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PubMed2000

Genetic analysis of lifespan in hybrid progeny derived from the SAMP1 mouse strain with accelerated senescence.

The SAMP1 mouse, a senescence-accelerated mouse prone (SAMP) strain, shows accelerated senescence coupled with a short lifespan as a genetic trait, and has been used in gerontological research. The accelerated senescence and short lifespan of SAMP strains is considered to be under the control of multiple genes. To identify the chromosomal regions encompassing the genes for the accelerated senescence and short lifespan, we performed whole genome scanning with polymorphic marker loci in a progeny from a cross between the SAMP1 strain and normal B10.BR strain. A genetically recessive effect of the amyloidogenic Apoa2(c) allele from SAMP1 on chromosome 1 to shorten the lifespan was demonstrated in the progeny, consistent with the previous report. The recessive effect was observed also at D1Mit67, D5Mit267, D6Mit384 and D19Mit33, suggesting the presence of genes for accelerated senescence in the SAMP strains around these loci. Other markers on chromosomes 8, 14, 16, and 17, however, exhibited a dominant or additive effect to shorten or prolong the lifespan, demonstrating a complex genetic control of the trait.

Aging↗

PubMed2002

A higher oxidative status accelerates senescence and aggravates age-dependent disorders in SAMP strains of mice.

The SAM strain of mice is actually a group of related inbred strains consisting of series of SAMP (accelerated senescence-prone, short-lived) and SAMR (accelerated senescence-resistant, longer-lived) strains. Comparing with the SAMR strains, the SAMP strains of mice show a more accelerated senescence process, shorter lifespan, and an earlier onset and more rapid progress of age-associated pathological phenotypes similar to several geriatric disorders observed in humans, including senile osteoporosis, degenerative joint disease, age-related deficits in learning and memory, olfactory bulb and forebrain atrophy, presbycusis and retinal atrophy, senile amyloidosis, immunosenescence, senile lungs, and diffuse medial thickening of the aorta. The higher oxidative stress observed in the SAMP strains of mice are partly caused by mitochondrial dysfunction, and may be one cause of the senescence acceleration and age-dependent alterations in cell structure and function, including neuronal cell degeneration. This senescence acceleration is also observed during senescence/crisis in cultures of isolated fibroblast-like cells from SAMP strains of mice, and was associated with a hyperoxidative status. These observations suggest that the SAM strains are useful tools in the attempt to understand the mechanisms of age-dependent degeneration of cells and tissues, and their aggravation, and to develop clinical interventions.

Aging↗

PubMed2006

Hyperfractionated or accelerated radiotherapy in head and neck cancer: a meta-analysis.

BACKGROUND: Several trials have studied the role of unconventional fractionated radiotherapy in head and neck squamous cell carcinoma, but the effect of such treatment on survival is not clear. The aim of this meta-analysis was to assess whether this type of radiotherapy could improve survival. METHODS: Randomised trials comparing conventional radiotherapy with hyperfractionated or accelerated radiotherapy, or both, in patients with non-metastatic HNSCC were identified and updated individual patient data were obtained. Overall survival was the main endpoint. Trials were grouped in three pre-specified categories: hyperfractionated, accelerated, and accelerated with total dose reduction. FINDINGS: 15 trials with 6515 patients were included. The median follow-up was 6 years. Tumours sites were mostly oropharynx and larynx; 5221 (74%) patients had stage III-IV disease (International Union Against Cancer, 1987). There was a significant survival benefit with altered fractionated radiotherapy, corresponding to an absolute benefit of 3.4% at 5 years (hazard ratio 0.92, 95% CI 0.86-0.97; p=0.003). The benefit was significantly higher with hyperfractionated radiotherapy (8% at 5 years) than with accelerated radiotherapy (2% with accelerated fractionation without total dose reduction and 1.7% with total dose reduction at 5 years, p=0.02). There was a benefit on locoregional control in favour of altered fractionation versus conventional radiotherapy (6.4% at 5 years; p<0.0001), which was particularly efficient in reducing local failure, whereas the benefit on nodal control was less pronounced. The benefit was significantly higher in the youngest patients (hazard ratio 0.78 [0.65-0.94] for under 50 year olds, 0.95 [0.83-1.09] for 51-60 year olds, 0.92 [0.81-1.06] for 61-70 year olds, and 1.08 [0.89-1.30] for over 70 year olds; test for trends p=0.007). INTERPRETATION: Altered fractionated radiotherapy improves survival in patients with head and neck squamous cell carcinoma. Comparison of the different types of altered radiotherapy suggests that hyperfractionation has the greatest benefit.

Aged↗

PubMed2001

Interlaboratory reproducibility of standard accelerated aging methods for oxidation of UHMWPE.

During accelerating aging, experimental uncertainty may arise due to variability in the oxidation process, or due to limitations in the technique that is ultimately used to measure oxidation. The purpose of the present interlaboratory study was to quantify the repeatability and reproducibility of standard accelerated aging methods for ultra-high molecular weight polyethylene (UHMWPE). Sections (200 microm thick) were microtomed from the center of an extruded rod of GUR 4150 HP, gamma irradiated in air or nitrogen, and circulated to 12 institutions in the United States and Europe for characterization of oxidation before and after accelerated aging. Specimens were aged for 3 weeks at 80 degrees C in an air circulating oven or for 2 weeks at 70 degrees C in an oxygen bomb (maintained at 503 kPa (5 atm.) of O2) in accordance with the two standard protocols described in ASTM F 2003-00. FTIR spectra were collected from each specimen within 24 h of the start and finish of accelerated aging, and oxidation indices were calculated by normalizing the peak area of the carbonyl region by the reference peak areas at 1370 or 2022 cm(-1). The mean relative interlaboratory uncertainty of the oxidation data was 78.5% after oven aging and 129.1% after bomb aging. The oxidation index measurement technique was not found to be a significant factor in the reproducibility. Comparable relative intrainstitutional uncertainty was observed after oven aging and bomb aging. For both aging methods, institutions successfully discriminated between air-irradiated and control specimens. However, the large interinstitutional variation suggests that absolute performance standards for the oxidation index of UHMWPE after accelerated aging may not be practical at the present time.

Biocompatible Materials↗

PubMed1999

Influence of packaging conditions on the properties of gamma-irradiated UHMWPE following accelerated ageing and shelf ageing.

The ageing behaviour of ultra-high molecular weight polyethylene (UHMWPE) has been studied following gamma irradiation (25 or 40 kGy) in air or in inert atmosphere (vacuum packed). Accelerated ageing procedures used elevated temperature (70 degrees C) and/or pressurised oxygen (5 bar). Shelf ageing for up to six months was also performed. The variation in polymer properties with depth into the polymer was determined using density measurements, infra-red spectroscopy and differential scanning calorimetry. Tensile properties of the irradiated polymer after accelerated ageing were also determined. Accelerated ageing in air for 20 days or pressurised oxygen for 4 days resulted in peaks in polymer density, crystallinity and degree of oxidation at the polymer surface. Accelerated ageing in pressurised oxygen for 8 days resulted in peaks in these properties 500 microns below the polymer surface. Where gamma irradiation was performed in inert atmosphere the amount of polymer degradation following accelerated ageing (in oxidising conditions) was generally lower but still significant. Differences were also observed in tensile properties between material gamma-irradiated in air and in vacuum. This study indicated that performing gamma sterilisation procedures under inert conditions can reduce the level of UHMWPE degradation when exposed to an oxidising environment.

Biocompatible Materials↗

PubMed1992

Age-related changes in radial-arm maze learning and basal forebrain cholinergic systems in senescence accelerated mice (SAM).

Age-related changes in learning performance and the brain cholinergic system were studied in a senescence accelerated mice-prone series (SAM-P/8) and a senescence accelerated mice-resistant series (SAM-R/1, control) bred under specific pathogen-free conditions. In a radial-arm maze task, SAM-P/8 mice at 4 and 12 months of age showed virtually no significant impairment in working memory or reference memory compared with SAM-R/1 mice at the same age, although they needed more time to complete a trial than SAM-R/1. In contrast, in a passive avoidance task, SAM-P/8 showed a marked age-accelerated deficit in acquisition performance relative to SAM-R/1. Also, SAM-P/8 showed an age-accelerated decrease in locomotion and rearing in an open-field box. At the end of these behavioral tasks, neurochemical analyses showed that there were no differences in the concentrations of acetylcholine (ACh) in the cortex, hippocampus, striatum, midbrain, or cerebellum between SAM-P/8 and SAM-R/1. Although SAM-P/8 mice did not demonstrate any age-accelerated decline in radial-arm maze performance, they showed a normal age-related decline particularly in working memory, equal to that observed in SAM-R/1. Also, ACh levels in the aged groups of SAM-P/8 showed a significant decrease related to normal aging in the hippocampus and striatum, and a slight decrease in the cortex compared to the young group of the same strain. Thus, we found that SAM-P/8 show dissociative effects of aging in spatial learning and passive avoidance performance.

Aging↗

PubMedDate not supplied

Risk assessment of dithiocarbamate accelerator residues in latex-based medical devices: genotoxicity considerations.

The Medical Devices Agency (MDA) has investigated potential human health hazards arising from the presence of dithiocarbamate vulcanization accelerators in latex products (mainly gloves). After collection of manufacturer's data on usage and residues of these accelerators, an independent investigation of solvent extractable residues and dithiocarbamate migration into aqueous simulants was commissioned, to complement equivalent "in-house" test data from two major manufacturers. The presence of extractable accelerator residues in commercial products was confirmed. Potential human health hazards associated with dithiocarbamates include genotoxicity and possible carcinogenicity: a review of published data was conducted to evaluate the evidence for this, with particular reference to three zinc dithiocarbamates with significant commercial usage (ZDMC, ZDEC and ZDBC: see Fig. 1). Data gaps were identified, and mutagenicity studies commissioned to fill these. These studies comprised tests both in vitro (bacterial and L5178Y cell gene mutation, cultured lymphocyte chromosome aberration) and in vivo (mouse bone marrow micronucleus, rat liver UDS). It is concluded that ZDMC must be considered a genotoxin (and thus a probable carcinogen): residues of this substance in latex medical devices should be minimized. ZDEC proved genotoxic in vitro but was not clearly genotoxic in vivo, and may have activity intermediate between that of ZDMC and that of ZDBC, which showed at most weak activity in a single in vitro (chromosome aberration) test. It is proposed that the use of ZDBC as a vulcanization accelerator in the manufacture of latex gloves, rather than ZDEC, ZDMC or their precursors, would reduce or remove the health concerns arising from accelerator residues.

Animals↗

PubMed1996

Accelerated radiation therapy for locally advanced squamous cell carcinomas of the oral cavity and oropharynx selected according to tumor cell kinetics--a phase II multicenter study.

PURPOSE: A Phase II multicenter trial testing an accelerated regimen of radiotherapy in locally advanced and inoperable cancers of the head and neck, in patients selected on the basis of 5-bromo-2-deoxyuridine/DNA flow cytometry-derived tumor potential doubling time (Tpot). METHODS AND MATERIALS: From September 1992 to September 1993, 23 patients consecutively diagnosed to have locally advanced, inoperable carcinomas of the oral cavity and the oropharynx, with Tpot of < or = 5 days, received an accelerated radiotherapy regimen (AF) based on a modification of the concomitant boost technique: 2 Gy/fraction once a day, delivered 5 days a week up to 26 Gy, followed by 2 Gy/fraction twice a day, with a 6-h interval, one of the two fractions being delivered as a concomitant boost to reduced fields, up to 66 Gy total dose (off-cord reduction at 46 Gy), shortening the overall treatment time to 4.5 weeks. A contemporary control group of 46 patients with Tpot of >5 days or unknown was treated with conventional fractionation (CF): 2 Gy/fraction once a day, 5 days a week, up to 66 Gy in 6.5 weeks, with fields shrinkage after 46 Gy. RESULTS: All patients completed the accelerated regimen according to protocol and in the prescribed overall treatment time. Immediate tolerance was fairly good: 65% of the patients in the AF group experienced Grade 3 mucositis vs. 45% in the CF group (p = n.s.). Symptoms related to mucosal reactions seemed to persist longer in AF than in CF patients. The crude proportion of mild (Grades 1 and 2) late effects on skin (p < 0.01) and salivary glands (p < 0.05) was higher in AF than in CF patients, although these reactions did not exceed the limits of tolerance. Three patients in the AF and 1 in the CF arm experienced a late Grade 4 bone complication. Actuarial estimates of severe (Grades 3 and 4) late complications showed a 2-year hazard of 33.3% in the AF arm and 49.7% in CF (p = NS). The actuarial 2-year local control rate of the AF patients was 49.4%, while actuarial 2-year overall survival for the same patients was 43.5%. CONCLUSION: The results suggested that this accelerated regimen is worth testing in a controlled randomized trial to compare different accelerated schedules. Our findings also confirmed the 5-bromo-2-deoxyuridine/DNA flow cytometry technique as a suitable method of evaluating tumor cell kinetics in multicenter clinical studies, on condition that all measurements are carried out by one most experienced laboratory.

Adult↗

PubMedDate not supplied

Genetic characterization of senescence-accelerated mouse (SAM).

The Senescence-Accelerated Mouse (SAM) strains are unique and appropriate models for genetic studies on aging because the SAMP strains have an "accelerated senescence" phenotype for which the SAMR strains are controls, and each SAMP strain has a strain-specific age-associated disorder. Furthermore, because they have gone through sufficient generations of sister-brother mating, they can be considered inbred strains, which can be analyzed genetically. There are now 11 SAMP strains and 3 SAMR strains descended from the progenitor litters. Analysis with the Gompertz function shows that the SAMP strains have the same initial mortality rate (IMR) as the SAMR strains but a shorter mortality rate doubling time (MRDT), presumably due to genes that accelerated the rate of senescence in the SAMP strains. This accelerated senescence may also occur in cultured fibroblast-like cells. We performed molecular genetic characterization of all the SAM strains to acquire a base of genetic information from which we could develop hypotheses on the mechanism of development of SAM strains and genetic factors that contribute to accelerated senescence.

Aging↗

PubMedDate not supplied

Characteristics of age-related behavioral changes in senescence-accelerated mouse SAMP8 and SAMP10.

Senescence-Accelerated Mouse (SAM), a murine model of accelerated senescence, has been established by Takeda et al. (1981). SAM consists of senescence-accelerated-prone mouse (SAMP) and senescence-accelerated-resistant mouse (SAMR), the latter of which shows normal aging characteristics. In 1991 there were eight different substrains in the P-series, which commonly exhibited accelerated aging with a shortened life span (Takeda et al., 1991). Among the P-series, we have found that SAMP8 mice show significant impairments in a variety of learning tasks when compared with SAMR1 mice (Miyamoto et al., 1986). Further studies suggest that SAMP8 exhibits an age-related emotional disorder characterized by reduced anxiety-like behavior (Miyamoto et al., 1992). On the other hand, it has been shown that SAMP10 exhibits brain atrophy and learning impairments in an avoidance task (Shimada et al., 1992, 1993). Here, characteristics of age-related deficits in learning and memory, changes in emotional behavior, and abnormality of circadian rhythms in SAMP8 and SAMP10 mice are described. In the experiments, SAMP8/Ta (SAMP8), SAMP10/(/)Ta (SAMP10) and SAMR1TA (SAMR1) reared under specific pathogen-free conditions at Takeda Chemical Industries were used.

Aging↗

PubMed2002

Accelerated dissolution testing for improved quality assurance.

In pharmaceutical production of controlled release tablets and capsules, a rapid and automated at-line dissolution test for quality assurance of semi-products is advantageous. For effective control of the production, the analysis should not take more than about an hour, without loss of correlation to the ordinary (USP) dissolution test of the final product. For almost a decade, the ACDRA apparatus (ACcelerated Dissolution Rate Analysis) have been used for this purpose at AstraZeneca Tablet Production Sweden (TPS). In this paper, we give examples on different ways to accelerate the dissolution process. We use the USP dissolution calibrator tablets of salicylic acid (non-disintegrating type) to illustrate the strategy. We investigate the accelerated dissolution of the dissolution calibrator tablets, and show how it can be correlated with the dissolution in the ordinary USP-II equipment. The dissolution process was accelerated by variation of temperature, solvent and stirring. For example, we show that by increasing the temperature to 70 degrees C, changing the solvent to water, and increasing the stirring, it is possible to accelerate the dissolution by a factor of 5, without any loss of correlation to the dissolution process in the ordinary test.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1995

The role of NK cell activity in the pathogenesis of poly I:C accelerated and spontaneous diabetes in the diabetes prone BB rat.

The development of insulin dependent diabetes mellitus (IDDM) and diabetes in the diabetes prone (DP) BB rat animal model of IDDM is thought to be due to an autoimmune process. Natural killer (NK) cells have been implicated but not proven to play a pathogenetic role in BB rats due to the increased NK cell number and activity found in these animals. We have recently reported that poly I:C, an inducer of cytokines and a potent enhancer of NK cell function, accelerates the development of diabetes in DP BB rats and induces diabetes in diabetes resistant (DR) BB rats. Since we have further demonstrated that poly I:C administration to BB rats increases NK cell number and levels of inducers of NK cell activity, interferon-alpha and IL-6 which is described therein, we tested the hypothesis that NK cell activity plays an important role in poly I:C accelerated disease. The role of NK cells in poly I:C accelerated diabetes and spontaneous diabetes was examined by determining whether selective depletion of NK cells using a rat NK cell specific antibody (anti-NKR-P1 antibody) alters the development of diabetes. The treatment of BB rats with anti-NKR-P1 antibody resulted in a significantly lower mean NK cell activity of splenic mononuclear cells than that found in control animals. However, the development of diabetes and degree of insulitis was not significantly different between treatment groups. BB rats administered anti-NKR-P1 antibody with poly I:C had a lower mean splenocyte NK cell activity and lower mean NK cell number within the peripheral blood and inflamed islets than rats administered poly I:C alone. However, anti-NKR-P1 antibody administration did not alter the accelerated development of diabetes or the degree of insulitis in poly I:C treated animals. These data document that NK cells do not play a major role in the pathogenesis of poly I:C accelerated diabetes or spontaneous diabetes in the DP BB rat.

Animals↗

PubMed1998

Variations in tumour oxygen tension (pO2) during accelerated radiotherapy of head and neck carcinoma.

The study was performed to assess the effect of accelerated radiotherapy on oxygenation of primary tumours and metastatic nodes in patients with advanced head and neck tumours. In 14 patients with head and neck tumour, oxygen tension (pO2) was evaluated in normal tissues and tumours (primary tumour or metastatic neck node) before (0 Gy) and after 2 weeks (32 Gy) of accelerated radiotherapy (70 Gy in 3.5 weeks, with three daily fractions). Radiotherapy was combined with carbogen breathing in 5 patients. pO2 was measured using a polarographic technique. For pooled normal tissues, median pO2 was 38 mmHg before treatment and 46 mmHg after 2 weeks. For tumours, very low values (< 2 mmHg) represented 20% of the recorded values before treatment and 10% after 2 weeks. The relative increase in tumour oxygenation was more pronounced for primary tumours (median pO2 12 mmHg before treatment versus 26 mmHg after 2 weeks, P < 0.05) than for metastatic nodes (respectively, 20 and 27 mmHg P = 0.1). For the 5 patients who breathed carbogen during accelerated radiotherapy, the median pO2 was 44 mmHg at 2 weeks, compared with 13.5 mmHg before treatment (P = 0.05). Very low pO2 values, corresponding to tumour hypoxia, were found in the tumours (primary and metastatic neck nodes) prior to accelerated treatment. During the first 2 weeks of accelerated treatment, an increase in median pO2 was found in nine of the 14 tumours, together with a decrease in the frequency of very low values.

Aged↗

PubMed2006

Heparin accelerates gelsolin amyloidogenesis.

The chemical environment of the extracellular matrix may influence the tissue-selective deposition observed there in gelsolin amyloid disease. Previously, we have identified the proteases that generate the amyloidogenic fragments from the full-length gelsolin variants and demonstrated that heparin is capable of accelerating gelsolin amyloidogenesis. Herein, we identify the structural features of heparin that promote the 8 kDa disease-associated gelsolin fragments (residues 173-243) generated at the cell surface to form amyloid. In conjunction with electron microscopy analyses, our kinetic studies demonstrate that heparin efficiently accelerates the formation of gelsolin amyloid by enabling intermolecular beta-sheet formation. The use of heparin analogues reveals that sulfation is important in accelerating amyloidogenesis and that the extent of acceleration is proportional to the molecular weight of heparin. In addition, heparin accelerated aggregation at both early and late stages of amyloidogenesis. Dynamic light scattering coupled to size exclusion chromatography showed that heparin promotes the formation of soluble aggregates. Collectively, these data reveal that heparin templates fibril formation and affords solubility to the aggregating peptides through its sulfated structure. By extension, the biochemical results herein suggest that tissue-selective deposition characteristic of the gelsolin amyloidoses is likely influenced by the extracellular localization of distinct glycosaminoglycans.

Amyloid↗

PubMed2006

Effect of accelerated aging of MSWI bottom ash on the leaching mechanisms of copper and molybdenum.

The effect of accelerated aging of Municipal Solid Waste Incinerator (MSWI) bottom ash on the leaching of Cu and Mo was studied using a "multisurface" modeling approach, based on surface complexation to iron/aluminum (hydr)oxides, mineral dissolution/precipitation, and metal complexation by humic substances. A novel experimental method allowed us to identify that the solid/liquid partitioning of fulvic acids (FA) quantitatively explains the observed beneficial effect of accelerated aging on the leaching of Cu. Our results suggestthat iron/aluminum (hydr)oxides are the major reactive surfaces that retain fulvic acid in the bottom ash matrix, of which the aluminum (hydr)oxides were found to increase after aging. A new modeling approach, based on the surface complexation of FA on iron/aluminum (hydr)oxides is developed to describe the pH-dependent leaching of FA from MSWI bottom ash. Accelerated aging results in enhanced adsorption of FA to (neoformed) iron/aluminum (hydr)oxides, leading to a significant decrease in the leaching of FA and associated Cu. Accelerated aging was also found to reduce the leaching of Mo, which is also attributed to enhanced adsorption to (neoformed) iron/aluminum (hydr)oxides. These findings provide important new insights that may help to improve accelerated aging technology.

Adsorption↗

PubMed2002

Intestinal transit of fat depends on accelerating effect of cholecystokinin and slowing effect of an opioid pathway.

Fat has been described to both accelerate and slow intestinal transit. We hypothesized that the fat-induced jejunal brake depends on the combined accelerating effect of CCK and the slowing effect of an opioid pathway. Using a multifistulated model, intestinal transit was measured in four dogs, while 60 mM oleate was delivered into the proximal gut with either 0 or 6 mg naloxone, and 0.1 mg/kg devazepide (a peripheral CCK-A-receptor antagonist) administered intraluminally and intravenously, respectively. In a second study, intestinal transit was measured in seven dogs, while naloxone was delivered intraluminally at 0-, 3-, 6-, or 12-mg doses. Compared to the jejunal brake (marker recovery of 50.1 +/- 2.6%), intestinal transit was slowed by the CCK-A antagonist (36.4 +/- 8.3%; P < 0.05) and accelerated by naloxone (82.0 +/- 6.8%; P < 0.05). The accelerating effect of CCK occurred early in the transit response, while the dose-dependent effect (P < 0.05) of naloxone occurred later. We conclude that fat-induced jejunal brake depends on the early accelerating effect of CCK and the later slowing effect of a naloxone-sensitive opioid pathway.

Animals↗

PubMed2002

Induction of mania and cycle acceleration in bipolar disorder: effect of different classes of antidepressant.

OBJECTIVE: To assess the effect of different antidepressants on induction of mania and cycle acceleration, commonly accepted unwanted effects of antidepressant treatment for acute bipolar depression. There is, however, the suggestion that certain classes of antidepressants may be less likely than others to cause these unwanted effects. METHOD: We conducted a prospective, open, naturalistic, life charting study to assess the occurrence of onset of mania and cycle acceleration attributable to two antidepressant classes: selective serotonin reuptake inhibitors (SSRIs) and bupropion. RESULTS: No difference was found between the two drug classes for either antidepressant-induced mania or cycle acceleration. Antidepressant-induced mania was much more likely to occur in bipolar I rather than bipolar II patients. The overall occurrence of induction of mania and cycle acceleration was low across antidepressant classes. CONCLUSION: These findings suggest that there is probably no difference in the risk of antidepressant-induced mania or cycle acceleration across commonly used classes of antidepressants for the treatment of bipolar depression.

Adolescent↗

PubMed2003

Time-to-contact estimation of accelerated stimuli is based on first-order information.

The goal of this study was to test whether 1st-order information, which does not account for acceleration, is used (a) to estimate the time to contact (TTC) of an accelerated stimulus after the occlusion of a final part of its trajectory and (b) to indirectly intercept an accelerated stimulus with a thrown projectile. Both tasks require the production of an action on the basis of predictive information acquired before the arrival of the stimulus at the target and allow the experimenter to make quantitative predictions about the participants' use (or nonuse) of 1st-order information. The results show that participants do not use information about acceleration and that they commit errors that rely quantitatively on 1st-order information even when acceleration is psychophysically detectable. In the indirect interceptive task, action is planned about 200 ms before the initiation of the movement, at which time the 1st-order TTC attains a critical value.

Adult↗