Showing papers by "University of Calgary published in 1979"
407 citations
TL;DR: A reliable decrease in question difficulty attributable to cueing prepositional relations explicitly in the text was found, interpreted as supporting and extending the arguments emerging from various “schema theories”.
Abstract: To investigate the applicability of schema-theoretic notions to young children's comprehension of textually explicit and inferrable information, slightly above-average second grade readers with str...
376 citations
TL;DR: A typology of social responsibility which incorporates this definition, and which is based on the Blau and Scott "prime beneficiary" and the Emery and Trim "causal texture of organizational environment" typologies is also presented as discussed by the authors.
Abstract: Several definitions and models of the phenomenon of corporate social responsibility are reviewed. These conceptualizations and definitions are found to lack either empirical and/or theoretical support; they have not provided a basis for a clear understanding of the phenomenon. They have, in fact, led to confusion in the literature. I propose a definition of social responsibility based on the notion of a “fit” between the two components of a “business ethic” and societal expectations of the private economic sector. A typology of social responsibility which incorporates this definition, and which is based on the Blau and Scott “prime beneficiary” and the Emery and Trim “causal texture of organizational environment” typologies is also presented.
287 citations
TL;DR: The evidence suggests that the great majority of localized pleural tumors arise from submesothelial mesenchymal elements and it is believed that the term mesothelioma should not be used in reference to these growths.
Abstract: A study of 40 localized primary tumors of the pleura in the files of the Canadian Tumour Reference Centre revealed a considerable diversity in their histologic structure. Collagenized, hemangiopericytoma-like and cellular areas were the main forms of growth pattern, with half of the tumors showing a mixture of two or more of these elements. Inclusions of non-neoplastic bronchiolealveolar epithelium were frequently seen in areas of tumor adjacent to lung substance but in only one tumor was there a neoplastic component of epithelial form. Eight tumors (20%) showed evidence of malignant behavior. All of these were large and cellular at the time of initial surgery and four had mitotic counts of 10 or more/10 H.P.F. in areas. The evidence suggests that the great majority of localized pleural tumors arise from submesothelial mesenchymal elements and it is believed that the term mesothelioma should not be used in reference to these growths.
184 citations
TL;DR: The results demonstrate that anaerobic bacteria unable to carry out oxygen- or nitrate-dependent electron transport are resistant to streptomycin and gentamicin because of failure to transport aminoglycosides.
Abstract: Cell-free amino acid incorporation using ribosomes from strains of either Clostridium perfringens or Bacteroides fragilis was shown to be susceptible to inhibition by streptomycin and gentamicin. Ribosomes bound dihydrostreptomycin as effectively as ribosomes from Escherichia coli. No inactivation of streptomycin or gentamicin was detected by cell extracts of either anaerobic bacterial species. B. fragilis, grown without added hemin, menadione, and fumarate, and C. perfringens did not show any time-dependent accumulation of dihydrostreptomycin or gentamicin at concentrations tested. Decreased resistance to aminoglycosides and time-dependent uptake of dihydrostreptomycin at 500 mug/ml was observed with B. fragilis grown with hemin, menadione, and fumarate. With the last additions, cytochrome b was detected by cytochrome spectra of B. fragilis. These results demonstrate that anaerobic bacteria unable to carry out oxygen- or nitrate-dependent electron transport are resistant to streptomycin and gentamicin because of failure to transport aminoglycosides. The induction of fumarate-dependent electron transport in B. fragilis is associated with some aminoglycoside transport that is of poor efficiency relative to bacteria with electron transport to oxygen or nitrate.
163 citations
TL;DR: The success in partially replacing the sucrose requirement for shoot formation with mannitol supports the view that part of the tissue carbohydrate is acting in an osmoregulatory role and is further interpreted in terms of the hypothesis of turgor-driven growth and cell expansion.
Abstract: Tobacco callus grown on medium containing 3% sucrose (w/v) shows optimum growth and produces the highest number of shoots; whereas cultures grown on medium with lower or higher sucrose levels show a reduced growth rate and capacity to form shoots. Cultures grown on a low sucrose containing medium produce a high number of shoots only if the medium is supplemented with mannitol to give the same water potential as that of the 3% sucrose medium. Mannitol cannot replace the sucrose requirement for growth. Increased levels of Bacto Agar, tricarboxylic acid cycle intermediates and amino acids added to the medium do not promote shoot formation or replace the carbohydrate requirement for that process. The success in partially replacing the sucrose requirement for shoot formation with mannitol supports the view that part of the tissue carbohydrate is acting in an osmoregulatory role. This finding is further interpreted in terms of the hypothesis of turgor-driven growth and cell expansion.
158 citations
TL;DR: In this paper, the importance of selective collembolan (Onychiurus subtenuis Folsom) grazing on the colonization of L layer leaf litter from a cool temperate deciduous forest by two common litter fungi (a Sterile dark form and a Basidiomycete) was assessed.
Abstract: Using simple laboratory systems, an attempt was made to assess the importance of selective collembolan (Onychiurus subtenuis Folsom) grazing on the colonization of L layer leaf litter from a cool temperate deciduous forest by two common litter fungi (a Sterile dark form and a Basidiomycete). The results indicate that relatively low selective grazing rates could have potentially important effects on the growth and competitive colonizing ability of individual fungi. The relation of such a laboratory study to actual field events is only feasible when there is a thorough knowledge of the organisms being used. Preamble In common with numerous other forest systems, detailed data have been accumulated over the last decade on various groups of organisms active in the litter layers of a cool temperate deciduous forest (Kananaskis, Alberta, Canada) where the major tree species is Populus tremuloides Michx. Detailed studies on fungi in the litter layers of this forest (Visser & Parkinson, 1975 a, b) indicate that the time of spring thaw is one of considerable and rapid change in the populations of these organisms. This change was particularly well seen when concurrent (April) replicate samples of L layer leaf litter were taken from the melting edge of snow patches and from areas where complete snow melt had occurred and fungal biomass and species complement were determined. The data obtained from this study are summarized in Table 1.
145 citations
TL;DR: Despite numerous studies, the reliability and validity of GAS remain questionable and more optimistically, GASprocedures can serve a useful education and intervention function, particularly in mental health settings, and patient in volvement in the goal-setting process as defined by GAS seems to enhance therapeutic effectiveness.
Abstract: Available published and unpublished studies on Goal Attainment Scaling (GAS), cur rently the most popular outcome evaluation technique in the human sciences, were cri tically reviewed. Forty-one of ninety-one initial studies, which met minimal criteria of completeness of information reported and quality of research, were subjected to in-depth review. Conclusions were rather mixed and somewhat discouraging. The proliferation m the use of GAS as an evaluative technique has been accompanied by serious procedural and methodological problems. Despite numerous studies, the reliability and validity of GAS remain questionable. More optimistically, GASprocedures can serve a useful educa tional and intervention function, particularly in mental health settings, and patient in volvement in the goal-setting process as defined by GAS seems to enhance therapeutic effectiveness.
143 citations
TL;DR: In this paper, the late Neoglacial Cavell Advance of the last few centuries is dated by dendrochronology and lichenometry and there is fragmentary, undated evidence of intermediate-age advance(s), mainly from rockglacier deposits.
130 citations
TL;DR: In this article, a beam bending finite element of circular cross section enabled obtaining an economical solution to the three-dimensional problem of static and dynamic laterally loaded piles embedded in elastic media.
Abstract: A previously formulated beam bending finite element of circular cross section enabled obtaining an economical solution to the three-dimensional problem of static and dynamic laterally loaded piles embedded in elastic media The general solution is almost solely a function of the ratio of Young's modulus (E) of the pile divided by E of the soil; neither Poisson's ratio of the soil nor the mass density of the pile are important for practical application purposes Static loading results are presented in the form of flexibility coefficients for a range of two-layer soil systems The dynamic loading fundamental solution for a pile embedded in an elastic half space is presented in terms of the statics solution multiplied by the associated complex, frequency-dependent factors Since this statics solution can be presented as a linear relationship between the logarithm of the flexibility coefficient and the logarithm of the Young's moduli ratio, both the statics and dynamics solutions can be approximated by a simple closed form expression
129 citations
Journal Article•
TL;DR: In this article, an electron microprobe study of mineral equilibria was conducted to estimate the temperature, pressure, and fluid compositions that prevailed during metamorphism of calcites and calc-silicates from staurolite and kyanite zone rocks of the Mica Creek area, British Columbia.
Abstract: Temperature, pressure, and fluid compositions that prevailed during metamorphism of pelites and calc-silicates from staurolite and kyanite zone rocks of the Mica Creek area, British Columbia, have been estimated from an electron microprobe study of mineral equilibria. Temperatures estimated from Fe-Mg distribution between garnet and biotite range from 570o to 640oC and are generally consistent with temperatures estimated from coexisting calcite and dolomite in nearby rocks. Pressure estimates based on garnet-plagioclase-kyanitequartz equilibria range systematically from 6 to 8.5 kbar. These estimates are consistent with the geological cross section, which suggests an increase in the depth of structural level exposed from south to north in the study area. Fluid compositions estimated from paragonite-quartzalbite-kyanite equilibria from the metapelites are dominated by HzO, and fluid compositions estimated for calc-silicates have XCO2 > XH2O. Calc-silicates formed at carbonate-pelite contacts appear to have equilibrated at temperatures near 610oC and XCO"near 0.25.
TL;DR: Olympic exercise increased oxygen uptake 4-fold, oxygen supply fell below demand during exercise, and considerable anaerobic metabolism resulted, as evidenced by a 9-fold increase in haemolymph lactate concentration.
Abstract: Scaphognathite and heart-pumping frequencies, ventilation volume, cardiac output, oxygen uptake and oxygen transport by haemolymph have been studied in unrestrained Dungeness crabs ( Cancer magister ) before, immediately after, and during recovery from 20 min of enforced exhausting activity. Exercise increased oxygen uptake 4-fold. This increase was achieved by more than 2-fold elevation of both ventilation volume and cardiac output and by greater participation of haemocyanin in oxygen delivery. The elevated ventilation volume resulted entirely from an increase in scaphognathite pumping frequency, while the rise in cardiac output resulted largely from increase in stroke volume. Prior to exercise haemocyanin accounts for less than 50% of the oxygen delivered to the tissues. Following exercise this increases to over 80%, the additional oxygen release being mediated by a depression of prebranchial oxygen tension and a substantial Bohr effect resulting from build up of lactate ion in the haemolymph and subsequent fall in pH. These changes allowed % oxygen extraction from branchial water to be maintained at 28% despite a 2-fold increase in ventilation volume, and allowed an increase in %. oxygen extraction by the tissues. Despite these changes oxygen supply fell below demand during exercise, and considerable anaerobic metabolism resulted, as evidenced by a 9-fold increase in haemolymph lactate concentration. The resulting oxygen debt required 8–24 h for repayment. Aerobic metabolic scope, and mechanisms of increasing oxygen uptake and transport in this crab are compared with those of a range of fish species.
TL;DR: The surface features of 39 Cretaceous and Paleocene sand samples from offshore Labrador and onshore western Greenland were examined by scanning electron microscopy as discussed by the authors, revealing the existence of 30 distinct surface features.
Abstract: The quartz-grain surface features of 39 Cretaceous and Paleocene sand samples from offshore Labrador and onshore western Greenland were examined by scanning electron microscope. The results of this study and those of other workers reveal the existence of 30 distinct surface features. The Labrador-Greenland sand grains show an abundance of pre-transportational surface features, imparted during liberation of the grains from crystalline source rocks. Impact features are relatively scarce, and features indicative of deltaic, aeolian and glacial environments are absent altogether. Among chemically produced surface features, those of precipitational origin far outweigh those due to silica dissolution. It is concluded that the Labrador-Greenland sands were derived, under acidic weathering conditions, from local crystalline parents and deposited in both marine and non-marine environments. Quartz overgrowths are present in all stages of development. A distinctive, high-relief surface texture ("gullying"), thought to originate by marine decapitation of pre-transportational pedologic overgrowths, is described and illustrated. Authigenic minerals adhering to quartz-grain surfaces include kaolinite, illite, dolomite, potassium feldspar, and pyrite.
TL;DR: A comprehensive and detailed outline of family therapy skills is presented to aid in providing a more precise focus in the training of clinicians in family therapy.
Abstract: This paper presents a comprehensive and detailed outline of family therapy skills to aid in providing a more precise focus in the training of clinicians in family therapy. The skills are based on an integrated treatment model within a systems framework. Four major functions performed by a family therapist are separated and are further differentiated into general therapeutic competencies. Specific perceptual, conceptual, and executive skills are described in the form of instructional objectives and are listed under each competency. Occasional clarifying notes or examples are cited along with particular skills. Clinicians and trainees should find this outline a useful guide in skill development.
TL;DR: In this paper, a reaction time procedure was used in two experiments to measure the times required to comprehend the meanings of projected slides of traffic signs, and the results indicated that siamese reaction time was equal to or equal to the response time of English.
Abstract: A “same”-“different” reaction time procedure was used in two experiments to measure the times required to comprehend the meanings of projected slides of traffic signs. The results indicated that si...
TL;DR: The study supported the hypothesis that there are two main generators of theta activity, the CA1 pyramidal region and the dentate region, and showed that the uncoordinated and limited locomotion of 6- to 9-day-old pups was associated with very low-amplitude, low-frequency, irregular activity, similar to that accompanying immobility.
TL;DR: It is concluded that flood-induced adventitious root formation is stimulated primarily by an accumulation of auxins in the hypocotyls, with ethylene being the major factor.
Abstract: The role of ethylene and auxins in flood-induced adventitious root formation and hypocotyl hypertrophy in sunflower (Helianthus annuus L. cv. Russian) plants was studied. Flooding without aeration (F) resulted in a steady increase in ethylene in hypocotyls, and flooding with aeration (FA) caused a transient increase. Low light intensity increased ethylene levels but decreased adventitious root formation. Treatment of shoots with benzyladenine (BA) increased ethylene content in non-flooded (NF) but not in F or FA shoots.
Twenty-four hours of flooding brought about a rise of endogenous indole-acetic acid (IAA) in hypocotyls. 14C-IAA applied to the shoot accumulated more in F and FA hypocotyls than in NF hypocotyls, and BA reduced this accumulation. There was less IAA metabolism in F and FA than in NF hypocotyls.
Tri-iodo benzoic acid (TIBA) applied to the hypocotyls of F plants inhibited root production. Benzyladenine (BA) applied to the leaves had similar effect but was not effective when supplied to the shoot apex. BA did not inhibit flood-induced hypocotyl hypertrophy. Ethrel did not affect adventitious root formation in NF plants but did increase hypocotyl thickening.
It is concluded that flood-induced adventitious root formation is stimulated primarily by an accumulation of auxins in the hypocotyls. Increases in ethylene might cause this auxin build up. Hypocotyl hypertrophy is presently thought to be the result of an interaction of auxin and ethylene with ethylene being the major factor.
TL;DR: Acidification of serum appears to increase SM-binding capacity while decreasing binding affinity of the 20,000--50,000 mol wt proteins in serum, which may not accurately reflect SM bioactivity and will require interpretative caution.
Abstract: Purification of a basic somatomedin (SM), with similarity to SM-C and insulin-like growth factor, from human plasma Conn fraction IV-1 enabled development of a RIA based on this SM. SM antiserum was produced by immunizing rabbits with partially purified SM. This antiserum (final dilution, 1:50,000) specifically bound approximately 40% of added [125I]- SM in this RIA. The RIA sensitivity was 2 i 10-4 U immunoreactive SM (IRSM). Highly purified SM-C, insulin-like growth factor 1, and our SM revealed parallel and approximately equipotent dose-response curves in this RIA; rat SM and multiplication stimulation activity revealed less cross-reactivity. IRSM was detected in sera of all species tested except fish. Acidification of sera, without subsequent chromatography, before assay permitted measurement of total IRSM with either an equilibrium or nonequilibrium RIA technique. Acidification of serum appears to increase SM-binding capacity while decreasing binding affinity of the 20,000–50,000 mol wt proteins in s...
TL;DR: Vasopressin was found to be an effective antipyretic when it was perfused through discrete regions of the brain of the sheep.
Abstract: Vasopressin was found to be an effective antipyretic when it was perfused through discrete regions of the brain of the sheep.
TL;DR: The proof is conerned with those subgraphs H of a graph G for which there is an edge-preserving map f of the set of vertices of G onto the set.
Abstract: Let G be an undirected graph without multiple edges and with a loop at every vertex—the set of edges of G corresponds to a reflexive and symmetric binary relation on its set of vertices. Then every edge-preserving map of the set of vertices of G to itself fixes an edge [{f(a), f(b)} = {a, b} for some edge (a, b) of G] if and only if (i) G is connected, (ii) G contains no cycles, and (iii) G contains no infinte paths. The proof is conerned with those subgraphs H of a graph G for which there is an edge-preserving map f of the set of vertices of G onto the set of vertices of H and satisfying f(a) = a for each vertex a of H.
TL;DR: A Davenport analysis based on measurements of pH and total CO 2 reveals a marked discrepancy between the amount of metabolic acid buffered by the haemolymph and the lactate anion concentration.
Abstract: Enforced activity causes a marked depression of haemofymph pH in Cancer magister . Both lactate concentration and P CO CO2 of the haemolymph are elevated immediately following exercise but resting P CO CO2 is restored within 30 min whereas resting lactate levels are not restored for at least 8 h. The haemolymph acid-base disturbance is caused largely by elevated haemolymph lactate levels but a Davenport analysis based on measurements of pH and total CO 2 reveals a marked discrepancy between the amount of metabolic acid buffered by the haemolymph and the lactate anion concentration. This appears due to a more rapid release of lactate from the tissues than H + ions produced with lactate.
TL;DR: In this paper, the roles of the primary dimensions of impulsivity, sensation seeking and decision time from Eysenck's extroversion dimension were examined in relation to driver behavior and to the ability to perceive traffic signs.
TL;DR: The galactomannan is clearly a dual-purpose polysaccharide, regulating water-balance during germination and serving as a substrate reserve for the developing seedling following germination.
Abstract: Some 30% of the reserve material in the fenugreek seed is galactomannan localised in the endosperm; the remainder is mainly protein and lipid in the cotyledons of the embryo. The importance of galactomannan to the germinative physiology of fenugreek has been investigated by comparing intact and endosperm-free seeds. From a purely nutritional point of view the galactomannan's role is not qualitatively different from that of the food reserves in the embryo. Nevertheless, due to its spatial location and its hydrophilic properties, the galactomannan is the molecular basis of a mechanism whereby the endosperm imbibes a large quantity of water during seed hydration and is able to “buffer” the germinating embryo against desiccation during subsequent periods of drought-stress. The galactomannan is clearly a dual-purpose polysaccharide, regulating water-balance during germination and serving as a substrate reserve for the developing seedling following germination. The relative importance of these two roles is discussed.
TL;DR: This article found that the number of false alarms increased with degree of self-reference of the adjectives, which was interpreted as evidence that the self is an important aspect of processing personal information.
Abstract: In a recognition memory study involving personal adjectives, the number of false alarms was found to increase with degree of self-reference of the adjectives. This was interpreted as: (1) evidence that the self is an important aspect of processing personal information, and (2) that the self functions as a cognitive prototype. The self can be seen to be a large and complex prototype that imparts a bias in processing personal information. This bias to perceive new, self-descriptive adjectives as being previously seen, has import for a theory of self and other-referent information processing.
TL;DR: Results obtained from Coenobita are compared with those from other terrestrial and littoral crabs to illustrate the influence of the adopted shell on the degree of modification needed to enter terrestrial habitats.
Abstract: The frequencies of heart ( f H ) and scaphognathite (ventilatory = f BC ) pumping, and responses to hypoxia, hypercapnia and wetting (simulated rain), as well as oxygen consumption ( M O O2 ), pre- and postbranchial haemolymph oxygen tension ( P O O2 ), oxygen content ( C O O2 ), carbon dioxide content ( C CO CO2 ) and pH were measured in adult land crabs Coenobita clypeatus . There was a large increase in f 8C in response to both hypoxia and wetting but a smaller increase in response to even severe hypercapnia. Some evidence suggests that ventilation via the scaphognathites may have been supplemented by a second (branchiostegal) pump when ventilatory requirement was high. f H was less responsive to either hypoxia or hypercapnia, but decreased with severe exposure to either. Haemolymph oxygen tensions were low ( P α,O α,O2 = 14, P vO vO2 = 8) but haemocyanin oxygen affinity was high in vivo ( P 50 = 10 torr at 23°C) and postbranchial haemocyanin was 60–80% saturated. Oxygen content was also high allowing adequate oxygen release to the tissues despite the low oxygen tensions. ΔP 50 /Δ t = 0.37 torr/Δ °C, log ΔP 50 /ΔpH = - 0.84 torr/pH unit, both determined in vitro were lower than literature values for marine and littoral species. As in other terrestrial species, C CO CO2 and P CO CO2 , (calculated) were high, as were both bicarbonate and non-bicarbonate buffering capacities. Water loss was less (0–08% body weight. h −1 ) in Coenobita than in other terrestrial crustaceans, this resulting from the protection of the adopted shell. Results obtained from Coenobita are compared with those from other terrestrial and littoral crabs to illustrate the influence of the adopted shell on the degree of modification needed to enter terrestrial habitats.
TL;DR: In this article, a psychobiological model of headache was proposed which integrates the numerous aspects of headache research within a unitary conceptual framework, and the authors examined the prevalence of musculoskeletal, vascular, and autonomic symptoms in a group of chronic and non-chronic headache patients.
Abstract: SYNOPSIS
A psychobiological model of headache is proposed which integrates the numerous aspects of headache research within a unitary conceptual framework. Central to the model is the development of a predisposition for headache that becomes more extensive and more autonomous in function as the disorder increases in severity and chronicity. Guided by the model, the present study examined the prevalence of musculoskeletal, vascular, and autonomic symptoms in a group of chronic headache patients and in a group of occasional headache sufferers. The symptoms were assessed by a 14-item questionnaire that permitted the respondents to indicate the extent to which each of the symptoms was perceived to be present across all headache attacks. In addition, a single item was included to assess the extent to which the respondents perceived their headache attacks to be a problem. The data indicated that the primary difference between the chronic and non-chronic headache sufferer was in terms of the frequency with which the different symptoms occurred rather than in terms of the kind of symptoms present. A stepwise regression analysis revealed that the symptom of nausea with the addition of four musculoskeletal symptoms accounted for 57.3% of the variance associated with the extent to which respondents perceived their headaches to be a problem. These data were interpreted as supportive of a severity model of chronic headache.
TL;DR: A patulin-negative mutant of Penicillium urticae was known to accumulate about 100mg per litre quantities of the 5,6-epoxygentisyl quinone, (-)-phyllostine and another metabolite (UIII) and was found to be a diastereoisomer of the known phytotoxin, (+)-epoxydon, hence its designation as (+)-iso- or epi-epoxYDon.
Abstract: A patulin-negative mutant (J1) of Penicillium urticae (N.R.R.L. 2159A) was known to accumulate about 100mg per litre quantities of the 5,6-epoxygentisyl quinone, (-)-phyllostine and another metabolite (UIII). Both were derived from acetate and hence were polyketides. Purified UIII (m.p. 53 degrees C, [alpha](32) (D)+206 degrees , lambda(methanol) (max.) 240nm; epsilon 3806 litre.mol(-1).cm(-1)) was characterized as a partially reduced derivative of (-)-phyllostine and was found to be a diastereoisomer of the known phytotoxin, (+)-epoxydon. Hence its designation as (+)-iso- or epi-epoxydon. From (1)H n.m.r. and c.d. data the stereochemistry of the epoxide ring in (+)-isoepoxydon was determined to be identical with that in (+)-epoxydon (i.e. R,R) but the configuration of the secondary alcohol at C-4 was S rather than R as in (+)-epoxydon. Isoepoxydon (compound UIII) is therefore (4S,5R,6R)-5,6-epoxy-4-hydroxy-2-hydroxymethylcyclohex-2-en-1-one. The boat conformation in which the C-4 hydroxy group is axial is preferred. In the range of 1mm to 5mm, the antibiotic activity of (+)-isoepoxydon against Bacillus subtilis sp. was 56% of that obtained with patulin. Over a period of 1 to 3h, [(14)C]isoepoxydon was efficiently converted into patulin by a shake culture of the parent strain of P. urticae. The precursor relationship of isoepoxydon to patulin was confirmed by feeding unlabelled isoepoxydon (1mm) to a washed-cell suspension of a mutant (J2) in which, over a period of 3 to 5h, a better than 60% conversion into patulin was attained. The enzymic relationship between isoepoxydon and phyllostine and their positions in the late portion of the patulin biosynthetic pathway are discussed.
Journal Article•
TL;DR: The isolation of microvessels (capillaries and arterioles) from guinea pig cerebral cortex is described and activation by adenosine analogues was demonstrable only when endogenously-generatedAdenosine was destroyed with adenosines deaminase.
Abstract: The isolation of microvessels (capillaries and arterioles) from guinea pig cerebral cortex is described. Adenylate cyclase in microvessel preparations was activated by guanylylimidodiphosphate in a time-dependent manner. The rate of guanyl nucleotide activation was enhanced by adenosine, 2-chloroadenosine, 2-azidoadenosine, norepinephrine, histamine, isoproterenol, prostaglandin E 1 , prostaglandin E 2 and prostacyclin. Activation by adenosine analogues was demonstrable only when endogenously-generated adenosine was destroyed with adenosine deaminase. Activation was also in evidence when microvessels were incubated with agonists together with guanine nucleotide, then washed by sedimentation prior to assay, reflecting persistence of the activated state.