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S Hale

Publications and source records attributed to S Hale.

51 records · Page 3Linked to original sources
PubMed1989

Global increase in response latencies by early middle age: complexity effects in individual performances.

Ten young women (age 20 to 22 years) and 10 middle-aged women (age 36 to 44 years) served as subjects in choice reaction time, letter classification, and abstract matching-to-sample tasks. In each of seven conditions, the older group responded more slowly than the younger group. Age differences showed a complexity effect. That is, differences between the latencies of young and old subjects increased as the latency of the young subjects increased. Both linear and power functions accurately described the relation between the latencies of the middle-aged and young adult groups. This was true not only for the relation between average latencies but also for the relation between corresponding quartiles of latency distributions. Similar results were observed at the individual level: All middle-aged subjects showed complexity effects, and, for each middle-aged subject, the relation between her latencies and those of the average young adult was well described by linear and power functions. These findings indicate that age-related slowing is apparent by age 40, and that complexity effects are observable in individual performances. This slowing is global and not specific to particular tasks, as indicated by the fact that the latencies of older adults can be predicted directly from those of younger adults without regard to the nature of the task.

Adult↗
PubMed1989

Properties of isolated nonciliated bronchiolar cells from mouse lung.

Nonciliated bronchiolar cells (Clara cells) are thought to provide important respiratory secretions in the small airways and to have other metabolic functions. In mice, nonciliated bronchiolar cells have been the subject of special investigation because tumors of these cells can be specifically induced by chemical carcinogens. A method for isolating nonciliated bronchiolar cells from mice has been reported. However, we have developed a method to isolate these cells from the lungs of BDF1 mice with approximately 80% purity. Cells were identified by electron microscopy, nitroblue tetrazolium dye reduction in the presence of NADPH, immunocytochemical staining of cytochrome P450 isozymes, and mitochondrial staining with rhodamine 123. The isolated cells were examined in culture for synthesis and secretion of proteins and phospholipids. Protein synthesis and secretion were examined in cells labeled with [34S]methionine for 16 h. Fresh medium was added to washed cells and the cells were incubated for an additional 3h. The secreted proteins were precipitated with 10% trichloroacetic acid. Molecular weights of the most prominent radiolabeled secreted proteins were 6, 36, 43, and 45 kDa. Phospholipid synthesis and secretion were examined in cells labeled with [14C]acetate and 32P. Less than 1% of the radioactive lipids was found in the medium, and secretion of lipid was not stimulated by terbutaline or tetradecanoylphorbol acetate compounds, which stimulate phospholipid secretion by type II cells. These data support the hypothesis that nonciliated bronchiolar cells synthesize and secrete proteins but do not secrete phospholipids in any appreciable amount.

Animals↗
PubMed1988

Age, variability, and speed: between-subjects diversity.

Two independent data sets were selected to examine the interrelations among reaction time (RT), between-subject variability or diversity (SD), and age. In both data sets, a strong correlation between RT and SD was obtained. This strong correlation was not affected when age was controlled in a partial correlation analysis. On the other hand, a weaker but significant correlation was obtained between age and SD. This correlation was eliminated when RT was controlled in a partial correlation analysis. Our analyses of the two data sets also indicated that the relation between RT and SD is identical for both young and elderly groups. Thus, the greater diversity often observed in performances of older groups is a direct consequence of slowing, rather than an independent effect of advancing age.

Adolescent↗
PubMed1988

Choice in transition: A comparison of melioration and the kinetic model.

Transition-state choice behavior of pigeons was examined in two experiments designed to test predictions of melioration and the kinetic model. Both experiments began with an initial training condition during which subjects were maintained on concurrent variable-interval schedules. In Experiment 1, subjects were then exposed to concurrent variable-ratio schedules, whereas in Experiment 2, subjects were then exposed to concurrent extinction. Contrary to the predictions of melioration, but consistent with the kinetic model, acquisition of preference on concurrent variable-ratio schedules followed a negatively accelerated logistic trajectory, and preference remained stable in concurrent extinction. Predictions made by the kinetic model concerning rates of switching between alternatives were also supported.

Journal Article↗
PubMed1987

General slowing of nonverbal information processing: evidence for a power law.

Data were analyzed from studies of nonverbal information processing in which the dependent measure was the latency of pressing or releasing a response key. Positively-accelerated power functions described the relationship between the response latencies of groups of older (50 to 60 years and 65 to 75 years) and younger adults (20 to 25 years) with extreme precision (r2 = .99). The exponent of the best-fitting power function increased with the age of the older group. The form of the relationship is allometric, and is consistent with a model (Botwinick, 1984) in which response latency increases exponentially with task difficulty. The present findings suggest that this model holds across a wide variety of information-processing tasks and over a very broad range of latencies.

Adult↗
PubMed1985

Contrast echocardiographic estimation of regional myocardial blood flow after acute coronary occlusion.

Contrast echocardiography can predict pathologic area at risk during acute coronary occlusion. In this study we evaluated (1) whether the intensity and timing of contrast appearance in ischemic regions can provide a quantitative measure of residual myocardial perfusion, and (2) whether changes in these parameters observed after serial injections reflect changes in blood flow to acutely ischemic tissue. Supra-aortic hydrogen peroxide contrast echocardiography was performed in 12 consecutive dogs at 1, 20, and 120 min after acute circumflex coronary occlusion. Contrast enhancement was determined qualitatively with a segmental four-point scoring system based on the appearance time and peak perceived intensity of contrast enhancement and quantitatively with a computer algorithm designed to reflect these parameters. Comparison was made in each segment to concomitant radioactive microsphere blood flow. Qualitative scoring related systematically to normalized segmental blood flow (3+ = 93%; 2+ = 61%; 1+ = 32%; 0 = 18%; p less than .01 for each vs adjacent value), as did quantitative analysis including all segments (r = .78; p less than .01) and isolated to the ischemic region (flow = 1.13 intensity change +6.8%; r = .83, p less than .001). Changes in microsphere flow in ischemic regions between sequential observations were correlated with changes in qualitative score (r = .88, p less than .001) and results of quantitative analysis (r = 0.70, p less than .01). The amount of contrast enhancement can provide quantitative information about residual myocardial blood flow in ischemic regions and can also be used to track changing patterns of flow in vivo after acute coronary occlusion.

Animals↗
PubMed1984

Practical implications of the matching law.

Many problem situations in applied settings are best conceptualized as choice situations. In addition, applied behavior analysts create choice situations when they reinforce a competing response to decrease inappropriate behavior. When such situations are analyzed using the matching law, variable interval (VI) schedules of reinforcement prove to be a superior intervention strategy regardless of the nature of the schedule maintaining other, less appropriate behavior. This conclusion is robust in that VI schedule superiority is observed in situations in which choice behavior is highly biased or shows pronounced undermatching as well as those in which the matching law holds precisely. Our analysis demonstrates the potential practical value of mathematical descriptions of behavior.

Journal Article↗
PubMed1983

Scar thinning due to ibuprofen administration after experimental myocardial infarction.

Although much attention has been directed toward interventions which reduce myocardial infarct size, the effect of such agents on the healing phase of myocardial infarction is not well understood. The present study examines the effect of the nonsteroidal anti-inflammatory agent ibuprofen, previously demonstrated to be able to reduce infarct size, and of aspirin on the healing of experimentally produced myocardial infarcts. Thirty-nine anesthetized, open-chest dogs were subjected to proximal left anterior descending coronary artery occlusions for 6 weeks. Four groups of dogs were studied: (1) a control (untreated) group: (2) ibuprofen, 12.5 mg/kg intravenously 15 minutes and 6, 12, 18, and 24 hours after occlusion (high dose); (3) ibuprofen, 12.5 mg/kg intravenously 15 minutes and 3 hours after occlusion (low dose); (4) aspirin, 30 mg/kg intravenously 15 minutes and 3 hours after occlusion. The average thickness of the transmural scar and of the noninfarcted left ventricular wall was determined from multiple measurements of formalin-fixed left ventricular slices. The ratio of transmural scar to noninfarcted wall thickness was determined. In control animals the ratio was 0.87 with only 1 of 15 animals having a ratio less than 0.60. High-dose ibuprofen-treated animals had an average ratio of 0.59 (difference not significant [NS] compared with control values), with 6 of 9 animals having a ratio less than 0.60 (p less than 0.02 compared with control values). Low-dose ibuprofen-treated animals had an average ratio of 0.66 (p less than 0.05 compared with control values), with 4 of 8 animals having a ratio less than 0.60 (p = NS compared with control values). In the aspirin-treated animals, the ratio was 0.88 (p = NS compared with control values), with 0 of 7 animals having a ratio less than 0.60 (p = NS compared with control values). Although 1 of 22 animals had ratios less than 0.60 in the control and aspirin groups, 10 of 17 had ratios less than 0.60 in the ibuprofen-treated groups (p less than 0.001). Scars in treated animals did not differ from those in control animals histologically or by analysis of hydroxyproline content per unit weight. Thus, ibuprofen, a nonsteroidal anti-inflammatory agent which reduces infarct size, is shown to increase the incidence of scar thinning after myocardial infarction.

Animals↗
PubMed1983

Indomethacin-induced scar thinning after experimental myocardial infarction.

We investigated the effect of indomethacin, a widely used nonsteroidal antiinflammatory drug, on the healing of myocardial infarction (MI). Experimental MI was produced in anesthetized, open-chest dogs by occluding the left anterior descending coronary artery. Ten dogs received indomethacin, 10 mg/kg i.v., and 11 received saline, 15 minutes and 3 hours after occlusion. After 6 weeks, the dogs were killed and their hearts were subjected to morphologic and biochemical analysis. The average thickness of the transmural scar and the noninfarcted left ventricular wall was measured at multiple sites in formalin-fixed left ventricular slices and the ratio of the thickness of the transmural scar to the noninfarcted wall determined. The average thickness of the noninfarcted wall was 8.80 +/- 0.19 mm (mean +/- SEM) in the control group and 8.44 +/- 0.26 mm in the indomethacin group (NS). The scar thickness was 7.24 +/- 0.64 mm in the control group and 3.56 +/- 0.40 mm in the indomethacin group (p less than 0.001). The ratio of scar to noninfarcted wall thickness was 0.83 +/- 0.07 in the control group and 0.43 +/- 0.04 in the indomethacin group (p less than 0.001). Scars in treated dogs did not differ from controls either by light microscopic histologic analysis or by analysis of hydroxyproline content per unit weight. We conclude that indomethacin results in marked scar thinning when given early after experimental MI.

Animals↗
PubMed1981

Prolonged abnormalities of myocardium salvaged by reperfusion.

The purpose of this study was to determine if biochemical, functional, and ultrastructural abnormalities persist in nonnecrotic postischemic myocardium salvaged by coronary reperfusion. Anesthetized dogs were subjected to 15 min of occlusion of the left anterior descending (LAD) coronary artery followed by 3 days of reperfusion. Biopsies were obtained for measurement of adenosine 5'-triphosphate (ATP) and creatine phosphate (CP) nmol/mg protein), and regional function was evaluated using sonomicrometry. Myocardial ATP concentration after 15 min of occlusion was 37 +/- 1 nmol/mg cardiac protein in nonischemic subendocardium and 19 +/- 2 nmol/mg in ischemic subendocardium. After the hearts underwent 90 min and 72 h of reperfusion, ATP remained significantly depressed in reperfused subendocardium with values of 25 +/- 5 and 29 +/- 2 nmol/mg, respectively (P less than 0.05 and P less than 0.01 compared with the nonischemic zone in which ATP remained normal). CP levels fell during ischemia but returned to normal by 90 min of reperfusion. Percent systolic shortening of myocardial segments fell from +18 +/- 1% (active shortening) to -13 +/- 2% (passive lengthening) during ischemia and was still significantly depressed at +11 +/- 1% (P less than 0.05 vs. preocclusion) at 72 h of reperfusion. Histological examination showed no necrosis, but ultrastructural abnormalities were present. Therefore brief periods of myocardial ischemia are not associated with necrosis but result in functional, biochemical, and ultrastructural abnormalities, which are present for at lest 3 days after coronary reperfusion.

Adenosine Triphosphate↗