Showing papers by "McMaster University published in 1984"

The prevalence of pain complaints in a general population

Abstract: The authors argue that the study of the complaint of pain falls within the purview of epidemiological study. An analytic survey of 500 randomly selected households on the roster of a group family practice clinic was undertaken. The purpose was to determine the self-reported prevalence rates of any pain complaint and to determine the distribution of pain rates according to selected demographic and socioeconomic variables. Sixteen percent of the individuals sampled from a family practice (H.S.O.) had experienced pain within the 2 weeks preceding the survey. The prevalence rate of those with persistent pain was approximately twice that of those with temporary pain. More women than men reported temporary and persistent pain. The age specific morbidity rate for persistent pain increased with age. The back, lower extremities, and head and face were the most frequently identified sites of pain in both subgroups. Persons with persistent pain used health services, both community physicians and hospital care, more frequently than did those with temporary pain. No significant differences between the two groups were reported for physical, social or emotional function although the persistent pain group characterized their general health status more poorly.

Nonanalytic Cognition: Memory, Perception, and Concept Learning

Abstract: Publisher Summary This chapter presents evidence that challenges major points in the usual, divergent treatment of perception, categorization, and episodic memory. Perceptual and categorical processing cannot be assumed to depend on high-level units that change only over many trials and that are relatively independent of context. The effect of attentive processing need not be the systematically discarded information about surface characteristics; many perceptual and conceptual judgments depend upon nominally irrelevant information about a source and format. Both generalizing and explicitly episodic memory tasks can be accomplished in several ways. The analytic extreme, emphasized in a usual cognitive framework, depends solely on relevant information. A nonanalytic procedure depends on tightly integrated combinations of relevant and irrelevant information. Perceptual identification and conceptual judgments are no less variable or context dependent than explicit memory for episodes. The chapter discusses the effects on perception and categorization of manipulations that have traditionally been employed in investigations of explicit episodic memory tasks.

Mucosal mast cells: III. Effect of quercetin and other flavonoids on antigen-induced histamine secretion from rat intestinal mast cells

Abstract: Quercetin, a naturally occurring flavonol structurally related to the antiallergic drug disodium cromoglycate inhibits anaphylactic histamine release from MMC isolated from the small bowel LP of the rat previously infected with the nematode Nippostrongylus brasiliensis. This contrasts with our previous observation that cromoglycate is inactive in this system. The present effect is immediate and does not decrease on preincubation with the drug. The flavonoids acacetin , apigenin , chrysin , and phloretin also demonstrate significant activity but are less potent than quercetin. Catechin, flavone, morin, and taxifolin are inactive. These results resemble those previously reported for the human basophil. In contrast, all compounds with the possible exception of taxifolin demonstrate significant activity against rat PMC. Acacetin and chrysin are the most effective inhibitors and are more active than quercetin. Rutin (the glycane of quercetin) and phlorezin (the glycane of phloretin) are inactive in both systems. These results are discussed in terms of the functional heterogeneity of mast cells from different sources and identify a group of compounds other than doxantrazole (reported previously), which inhibit histamine secretion by MMC.

Vasoactive intestinal polypeptide-like substance: the potential transmitter for cerebral vasodilation

Abstract: In vitro pharmacological studies demonstrated that exogenously applied vasoactive intestinal polypeptide (VIP) relaxes the smooth muscle cells of cat cerebral arteries, whereas substance P constricts them. Ultrastructural-immunocytochemical techniques show that a VIP-like substance is present in the large granular vesicles of nonsympathetic nerve axons and terminals in the cerebral arterial walls. These results provide strong evidence in favor of the hypothesis that a VIP-like substance is the transmitter for vasodilation in cerebral blood vessels.

Effect of plasma dilution on adsorption of fibrinogen to solid surfaces.

Abstract: The adsorption of various plasma proteins to three solid surfaces has been studied as a function of plasma concentration. Albumin adsorption on glass showed no dependence on plasma concentration and increased to a plateau value on both polyethylene and siliconized glass. Immunoglobulin G (IgG) adsorption showed no dependence on plasma concentration on any surface. Fibrinogen adsorption increased with plasma concentration and then decreased, the maximum occurring at about 1% normal plasma concentration and varying somewhat with the surface. On glass the kinetics of fibrinogen adsorption was dependent on plasma concentration: at concentrations less than the adsorption maximum, the kinetics was conventional, with adsorption increasing onto a plateau; at concentrations greater than the adsorption maximum, kinetics curves also showed maxima the position of which shifted to longer times as plasma concentration decreased. These data are interpreted in terms of competitive adsorption between fibrinogen and other, as yet unidentified species in plasma. The data reported are in general agreement with the model of Vroman (12) for plasma-surface interactions which holds that initially adsorbed fibrinogen is later replaced by high molecular weight kininogen (HMWK), the rate of replacement depending on the relative activity of the surface in promoting coagulation.

Endorphins and Exercise

Abstract: The endogenous opioids seem likely to be assigned a significant role in the integrated hormonal and metabolic response to exercise. This article reviews the present evidence on exercise and the endogenous opioids, and examines their involvement in a number of widely disparate physiological processes. In considering the role of individual opioid peptides, it is important to remember that many of the tools and techniques now used are still relatively crude. Most studies have demonstrated that serum concentrations of endogenous opioids, in particular beta-endorphin and beta-lipotrophin, increase in response to both acute exercise and training programmes. Elevated serum beta-endorphin concentrations induced by exercise have been linked to several psychological and physiological changes, including mood state changes and 'exercise-induced euphoria', altered pain perception, menstrual disturbances in female athletes, and the stress responses of numerous hormones (growth hormone, ACTH, prolactin, catecholamines and cortisol). Many reports have described a role for the endorphin response as seen during exercise and have used the opioid receptor antagonist, naloxone, to investigate and verify the degree of involvement of the opioids. However, whether the observed increases in peripheral endorphin concentrations are sufficient to cause immediate mood changes, create menstrual cycle dysfunction or alter pain perception is still not resolved. A relatively new implication for the endorphins and associated changes with exercise is in ventilatory regulation. A number of studies have suggested that endogenous opioids depress ventilation and may, therefore, play a role in ventilatory regulation by carbon dioxide, hypoxia and exercise. It may also be possible that during exercise, the perception of fatigue is modulated by an increase of endogenous opioids.

Receptor-Induced Diacylglycerol Formation in Permeabilized Platelets; Possible Role for a Gtp-Binding Protein

Abstract: Exposure of human platelets to 10 discharges from a 4.5 μF capacitor charged at 3 kV permitted isolation of a stable preparation of permeabilized platelets that, after equilibration with Ca2+ buffers (pCa < 6) for 15 min at 0°C, secreted 5-hydroxytryptamine (5-HT) at 25°C. Thrombin enhanced the sensitivity to Ca2+ of the secretion of 5-HT by about 10-fold, whereas Arg -vasopressin and the prostaglandin endoperoxide analogue, U-46619, increased sensitivity to Ca2+ by 3 to 4-fold. This action of thrombin was associated with stimulation of diacylglycerol formation, a marked increase in phosphorylation of protein P47 and a smaller increase in phosphorylation of the P-light chain of myosin. Thrombin exerted these effects at a [Ca2+ free] of 0.1 μM, suggesting that the receptor-activated breakdown of platelet phosphoinositides to diacylglycerol may not require prior Ca2+ mobilization in intact platelets. In both the presence and absence of thrombin, a higher [Ca2+ free] was required for optimal secretio...

The Strategy‐Performance Link in Product Innovation

Abstract: The strategy a firm elects for its new product program is a critical element of the firm's corporate strategy. But little research has probed the performance results of firms' new product programs, and the strategy-performance link. This article reports the results of an empirical study of 122 firms, whose purpose was to identify the levels of new product performance achieved, and the strategies leading to different types of performance. Eight different performance gauges yielded three independent dimensions of new product performance. A total of five different types or clusters of “performers” were identified. And the strategies and characteristics that the “top performers” shared are described.

Risk Attitude and Time Preference in Health

Abstract: Risk attitude and time preference are well-known and distinct concepts in the study of individuals' preferences for goods such as money. This paper reviews and explores the application of these concepts to the field of health. A mathematical model is presented, both in a general form and in an exponential form, which relates an individual's risk attitude in health to three effects-a quantity effect, a gambling effect and a time preference effect. It is shown that the overall risk attitude, as measured by its direction and magnitude, is merely the sum of the individual effects, as measured by their directions and magnitudes. Measurement methods are presented which can be used in a given situation to determine which effects are operating, in what directions and with what magnitudes. A new measurement procedure based on the temporary palliation of a chronic condition is described as a method of obtaining an individual's time preference pattern for health.

Dynamic model of peak period congestion

Abstract: This paper examines the problems of peak period traffic congestion and the analysis of alternative congestion relief methods. It presents a dynamic model of the queues and delays at a single point of traffic congestion because there is ample evidence to suggest that the major delays to users occur at bottlenecks. The model consists of a deterministic queueing model and a model of arrival rate as a function of travel time and schedule delay. A dynamic simulation model also describes the evolution of queues from day to day. The model is used to study the impacts of changes in capacity, total demand, flexibility of work start time and traffic control. Among the numerical results is a demonstration that additional capacity always significantly reduces the duration of the congestion period, but may result in a less significant improvement in maximum delays.

The role of opioid peptides in the hormonal responses to acute exercise in man.

Abstract: Opioid involvement in the physiological and hormonal responses to acute exercise was investigated in six normal male subjects. Each was exercised to 40% (mild exercise) and 80% (severe exercise) of his previously determined maximal oxygen consumption on two occasions, with and without an infusion of high-dose naloxone. The exercise task was a bicycle ergometer; mild and severe exercise were performed for 20 min each, followed by a recovery period. Exercise produced the expected increases in heart rate, blood pressure, ventilation, tidal volume, respiratory rate, oxygen consumption and carbon dioxide production. After severe exercise, naloxone infusion increased ventilation from 94.8 +/- 4.9 litres/min to 105.7 +/- 5.0 litres/min (P less than 0.05), but had no effect on any of the other physiological variables. Exercise-induced changes in several hormones and metabolites were noted, including elevations in circulating lactate, growth hormone (GH), prolactin, cortisol, luteinizing hormone (LH), follicle stimulating hormone (FSH), adrenaline noradrenaline, plasma renin activity (PRA) and aldosterone. There was no change in plasma met-enkephalin. Naloxone infusion produced the expected increases in LH and cortisol, but also significantly enhanced the elevations in prolactin, adrenaline, noradrenaline, plasma renin activity and aldosterone (P less than 0.05). Psychological questionnaires revealed minor mood changes after exercise, but no evidence was found for the suggested 'high' or euphoria of exercise. Effort was perceived as greater during the naloxone infusion than the saline infusion in every subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitality Perceptions and Language Attitudes: Some Canadian Data:

Abstract: Italian (IC) and English (EC) Canadians, in two school settings, completed the Subjective Vitality Questionnaire (SVQ) and a sociolinguistic questionnaire concerning self-reported usage and evaluations of Italian and English in different domains. SVQ results from the two settings showed that subject perceptions do not necessarily match objective assessments of ethnolinguistic vitality. Both ECs and ICs had more realistic perceptions in a majority setting (study 2) than in an equal setting (study 1). Whereas in both studies, self reports of language usage reflected the dominance of the English language in Hamilton, ECs were more biased against Italian language usage in study 1 than in study 2. Setting and subjective vitality perceptions seemed to affect evaluations of language use rather than self-reported usage. These results show that the SVQ and sociolinguistic surveys, in combination, can prove to be powerful instruments in studying the dynamics of ethnic group perceptions and language attitudes in mul...

Gut- and bronchus-associated lymphoid tissue

Abstract: Bronchus-associated and gut-associated lymphoid tissues (BALT and GALT) have both functional and morphologic similarities and are involved in seeding lung, gut, and other mucosal sites with predominantly IgA-containing B cells Both types of lymphoid tissue are engaged in the regulation and the controlled amplification of immune responses, which vary from positive mucosal responses in both mucosae and peripheral tissues to local mucosal responses and systemic tolerance Their further involvement in provision of cells destined to reside in the epithelial compartment of the body appears likely but requires further investigation Their role in the provision of precursors of mucosal mast cells must also be explored further, but some participation in this event appears likely The mucosa-associated lymphoid tissue (MALT) system appears to be integrated with the systemic immune system but may be considered as separate from it in several functional ways

Transfer of information concerning distant foods in rats: A robust phenomenon

Abstract: Following interaction with a “demonstrator” rat, an “observer” rat prefers that diet eaten by its demonstrator prior to their interaction (Galef & Wigmore, 1983). The present series of studies demonstrates that such demonstrator influence on observer diet preference can be found in: (1) first-generation laboratory bred wild rats as well as domesticated rats, (2) food-deprived as well as nondeprived observers, (3) unfamiliar as well as familiar demonstrator-observer pairs, (4) both 21-day-old and adult observers, and (5) rats selecting fluids as well as solids for ingestion. These data indicate that the social transmission of information concerning distant diets is a general and robust phenomenon, observable under a wide variety of experimental conditions.

Recovery of uranium from biological adsorbents—desorption equilibrium

Abstract: Results are presented of the experimental investigations of uranium elution and reloading for the waste inactive biomass of Rhizopus arrhizus. The experimental data and the analysis of the present work suggest the following conclusions: recovery of uranium that has been taken up by R. arrhizus is possible by elution; of the six elution systems examined, sodium bicarbonate solutions appear to be the most promising because they can effect near complete uranium recovery and high uranium concentration factors; the bicarbonate solution causes the least damage to the biomass; solid-to-liquid ratios in bicarbonate elution systems can exceed 120:1 (mg:mL) for a 1N NaHCO/sub 3/ solution, with almost complete uranium recovery and eluate uranium concentrations of over 1.98 x 10/sup 4/ mg/L; mineral acids, although good elution agents, result in substantial damage to the biomass thus limiting the biomass reuse potential; sulfate ions in the elutions solution limit the elution potential of the biomass, possibly by conferring novel crystallinity to the cell wall chitin network and confining inside the chitin network more biosorbed uranium.