An information processing account of perception seeks to delineate the stages of processing through which a stimulus passes and determine the properties of the representation at each stage. Research in phonetic perception has identified two stages, the second of which is thought to encode abstract acoustic attributes of sounds. The present study provided a further test of this proposal by assessing whether nonphonetic stimuli could yield results similar to those obtained with phonetic stimuli. Five selective adaptation experiments were carried out with a trumpet-piano timbre continuum. Two manipulations were used to measure abstract encoding: cross-ear presentation of adaptor and test series, and the use of adaptors that were acoustically different from the continuum end-points. The results provide evidence for an abstract representation of timbre. The similarity of the findings to those in the phonetic adaptation literature is discussed.