Contralateral suppression of transiently evoked otoacoustic emissions by harmonic complex tones in humans

Variations in the amplitude of transiently evoked otoacoustic emissions (TEOAEs) produced by a contralateral complex tone were measured in 26 normal-hearing human subjects. TEOAEs were evoked using a 1-kHz tone pip at 60 dB SPL. The contralateral complex consisted of harmonic components with frequencies between 400 and 2000 Hz; it was presented at levels ranging from 40 to 50 dB SL and its fundamental frequency (F0) was varied. In experiment 1, the dependence of TEOAE amplitude variations on the F0 of the contralateral complex was measured by varying the F0 from 50 to 400 Hz in octave steps. The results revealed a nonmonotonic dependence of TEOAE amplitude variations on contralateral F0, with significantly larger TEOAE suppression for F0's of 100 and 200 Hz than for F0's of 50 and 400 Hz. Experiment 2, in which the harmonics were summed in alternating sine-cosine phase instead of constant sine phase, showed a shift of the function relating TEOAE attenuation to F0 towards lower F0's, indicating that the waveform repetition rate, rather than harmonic spacing, was the actual factor of the dependence of contralateral TEOAE attenuation on F0. Furthermore, significantly smaller suppression was observed with the alternating-phase complexes than with the sine-phase complexes, suggesting an influence of the waveform crest factor. Experiment 3 showed no difference between the contralateral TEOAE attenuation effects produced by positive and negative Schroeder-phase complexes. Overall, these results bring further arguments for the notion that contralaterally induced medial olivocochlear bundle (MOCB) activity, as measured through the contralateral suppression of TEOAEs in humans, is sensitive to the rate of temporal envelope fluctuations of the contralateral stimulus, with preferential rates around 100-200 Hz.     

Gompertzian growth curves in parathyroid tumours: further evidence for the set-point hypothesis

BACKGROUND: Clinical and cell kinetic data in parathyroid tumours show that their rate of growth slows down progressively and that tumour size approaches an asymptotic value. The Gompertz equation has been widely used in oncology to model growth retardation in malignant tumours; we describe its first application to a benign tumour. METHODS: In 41 patients with radiation associated hyperparathyroidism, individual solutions were derived for the Gompertz equation: Nt = Exp[A/ a(1 - Exp - at)], where A is the rate constant (years-1) for initial exponential growth and a is the rate constant (years-1) for exponential decline in A. Input data comprised three estimates of tumour age at surgery, 100%, 75% and 50% of the time since irradiation, cell number estimated from tumour weight, and current tumour growth rate, representing the difference between current cell birth rate, estimated from the prevalence of mitotic figures, and an assumed mean rate of cell loss of 5%. RESULTS: With 100% tumour age, geometric mean values were 2.76 for A, 0.134 for a, and 0.87 g for the growth asymptote. As assumed tumour age decreased, the rate constants increased and the growth asymptotes declined from 22% to 9% greater than the geometric mean tumour weight. Depending on assumed tumour age, the rate constants were about 15-45 times smaller than in myeloma and in testicular tumours, and the growth asymptotes about 2500 and about 60 times smaller, respectively. A and a were highly correlated (r2 = 0.993), with a slope of 20.9 and no significant intercept. Depending on assumed tumour age, the geometric mean time from the initial mutation to the first cell division ranged from 39 to 92 days, much longer than in malignant tumours. CONCLUSIONS: (1) The Gompertz modelling demonstrates that both the nonprogressive clinical course and the slow growth of parathyroid tumours can be accounted for by a single mutation. (2) The extremely low values for A and a, and consequent very long delay before the first cell division, support the notion that the initial mutation does not affect a growth regulatory gene, but increases growth indirectly via an increase in secretory set-point, the clone of mutant cells behaving as if they were in a hypocalcaemic environment until the plasma calcium rises to the new set-point. (3) The clinical characteristics of radiation-induced parathyroid tumours are modelled more closely if there is a substantial delay between time of irradiation and onset of tumour growth. (4) The rate constants A and a are highly correlated because the variability of tumour weight on a logarithmic scale is much lower than the variability of the rate constants.     

Karyomegalic interstitial nephritis: further support for a distinct entity and evidence for a genetic defect

Karyomegalic interstitial nephritis was first described in 1979 by Mihatsch, who was reporting three such cases. We report here four additional cases as well as two family investigations. Our findings support the association of karyomegaly and interstitial nephritis as a distinct entity. Typical clinical features are asymptomatic progressive renal failure in the third decade of life and recurrent infections, mostly of the upper respiratory tract. Histologic alterations consist of markedly enlarged and hyperchromic nuclei in many tubular epithelial cells throughout the nephron accompanied by interstitial fibrosis in the surrounding atrophic tubules. Karyomegaly is not limited to the kidneys. In one case, autopsy revealed karyomegaly in epithelial and mesenchymal cells of many other organs. However, no association of karyomegaly with further histologic damage is evident except in the kidneys. Because of the familial clustering, karyomegalic interstitial nephritis seems to be an inherited disease. Examination of the nuclear proliferation-associated structures proliferating cell nuclear antigen/cyclin, Ki 67, and p53 suggests an inhibition of mitosis in karyomegalic cells. The finding of the same HLA haplotype, A9/B35, in four of six HLA-typed cases suggests the possibility of a genetic defect on chromosome 6, which is inherited and linked to the HLA locus.     

Electrophysiological evidence for a postperceptual locus of suppression during the attentional blink

When an observer detects a target in a rapid stream of visual stimuli, there is a brief period of time during which the detection of subsequent targets is impaired. In this study, event-related potentials (ERPs) were recorded from normal adult observers to determine whether this "attentional blink" reflects a suppression of perceptual processes or an impairment in postperceptual processes. No suppression was observed during the attentional blink interval for ERP components corresponding to sensory processing (the P1 and N1 components) or semantic analysis (the N400 component). However, complete suppression was observed for an ERP component that has been hypothesized to reflect the updating of working memory (the P3 component). Results indicate that the attentional blink reflects an impairment in a postperceptual stage of processing.     

The Pain Beliefs and Perceptions Inventory: further evidence for a 4-factor structure

Clinical observations have suggested that cholestasis is associated with increased neurotransmission mediated by the opioid system in the central nervous system. As opiate agonists (e.g. morphine) mediate analgesia, increased opioidergic tone in cholestasis should be associated with a decreased response to pain. To test this hypothesis, the response of rats with acute cholestasis to a nociceptive stimulus was measured by the use of the tail-flick test, an extensively validated assay for measuring opiate-induced antinociception. Five and 7 days after bile-duct resection, the mean tail-flick latency was longer than before surgery (p < 0.05), whereas the corresponding means for unoperated and sham-resected controls were not significantly different from their respective baseline values. The increase in the mean tail-flick latency in the bile-duct resection group was reversed by (-)-naloxone (1 mg/kg subcutaneously), but not by its enantiomer (+)-naloxone (10 mg/kg subcutaneously) (p < 0.001). The stereoselective reversal of antinociception in cholestasis by naloxone indicates that this phenomenon is opioid-receptor mediated. In contrast, prolongation of the mean TFL found in the rat model of thioacetamide-induced acute hepatocellular necrosis was not reversed by (-)-naloxone, indicating that antinociception in this model is not opioid mediated. These findings provide support for the hypothesis that cholestasis is associated with increased opioidergic tone.     

Lexical and conceptual processing in Chinese-English bilinguals: further evidence for asymmetry

According to the asymmetry model of bilingual representation (Kroll & Stewart, 1994), the first language (L1) lexicon is closely tied to an underlying conceptual memory, whereas second language (L2) items are mostly associated with their L1 equivalents. An outcome of this architecture is that L1-to-L2, or forward, translation must be mediated by the conceptual memory, whereas L2-to-L1 (backward) translation takes a direct lexical path. Some predictions derived from this hypothetical structure were tested in the present study, which took into account, through analysis of covariance, variations in response production time, concept retrieval time, and some other characteristics associated with the individual test items. Proficient Chinese-English bilinguals were tested on delayed production (Balota & Chumbley, 1985), picture naming, word translation, and category matching. The expected asymmetrical pattern of translation latencies (i.e., forward > backward) was demonstrated, although it could be statistically explained by the item characteristic of familiarity; matching an L1 item to a category name was faster than matching an L2 item, suggesting relatively strong L1 conceptual links. The present results are best accommodated by a form of asymmetry that allows for nondominant L2-concept linkage, the use of which is conditional upon the familiarity of the test item to the bilingual.     

Well-being affects changes in perceptual speed in advanced old age: Longitudinal evidence for a dynamic link.

This study examined competing hypotheses about dynamic cross-domain associations between perceptual speed and well-being in advanced old age. We applied the bivariate dual change score model (J. J. McArdle & F. Hamagami, 2001) to 13-year incomplete longitudinal data from the Berlin Aging Study (P. B. Baltes & K. U. Mayer, 1999; N = 516, 70-103 years at T1, M = 85 years). Reports of well-being were found to influence subsequent decline in perceptual speed (time lags of 2 years). No evidence was found for a directed effect in the other direction. None of the potential covariates examined (initial health constraints, personality, and social participation) accounted for these differential lead-lag associations. Our results suggest that well-being is not only a consequence of but also a source for successful aging. The discussion focuses on conceptual implications and methodological considerations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feeling-of-knowing in fact retrieval: further evidence for preservation in early Alzheimer's disease

The ability to retrieve and monitor factual information varying in datedness (i.e., dated vs. contemporary) was examined in healthy older adults and patients in an early phase of Alzheimer's disease (AD). Subjects were given free recall and multiple-choice recognition tests of 48 general knowledge questions. For all questions not responded to in recall, subjects made feeling-of-knowing (FOK) judgments. Results indicated dementia-related deficits in both recall and recognition, although both groups showed better recall and recognition with the dated compared with the contemporary questions. Importantly, despite deficits in fact retrieval, the AD patients showed intact monitoring of stored knowledge, as indicated by equivalent FOK accuracy for both groups. In addition, FOK accuracy was similar for the dated and the contemporary information in both groups, suggesting independence between level of general knowledge and the ability to supervise information stored in memory.     

Epstein-Barr virus and Hodgkin's disease: further evidence for the three disease hypothesis

The epidemiology of Hodgkin's disease suggests that it is a heterogeneous condition comprising more than one disease entity. The Epstein-Barr virus (EBV) is present in the Reed-Sternberg cells of a proportion of cases and is likely to play a role in the pathogenesis of these cases. In this study we show that EBV association rates vary with age at diagnosis. We suggest that Hodgkin's disease can be divided into three disease entities on the basis of EBV association and age, thereby providing biological support for the multiple aetiology hypothesis proposed by MacMahon (Cancer Res 1966; 26: 1189-1290).     

On the relationship between recognition familiarity and perceptual fluency: evidence for distinct mnemonic processes

Fluent reprocessing of perceptual aspects of recently experienced stimuli is thought to support repetition priming effects on implicit perceptual memory tests. Although behavioral and neuropsychological dissociations demonstrate that separable mnemonic processes and neural substrates mediate implicit and explicit test performance, dual-process theories of memory posit that explicit recognition memory judgments may be based on familiarity derived from the same perceptual fluency that yields perceptual priming. Here we consider the relationship between familiarity-based recognition memory and implicit perceptual memory. A select review of the literature demonstrates that the fluency supporting implicit perceptual memory is functionally and anatomically distinct from that supporting recognition memory. In contrast to perceptual fluency, recognition familiarity is more sensitive to conceptual than to perceptual processing, and does not depend on modality-specific sensory cortices. Alternative possible relationships between familiarity in explicit memory and fluency in implicit memory are discussed.     

Judgmental overshadowing: further evidence of cue interaction in contingency judgment

We investigated a phenomenon called judgmental overshadowing. Subjects predicted whether each of several patients had a disease on the basis of whether or not the patient had each of two symptoms. For all the subjects, the presence of the disease was moderately contingent on the presence of one of the symptoms (S1). In Condition 1 of our first experiment, the presence of the disease was highly contingent on the presence of the other symptom (S2). In Condition 2, the presence of the disease was independent of S2. Judgmental overshadowing occurred in that the S1-disease contingency was judged to be stronger in Condition 2 than in Condition 1. Subsequent experiments showed that judgmental overshadowing depends little on the form of the judgment, is not due to a response bias or contrast effect, and does not depend on subjects' actively diagnosing each patient. These results are consistent with, and are generally predicted by, an associative-learning model of contingency judgment.     

Direct evidence for suppression of recombination within two pericentric inversions in humans: a new sperm-FISH technique

The tuberculin reaction following the intradermal injection of PPD appears 48-72 hours after injection. The positivity is shown by an > 5 mm area of induration of the skin. Tuberculin reaction is an invaluable instrument of epidemiologic investigation. Clinically, the value of tuberculin test, though remarkable, is limited by the fact that its positivity is not necessarily a sign of active tuberculosis. The three control strategies of tuberculosis are: prompt identification and correct management of cases, vaccination, prophylaxis. The latter, that in most cases is performed with isoniazid (300 mg/daily for 12 months) is indicated in the following situations: subjects with > 5 mm tuberculin test; recent contacts with patients with infective tuberculosis; chest X-ray indicative for old fibrotic lesions, HIV infection; subjects with > 10 mm tuberculin test: HIV-negative drug-addicts; clinical conditions at high risk for tuberculosis (e.g. silicosis, hematologic malignancy, iatrogenic immunosuppression).     

Membrane properties and esterase activity of synovial lining cells: further evidence for a mononuclear phagocyte subpopulation

Recent work in our laboratory with mouse radiation chimeras suggests that the macrophage type of synovial lining cell is derived from bone marrow. Further evidence for including this cell type in he mononuclear phagocyte system is now presented. Rosette formation with IgG coated sheep red cells, immunofluorescent staining for surface Ia antigens, and nonspecific esterase staining all show the presence in the synovial lining of a subpopulation of cells carrying these markers. The proportion of such cells in the lining is very variable, as is the proportion of 'type A' cells recognised with the electron microscope.     

Progressive behavioral response to repeated d-amphetamine challenge: further evidence for sensitization in humans

BACKGROUND: Behavioral sensitization is the process whereby intermittent stimulant exposure produces a time-dependent, enduring, and progressive behavioral response. Although animal models of sensitization are well established, the phenomenon has been relatively little studied in humans. In a previous study, we reported enhanced responses following a second as compared to a first amphetamine dose in eye-blink rate and ratings of increased motor activity/energy, increased speech, and elevated mood in normal human volunteers. This current study extends those findings in a new sample of normal volunteers. METHODS: Eleven normal human volunteers were administered three single oral doses of d-amphetamine (0.25 mg/kg) at 48-hour intervals, alternating with matched placebo in a randomized, double-blind trial. Hourly behavioral ratings included eye-blink rate, symptoms (elevated mood, increased speech, increased motor activity/energy), and subjective drug effects. RESULTS: Eye-blink rate and increased motor activity/energy ratings progressively increased following each challenge with the third amphetamine dose response significantly greater than all other conditions 4 hours postadministration. Similar, although less pronounced, responses were observed for elevated mood and subjective drug effect. CONCLUSIONS: These results provide further evidence for sensitization of some amphetamine-induced behaviors in human subjects.     

TWIST gene mutation in a patient with radial aplasia and craniosynostosis: further evidence for heterogeneity of Baller-Gerold syndrome

BACKGROUND: The optimal management of high-grade dysplasia in patients with Barrett's esophagus is controversial. The aim of this study was to assess the prevalence of unsuspected carcinoma at esophagectomy in patients with Barrett's esophagus with high-grade dysplasia after endoscopic surveillance with jumbo biopsy forceps compared with standard biopsy forceps. METHODS: Twelve patients with high-grade dysplasia in Barrett's esophagus without gross or microscopic evidence of carcinoma underwent esophagectomy after preoperative endoscopy with 4-quadrant jumbo biopsies at 2-cm intervals. The findings in this group were compared with those in a group of patients with Barrett's esophagus who underwent esophagectomy for high-grade dysplasia after biopsies obtained at 2-cm intervals with standard biopsy forceps. RESULTS: Unsuspected cancer was found in 4 of 12 (33%) patients in the jumbo biopsy group compared with 6 of 16 (38%) in the standard biopsy group (p = NS). All 6 cancers in the standard biopsy group were intramucosal, whereas 2 were intramucosal and 2 were submucosal in the jumbo biopsy group. No patients in either group had lymph node metastases. CONCLUSIONS: Unsuspected cancer is found frequently in patients with Barrett's esophagus who are undergoing esophagectomy for high-grade dysplasia despite the use of a rigorous jumbo biopsy protocol. Esophageal resection is still indicated in appropriately selected patients with high-grade dysplasia until better markers of cancer risk are available.     

Squamous cell carcinomas after allogeneic bone marrow transplantation for aplastic anemia: further evidence of a multistep process

Two new potent serine protease inhibitors, cyclotheonamides E2 (3) and E3 (4), have been isolated from a marine sponge of the genus Theonella. Their structures were determined by interpretation of spectral data and chemical degradation studies. They are closely related to the previously reported cyclotheonamide E, from which they differ in the N-acyl group of the alanyl side chain. Cyclotheonamides E, E2, and E3 were more active against thrombin than against trypsin.     

Camera perspective bias in videotaped confessions: Experimental evidence of its perceptual basis.

The camera perspective from which a criminal confession is videotaped influences later assessments of its voluntariness and the suspect's guilt. Previous research has suggested that this camera perspective bias is rooted in perceptual rather than conceptual processes, but these data are strictly correlational. In 3 experiments, the authors directly manipulated perceptual processing to provide stronger evidence of its mediational role. Prior to viewing a videotape of a simulated confession, participants were shown a photograph of the confessor's apparent victim. Participants in a perceptual interference condition were instructed to visualize the image of the victim in their minds while viewing the videotape; participants in a conceptual interference condition were instructed instead to rehearse an 8-digit number. Because mental imagery and actual perception draw on the same available resources, the authors anticipated that the former, but not the latter, interference task would disrupt the camera perspective bias, if indeed it were perceptually mediated. Results supported this conclusion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alveolar soft-part sarcoma: further evidence by FISH for the involvement of chromosome band 17q25

BACKGROUND/PURPOSE: Down's syndrome is a common association in patients with anorectal malformations. The purpose of this study was to determine whether the anorectal defect in patients with Down's syndrome had specific characteristics and whether the presence of Down's syndrome represented a serious detriment to the patient's functional prognosis. METHODS: Nine hundred eighty-seven patients with anorectal malformations were studied retrospectively. Twenty patients (2%) had Down's syndrome. Nineteen of these (95%) had the same specific type of anorectal defect: imperforate anus with no fistula. This defect has a good prognosis, the rectum is located about 2 cm above the perineal skin, the sacrum is normal, and the sphincter mechanism is good. For comparison, a group of 34 patients with the same defect but without Down's syndrome was also studied. All patients were operated on via posterior sagittal approach by the same surgeon. RESULTS: Imperforate anus without fistula occurs in 5% of all patients with anorectal malformations and in 95% of those patients who also suffer from Down's syndrome. The characteristics of the defect were the same in both groups of patients, and surprisingly, the prognosis was good in both groups (80% to 96% of patients had voluntary bowel movement, 100% had urinary continence). CONCLUSIONS: The association of Down's syndrome with imperforate anus without fistula is not coincidental. This particular benign defect can be predicted to occur in most patients with Down's syndrome. The presence of Down's syndrome in cases of anorectal malformations should not be a contraindication to repairing the imperforate anus and to closing the colostomy.