On the dichotic pitch of simultaneously presented interaurally delayed white noises. Implications for binaural theory.

A dichotic pitch known as Fourcin Pitch (FP) is perceived when two independent interaurally delayed white noises are presented simultaneously. Experiments in the past mainly dealt with stimulus situations where one interaural delay was smaller than 4 ms and the other was in the range 0-10 ms. Here, experiments are reported showing a novel pitch percept that occurs when one noise is interaurally delayed at the left ear and the other noise is about equally delayed at the right ear, for delays in the range of 4-10 ms. It is shown that, for both the previously reported FP and the novel pitch, the Central Spectrum (CS) theory [Raatgever and Bilsen, J. Acoust. Soc. Am. 80, 429-441 (1986)] provides a correct prediction of both the pitch value and the lateral position of the pitch image, where other current theories partly or completely fail. Further experiments indicate that the lateralized position of the pitch image is essentially not influenced by an interaural intensity difference (IID). This is also predicted by the CS model and leads to the generalized conclusion that interaural time and intensity differences are processed separately in the auditory system until, at least, the level where the dichotic pitch is generated.

Physical characteristics and factors related to sexual development and behaviour and the risk for prostatic cancer.

A case-control study of prostatic cancer was carried out to examine the association between selected physical characteristics and factors related to sexual development and behaviour and the risk for this disease. In consideration of an endocrinologic mechanism for these putative risk factors, the association between selected factors and serum hormone level in a comparison group, free of prostate cancer, was also examined. One-hundred cases and 113 controls were included for study. An elevated risk for prostatic cancer was found for those currently married (odds ratio (OR) = 4.0), those who had been married once (OR = 2.8), and those who were currently practising a religion (OR = 2.0). Compared to subjects with one child, those with more than one child and those with no children were more common among cases than controls. Prostatic cancer risk was associated with large body size and, in particular, with greater weight (p < 0.01). Early age at attainment of adult height was also associated with prostatic cancer risk (p < 0.01). Only moderate associations were found between increased frequency of sexual intercourse and prostatic cancer risk. The levels of testosterone (T), dihydrotestosterone, salivary testosterone and T/SHBG (sex hormone binding globulin) did not vary with age. Older men had higher oestradiol levels. Further, little association between hormone levels and risk factors was found, except for married subjects having increased serum androgens (p < 0.05) and heavy subjects having decreased serum androgens (not significant).

Peripheral hormone levels in controls and patients with prostatic cancer or benign prostatic hyperplasia: results from the Dutch-Japanese case-control study.

The possible relationship between changes in peripheral hormone levels and the occurrence of prostatic pathology was studied in a case-control study, involving estimation of various plasma hormones in 368 Dutch and 258 Japanese men, who were grouped as controls and patients with benign prostatic hyperplasia, focal prostatic carcinoma, or clinically evident prostatic carcinoma. Results of a number of previous, smaller studies concerning interrelationships between hormone levels in elderly men were confirmed within the Dutch and Japanese groups. Plasma levels of testosterone and estradiol were significantly lower in the Japanese men, when compared with those in Dutch men. Probably as a result of this difference in testosterone levels, the ratio between serum levels of testosterone and sex hormone-binding globulin (SHBG) was decreased in the Japanese men, while the ratio between the concentrations of dihydrotestosterone and testosterone was increased. These differences were also found when results from Japanese subgroups (controls and patients with prostate pathology) were compared with those from the Dutch subgroups. There were no significant differences in plasma androgen levels between Japanese or Dutch prostate cancer cases and their respective control subgroups. These findings do not support a correlation between the lower plasma testosterone levels and a lower incidence of prostate cancer in the Japanese men. Furthermore, no significant differences were found between salivary levels of testosterone or the ratio between testosterone and SHBG in the various Dutch subgroups. In Japanese benign prostatic hyperplasia patients, the testosterone to SHBG ratio was significantly increased. In conclusion, the results of this retrospective, cross-sectional study do not indicate that hormonal levels play a primary role in the origin or promotion of prostatic abnormalities. The finding of a lower plasma testosterone in the Japanese men, however, remains suggestive, warranting a more extensive prospective study.

Relationship between airway obstruction, desaturation during exercise and nocturnal hypoxaemia in cystic fibrosis patients.

We measured pulmonary function, responses to exercise and oxygen saturation (So2) at rest, and also before and during sleep in 24 patients with cystic fibrosis in a varying degree of severity. The pulmonary function indices analysed were forced expiratory volume in one second (FEV1), total lung capacity (TLC), measured by body plethysmography (TLC box) and Helium dilution (TLC He), residual volume measured by body plethysmography (RV) and the amount of trapped air (TA = TLC box-TLC He). The exercise variables included symptom limited maximal oxygen uptake (Vo2max), maximum minute ventilation (VEmax) and So2, at rest in sitting position and during maximal exercise. So2 was measured by ear oximetry. The lowest mean So2 obtained in two consecutive nights over a period of 1 hour was taken as the indicator of nocturnal oxygen saturation. A high correlation existed between resting supine and sitting So2, and the degree of nocturnal hypoxaemia (0.84 and 0.76, respectively). Highly significant correlations existed also for the indices of airway obstruction, Vo2 max and lowest So2 at exercise versus the nocturnal lowest hourly mean So2. From all variables a resting So2 in the sitting position lower than 94% appeared to be most predictive of nocturnal desaturation and indicates a risk of nocturnal hypoxaemia in patients with cystic fibrosis.

Serum retinol and prostate cancer.

Levels of retinol, beta carotene, and alpha tocopherol were assayed by high performance liquid chromatography (HPLC) in serum from subjects with clinical prostatic cancer (n = 94), focal prostatic cancer (n = 40), benign prostatic hyperplasia (n = 130), and from hospital controls (n = 130). Levels of beta carotene and alpha tocopherol varied for prostatic cancer patients by disease stage and by the period in the treatment sequence when blood was collected. This made any assessment of their association with prostatic cancer risk difficult. The mean level of serum retinol was significantly lower (P less than 0.05) in prostatic cancer patients than in the controls. For serum retinol this difference did not appear to be attributable to age, stage of disease, period in which the blood was collected, or to several other potentially confounding factors. When the serum retinol level was considered in quintile classes, there was a statistically significant (P less than 0.05) trend of increased prostatic cancer risk associated with decreasing serum retinol levels.

Wood-related occupations, wood dust exposure, and sinonasal cancer.

A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

A central spectrum theory of binaural processing. Evidence from dichotic pitch.

A theory is presented that describes the binaural processing of interaural time or phase differences. It is an elaboration of the central spectrum concept for the explanation of dichotic pitch phenomena [F. A. Bilsen, "Pitch of noise signals: Evidence for a 'central spectrum'," J. Acoust. Soc. Am. 61, 150-161 (1977)]. The generation is postulated for central activity patterns (CAP) due to binaural interaction. From these CAPs the central processor selects specific spectral information that constitutes the information for lateralization, dichotic pitch, binaural masking, etc. Here, a strategy is assumed to be based on central spectra (CS) rather than on interaural cross correlation. For the calculation of the central activity patterns a number of assumptions have been introduced. The peripheral filters are supposed to be infinitesimally narrow. The analog filter outputs from corresponding filters at both ears are thought to interact by means of a linear delay-and-add mechanism. The squared output (power) of such a binaural (addition) network constitutes the CAP. The theory has been tested with lateralization and BMLD measurements using dichotic stimulus configurations characteristic of the perception of dichotic pitch. The predictions of the model concerning the pitch and the lateralization of the pitch images as well as the BMLD patterns for this kind of stimuli are confirmed.

A central spectrum theory of binaural processing. The binaural edge pitch revisited.

Recently, Klein and Hartmann [J. Acoust. Soc. Am. 70, 51-61 (1981)] investigated a new dichotic pitch, called the binaural edge pitch (BEP). They used computer-generated periodic noise signals to generate BEP. In the study presented here, the BEP is investigated in order to evaluate the predictions of the central spectrum theory with regard to this stimulus. Pitch-matching experiments using a nonperiodic BEP stimulus, produced by means of a modulation technique, led to the conclusion that the strongest pitch sensation in the BEP has the character of a weak fluctuating pure tones in noise, which corresponds to a frequency, equal or almost equal to the frequency of the phase transition. This result fits in with the predictions of the central spectrum theory, which, for instance, does not need the assumption of central lateral inhibition for explaining this pitch. Furthermore, it is shown that this theory can also predict the results obtained in lateralization measurements and BMLD measurements using BEP stimuli as well as related stimuli. The results are compared with the data obtained by Klein and Hartmann.

Cancer of the nasal cavity and paranasal sinuses, and formaldehyde exposure.

This case-control study of nasal and paranasal sinus tumors, in males diagnosed between 1978 and 1981 in the Netherlands, was designed to identify environmental risk factors. Special attention was given to assessing any association between nasal cancer and an occupational history of possible formaldehyde exposure while taking into account histologic type of tumor, history of tobacco use, and occupational exposure to wood dust. Of the 116 cases and 259 controls identified, interviews were completed for 91 (78%) of the cases and 195 (75%) of the controls. Adenocarcinoma was strongly associated with a history of high wood dust exposure (RR = 27.0). Two independent assessments of the association between possible formaldehyde exposure and the risk for nasal cancer were carried out (Assessments A and B). By Assessment A the relative risk for nasal cancer associated with possible formaldehyde exposure was 2.5 and by Assessment B it was 1.9. The risk appeared to be most strongly associated with squamous-cell carcinoma and could not be attributed to differences between cases and controls in age, smoking habits, or wood dust exposure. By its retrospective nature, the classification of formaldehyde exposure in this study is not based on known exposures to formaldehyde but on assessment of employment in jobs where formaldehyde exposure is thought possible. Given the limitations of the study, the authors do not consider that it provides conclusive evidence of a carcinogenic effect for formaldehyde, but that it indicates a need for further research--particularly into formaldehyde and squamous carcinoma of the nose.

Aflatoxin exposures in the industrial setting: an epidemiological study of mortality.

Mortality occurring between 1963 and 1980 in a small cohort (N = 71) of Dutch oil-press workers exposed between 1961 and 1969 to aflatoxins primarily via the respiratory route, was assessed and compared to that of a similar group of unexposed workers (N = 67). For the entire period of study, the observed mortalities for total-cancer and respiratory cancer were higher than expected in the aflatoxin-exposed group. Mortality observed in the comparison group was within the expected range. While two deaths in the exposed group were attributed to non-malignant liver disease, no primary liver tumours were observed. The greatest difference between observed and expected mortality was in the period between 1963 and 1968.

Quantitative analysis of the nuclear area variation in benign and malignant breast cytology specimens.

The diagnostic value of the nuclear size for discriminating between benign and malignant breast lesions was studied by karyometric analysis of the nuclear area in May-Grünwald-Giemsa-stained imprints from 173 benign and 103 malignant breast lesions. The mean nuclear area, the maximum nuclear area and the percentage of nuclei larger than 200 sq micrometer discriminated between about 60% of the breast carcinomas and 95% of the benign lesions. The coefficient of variation had considerably less discriminatory power and also showed the lowest correlation with the mean nuclear area. A weak negative correlation was found between the mean nuclear area and the age of the patients with benign lesions. Carcinomas with small nuclei (area less than 110 sq micrometer) were found more frequently in patients with negative lymph nodes than in patients with positive nodes. Additional parameters for nuclear shape and texture may lead to a further objectification of nuclear pleomorphism in breast cytology specimens.

Automated selection of metaphase cells by quality.

The performance of metaphase-finding systems could be improved if they were able to determine the quality of the cells detected. This paper discusses the extent to which this may be realized by the introduction of a metaphase-quality parameter. Data obtained from 300 cells were statistically analyzed. Seventeen features were measured and nine visual properties were determined for each cell. Discriminant analysis and regression analysis were used to extract those features and visual properties which contribute to assessment of metaphase quality. Rather low correlations were found between the selected measured features and visual properties. A quality-parameter based on a linear combination of cluster projections, areas and perimeters was found to account for 64% of the variation between visual and measured quality indicators. In addition, an increase in the predictive value for finding usable metaphases from 28-68% was achieved.