Showing papers by "McMaster University published in 1986"

The Stigma of Involuntary Childlessness

Abstract: In this paper, I analyze the stigma associated with involuntary childlessness and compare the perceptions and behavior of physically infertile women and physically fertile women who are involuntarily childless. I also consider information management strategies developed to offset this stigma. These strategies include selective concealment, therapeutic and preventive disclosure, medical disclaimers, deviance avowal, and a process of practiced deception. I conclude that, although physically infertile women feel more stigmatized, physically fertile women manage information more actively to protect their husbands from the stigma associated with sexual dysfunction. Theoretically, I suggest that these women self-label infertility as discreditable or stigmatizing apart from any formal or informal response.

Tissue intracellular acid-base status and the fate of lactate after exhaustive exercise in the rainbow trout.

Abstract: Exhaustive ‘burst-type’ exercise in the rainbow trout resulted in a severe acidosis in the white muscle, with pHi dropping from 7.21 to a low of 6.62, as measured by DMO distribution. An accumulation of lactate and pyruvate, depletions of glycogen, ATP and CP stores, and a fluid shift from the extracellular fluid to the intracellular fluid of white muscle were associated with the acidosis. The proton load was in excess of the lactate load by an amount equivalent to the drop in ATP, suggesting that there was an uncoupling of ATP hydrolysis and glycolysis. Initially, lactate was cleared more quickly than protons from the muscle, a difference that was reflected in the blood. It is suggested that during the early period of recovery (0–4 h), the bulk of the lactate was oxidized in situ, restoring pHi to a point compatible with glyconeogenesis. At that time, lactate and H+ were used as substrates for in situ glyconeogenesis, which was complete by 24 h. During this time, lactate and H+ disappearance could account for about 75% of the glycogen resynthesized. The liver and heart showed an accumulation of lactate, and it is postulated that this occurred as a result of uptake from the blood. Associated with the lactate load in these tissues was a metabolic alkalosis. Except for an apparent acidosis immediately after exercise, the acid-base status of the brain was not appreciably affected. Despite the extracellular acidosis, red cell pHi remained nearly constant.

A preliminary evaluation of the dimensionality and clinical importance of pain and disability in osteoarthritis of the hip and knee

Abstract: Current methods of clinical assessment in osteoarthritis show a high degree of variability. By contrast, patients with rheumatoid arthritis may be evaluated using a number of standardised and validated indices. One hundred patients with primary osteoarthritis of the hip and knee were interviewed in order to determine the dimensionality of their discomfort and disability and to define the clinical importance of each component item. The symptomatology of osteoarthritis was captured by five pain, one stiffness, twenty-two physical, eight social and eleven emotional items. In spite of a high degree of variability in the frequency of involvement of the individual items, their clinical importance was similar both within as well as across dimensions. Further studies are indicated to determine the reliability, validity and responsiveness of each of the items identified as a prelude to developing a standardized method of assessing patients with osteoarthritis of the hip and knee.

Permafrost hydrology in North America 1

Abstract: This paper reviews hydrologic processes in the permafrost regions of northern North America. Much work has recently been done at specific experimental plots to parallel the progress in laboratory investigations, improving our understanding of the heat and water fluxes in thawed and frozen grounds, infiltration in frozen soils, evaporation in a cold environment, interaction between snow and its frozen substrate, and the dynamics of storage in the active layer. Field research on permafrost slopes and in northern research basins adds to our knowledge of permafrost groundwater hydrology, runoff generating processes, river freeze‐up and breakup processes and allows more precise definition of basin water balance. Sufficient hydrometric data are now available to analyse the streamflow characteristics in an area with permafrost, and more work should be done along this line. It is urged that process studies be continued to gain a better understanding of the effect of permafrost upon the hydrologic cycle. ...

Existence and non-existence of homogeneous Einstein metrics

Abstract: On demontre un theoreme d'existence general pour des metriques d'Einstein homogenes et on presente des espaces homogenes compacts simplement connexes qui ne portent pas une metrique d'Einstein homogene

The origin of airway hyperresponsiveness

Abstract: Consideration of the origin of airway hyperresponsiveness appears central to understanding the origin of asthma. Subjects with and without asthma differ both in the ease with which airway narrowing is produced by inhalation of histamine or methacholine and in the ability to demonstrate a maximal response to these agents. The latter appears, on present evidence, to be due to an added mechanism in asthma rather than the absence of a potent inhibitory process. Airway hyperresponsiveness is probably acquired during life as a result of airway reactions to various stimuli, although genetic factors such as atopy are likely to predispose the person to develop hyperresponsiveness. Environmental stimuli include inhaled allergens, chemical sensitizers, airway infections, immunization, and ozone. Allergen-induced airway hyperresponsiveness occurs in association with late-phase asthmatic responses. This and ozone-induced hyperresponsiveness have been demonstrated to be associated with release of chemical mediators and the cellular phase of inflammation. Their effect does not appear to be accounted for by increase in airway epithelial permeability, decrease in airway caliber, reflex bronchoconstriction, or beta-adrenoceptor blockade. The mechanism(s) responsible for the induced hyperresponsiveness are unknown but may involve airway epithelial damage, edema in and around the airway walls, stimulation of the noncholinergic excitatory or inhibition of the nonadrenergic inhibitory systems, or a change in function of airway smooth muscle. Airway hyperresponsiveness can be transient or persistent. Transient increases in responsiveness are almost certainly associated with mediator release and inflammation. It is not known whether persistent hyperresponsiveness is due to the same process, fired, for example, by leaky mediator-releasing cells and/or to some persisting change in neurogenic or smooth muscle function.

Endurance capacity of untrained males and females in isometric and dynamic muscular contractions.

Abstract: The capacity to perform isometric and dynamic muscle contractions at different forces has been measured in two separate groups of subjects: 25 men and 25 women performed sustained isometric contractions of the knee-extensor muscles of their stronger leg to fatigue, at forces corresponding to 80%, 50% and 20% of the maximum voluntary force of contraction (MVC). The second experimental model involved a bilateral elbowflexion weight lifting exercise. Eleven women and 12 men performed repetitions at loads corresponding to 90%, 80%, 70%, 60% and 50% of maximum load (lRM), at a rate of 10 · min−1 to the point of fatigue. Males were stronger (p<0.001) than females in both the static (675±120 N vs 458±80 N; mean±SD) and dynamic (409±90 N vs 190±33 N) contractions. Isometric endurance time of the males at a force corresponding to 20% of MVC was less than that of the females (180±51 s vs 252±56 s; p<0.001) but there was no difference between the sexes at 50% or 80% of MVC. Similarly, when the sexes were compared using dynamic elbow-flexion exercise, the female subjects were able to perform a greater number of repetitions than males at loads of 50% (p<0.005), 60% (p<0.001) and 70% (p<0.025) of lRM, but there was no difference between the sexes at loads of 80% or 90% of lRM. The results suggest that the endurance capacity of women is greater than that of men in both isometric and dynamic muscular exercise when the work load is relatively low compared with maximum; at higher forces, there is no difference between the sexes in endurance performance.

Characterization of acquired epipodophyllotoxin resistance in a Chinese hamster ovary cell line: loss of drug-stimulated DNA cleavage activity.

Abstract: Recent evidence indicates that type II DNA topoisomerases mediate epipodophyllotoxin-induced DNA damage and may be intrinsic to the drug9s antitumor effects. Using an epipodophyllotoxin-resistant cell line, we have now further defined the relationship between DNA damage and cell death and delineated the significance of certain drug-enzyme interactions. When compared to wild-type cells, the mutant Chinese hamster ovary cell line, Vpm R -5, exhibits marked resistance to both the cytotoxic and DNA cleavage activities of etoposide (VP-16). Steady-state concentrations of radiolabeled VP-16 are identical in both cell lines. Catalytic activity in crude nuclear extracts from wild-type and Vpm R -5 cells is equal and is equally sensitive to inhibition by VP-16. However, using an assay that specifically measures generation of 5′ protein-linked breaks in 32 P-labeled 3′ DNA, we have found that DNA cleavage activity in nuclear extract from the Vpm R -5 line is profoundly resistant to stimulation by VP-16. Further, a somatic cell hybrid line of Vpm R -5 cells and drug-sensitive EOT-3 cells exhibits recovery of VP-16 sensitivity in concert with reconstitution of DNA cleavage activity. These data indicate that stimulation of enzyme-mediated DNA cleavage, rather than loss of normal topoisomerase function, is responsible for epipodophyllotoxin-induced cytotoxicity.

Intracellular and extracellular acid-base status and H+ exchange with the environment after exhaustive exercise in the rainbow trout.

Abstract: Exhaustive exercise induced a severe short-lived (0-1 h) respiratory, and longer-lived (0-4 h) metabolic, acidosis in the extracellular fluid of the rainbow trout. Blood 'lactate' load exceeded blood 'metabolic acid' load from 1-12 h after exercise. Over-compensation occurred, so that by 8-12 h, metabolic alkalosis prevailed, but by 24 h, resting acid-base status had been restored. Acid-base changes were similar, and lactate levels identical, in arterial and venous blood. However, at rest venous RBC pHi was significantly higher than arterial (7.42 versus 7.31). After exercise, arterial RBC pHi remained constant, whereas venous RBC pHi fell significantly (to 7.18) but was fully restored by 1 h. Resting mean whole-body pHi, measured by DMO distribution, averaged approx. 7.25 at a pHe of approx. 7.82 and fell after exercise to a low of 6.78 at a pHe of approx. 7.30. Whole-body pHi was slower to recover than pHe, requiring up to 12 h, with no subsequent alkalosis. Whole-body ECFV decreased by about 70 ml kg-1 due to a fluid shift into the ICF. Net H+ excretion to the water increased 1 h after exercise accompanied by an elevation in ammonia efflux. At 8-12 h, H+ excretion was reduced to resting levels and at 12-24 h, a net H+ uptake occurred. Lactate excretion amounted to approx. 1% of the net H+ excretion and only approx. 2% of the whole blood load. Only a small amount of the anaerobically produced H+ in the ICF appeared in the ECF and subsequently in the water. By 24 h, all the H+ excreted had been taken back up, thus correcting the extracellular alkalosis. The bulk of the H+ load remained intracellular, to be cleared by aerobic metabolism.

Children's Attitudes Toward Disabled Peers: A Self-Report Measure

Abstract: Reliable and valid measures of children's attitudes toward disabled peers are critical prerequisites for the study of determinants and modifiability of attitudes. Methodological guidelines exist by which to develop and assess children's self-report measures, however existing instruments seldom fulfill these criteria. The present report describes the development of a measure of children's attitudes toward handicapped peers. Results indicated that the measure is reliable, internally consistent, and shows good construct validity. The measure has potential value in the study of determinants of children's attitudes and in the evaluation of programs designed to improve attitudes.

Phenomenology and mechanism of the transient adsorption of fibrinogen from plasma (Vroman effect)

Abstract: Additional data are presented on the transient adsorption of fibrinogen from blood plasma (the Vroman effect) reported previously (Brash, J. L., and ten Hove, P., Thromb. Haemostasis 51, 326, 1984; Horbett, T. A., Thromb. Haemostasis 51, 174, 1984). This effect is believed to result from rapid initial adsorption followed by displacement by other proteins. Adsorption was measured using radioiodine-labeled fibrinogen added to plasma as a tracer and surfaces were in the form of tubing. Plasma dilution and time were the main experimental variables. Initial adsorption was found to be diffusion-limited and diffusivities of about 1.5 × 10−7 cm2 s−1 were obtained independent of the surface. Various surfaces were compared on the basis of fibrinogen adsorption versus plasma concentration curves, all of which showed peaks at about 1% plasma concentration in accord with the Vroman effect. For 5-min adsorptions it was found that the height of the peaks was inversely related to the displacement “rate.” At 24 h the peak heights were in a different relative order and indeed one surface (a polyurethane) showed no peak. At these long times, the fibrinogen adsorption appears to be determined by a surface-solution equilibrium. None of the characteristics of the adsorption-concentration curves (peak height, displacement phase, “equilibrium” adsorption) were correlated with water contact angle of the different surfaces. Preadsorbed fibrinogen showed rates of displacement after exposure to plasma considerably slower than the rates observed “in situ.” This effect is tentatively attributed to orientational and/or conformational changes occurring as a function of residence time on the surface. Experiments on glass in which the plasma fibrinogen concentration was changed over a wide range (about one-eighth normal to twice normal) gave 5-min adsorption-concentration curves which differed in peak height and initial slope. The latter was proportional to fibrinogen concentration as expected. The peak heights did not show any such simple relationship but were used to demonstrate that about 50% of the glass surface may be covered with fibrinogen under normal conditions, again demonstrating the high surface activity of this protein.

Human Dignity, Human Rights, and Political Regimes

Abstract: It is often argued that internationally recognized human rights are common to all cultural traditions and adaptable to a great variety of social structures and political regimes. Such arguments confuse human rights with human dignity. All societies possess conceptions of human dignity, but the conception of human dignity underlying international human rights standards requires a particular type of “liberal” regime. This conclusion is reached through a comparison of the social structures of ideal type liberal, minimal, traditional, communist, corporatist and developmental regimes and their impact on autonomy, equality, privacy, social conflict, and the definition of societal membership.

Mast Cell Differentiation and Heterogeneity

Abstract: Major differences between mast cells from different tissues and species have been known for at least 20 years but have been rigorously studied only recently. A recent meeting focused on the ontogeny and differentiation of mast cells, their functional characteristics and the clinical and biological significance of their heterogeneity.

Effect of photosensitizer concentration in tissue on the penetration depth of photoactivating light

Abstract: The additional optical absorption in tissue resulting from the uptake of exogenous photosensitizers increases the effective attenuation of photoactivating light. This may be significant for the irradiation of solid tumours in photodynamic therapy, since it reduces the depth or volume of tissue treated. The effect has been studied in vitro by using dihaematoporphyrin ether (DHE) and 630 nm light in tissues representing a wide range of absorption and scattering conditions. While the attenuation may be markedly changed by small concentrations of DHE in pure scattering media, tissues with significant inherent light absorption are little affected by the additional absorption of DHE at concentrations relevant to clinical photodynamic therapy. However, it is shown that for other potential photosensitizers such as the phthalocyanines, which have substantially greater absorption at the treatment wavelength than DHE, the penetration of light in tissues may be significantly reduced.

Human rights and the search for community

Abstract: Human Rights and the Search for Community Liberal Society Cultural Absolutism and Nostalgia for Community Rights, Dignity, and Secular Society The Modern Community Honor and Shame Social Exclusion Individualism and Social Obligation

Finite element simulation of fountain flow in injection molding

Abstract: Fountain flow is the phenomenon of deceleration and outward motion of fluid particles as they approach a slower moving interface. The use of a general purpose finite element program for the appropriate boundary conditions made possible the detailed flow description behind an advancing liquid front moving at constant speed inside two-dimensional channels and tubes. The results were qualitatively the same for both Newtonian and shear-thinning fluids.

Carbon K‐shell excitation of gaseous and condensed cyclic hydrocarbons: C3H6, C4H8, C5H8, C5H10, C6H10, C6H12, and C8H8

Abstract: The carbon K‐shell excitation spectra of gaseous cyclic hydrocarbons, both saturated (cyclopropane, cyclobutane, cyclopentane, cyclohexane) and unsaturated (cyclopentene, cyclohexene, and cyclooctatetraene), have been recorded by electron energy loss spectroscopy under dipole‐dominated conditions. These are compared to the NEXAFS spectra of multilayers and monolayers of C4H8, C5H8, C6H12, and C8H8 on Pt(111). Multiple scattering Xα calculations of the spectra of cyclopropane, cyclobutane, and cyclohexane are also reported. In most cases the gas and solid spectra are essentially the same indicating that intramolecular transitions dominate in the condensed phase. The NEXAFS polarization dependence of the condensed phases has assisted spectral assignments and the determination of the molecular orientation in the monolayer phase. In the saturated species a sharp feature about 3 eV below the carbon 1s ionization threshold is identified as a transition to a state of mixed Rydberg/valence character with the π*(C...

Cellular basis for the species differences in sensitivity to cardiac glycosides (digitalis)

Abstract: The relative toxicity of numerous cardiotonic steroids (viz. ouabain, digitoxin, digoxin, convallatoxin, SC4453, bufalin, gitaloxin, digoxigenin, actodigin, oleandrin, digitoxigenin, gitoxin, strophanthidin, gitoxigenin, lanatosides A, B and C, alpha- and beta-acetyl digoxin, alpha- and beta-methyl digoxin) and related compounds towards a number of independent cell lines established from human, monkey, mouse, Syrian hamster, and Chinese hamster have been determined. All cardiac glycosides and their genins, as well as the cardiotonic alkaloid cassaine, exhibited greater than 100-fold higher toxicity towards cultured human and monkey cells in comparison to the cell lines of mouse, Syrian hamster, and Chinese hamster origins. These differences are species-related as all cell lines (both normal as well as transformed) from any one species, as well as cells from the closely related species (e.g., man and monkey or mouse, Chinese hamster, and Syrian hamster), showed similar sensitivity towards these drugs. The failure to see any significant differences in cellular toxicity for a larger number of other compounds which either bear limited structural resemblance to cardiac glycosides (viz. estradiol 17-beta-acetate, testosterone propionate, 21-acetoxy pregnenolone, beta-estradiol, digitonin, tigogenin, and tomatine) or interact with the Na+/K+ ATPase in a different manner (viz. veratridine, sanguinarine nitrate, penicillic acid, vanadium pentoxide, harmaline-HCI,5,5'-diphenyl hydantoin, quindonium bromide, and methyl quinolizinum bromide) provides strong evidence that the observed species-related differences are highly specific for cardiotonic steroids. Studies on the binding of [3H]ouabain show that, in comparison to human and monkey cell lines, no significant binding of the drug is observed in cells derived from the resistant species (i.e., mouse and Chinese hamster). The Na+/K+ ATPase from cells of the resistant species is inhibited at much higher concentrations of ouabain and digitoxin in comparison to the enzyme from human cells, and a good correlation is observed between these concentrations and those reported for inhibition of the enzyme from isolated heart muscles of the same species. These results provide strong evidence that the species-related differences in sensitivity to digitalis have a cellular basis and that the cultured cells from various mammalian species provide a useful model system for investigating the mechanism of action of cardiac glycosides.

Depositional process and alluvial fan-drainage basin morphometric relationships near banff, Alberta, Canada

Abstract: Two distinct types of alluvial fans occur in the Bow River Valley, Alberta, Canada: fluvially dominated and debris flow dominated. Large, gently sloping fans dominated by fluvial processes are associated with large and less rugged drainage basins, and small rugged basins have produced small, steep fans dominated by debris flow processes. Quantitative analysis demonstrates that strong fan-basin morphometric relationships occur despite a short fan history. Statistical analysis of fan area-basin area relationships indicate that debris flow fan areas do not increase in size as quickly as contributing basins. The relationship of fluvial fan area to basin area is not statistically significant. However, this relationship is probably affected by fan erosion. Examination of fan slope to basin ruggedness relationships indicates that fan slope increases more rapidly than basin ruggedness for both fan types. This is likely related to non-linear discharge and sediment size effects on fluvial fans, and reworking of larger fan surfaces by fluvial processes on debris flow fans.