Cytokeratin profiles of male breast cancers.

AIMS: The prognostic factors and expression of molecular markers in male breast carcinomas are similar to those in female breast cancers. The identification of distinct cytokeratin (CK) profiles (basal as opposed to luminal cells) helps to identify subsets of tumours with different clinical behaviour. The aim of this study was to investigate CK expression in male breast cancer. METHODS AND RESULTS: Thirty-two cases of male breast cancer were studied. The panel of CKs studied by immunohistochemistry included: 5/6, 14, 17, 18 and 19. Pathological findings and CK expression were analysed in all cases. Histological patterns included ductal carcinoma in situ, invasive ductal carcinoma and mixed patterns. Four cases were positive for CK5/6 and CK14, identifying a basal-like phenotype. CK17 was negative in all but two cases. All cases expressing either CK5/6 or CK14 were invasive carcinomas of high nuclear and histological grade and were also larger compared with the tumours not expressing CK5/6 and CK14. All tumours except three (also negative for CK5/6) expressed CK18 and CK19. The four basal-like tumours were negative for Her-2 expression. CONCLUSIONS: Male breast carcinomas have a basal-like phenotype that is similar in frequency to that of female breast carcinomas. The expression of CK5/6 and CK14 identifies a subset of pathologically aggressive male breast cancers.

Perception of aspiration and place of articulation of Cantonese initial stops by normal and sensorineural hearing-impaired listeners.

This study investigated the use of acoustic cues to the perception of aspiration and place of articulation of Cantonese initial stops by bilateral severely hearing-impaired (n = 14) and normal-hearing (n = 14) adolescents. The stimuli were consonant-vowel (CV) words spoken by two male speakers in which the initial consonants /ph, p, th, t, kh, k/ were followed by the diphthong /[symbol: see text]i/. Subjects listened to the stimuli through a loudspeaker and chose the correct initial consonant among six choices. Three test conditions (short, medium and long voice onset time, or VOT) were prepared by increasing the VOT of unaspirated stops and by decreasing the VOT of aspirated stops. The results showed that the presence of aspiration noise was an important cue for normal listeners in the perception of aspiration, but not for hearing-impaired listeners. Hearing-impaired listeners used formant transitions as the main cue to the perception of aspiration. VOT was a weak aspiration cue for both groups. In the perception of place of articulation, normal listeners appeared to rely mainly on formant transitions and release burst information rather than VOT. The recognition of place by hearing-impaired listeners was at chance level for all the experimental stimuli, showing that these listeners were unable to use VOT, formant transitions or release burst information as cues to place.

Perceptual-phonetic predictors of single-word intelligibility: a study of Cantonese dysarthria.

This study investigated the perceptual-phonetic predictors of intelligibility in Cantonese speakers with dysarthria. The speakers were 20 young adults with cerebral palsy. The listener group consisted of 12 native Cantonese speakers. A single-word intelligibility test was constructed, based on 17 phonetic contrasts. There were no significant differences in intelligibility for gender, age, or type of cerebral palsy. A regression analysis showed that intelligibility could be predicted with 97% accuracy by 5 out of the 6 most problematic contrasts. Three contrasts (glottal vs. null, final vs. null, and long vs. short vowel) predicted variation on an independent intelligibility measure obtained for the same speakers with 84% accuracy. Principal components analysis derived 4 components, which accounted for 81% of the variance in the 17 contrasts. Physiological explanations and language-specific contributions to speech disorder in this group of speakers are discussed.

Evidence against an effect of grouping by spectral regularity on the perception of virtual pitch.

Two experiments investigated the role of the regularity of the frequency spacing of harmonics, as a separate factor from harmonicity, on the perception of the virtual pitch of a harmonic series. The first experiment compared the shifts produced by mistuning the 3rd, 4th, and 5th harmonics in the pitch of two harmonic series: the odd-H and the all-H tones. The odd-H tone contained odd harmonics 1 to 11, plus the 4th harmonic; the all-H tone contained harmonics 1 to 12. Both tones had a fundamental frequency of 155 Hz. Pitch shifts produced by mistuning the 3rd harmonic, but not the 4th and 5th harmonics, were found to be significantly larger for the odd-H tone than for the all-H tone. This finding was consistent with the idea that grouping by spectral regularity affects pitch perception since an odd harmonic made a larger contribution than an adjacent even harmonic to the pitch of the odd-H tone. However, an alternative explanation was that the 3rd mistuned harmonic produced larger pitch shifts within the odd-H tone than the 4th mistuned harmonic because of differences in the partial masking of these harmonics by adjacent harmonics. The second experiment tested these explanations by measuring pitch shifts for a modified all-H tone in which each mistuned odd harmonic was tested in the presence of the 4th harmonic, but in the absence of its other even-numbered neighbor. The results showed that, for all mistuned harmonics, pitch shifts for the modified all-H tone were not significantly different from those for the odd-H tone. These findings suggest that the harmonic relations among frequency components, rather than the regularity of their frequency spacing, is the primary factor for the perception of the virtual pitch of complex sounds.

The integration of nonsimultaneous frequency components into a single virtual pitch.

The integration of nonsimultaneous frequency components into a single virtual pitch was investigated by using a pitch matching task in which a mistuned 4th harmonic (mistuned component) produced pitch shifts in a harmonic series (12 equal-amplitude harmonics of a 155-Hz F0). In experiment 1, the mistuned component could either be simultaneous, stop as the target started (pre-target component), or start as the target stopped (post-target component). Pitch shifts produced by the pre-target components were significantly smaller than those obtained with simultaneous components; in the post-target condition, the size of pitch shifts did not decrease relative to the simultaneous condition. In experiment 2, a silent gap of 20, 40, 80, or 160 ms was introduced between the nonsimultaneous components and the target sound. In the pre-target condition, pitch shifts were reduced to zero for silent gaps of 80 ms or longer; by contrast, a gap of 160 ms was required to eliminate pitch shifts in the post-target condition. The third experiment tested the hypothesis that, when post-target components were presented, the processing of the pitch of the target tone started at the onset of the target, and ended at the gap duration at which pitch shifts decreased to zero. This hypothesis was confirmed by the finding that pitch shifts could not be observed when the target tone had a duration of 410 ms. Taken together, the results of these experiments show that nonsimultaneous components that occur after the onset of the target sound make a larger contribution to the virtual pitch of the target, and over a longer period, than components that precede the onset of the target sound.

EGF activates ErbB-2 and stimulates phosphatidylinositol 3-kinase in human airway smooth muscle cells.

The epidermal growth factor (EGF)-receptor (EGFR) family includes four homologous transmembrane receptor protein tyrosine kinases, EGFR, ErbB-2, ErbB-3, and ErbB-4. This receptor family plays a pivotal role in regulating cell proliferation, differentiation, and transformation. Ligand-induced activation of these receptors results in formation of homo- and heterodimers, which undergo transphosphorylation and transactivation. The aim of this study was to characterize the role of EGFR family members in signaling EGF-induced human airway smooth muscle (HASM) cell proliferation. Here, we show that EGF stimulates activation of EGFR and transactivation of ErbB-2 in quiescent HASM cells. Phosphatidylinositol (PI) 3-kinase, a critical signaling enzyme that modulates HASM cell growth, is preferentially associated with ErbB-2, and EGF-stimulated transactivation of ErbB-2 induces PI 3-kinase activation. ErbB-3 and ErbB-4 are present in HASM cells; however, EGF has no effect on their activation. Betacellulin, a ligand for EGFR, ErbB-3, and ErbB-4, induced DNA synthesis of HASM cells and stimulated signaling through the activation of EGFR and ErbB-2 but not of ErbB-3 and ErbB-4. Heregulin, a specific ligand for ErbB-3 and ErbB-4, did not effect DNA synthesis and did not activate its specific receptors. These data suggest that EGF imparts signals that involve activation of ErbB-2 and are associated with ErbB-2 PI 3-kinase activation. Despite the mRNA and protein expression of all members of the EGFR family, ligand-stimulated signaling induced activation of EGFR and ErbB-2 but not of ErbB-3 and ErbB-4.

The substitution of [s] for aspirated targets: perceptual and acoustic evidence from Cantonese.

The substitution of [s] for word-initial aspirated targets was examined in a Cantonese-speaking pre-school child. Perceptual analysis showed that the child produced [ph] accurately, but substituted [s] for /t(h)/, /ts(h)/ and /k(h)/. Acoustic analysis revealed no subphonemic contrast between the target /s/, and the substituted [s] for /t(h)/, /ts(h)/ and /k(h)/. The unusual substitution of [s] for aspirated lingual targets, and the lack of a subphonemic contrast among [s] productions were described in terms of feature geometry. The target feature patterns of [-continuant, +spread] were produced as [+continuant, +spread], with maintenance of the default place feature (coronal). It is proposed that the child had immature motor control of the coordination of supralaryngeal and laryngeal movements. Examination of the child's productions of aspirated lingual targets at pre-, mid- and post-therapy revealed that compensatory articulation changed over time as the child learned to coordinate laryngeal and oral movements.

Effects of LTD4 on human airway smooth muscle cell proliferation, matrix expression, and contraction In vitro: differential sensitivity to cysteinyl leukotriene receptor antagonists.

The cysteinyl leukotrienes (CysLTs) mimic many of the features of asthma and are implicated in its pathophysiology. Little, however, is known about the effects of the CysLTs on airways remodeling. In this study the effects of leukotriene D4 (LTD4) on human airway smooth muscle (HASM) cell proliferation and expression of extracellular matrix proteins were investigated. LTD4 (0.1-10 microM) alone had no effect on DNA synthesis in HASM. LTD4, however, markedly augmented proliferation induced by the mitogen, epidermal growth factor (EGF, 1 ng/ml). The potentiating effect of LTD4 (1 microM) on EGF-induced DNA synthesis was abolished by pranlukast (1 microM) or pobilukast (30 microM), but unaffected by zafirlukast (1 microM). In contrast, pranlukast (pKB = 6.9), pobilukast (pKB = 7.0), and zafirlukast (pKB = 6.5) had equivalent potencies for inhibition of LTD4-induced contraction in human bronchus. LTD4 (0.1 or 10 microM) did not increase the total messenger RNA expression of the extracellular matrix proteins (pro-alpha[I] type I or alpha1[IV] type IV collagen), elastin, biglycan, decorin, and fibronectin, and did not influence tumor growth factor-beta (10 ng/ml)-induced effects on the expression of these proteins in HASM cells. These data indicate that LTD4 augments growth factor-induced HASM proliferation but does not alter the expression of various extracellular matrix components. The observed differences in sensitivity to the antagonists suggests that the former phenomenon may be mediated by a CysLT receptor distinct from that which mediates LTD4-induced HASM contraction. Collectively, these results provide preliminary evidence that CysLTs may play a role in airways remodeling in asthma.

TGF-beta 1 modulates human airway smooth-muscle cell proliferation induced by mitogens.

Asthma is a disease of airway inflammation and bronchoconstriction that results in airway smooth-muscle cell hypertrophy and hyperplasia. The underlying mechanisms that induce myocyte proliferation remain unknown. Evidence suggests that cytokines such as transforming growth factor (TGF)-beta 1 may play a role in modulating this process. In this study, we examined the effects of TGF-beta 1 on human airway smooth-muscle (HASM) cell proliferation. We found that treatment of HASM cells with TGF-beta 1 inhibited epidermal growth factor (EGF)- and thrombin-induced DNA synthesis. This inhibition was both dose and time dependent. We then investigated whether these effects are mediated through activation of mitogen-activated protein kinase (MAP kinase), an enzyme that is thought to play a central role in the regulation of cell proliferation. We found that MAP kinase activation induced by EGF was not modulated by TGF-beta 1, despite TGF-beta 1 inhibiting EGF-induced HASM cell growth. These data suggest that TGF-beta 1 inhibits mitogen-induced HASM cell proliferation, but does so downstream from MAP kinase activation, or via a parallel pathway that is independent of MAP kinase activation.

TGF-beta 1 modulates EGF-stimulated phosphatidylinositol 3-kinase activity in human airway smooth muscle cells.

Regulation of phosphatidylinositol (PI) 3-kinase plays an important role in modulating cellular function. We have previously shown that transforming growth factor (TGF)-beta 1 inhibited epidermal growth factor (EGF)-induced human airway smooth muscle (hASM) cell proliferation and that PI 3-kinase activation is a necessary signaling event in mitogen-induced hASM cell growth. In this study, we postulated that TGF-beta 1 may modulate EGF-induced PI 3-kinase activation. To date, no study has examined the effects of TGF-beta 1 on PI 3-kinase activity. In cultured hASM cells, EGF induced a 5.7 +/- 1.2-fold activation of PI 3-kinase compared with diluent-treated cells. Although TGF-beta 1 alone did not alter PI 3-kinase activation, TGF-beta 1 markedly enhanced EGF-induced PI 3-kinase activity, with a 16.6 +/- 1.9-fold increase over control cells treated with diluent alone. EGF significantly increased the association of PI 3-kinase with tyrosine phosphorylated proteins, and TGF-beta 1 pretreatment before EGF stimulation apparently did not alter this association. Interestingly, TGF-beta 1 did not modulate EGF-induced p70 S6 kinase activity, which is important for the progression of cells from the G0 to the G1 phase of the cell cycle. Immunoprecipitation of type I and type II TGF-beta receptors showed that PI 3-kinase was associated with both type I and type II TGF-beta receptors. TGF-beta 1, however, enhanced PI 3-kinase activity associated with the type I TGF-beta receptor. Although in some cell types inhibition of PI 3-kinase and treatment of cells with TGF-beta 1 mediate apoptosis, cell cycle analysis and DNA ladder studies show that PI 3-kinase inhibition or stimulation of hASM cells with TGF-beta 1 did not induce myocyte apoptosis. Although the inhibitory effects of TGF-beta 1 on hASM cell growth are not mediated at the level of PI 3-kinase and p70 S6 kinase, we now show that activation of the TGF-beta 1 receptor modulates PI 3-kinase activity stimulated by growth factors in hASM cells.

Effects of frequency and amplitude modulation on the pitch of a complex tone with a mistuned harmonic.

It has previously been found that when a single low-numbered harmonic of a complex tone is progressively mistuned, for mistunings up to about 3%, the pitch of the complex changes in the direction of the mistuning but for larger mistunings (by about 8%) the pitch returns to its original value. This result is compatible with the operation of a mechanism such as a graded harmonic sieve, which can reject from the calculation of pitch those frequency components that are implausibly distant from a harmonic frequency. The first experiment shows that the tolerance of such a sieve is increased when all the components of the complex tone (including the mistuned component) share a common pattern of frequency modulation at a rate of 6 Hz. The second experiment shows that the tolerance of the sieve is not increased when the components share a common pattern of amplitude modulation at 17 Hz. The third experiment replicates these findings and further shows that the increase in sieve tolerance for FM, but not for AM, occurs at both 6 and at 17 Hz.

Organization in audition by similarity in rate of change: evidence from tracking individual frequency glides in mixtures.

In audition, sound energy is assigned to separate auditory "streams" following principles of organization that closely parallel the visual gestalt principles that guide the perception of distinct forms or objects. Metzger (1934) provided evidence for organization in vision based on similarity in the velocity of moving forms. If two dots approach one another along one spatial dimension, they may appear to cross and continue beyond their meeting point if their velocities differ; otherwise, they usually appear to change direction abruptly and retrace their movements. If an analogous auditory principle exists, with rate of change in frequency substituted for velocity of movement, two frequency glides that sweep through the same frequency range in opposite directions should be able to perceptually cross if their rates of change differ; otherwise, they should usually appear to change direction and retrace the same frequency region. Four experiments provided data in support of this hypothesis, and the results were consistent across experiments with varying stimuli and methods of presentation. When properties of the stimuli favored organization according to a principle of frequency proximity, the effect of a principle of rate similarity was attenuated but still evident.

Effects of onset asynchrony on pitch perception: adaptation or grouping?

A previous paper by Darwin and Ciocca [J. Acoust. Soc. Am. 91, 3381-3390 (1992)] showed that a slightly mistuned frequency component of a (target) harmonic complex produced smaller pitch shifts in the target if it started 160 ms or more before the other components than if all the components were simultaneous. Three experiments investigated whether this effect of onset asynchrony is due to peripheral adaptation to the leading portion of the mistuned component or to perceptual grouping. The first two experiments showed that the effect of asynchrony could be influenced by grouping mechanisms without changing the amount of adaptation produced by the leading portion of the mistuned component. In the first experiment, the effect of asynchrony was reduced by the presence of an additional (captor) complex which was harmonically related to the mistuned component and synchronous with just its leading portion. In experiment 2, the effect of asynchrony was increased by presenting a captor that was synchronous with the entire mistuned component. This capturing effect was independent of the harmonic relation between the captor and the mistuned component at 40-ms asynchrony; at 160 ms the effect of asynchrony increased further only if the captor and the mistuned component were harmonically related. In the third experiment, the expected amount of adaptation was increased (relative to that produced by a single sine precursor) by presenting several components that were close in frequency to the mistuned component and synchronous with its leading portion.(ABSTRACT TRUNCATED AT 250 WORDS)

Grouping in pitch perception: effects of onset asynchrony and ear of presentation of a mistuned component.

Three experiments investigated how the onset asynchrony and ear of presentation of a single mistuned frequency component influence its contribution to the pitch of an otherwise harmonic complex tone. Subjects matched the pitch of the target complex by adjusting the pitch of a second similar but strictly periodic complex tone. When the mistuned component (the 4th harmonic of a 155 Hz fundamental) started 160 ms or more before the remaining harmonics but stopped simultaneously with them, it made a reduced contribution to the pitch of the complex. It made no contribution if it started more than 300 ms before. Pitch shifts and their reduction with onset time were larger for short (90 ms) sounds than for long (410 ms). Pitch shifts were slightly larger when the mistuned component was presented to the same ear as the remaining 11 in-tune harmonics than to the opposite ear. Adding a "captor" complex tone with a fundamental of 200 Hz and a missing 3rd harmonic to the contralateral ear did not augment the effect of onset time, even though the captor was synchronous with the mistuned harmonic, the mistuned component was equal in frequency to the missing 3rd harmonic of the captor complex tone and it was played to the same ear as the captor. The results show that a difference in onset time can prevent a resolved frequency component from contributing to the pitch of a complex tone even though it is present throughout that complex tone.

The phonetic integration of speech and non-speech sounds: effects of perceived location.

The third-formant (F3) transition of a three-formant /da/ or /ga/ syllable was extracted and replaced by sine-wave transitions that followed the F3 centre frequency. The syllable without the F3 transition (base) was always presented at the left ear, and a /da/ (falling) or /ga/ (rising) sine-wave transition could be presented at either the left, the right, or both ears. The listeners perceived the base as a syllable, and the sine-wave transition as a non-speech whistle, which was lateralized near the left ear, the right ear, or the middle of the head, respectively. In Experiment 1, the sine-wave transition strongly influenced the identity of the syllable only when it was lateralized at the same ear as the base (left ear). Phonetic integration between the base and the transitions became weak, but was not completely eliminated, when the latter was perceived near the middle of the head or at the opposite ear as the base (right ear). The second experiment replicated these findings by using duplex stimuli in which the level of the sine-wave transitions was such that the subjects could not reliably tell whether a /da/ or a /ga/ transition was present at the same ear as the base. This condition was introduced in order to control for the possibility that the subjects could have identified the syallables by associating a rising or falling transition presented at the left ear with a /da/ or /ga/ percept. Alternative suggestions about the relation between speech and non-speech perceptual processes are discussed on the basis of these results.

The effects of auditory streaming on duplex perception.

When a formant transition and the remainder of a syllable are presented to subjects' opposite ears, most subjects perceive two simultaneous sounds: a syllable and a nonspeech chirp. It has been demonstrated that, when the remainder of the syllable (base) is kept unchanged, the identity of the perceived syllable will depend on the kind of transition presented at the opposite ear. This phenomenon, called duplex perception, has been interpreted as the result of the independent operation of two perceptual systems or modes, the phonetic and the auditory mode. In the present experiments, listeners were required to identify and discriminate such duplex syllables. In some conditions, the isolated transition was embedded in a temporal sequence of capturing transitions sent to the same ear. This streaming procedure significantly weakened the contribution of the transition to the perceived phonetic identity of the syllable. It is likely that the sequential integration of the isolated transition into a sequence of capturing transitions affected its fusion with the contralateral base. This finding contrasts with the idea that the auditory and phonetic processes are operating independently of each other. The capturing effect seems to be more consistent with the hypothesis that duplex perception occurs in the presence of conflicting cues for the segregation and the integration of the isolated transition with the base.