Auditory perception of breaking and bouncing events: a case study in ecological acoustics.

The mechanical events of bouncing and breaking are acoustically specified by single versus multiple damped quasi-periodic pulse patterns, with an initial noise burst in the case of breaking. Subjects show high accuracy in categorizing natural tokens of bouncing and breaking glass as well as tokens constructed by adjusting only the temporal patterns of components, leaving their spectral properties constant. Differences in average spectral frequency are, therefore, not necessary for perceiving this contrast, though differences in spectral consistency over successive pulses may be important.

Perceiving affordances: visual guidance of stair climbing.

How do animals visually guide their activities in a cluttered environment? Gibson (1979) proposed that they perceive what environmental objects offer or afford for action. An analysis of affordances in terms of the dynamics of an animal-environment system is presented. Critical points, corresponding to phase transitions in behavior, and optimal points, corresponding to stable, preferred regions of minimum energy expenditure, emerge from variation in the animal-environment fit.

Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration.

Biopsy specimens were taken from intact areas of antral mucosa in 100 consecutive consenting patients presenting for gastroscopy. Spiral or curved bacilli were demonstrated in specimens from 58 patients. Bacilli cultured from 11 of these biopsies were gram-negative, flagellate, and microaerophilic and appeared to be a new species related to the genus Campylobacter.

Monitoring of somatosensory evoked responses during carotid endarterectomy.

During carotid endarterectomy (CEA), we monitored somatosensory evoked responses (SERs) ipsilaterally over the scalp following stimulation of the contralateral median nerve at the wrist. Thirty-eight CEAs in 36 patients were studied. Of the 10 CEAs performed with patients under general anesthesia, three involved marked changes in SERs, reversed by shunt insertion.

Cell differentiation in pancreatic cancer.

Cell differentiation in cancer of the exocrine pancreas is currently under intensive study. In this report, new developments are critically reviewed on the use of transplantable pancreatic carcinoma and the hybridoma technique to define cell membrane changes during pancreatic cancer growth. It is concluded that two categories of plasmalemma structure hold promise as differentiation markers specific for pancreatic cancer: (1) membrane receptors for cholinergic and peptide secretagogues and (2) membrane glycoproteins as detected by monoclonal antibodies.

Evoked response studies in patients with adrenoleukodystrophy and heterozygous relatives.

Brain-stem auditory evoked responses (BAERs) and somatosensory evoked responses (SERs) were studied in three patients and seven female relatives in three families with adrenoleukodystrophy (ALD). All patients with ALD had abnormal BAERs and SERs, reflecting the central demyelination occurring in ALD. Four of the seven female family members had abnormalities of SERs with or without abnormalities of BAERs, similar to those seen in the patients.

Tax policy and equipment leasing after TEFRA.

The Tax Equity and Fiscal Responsibility Act of 1982 substantially modified the "safe harbor" leasing provisions enacted by the Economic Recovery Tax Act of 1981. In this Comment, Professors Warren and Auerbach argue that the modifications did not remedy the defects they identified in an earlier Article and that a new category of "finance leases" may prove to be nearly as valuable for some taxpayers as were safe harbor leases before the 1982 changes.

Experiments with active phase matching of parallel-amplified Multiline HF laser beams by a phase-locked Mach-Zehnder interferometer.

Active phase matching of multiline HF laser beams by means of a phase-locked Mach-Zehnder interferometer was demonstrated by locking the interferometer to the central interference fringe at zero optical path length difference. The central fringe could be found by varying the spectral content of the input beam. Laser amplification in one leg of the interferometer decreased fringe visibility without adversely affecting locking.

Transformation of human erythrocyte shape by endotoxic lipopolysaccharide.

Human erythrocytes were observed to undergo a discocyte to echinocyte to spheroechinocyte shape transformation during brief incubation with endotoxic lipopolysaccharide. It was concluded that lipopolysaccharide-membrane interactions alter the curvature of erythrocyte membranes.

Phthalate esters as peroxisome proliferator carcinogens.

The phthalate ester di(2-ethylhexyl) phthalate is both a peroxisome proliferator and a hepatic carcinogen. Peroxisome proliferators as a class are hepatocarcinogenic in rodent species. However, none of the peroxisome proliferators tested to date including the phthalate esters and related alcohol and acid analogs have demonstrated mutagenic or DNA-damaging activity in the in vitro Salmonella typhimurium/microsomal or the lymphocyte 3H-thymidine assays.

Secretagogue response in rat pancreatic acinar carcinoma.

The secretion of protein, like cell proliferation, is an integrated response that reflects structural organization of the cell periphery. Stimulation of protein secretion was thus utilized for comparison of integrated responses of the cell periphery in pancreatic acinar carcinoma of the rat and integrated responses in normal rat pancreas. Results of this comparison include: a) The stimulation of protein secretion in acinar carcinoma fragments by carbamylcholine chloride and cholecystokinin octapeptide, pancreatic secretagogues that interact with specific plasma membrane receptors, was only a fraction (one-fifth to one-half) of that observed in normal pancreatic minilobules.

Concanavalin A binding and cytodifferentiation in pancreatic acinar carcinoma of rat.

The binding of concanavalin A to the plasmalemma of acinar carcinoma cells was characterized by electron microscopy utilizing horseradish peroxidase. Heavy labeling due to specific concanavalin A binding was detected on the plasmalemma of undifferentiated carcinoma cells lacking zymogen maturation, neoplastic cells of intermediate differentiation with only occasional zymogen granules, and highly differentiated acinar carcinoma cells containing numerous cytoplasmic zymogen granules. The plasmalemma of acinar carcinoma cells was also compared to the normal pancreatic acinar cell plasmalemma by measurement of specific 125I-labeled concanavalin A binding.

Carbamylcholine stimulation of protein secretion in pancreatic acinar carcinoma of rat.

Pancreatic acinar carcinoma fragments, pulse-chase labeled with [3H]-leucine, responded to carbamylcholine chloride by increased secretion of [3H]leucine-labeled protein into external buffer medium. Secretion of labeled protein by the carcinoma fragments increased in concentration-dependent fashion between 10(-8) -10(-5) M carbamylcholine, was completely inhibited at 4 degrees C, and was accompanied by an equivalent increase in the secretion of preformed amylase. A maximally effective carbamylcholine concentration of 10(-5) M was observed for both carcinoma fragments and normal pancreas lobules.

Polymyxin B suppresses the endotoxin inhibition of concanavalin a-mediated erythrocyte agglutination.

The lectin agglutinability of human erythrocytes has been utilized to examine interactions of gram-negative endotoxin with mammalian cell plasma membranes. Erythrocytes treated in buffer with Escherichia coli 0127:B8 lipopolysaccharide (LPS) or Salmonella minnesota Re595 glycolipid for 1 h became resistant to agglutination by the lectin concanavalin A (ConA) in buffer free of LPS or glycolipid. Polymyxin B, a cationic cyclic lipopeptide which specifically binds to the lipid A toxophore, was tested for possible effects on the LPS and glycolipid inhibition of Con A erythrocyte agglutination.

Visual perception of relative mass in dynamic events.

Two experiments are reported which examine how the dynamic property of relative mass in collision events is specified by kinematic properties of a visual motion display. In most cases observers are accurate at detecting the 'heavier' of two objects, although they do not take advantage of the completely general optic information that is available. Instead, they rely on limited information that breaks down at extreme values of elasticity and relative initial velocity.

Transplantable pancreatic acinar carcinoma.

Fragments of the nafenopin-induced pancreatic acinar cell carcinoma of rat have been examined in vitro for patterns of intracellular protein transport and carbamylcholine-induced protein discharge. Continuous incubation of the fragments with [3H]-leucine for 60 minutes resulted in labeling of rough endoplasmic reticulum, Golgi cisternae, and mature zymogen granules, revealed by electron microscope autoradiography. This result indicates transport of newly synthesized protein from the rough endoplasmic reticulum to mature zymogen granules in approximately 60 minutes.

Activity of carcinogens, carcinogen analogs, and metabolic inhibitors in the lymphocyte tritiated thymidine assay.

Inhibition of tritiated thymidine ([3H]dThd) incorporation into replicating DNA of concanavalin A (Con A)-stimulated C57BL/6J splenic lymphocytes has been further evaluated as an end point for rapid in vitro discrimination between carcinogenic and noncarcinogenic chemicals. Results of this evaluation include: a) Inhibition of [3H]dThd incorporation into DNA of Con A-stimulated cells clearly discriminated between known DNA-damaging chemical carcinogens (N-methyl-N-nitrosourea, 4-nitroquinoline 1-oxide, 4-(hydroxyamino)quinoline 1-oxide, benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene, and benz[a]anthracene) and non-DNA-damaging metabolic inhibitors of replication (dimethyl sulfoxide, ethanol, hydroxyurea, cycloheximide, potassium cyanide, and oligomycin). b) Inhibition of [3H]dThd incorporation also discriminated between carcinogens and noncarcinogens in the two pairs 4-nitroquinoline 1-oxide versus quinoline-N-oxide, and benzo[a]pyrene versus pyrene.

Kinetics of a carbamazepine-ethosuximide interaction.

Carbamazepine and ethosuximide are used together to treat epileptic mixed-seizure patterns. Since carbamazepine has been shown to induce drug-metabolizing enzyme(s) in the liver, it follows that carbamazepine may alter ethosuximide disposition. Six normal subjects took one 250-mg ethosuximide capsule twice each day for 55 consecutive doses (study days 1 to 28) and one 200-mg carbamazepine tablet each evening from study days 11 to 27.