Variations on a theme by chopin: relations between perception and production of timing in music

A note interonset interval (IOI) increment in mechanically timed music is more difficult to detect where expressive lengthening typically occurs in artistic performance. Experiment 1 showed this in an excerpt from a Chopin etude and extended the task to IOI decrement detection. A simple measure of variation in perceptual bias was derived that correlated highly with the average timing pattern of pianists' performances, more so than with acoustic surface properties of the music. Similar results, but decreasing correlations, were obtained in each of four subsequent experiments in which the music was simplified in stages. Although local psychoacoustic effects on time perception cannot be ruled out completely, the results suggest that musical structure (melodic-rhythmic grouping in particular) has temporal implications that are reflected not only in musicians' motor behavior but also in listeners' time-keeping abilities.     

Gross, histological and histomorphometric features of the navicular bone and related structures in the horse

Forelimb navicular bones and associated soft tissues were collected from 3 groups of horses and subjected to pathological examinations. The groups consisted of 38 horses with clinical navicular disease (ND) and 2 control groups, with no history of forelimb lameness, consisting of 25 age-matched mature horses (A-MC) and 9 immature horses (IC). Histological and histomorphometric studies were performed on tissue samples from 10 ND, 10 A-MC and 5 IC horses. Gross changes seen only in ND horses included: full thickness defects in the palmar surface fibrocartilage, palmar cortex erosion, medullary lysis, flexor digitorum profundus tendon (FDPT) surface fibrillation, FDPT core lesions and adhesions between the FDPT and navicular bone. Palmar surface partial thickness fibrocartilage loss and distal border fragmentation were seen with a significantly greater incidence in ND than in A-MC and not observed in IC. Remodelling of the proximal border, FDPT surface colouration, palmar surface fibrocartilage colouration and proximal border entheseous bone were identified in ND and A-MC but not in IC. Mid-ridge synovial fossae and horizontal depressions in the palmar surface were identified in all groups. Histologically palmar fibrocartilage thinning and loss were associated with reduced palmar fibrocartilage cell density and chondrocyte cluster formation. Palmar fibrocartilage fibrillation, palmar cortical bone defects, fibromyxoid stromal change in the medulla, medullary pseudocyst formation and entheseous new bone formation were all seen in ND. The adjacent FDPT showed fibrillation, tag formation and degeneration of the dorsal surface. Necrotic foci were also present within the body of the tendon. Although not always present, medullary bone pseudocysts, separate mineralised foci and most changes on the dorsal surface of the FDPT were specific to ND. Bone histomorphometric parameters were compared among groups. Cross-sectional area reduced from the sagittal ridge to the medial and lateral margins of each navicular bone. IC navicular bones had a smaller subchondral area, subchondral bone volume and a greater osteoid volume than in the AC, indicating that these differences were age-related. In ND the medullary area was decreased but the trabecular bone volume increased. The palmar subchondral area was increased but contained bone with an increased porosity and osteoid volume. Changes occurred from the medial to the lateral margins of the bone in horses with ND indicating remodelling of the bony elements throughout the bone in ND. The histological and histomorphometric changes in the navicular bone and palmar fibrocartilage were considered similar of those found in articular hyaline cartilage and subchondral bone in osteoarthritis.     

beta-Amyloid precursor protein fragments and lysosomal dense bodies are found in rat brain neurons after ventricular infusion of leupeptin

Infusion of the serine and thiol protease inhibitor, leupeptin, is known to cause a reduction of fast axoplasmic transport, and accumulation of lysosomal dense bodies in neuronal perikarya. We have found these dense bodies in hippocampal and cerebellar neurons contain ubiquitin conjugated proteins. We now demonstrate that these accumulated neuronal lysosomes are labeled by antisera to the cytoplasmic, transmembrane and extracellular domains of beta-amyloid precursor protein (APP) and also that lysosomal APP is fragmented. This in vivo model confirms that neurons can process APP via a lysosomal pathway and that neuronal lysosomes in vivo contain both N-terminal and potentially amyloidogenic C-terminal fragments of APP. We also show that increased APP immunoreactivity after leupeptin treatment is seen first in neurons and later in astrocytes. On recovery from infusion, APP N-terminal immunoreactivity diminishes whilst C-terminal reactivity remains in neurons. These findings are consistent with production in whole brain of potentially amyloidogenic fragments of APP within neuronal lysosomes in perikarya and dendrites implying that neurons may play a role in forming the beta-amyloid of plaques.     

Degenerative joint disease in poultry--differences in composition and morphology of articular cartilage are associated with strain susceptibility

The importance of recovery following pulsed and continuous exposure was determined by measuring the acute toxicity of two organophosphorus (parathion and malathion) and four carbamate (aldicarb, carbaryl, carbofuran and propoxur) insecticides. Two 1-h pulses caused significantly fewer symptoms of intoxication than 2 h of continuous exposure if at least 2 to 6 h in clean water were provided between doses for the four carbamates. Two 1-h pulses were equally toxic as a single 2-h continuous exposure for the two organophosphorus insecticides. Acetylcholinesterase activity in midges given two 1-h pulses of carbaryl separated by 24 h in clean water showed reactivation to control levels between the two exposures. These results contribute to the belief that episodic exposure to insecticides is less toxic if recovery in clean water is provided.     

Metallic stents in malignant biliary obstruction: prospective long-term clinical results

OBJECTIVE: The purpose of this prospective study was to evaluate the long-term clinical efficacy of metallic stents when used as the initial palliative treatment of patients with inoperable malignant biliary obstruction. SUBJECTS AND METHODS: From August 1991 through May 1995, 100 consecutive patients with malignant biliary obstruction were treated with percutaneous placement of metallic stents. The causes of obstruction were bile duct carcinoma (n = 50), pancreatic carcinoma (n = 17), gallbladder carcinoma (n = 6), hepatocellular carcinoma (n = 2), and metastatic lymphadenopathy in the hepatoduodenal ligament (n = 25). We used 123 stents: 64 Gianturco Z stents, 39 Hanaro spiral stents, 16 Wallstents, two tantalum Strecker stents, one Endocoil stent, and one Memotherm nitinol stent. Every 3 months we followed up all patients except those who died. The average length of follow-up was 220 days (range, 4-1125 days). Patient survival and stent patency rates were estimated by life-table analysis. RESULTS: The median length of survival for the entire patient group was 246 days: 25-week and 50-week survival rates were 62% and 25%, respectively. We found no statistically significant difference in the median length of survival between patients with hilar obstruction (256 days) and patients with common bile duct (CBD) obstruction (227 days). Patients with bile duct carcinoma had longer median survival (269 days) than did patients with other conditions (197 days). The overall median length of patency for all stents was 360 days; the 25-week and 50-week patency rates were 81% and 53%, respectively. The stent patency rate at the median length of survival was 71%. The median length of stent patency in patients with hilar obstruction (617 days) was nearly double that of patients with CBD obstruction (324 days). However, the median length of stent patency in patients with bile duct carcinoma showed no statistically significant difference from the median length in patients with other disease. Four patients (4%) died within 1 month after stent placement. Twenty-one patients (21%) developed recurrent jaundice or cholangitis. In order of frequency, the causes of recurrent jaundice were tumor overgrowth, incrustation of bile sludge, duodenal obstruction due to tumor invasion, stent impaction into the bile duct wall, stent malposition, and tumor ingrowth. CONCLUSION: Metallic stents showed a favorable patency rate with regard to patient survival. In patients with hilar obstruction, the clinical efficacy of metallic stents was superior to that in patients with CBD obstruction. We believe that placement of metallic stents is the procedure of choice for palliation of malignant biliary obstruction.     

Budesonide and beclamethasone dipropionate inhalation powders. The effect on bone and collagen turnover in children

The objective of the study was to assess bone and collagen turnover in asthmatic children treated with dry powder budesonide from the Turbohaler and dry powder beclomethasone dipropionate from the Diskhaler in a dose of 800 micrograms/day. Thirteen prepubertal children with asthma were studied. The study was conducted as an open crossover study with two treatment periods and treatment free run-in and wash-out periods. All periods were of two weeks' duration. At day 14 in each period blood samples were taken for assessment of serum osteocalcin, the carboxyterminal propeptide of type I collagen (PICP), and the aminoterminal propeptide of type III collagen (PIIINP). At the same time urine was collected for assessment of creatinine corrected pyridinoline (uPYR/cr) and deoxypyridinoline (udPYR/cr) crosslinks. Results: Osteocalcin concentrations were not influenced by any of the treatments. During budesonide treatment PICP was reduced by 18% (p = 0.03), PIIINP by 24% (p = 0.0002), uPYR/cr by 16% (p = 0.03) and udPYR/cr by 21% (p = 0.12). During treatment with beclomethasone dipropionate PICP was reduced by 20% (p = 0.01), PIIINP by 36% (p = 0.0002), uPYR/cr by 18% (p = 0.004) and udPYR/cr by 13% (p = 0.02). The suppressive effect of beclomethasone dipropionate on PIIINP was more marked than that of budesonide (p = 0.001). It is concluded that treatment with dry powder budesonide and beclomethasone dipropionate 800 micrograms/day is associated with suppression of bone and collagen turnover. The suppression seems to be more marked during treatment with beclomethasone dipropionate. Long term effects and effects of lower doses of budesonide and beclomethasone dipropionate on bone and collagen markers needs further study.     

Spectral envelope and context effects in the tritone paradox

In previous studies of the 'tritone paradox' Deutsch has suggested that, when listeners are presented with pairs of octave-complex tones that are equal in average log frequency but differ in chroma by 6 semitones (a tritone), they perceive the direction of the chroma difference according to an individual pitch-class template. However, it has also been found that the perceived direction changes for many listeners when the spectral envelope of the tones is shifted along the frequency axis. Reanalysis of these data indicates a strong tendency to perceive the pitch class corresponding to the frequency on which the spectral envelope is centered as subjectively lowest. In experiment 1 this spectral-envelope effect was replicated with tone pairs presented in isolation, at the rate of one a day, which rules out artifacts of test format. In experiment 2, involving another context-free format, envelope center frequency was varied over a wide range and it was shown that some individuals are totally envelope dependent, whereas others rely more on pitch class, and yet others show mixed patterns. Experiment 3 demonstrated that listeners' judgments of tritone pairs can be swayed easily by preceding context. Finally, experiment 4 showed that strong envelope effects are also obtained with Deutsch's own tritone test (issued on CD). The subjective relative pitch height of octave-complex tones thus depends on several competing factors, only one of which is pitch class.     

Striatal dopamine-glutamate interactions reflected in substantia nigra reticulata firing

To gain insight into the role of striatal dopamine in basal ganglia functioning, dopaminergic drugs alone and in combination with the glutamate receptor agonist kainic acid were infused in the lateral striatum via a microdialysis probe, while single-unit recordings of substantia nigra reticulata neurons were made in chloral hydrate-anaesthetized rats. Striatal infusion of dopaminergic drugs did not significantly affect the firing rate of substantia nigra reticulata neurons, which was related to the low activity of striatal cells under basal conditions, illustrated by the lack of effect of striatal infusion of TTX on substantia nigra reticulata activity. Under glutamate-stimulated conditions, striatal infusion of d-amphetamine potentiated the inhibition of substantia nigra reticulata neurons induced by striatal kainic acid. Thus, under stimulated but not basal conditions, the modulatory role of dopamine in the striatum could be demonstrated. Dopamine potentiated the inhibitory effect of striatal kainic acid on the firing rate of the basal ganglia output neurons.     

Late capsular hematoma after breast reconstruction with polyurethane-covered implants

We report two patients who developed late hematomas after breast reconstruction with polyurethane-covered implants. Although the cause of these hematomas is not absolutely clear, they are believed to have been caused by the intense, highly vascular inflammatory response that polyurethane coating is known to elicit. The development of late hematoma has not been previously stressed in the literature as a late complication of polyurethane-covered breast implants.